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Solar panel controller
I am considering purchasing a Blue Sky Energy Solar Boost 2000E controller
(regulator) to use with my solar panels. The manufacturer claims an increase in current power of 30%. Does anyone have experience with these controllers? John Helgerson |
Solar panel controller
"John" wrote in
: The manufacturer claims an increase in current power of 30%. What nonsense. The controller turns the panels OFF at the appropriate time. It doesn't manufacture power from thin air. I wouldn't buy his product because he lied to me. Larry -- Democracy is when two wolves and a sheep vote on who's for dinner. Liberty is when the sheep has his own gun. |
Solar panel controller
"Larry" wrote in message ... "John" wrote in : The manufacturer claims an increase in current power of 30%. What nonsense. The controller turns the panels OFF at the appropriate time. It doesn't manufacture power from thin air. I wouldn't buy his product because he lied to me. Larry -- Democracy is when two wolves and a sheep vote on who's for dinner. Liberty is when the sheep has his own gun. IIRC, Practically A Sailor did a test and review on those units, and verified the manufacturer's claims. |
Solar panel controller
KLC Lewis inscribed in red ink for all to know:
"Larry" wrote in message ... "John" wrote in : The manufacturer claims an increase in current power of 30%. What nonsense. The controller turns the panels OFF at the appropriate time. It doesn't manufacture power from thin air. I wouldn't buy his product because he lied to me. Larry -- Democracy is when two wolves and a sheep vote on who's for dinner. Liberty is when the sheep has his own gun. IIRC, Practically A Sailor did a test and review on those units, and verified the manufacturer's claims. How do the Maximum Power Point controllers work? bob s/v Eolian Seattle |
Solar panel controller
On Feb 8, 12:50 pm, "KLC Lewis" wrote:
"Larry" wrote in message ... "John" wrote in : The manufacturer claims an increase in current power of 30%. What nonsense. The controller turns the panels OFF at the appropriate time. It doesn't manufacture power from thin air. I wouldn't buy his product because he lied to me. Larry -- Democracy is when two wolves and a sheep vote on who's for dinner. Liberty is when the sheep has his own gun. IIRC, Practically A Sailor did a test and review on those units, and verified the manufacturer's claims.- Hide quoted text - - Show quoted text - Yes, Have the exact model controlling 4 x 75 watt panels. Great unit - Definitely get the IPN Remote display and battery temperature monitor. Exellent customer service - remedied my situation with class and speed. Difficult for me to tell you if 30% is accurate, but I have read outside verification of the technology, and IMO, even without the "boost" the product is worth every penny. I would recommend. |
Solar panel controller
beaufortnc wrote:
On Feb 8, 12:50 pm, "KLC Lewis" wrote: "Larry" wrote in message ... "John" wrote in : The manufacturer claims an increase in current power of 30%. What nonsense. The controller turns the panels OFF at the appropriate time. It doesn't manufacture power from thin air. I wouldn't buy his product because he lied to me. Larry -- Democracy is when two wolves and a sheep vote on who's for dinner. Liberty is when the sheep has his own gun. IIRC, Practically A Sailor did a test and review on those units, and verified the manufacturer's claims.- Hide quoted text - - Show quoted text - Yes, Have the exact model controlling 4 x 75 watt panels. Great unit - Definitely get the IPN Remote display and battery temperature monitor. Exellent customer service - remedied my situation with class and speed. Difficult for me to tell you if 30% is accurate, but I have read outside verification of the technology, and IMO, even without the "boost" the product is worth every penny. I would recommend. I friend has one of their products, perhaps the same one. He live at anchor and relies on 4 large panels for most of his electrical needs. The last time I was aboard he did a brief demonstration, turning it off and back on. IIRC, the panels were putting out about 8 Amps without, and 10+ Amps with the boost, for a 25+% gain. I've been strongly considering getting one; I would certainly do it if I was in need of a controller, or had a large number of panels. |
Solar panel controller
RW Salnick inscribed in red ink for all to know:
KLC Lewis inscribed in red ink for all to know: "Larry" wrote in message ... "John" wrote in : The manufacturer claims an increase in current power of 30%. What nonsense. The controller turns the panels OFF at the appropriate time. It doesn't manufacture power from thin air. I wouldn't buy his product because he lied to me. Larry -- Democracy is when two wolves and a sheep vote on who's for dinner. Liberty is when the sheep has his own gun. IIRC, Practically A Sailor did a test and review on those units, and verified the manufacturer's claims. How do the Maximum Power Point controllers work? bob s/v Eolian Seattle OK, nobody's answering me - I'll try it myself... IIUC, the "power Point' controllers are basically DC-DC converters, converting the 19 volts or so that the panels produce to 12.6 (or something), thus drawing from the panels at their output voltage instead of the battery's voltage. Presuming minimal change in current delivery, this would represent an increase in delivered power. OK, where am I wrong here? bob s/v Eolian Seattle |
Solar panel controller
"RW Salnick" wrote in message ... RW Salnick inscribed in red ink for all to know: KLC Lewis inscribed in red ink for all to know: "Larry" wrote in message ... "John" wrote in : The manufacturer claims an increase in current power of 30%. What nonsense. The controller turns the panels OFF at the appropriate time. It doesn't manufacture power from thin air. I wouldn't buy his product because he lied to me. Larry -- Democracy is when two wolves and a sheep vote on who's for dinner. Liberty is when the sheep has his own gun. IIRC, Practically A Sailor did a test and review on those units, and verified the manufacturer's claims. How do the Maximum Power Point controllers work? bob s/v Eolian Seattle OK, nobody's answering me - I'll try it myself... IIUC, the "power Point' controllers are basically DC-DC converters, converting the 19 volts or so that the panels produce to 12.6 (or something), thus drawing from the panels at their output voltage instead of the battery's voltage. Presuming minimal change in current delivery, this would represent an increase in delivered power. OK, where am I wrong here? bob s/v Eolian Seattle Wish I could give you an answer, but electrically I'm just shy of being a low-grade moron. I can follow directions and connect wires, but that's about it. |
Solar panel controller
John,
Practical Sailor (magazine, or www.practical-sailor.com) tested one of these types of controllers, don't recall if it was this model, within the last couple of months and confirmed it's not snake oil. I imagine the manufacturer can find the article and get you a copy. Practical Sailor has a history of recommending and trashing products on a fair basis, and is very reliable. I recall the explination in practical sailor was something like Bob posted (DC-DC controllers) above, rather then typical contollers that throw away the extra voltage above 12.6 (in the form of heat) from the solar panels, these types of devices will convert the energy to a lower voltage (and higher amperage) and give your batteries more of the watts produced by the solar batteries instead of throwing them away as heat via a voltage regulator. There are not many caveats, but one important one is that the controller does not provide a gain in all conditions. Solar Panels are only producing voltages excessively over 12.6 during sunny days without excessive shadows (e.g. mast, etc.) over the panel. Dan |
Solar panel controller
RW Salnick wrote:
RW Salnick inscribed in red ink for all to know: KLC Lewis inscribed in red ink for all to know: "Larry" wrote in message ... "John" wrote in : The manufacturer claims an increase in current power of 30%. What nonsense. The controller turns the panels OFF at the appropriate time. It doesn't manufacture power from thin air. I wouldn't buy his product because he lied to me. Larry -- Democracy is when two wolves and a sheep vote on who's for dinner. Liberty is when the sheep has his own gun. IIRC, Practically A Sailor did a test and review on those units, and verified the manufacturer's claims. How do the Maximum Power Point controllers work? bob s/v Eolian Seattle OK, nobody's answering me - I'll try it myself... IIUC, the "power Point' controllers are basically DC-DC converters, converting the 19 volts or so that the panels produce to 12.6 (or something), thus drawing from the panels at their output voltage instead of the battery's voltage. Presuming minimal change in current delivery, this would represent an increase in delivered power. OK, where am I wrong here? bob s/v Eolian Seattle Assuming the panels can be modelled as an ideal voltage source with a (variable) series resistor (they cant but its a useful approximation) you are extracting the *maximum* power from the panel when its loaded to half its open circuit voltage, BUT you are unavoidably wasting the *same* amount of energy in heating up the panel. (n.b. this does *not* work for getting maximum *energy* out of a battery). I suspect they will actually be boosting 9.5V up to 12.6. -- Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED) ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk [at]=@, [dash]=- & [dot]=. *Warning* HTML & 32K emails -- NUL: 'Stingo' Albacore #1554 - 15' Early 60's, Uffa Fox designed, All varnished hot moulded wooden racing dinghy. |
Solar panel controller
On Thu, 08 Feb 2007 21:31:26 +0000, Ian Malcolm
wrote: Assuming the panels can be modelled as an ideal voltage source with a (variable) series resistor (they cant but its a useful approximation) Assume what you like... |
Solar panel controller
Ian Malcolm wrote in
: Assuming the panels can be modelled as an ideal voltage source Geez. If boat technology gets any better, we'll be able to run a light bulb off the panel, shining on the panel, and the panel will have so much power boost there'll be a surplus to charge the batteries! Larry -- Democracy is when two wolves and a sheep vote on who's for dinner. Liberty is when the sheep has his own gun. |
Solar panel controller
On Feb 8, 12:36 pm, Charlie Morgan wrote:
On 8 Feb 2007 12:48:58 -0800, "b393capt" wrote: .... Practical Sailor has a history of recommending and trashing products on a fair basis, and is very reliable. I would dispute that in very strong terms. Their testing methods are about as unscientific as possible, and their "recommendations" often have nothing to do with what product was better. .... There are certainly some problems with PS. They are a small shop, perhaps even a little inbred, and have limited human and financial resources. I suspect their work is sometimes influenced by their need to maintain some good will with the industry. Despite this, they appear far less beholden to the industry than any other marine publication I know. I'm convinced that they are making an effort to be honest in their evaluations and are concerned about their reputation. I read them. Still, your point about testing and rating has some validity. For instance, I think their recent review of winches was worse than useless. I've put thousands of hours onto three of the brands of winches they reviewed and can attest that there are huge differences in design, quality and maintainability between them, and some have well known failure modes. Yet they missed all of that and concluded that there was no significant difference between the brands... So, I don't take their opinion as gospel, but I do think that, on the whole, they do a better job of reviewing marine gear than anyone else and their opinions deserve a sympathetic reading. -- Tom. |
Solar panel controller
Larry wrote:
Ian Malcolm wrote in : Assuming the panels can be modelled as an ideal voltage source Geez. If boat technology gets any better, we'll be able to run a light bulb off the panel, shining on the panel, and the panel will have so much power boost there'll be a surplus to charge the batteries! Why not see if you can patent that idea? .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. Anyway, if it was possible to get a net energy gain, you'd still be dissipating half the energy in heating the panel so you'd burn it up for sure if you tried to get out more than you put in. This may in fact be a problem in real life in hot climates unless you have very good air flow over the panels, as the MPPT controller will be working them harder and they *will* be getting hotter. Will the supplier stand behind their product if its connected to an advanced controller? If they are on an elevated mount, it may well be worth spraying the backs with the thinnest possible coat of matte black paint to help dissipate the heat. -- Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED) ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk [at]=@, [dash]=- & [dot]=. *Warning* HTML & 32K emails -- NUL: 'Stingo' Albacore #1554 - 15' Early 60's, Uffa Fox designed, All varnished hot moulded wooden racing dinghy. |
Solar panel controller
Get a controller that diverts voltage above the maximum charging voltage of
the battery to a resistive load. In my case this is the water heater with 12V and 120V heater elements. 100% of the power of the solar panels will go to charging the panels up to that point. You can't produce more power than the panels are generating. I personally use a Morning Star TriStar controller to control both my wind generator and solar panels and it works great. -- Geoff |
Solar panel controller
Geoff Schultz wrote:
Get a controller that diverts voltage above the maximum charging voltage of the battery to a resistive load. In my case this is the water heater with 12V and 120V heater elements. 100% of the power of the solar panels will go to charging the panels up to that point. You can't produce more power than the panels are generating. I personally use a Morning Star TriStar controller to control both my wind generator and solar panels and it works great. -- Geoff So, are you saying that if the panels are putting out 17 volts and the battery is only taking 14, then 3 volts are applied to the heater? I don't think that's the way it works. |
Solar panel controller
On Feb 8, 3:21 pm, Charlie Morgan wrote:
... You seem to agree that they have big problems, and then you ask that they be given some undeserved "break". [Why?]... It's junk and it's deceitful. They deserve no special consideration. ... They have problems. However, I don't think they are deceitful at all. They tell you just what they've tested and just how they tested it and then they give their opinions about the results. Sometimes their tests aren't very useful and sometimes it isn't all that clear how their opinions follow from their testing, but I've never come away feeling that they are doing anything less than their honest best. Moreover, some of their tests are perfectly useful and even when they are a little silly the product descriptions can be helpful in and of themselves. Also, I am not aware of any other industry publication that even tries to provide disinterested product reviews (though I know of one that routinely trades endorsements in return for free products). So, yes, I think they are worth a read, but I agree with you that calling them "very reliable" is a stretch. -- Tom. |
Solar panel controller
I agree with Tom.
One need not take what PS concludes as Gospel, but they bring information that can be helpful. More so than any other sailing publication I know of, especially when it comes to new developments/products. You can come to your own conclusions, based on what data they develop. Certainly you don't think they falsly report their findings do you? What kind of scientific methods would you want ? How much would you be willing to pay for this ? PS has time to look into and evaluate many more items/systems/whatever than I do. They more often than not do this in a way that makes sense to me. They provide useful information. Their readers provide useful information. And I think that the knowledge of their readers, as appears from their letters, would suggest there must be some value to the magazine, or they wouldn't waste their time and money on it. But, it's a free country. "Charlie Morgan" wrote in message ... On 8 Feb 2007 16:03:48 -0800, " wrote: On Feb 8, 12:36 pm, Charlie Morgan wrote: On 8 Feb 2007 12:48:58 -0800, "b393capt" wrote: ... Practical Sailor has a history of recommending and trashing products on a fair basis, and is very reliable. I would dispute that in very strong terms. Their testing methods are about as unscientific as possible, and their "recommendations" often have nothing to do with what product was better. ... There are certainly some problems with PS. They are a small shop, perhaps even a little inbred, and have limited human and financial resources. I suspect their work is sometimes influenced by their need to maintain some good will with the industry. Despite this, they appear far less beholden to the industry than any other marine publication I know. I'm convinced that they are making an effort to be honest in their evaluations and are concerned about their reputation. I read them. Still, your point about testing and rating has some validity. For instance, I think their recent review of winches was worse than useless. I've put thousands of hours onto three of the brands of winches they reviewed and can attest that there are huge differences in design, quality and maintainability between them, and some have well known failure modes. Yet they missed all of that and concluded that there was no significant difference between the brands... So, I don't take their opinion as gospel, but I do think that, on the whole, they do a better job of reviewing marine gear than anyone else and their opinions deserve a sympathetic reading. -- Tom. Why? You seem to agree that they have big problems, and then you ask that they be given some undeserved "break". That makes as much sense as their reviews where they praise one product in the story and then rate another lesser product better in the final tally. They do not use even basic journalism or scientific standards and methods. It's junk and it's deceitful. They deserve no special consideration. CWM |
Solar panel controller
Jeff wrote in
: Geoff Schultz wrote: Get a controller that diverts voltage above the maximum charging voltage of the battery to a resistive load. In my case this is the water heater with 12V and 120V heater elements. 100% of the power of the solar panels will go to charging the panels up to that point. You can't produce more power than the panels are generating. I personally use a Morning Star TriStar controller to control both my wind generator and solar panels and it works great. -- Geoff So, are you saying that if the panels are putting out 17 volts and the battery is only taking 14, then 3 volts are applied to the heater? I don't think that's the way it works. That's exactly what I'm saying. It's called Diversion Mode and on the controller you set the maximum voltage which is allowed to be applied to the batteries. Anything above that is diverted to the load. The only time that this occurs is when the batteries are fully charged. The vast majority of the time the charging load of the batteries drops the output of the solar cells to a voltage less than the maximum allowable voltage and thus nothing is diverted. For details please see the manual: http://www.mrsolar.com/pdf/morningstar/TS_Manual.pdf -- Geoff |
Solar panel controller
Geoff Schultz wrote in
: You can't produce more power than the panels are generating. Ok, here's a little electricity for everyone.... This is the schematic of a solar panel: --[cell]---[cell resistance]-- Now, what this controller with the variable inverter load in it is doing is simplified into this circuit: |--[cell]---[cell resistance]---| | | | | |-[controller input resistance]-| In any series circuit like this where the SOURCE has a series resistance (impedance in AC and RF circuits), Load POWER is "optimized" to a peak level whenever load impedance (resistance) EQUALS source impedance (source resistance). Moving away from this optimum power peak in either direction of load impedance creates LESS POWER in the load, in this case the controllable inverter's panel input. If the inverter's loading of the panel can be made to electronically change its load resistance on the panel to the same resistance as the panel's own built-in resistance, which is quite substantial, Yes, the power generated will be greater than if the panel were simply connected through a blocking diode to the batteries. Very ingenious. This is NOT magic. It's math. The source voltage is 19VDC, that's what the cell puts out due to the number of cells in series, a function of silicon junction voltage. Just for demonstration of this effect, let's say the panel cell resistance (which varies, by the way with cell temperature quite a bit) is 10 ohms. Two simple electric calculations are needed: Power = current squared times resistance. Current = Voltage divided by resistance. Let's check 3 points...varying the load resistance...to see what power develops in the load. Let's check a load R of 10 ohms, same as source, for a reference. Total resistance is 20 ohms. 19V/20 ohms = .95A circuit current. Now square that (.9025) x the 10 ohm load resistance = 9.025 watts "output" for the inverter to send to the battery, minus its losses, of course, in conversion. OK, now let's change the load resistance to 8 ohms (lower). Total resistance is 18 ohms. 19V/18 ohms = 1.055A circuit current. Now square 1.055A (1.113) times 8 ohms = 8.9 watts...POWER OUT DROPPED OFF from our peak. OK, now let's change the load resistance to 12 ohms (higher). Total resistance is 22 ohms. 19V/22 ohms = .8636A circuit current. Now square ..8636 (.7458) times 12 ohms = 8.94 watts...POWER OUT DROPS OFF THIS WAY TOO! So, if the panels resistance right now equals the controller's input resistance, right now, the maximum power output peak of the panel will be realized. This can be accomplished with a little electronic trickery in IC regulators, probably custom made for this purpose, so that at any panel resistance, the IC can sense and adjust the controller's load resistance on the panel to maximize panel output. With switching power supplies now in the 99% efficient range, this is very feasable. By the way, this is the exact same reason we strive to make a radio with an output impedance of 52 ohms connected to coaxial cable with an impedance of 52 ohms connected at the top of the mast to a 52 ohm antenna....because it creates maximum power transfer from the transmitter to the antenna. (The radio is actually designed to match certain types of antenna's natural impedances, not the other way around.) It even works the other way on receive....so we use a 52 ohm input receiver, too. This completes today's electrical lecture. Please read pages 324 through 468 in your textbook and complete the workbook section 3-6 to hand in by tomorrow's class. The workbook answers are 40% of your grade in this course. (God, they all looked like they could kill me when I used to tell 'em this just before the bell rang.)....(c; Larry -- I just can't stand it when I don't know why something does what it does! I had to learn how our ship's steam turbine plant worked, to the dismay of the ratings in the engine room, even though I was an Electronics Tech. If you need power, give me a little time to fire the boilers and get the pressure up and we'll go! |
Solar panel controller
"Larry" wrote in message ... Ian Malcolm wrote in : Assuming the panels can be modelled as an ideal voltage source Geez. If boat technology gets any better, we'll be able to run a light bulb off the panel, shining on the panel, and the panel will have so much power boost there'll be a surplus to charge the batteries! Larry Here is something I posted to the "Cruiser's Forum", about MPPT charge controllers. They are real, and in many cases will increase the charging current into your batteries. No black magic is needed, but I suppose that some designs will be better than others. What follows is mostly theoretical: ------------- MPPT stands for "Maximum Power-Point Transfer", and it is equivalent to two switching regulators in series. It operates the solar panel at the load where the panel delivers it's maximum output power, then converts whatever Voltage this may be to a Voltage appropriate for the battery (depending on the battery's charge-state). This is in contrast to the series-pass, Pulse-Width-Modulation (PWM), or shunt regulators. In these, the panel output is essentially connected directly to the battery during the charge-acceptance portion of the charge cycle, and the panel output is reduced once the battery approaches full-charge. An example from my boat: I have three BP 110W panels, wired in parallel. Each panel has an open-circuit (no-load) output Voltage of 21.7V (ratings at full noonday sun conditions, with a cell temperature of 25deg C). Each panel has a short-circuit current of 6.9A. The panel has a maximum output power of 110W, at 17.5V and 6.3A. At any other output Voltage the panel will deliver less than max power. When I am charging a low battery at (say) 12V, using a non-MPPT controller (or directly hooking the panel to the battery), the panel is not operating at maximum power. Looking at the output curve for the panel, at 12V the panel will be delivering about 6.8A, which is 81.6 W. (I am reading these Volt/Amp numbers from a chart in the panel specifications.) With a MPPT controller, the panel would be operated at 17.5V, and be putting out 110W. Switching the 17.5V down to 12V (assuming 95% efficiency, a number I pulled out of the air) would give me 8.7 A into my 12V battery. This is a 28% increase in charging current. Of course, the battery won't stay at 12V for long. As the battery Voltage rises, the current-boost will be less. At 13.5V, a directly-connected panel would deliver 6.75A (91W). With an MPPT controller the charge current (at 95% efficiency) would be 7.74A -- still one amp better. Once the battery reaches full charge and the controller goes into trickle-mode, an MPPT controller will have no advantage. These numbers will be different in practice, as the panels won't see constant full sun, and the panel temperature will usually be hotter. Still, the MPPT controller ought to give some charging improvement. MPPT controllers don't use fixed settings, but are constantly dithering the panel load, monitoring the panel Voltage, and looking for the point of maximum power. These days, many panels are wired for 24V (instead of 12V) output, and the MPPT controller can efficiently convert the output of these panels for use in charging a 12V battery. I still have the old-style controller for my panels, but I will probably be installing MPPT before too long. I may end up putting a seperate controller on each panel (instead of one controller driven by the three panels in parallel), because my panels are often partially shaded, and I think I will get more output if each panel can be independently optimized. I need to do some testing or modelling to be sure of this. I can't easily add more panels, so I need to make maximum use of the ones I have. ------------- Hope this helps. -Paul |
Solar panel controller
After reading what I wrote below, I decided that it needed a small
correction/comment. It's down at the bottom. -Paul "Paul" wrote in message ... "Larry" wrote in message ... Ian Malcolm wrote in : Assuming the panels can be modelled as an ideal voltage source Geez. If boat technology gets any better, we'll be able to run a light bulb off the panel, shining on the panel, and the panel will have so much power boost there'll be a surplus to charge the batteries! Larry Here is something I posted to the "Cruiser's Forum", about MPPT charge controllers. They are real, and in many cases will increase the charging current into your batteries. No black magic is needed, but I suppose that some designs will be better than others. What follows is mostly theoretical: ------------- MPPT stands for "Maximum Power-Point Transfer", and it is equivalent to two switching regulators in series. It operates the solar panel at the load where the panel delivers it's maximum output power, then converts whatever Voltage this may be to a Voltage appropriate for the battery (depending on the battery's charge-state). This is in contrast to the series-pass, Pulse-Width-Modulation (PWM), or shunt regulators. In these, the panel output is essentially connected directly to the battery during the charge-acceptance portion of the charge cycle, and the panel output is reduced once the battery approaches full-charge. An example from my boat: I have three BP 110W panels, wired in parallel. Each panel has an open-circuit (no-load) output Voltage of 21.7V (ratings at full noonday sun conditions, with a cell temperature of 25deg C). Each panel has a short-circuit current of 6.9A. The panel has a maximum output power of 110W, at 17.5V and 6.3A. At any other output Voltage the panel will deliver less than max power. When I am charging a low battery at (say) 12V, using a non-MPPT controller (or directly hooking the panel to the battery), the panel is not operating at maximum power. Looking at the output curve for the panel, at 12V the panel will be delivering about 6.8A, which is 81.6 W. (I am reading these Volt/Amp numbers from a chart in the panel specifications.) With a MPPT controller, the panel would be operated at 17.5V, and be putting out 110W. Switching the 17.5V down to 12V (assuming 95% efficiency, a number I pulled out of the air) would give me 8.7 A into my 12V battery. This is a 28% increase in charging current. Of course, the battery won't stay at 12V for long. As the battery Voltage rises, the current-boost will be less. At 13.5V, a directly-connected panel would deliver 6.75A (91W). With an MPPT controller the charge current (at 95% efficiency) would be 7.74A -- still one amp better. Once the battery reaches full charge and the controller goes into trickle-mode, an MPPT controller will have no advantage. These numbers will be different in practice, as the panels won't see constant full sun, and the panel temperature will usually be hotter. Still, the MPPT controller ought to give some charging improvement. MPPT controllers don't use fixed settings, but are constantly dithering the panel load, monitoring the panel Voltage, and looking for the point of maximum power. These days, many panels are wired for 24V (instead of 12V) output, and the MPPT controller can efficiently convert the output of these panels for use in charging a 12V battery. I still have the old-style controller for my panels, but I will probably be installing MPPT before too long. I may end up putting a seperate controller on each panel (instead of one controller driven by the three panels in parallel), because my panels are often partially shaded, and I think I will get more output if each panel can be independently optimized. I need to do some testing or modelling to be sure of this. I can't easily add more panels, so I need to make maximum use of the ones I have. ------------- Hope this helps. -Paul Comment: I wrote "equivalent to two switching regulators in series", but this isn't really true, or even helpful. The MPPT controller is essentially a single switcher, with a power-sensing control loop. The rest of what I wrote should be OK. -Paul |
Solar panel controller
Geoff Schultz wrote:
Jeff wrote in : Geoff Schultz wrote: Get a controller that diverts voltage above the maximum charging voltage of the battery to a resistive load. In my case this is the water heater with 12V and 120V heater elements. 100% of the power of the solar panels will go to charging the panels up to that point. You can't produce more power than the panels are generating. I personally use a Morning Star TriStar controller to control both my wind generator and solar panels and it works great. -- Geoff So, are you saying that if the panels are putting out 17 volts and the battery is only taking 14, then 3 volts are applied to the heater? I don't think that's the way it works. That's exactly what I'm saying. It's called Diversion Mode and on the controller you set the maximum voltage which is allowed to be applied to the batteries. Anything above that is diverted to the load. The only time that this occurs is when the batteries are fully charged. The vast majority of the time the charging load of the batteries drops the output of the solar cells to a voltage less than the maximum allowable voltage and thus nothing is diverted. For details please see the manual: http://www.mrsolar.com/pdf/morningstar/TS_Manual.pdf Yes, this is how the tristar works. And for some people, it works fine. However, for those of us whose power usage far exceeds the charging ability, the diversion mode would rarely be turned on. In my case, it would only happen if I had just run the engine, and at that time the water tank is fully heated. The diversion mode is suited to boats with excess generating capability, such as trade wind passagemakers with wind or hydro generation. For systems where the solar panels will fall behind the load, the new MPPT (Maximum Power Point Tracking) systems will generate more power at the battery. Many panels will put out up to 17 Volts, and their Wattage will be rated at this level. A normal regulator will reduce this to an appropriate charging Voltage, perhaps 13.5 Volts if the battery is discharged. However, the current is not increased so the net Wattage will be reduced. A MPPT controller is a DC-DC converter that will drop the Voltage down without reducing the Wattage. An 85 Watt panel that can put out 5 Amps at 17V will put out 6.3 Amps at 13.5 and stay up at 85 Watts. A normal controller would only allow 67 Watts. Thus, the controller is not "creating more power than the panel outputs," its adjusting the Voltage so that 30% of the power isn't thrown away. As I've said, I've watched the current go from 8 to 10 Amps when the MPPT is turned on. |
Solar panel controller
Larry wrote in
: Geoff Schultz wrote in : You can't produce more power than the panels are generating. Ok, here's a little electricity for everyone.... Thank you Professor Larry for the edification. I always enjoy it when this forum is used to exchange information instead of throwing barbs at one another. I am of the personal opinion that boats should have a combination of solar and wind. I believe that a wind generator gives you a much bigger bang for the buck, but there are days when the wind doesn't blow and likewise when it isn't sunny. You need to regulate both sources. I spend about 6-7 months a year cruising (at anchor) and rarely have seen the regulator regulate as my power demands almost always exceed my wind/solar generation capacity. Any time that I do see the batteries getting topped off, I can always make more water. If you spend lots of time at a dock connected to a power cord and your batteries fully charged, then yes, you do need regulation. (I actually pull the fuse for the solar panels and feather the generator at dock.) Solar panels don't care if there's no load attached to them, but wind generators need a load to keep them from free-wheeling. As a result you need a controller which can be used in diversion mode with a resistive load. Due to space and $ constraints, I don't want to have multiple controllers. I would rather put the cost of another controller towards more generation capacity. -- Geoff |
Solar panel controller
On Fri, 09 Feb 2007 07:58:23 -0600, Geoff Schultz
wrote: Larry wrote in : Geoff Schultz wrote in : You can't produce more power than the panels are generating. Ok, here's a little electricity for everyone.... Thank you Professor Larry for the edification. I always enjoy it when this forum is used to exchange information instead of throwing barbs at one another. Unfortunately the information is wrong. |
Solar panel controller
On Fri, 09 Feb 2007 07:58:23 -0600, Geoff Schultz
wrote: I am of the personal opinion that boats should have a combination of solar and wind. ================== So I guess you would disapprove of my 15 and 20kw generators? :-) We have to keep those computers and WiFi bridges going somehow, not to mention the ice maker, freezer full of Hagen Daz ice cream and steak, 4 zones of A/C, etc. |
Solar panel controller
Geoff Schultz wrote:
You can't produce more power than the panels are generating. Larry wrote: Ok, here's a little electricity for everyone.... Geoff Schultz wrote: Thank you Professor Larry for the edification. I always enjoy it when this forum is used to exchange information instead of throwing barbs at one another. Goofball_star_dot_etal wrote: Unfortunately the information is wrong. Well without any references or explanation and as an anonymous poster, your word isnt worth anything near as much as if it was printed out on used toilet paper . . If I didnt have concerns about RFI, I am capable of designing and building my own MPPT solar panel controller. It isn't rocket science, any competent EE tech or HAM operator (e.g. Larry) could knock one up in a weekend or two, its just that it would take too much time so unless I cant find something to do that brings in more beer tokens, its easier to just buy one. Also it gives you someone *else* to yell at if it b***ers up your reception on VHF channel 16. For anyone else considering designing a MPPT controller (or just curious), http://www.intusoft.com/nlhtm/nl78.htm is good reading and even has Spice models for various types of solar panel. To summerise, they conclude that peak power is delivered at 83% of the open circuit voltage (rather different from my estimate of 50% as I initially was using an model that was an extremely bad approximation to a solar cell. I should have googled :-( ), which varies with temperature and illumination, and that a 10% gain in efficiency is achievable. This means, if the controller is under 10% of the panel cost, buy it, its a no-brainer, otherwise get a bigger panel (gross over-simplification ignoring cost of a liniar regulator, assuming you CAN fit a bigger panel (or more), you need more power and assuming price/performance for the panel is a streight line.) -- Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED) ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk [at]=@, [dash]=- & [dot]=. *Warning* HTML & 32K emails -- NUL: 'Stingo' Albacore #1554 - 15' Early 60's, Uffa Fox designed, All varnished hot moulded wooden racing dinghy. |
Solar panel controller
On Fri, 09 Feb 2007 17:45:41 +0000, Ian Malcolm
wrote: Geoff Schultz wrote: You can't produce more power than the panels are generating. Larry wrote: Ok, here's a little electricity for everyone.... Geoff Schultz wrote: Thank you Professor Larry for the edification. I always enjoy it when this forum is used to exchange information instead of throwing barbs at one another. Goofball_star_dot_etal wrote: Unfortunately the information is wrong. Well without any references or explanation and as an anonymous poster, your word isnt worth anything near as much as if it was printed out on used toilet paper . . You mean you would like me to post references to the equivalent circuit AGAIN? http://groups.google.co.uk/group/rec...13bf8612?hl=en If people did some homework instead of making wrong assumptions before posting them as fact, there would be less BS. Here is a new link for you: http://patft.uspto.gov/netacgi/nph-P...391&RS=6111391 or http://tinyurl.com/yobfz3 If I didnt have concerns about RFI, I am capable of designing and building my own MPPT solar panel controller. It isn't rocket science, any competent EE tech or HAM operator (e.g. Larry) could knock one up in a weekend or two, its just that it would take too much time so unless I cant find something to do that brings in more beer tokens, its easier to just buy one. Also it gives you someone *else* to yell at if it b***ers up your reception on VHF channel 16. For anyone else considering designing a MPPT controller (or just curious), http://www.intusoft.com/nlhtm/nl78.htm is good reading and even has Spice models for various types of solar panel. To summerise, they conclude that peak power is delivered at 83% of the open circuit voltage (rather different from my estimate of 50% as I initially was using an model that was an extremely bad approximation to a solar cell. I should have googled :-( ), which varies with temperature and illumination, and that a 10% gain in efficiency is achievable. This means, if the controller is under 10% of the panel cost, buy it, its a no-brainer, otherwise get a bigger panel (gross over-simplification ignoring cost of a liniar regulator, assuming you CAN fit a bigger panel (or more), you need more power and assuming price/performance for the panel is a streight line.) |
Solar panel controller
Me too! No wimpy wind generator for me. The big screen TV with surround
sound needs more than that can put out...g, not to mention the AC and other neat stuff that needs MORE POWER!! "Wayne.B" wrote in message ... On Fri, 09 Feb 2007 07:58:23 -0600, Geoff Schultz wrote: I am of the personal opinion that boats should have a combination of solar and wind. ================== So I guess you would disapprove of my 15 and 20kw generators? :-) We have to keep those computers and WiFi bridges going somehow, not to mention the ice maker, freezer full of Hagen Daz ice cream and steak, 4 zones of A/C, etc. |
Solar panel controller
On Fri, 09 Feb 2007 00:19:38 -0500, Larry wrote:
By the way, this is the exact same reason we strive to make a radio with an output impedance of 52 ohms connected to coaxial cable with an impedance of 52 ohms We do for transmission lines, antennas etc., we don't for TX output tank circuits, I think.. http://www.jaycar.com.au/images_uploaded/impmatch.pdf connected at the top of the mast to a 52 ohm antenna....because it creates maximum power transfer from the transmitter to the antenna. (The radio is actually designed to match certain types of antenna's natural impedances, not the other way around.) It even works the other way on receive....so we use a 52 ohm input receiver, too. |
Solar panel controller
So here you are cruising along with more wind then needed for hull speed, why not drag a surfboard with an alternator with big paddle wheels on each side to make electricity? Gordon (As you can see, this hasn't been quite thought out completely yet!) |
Solar panel controller
Goofball_star_dot_etal wrote:
On Fri, 09 Feb 2007 17:45:41 +0000, Ian Malcolm wrote: Geoff Schultz wrote: You can't produce more power than the panels are generating. Larry wrote: Ok, here's a little electricity for everyone.... Geoff Schultz wrote: Thank you Professor Larry for the edification. I always enjoy it when this forum is used to exchange information instead of throwing barbs at one another. Goofball_star_dot_etal wrote: Unfortunately the information is wrong. Well without any references or explanation and as an anonymous poster, your word isnt worth anything near as much as if it was printed out on used toilet paper . . You mean you would like me to post references to the equivalent circuit AGAIN? http://groups.google.co.uk/group/rec...13bf8612?hl=en If people did some homework instead of making wrong assumptions before posting them as fact, there would be less BS. Didnt show up here, first I saw was you saying 'assume what you like'. Obviously Google has it so I suspect its a USENET propagation issue at the european end. Anyway the problem with quoting Wikis is some @sshole usually vandelises them mid discussion, Its always advisable to go back to original sources or Wikipedia gets further damaged :-( I do see where you are coming from, as both myself and Larry made the obvious but incorrect assumption that a PV panel could be modelled adequately as a controlled voltage source. It was labelled as an assumption and an approximation, i.e. a simplification, NOT A FACT. As it happens, the only effect that correcting that has is to move the modelled MPP for the better panels above the charging voltage of a Lead acid battery. This means a small simplification in the topology of the switching converter. A closed loop converter based on the simplistic analysis would soon settle within a few percent of the MPP anyway so the results would be almost identical. You get what you pay for on USENET, and neither of us were being offered any beer coupons :-) Now what point were you trying to make? Tying to stomp BS offseason just gets you covered in sh!t and sprays it all over the place. ;-) Lighten up. At least this isnt a political thread. Here is a new link for you: http://patft.uspto.gov/netacgi/nph-P...391&RS=6111391 or http://tinyurl.com/yobfz3 And of what use is that link? If you can muster the patience to wade through their claims, you find there is nothing new under the sun there. They've tried to claim a unique application to gasoline powered motorhomes. The Saudis were installing MPPT panel arrays on a large scale back in the early 80's (lots of cash, lots of sun) so there is a hell of a lot of 'prior art' That patent *might* be usefull as toilet paper . . . The link I found has usable Spice models so if one grabs a copy of SwitcherCad (google it) the rest is just tedious engeneering . . . -- Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED) ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk [at]=@, [dash]=- & [dot]=. *Warning* HTML & 32K emails -- NUL: 'Stingo' Albacore #1554 - 15' Early 60's, Uffa Fox designed, All varnished hot moulded wooden racing dinghy. |
Solar panel controller
On Fri, 09 Feb 2007 20:32:54 +0000, Ian Malcolm
wrote: Goofball_star_dot_etal wrote: On Fri, 09 Feb 2007 17:45:41 +0000, Ian Malcolm wrote: Geoff Schultz wrote: You can't produce more power than the panels are generating. Larry wrote: Ok, here's a little electricity for everyone.... Geoff Schultz wrote: Thank you Professor Larry for the edification. I always enjoy it when this forum is used to exchange information instead of throwing barbs at one another. Goofball_star_dot_etal wrote: Unfortunately the information is wrong. Well without any references or explanation and as an anonymous poster, your word isnt worth anything near as much as if it was printed out on used toilet paper . . You mean you would like me to post references to the equivalent circuit AGAIN? http://groups.google.co.uk/group/rec...13bf8612?hl=en If people did some homework instead of making wrong assumptions before posting them as fact, there would be less BS. Didnt show up here, first I saw was you saying 'assume what you like'. Obviously Google has it so I suspect its a USENET propagation issue at the european end. Anyway the problem with quoting Wikis is some @sshole usually vandelises them mid discussion, Its always advisable to go back to original sources or Wikipedia gets further damaged :-( Never mind the "problem with Wikis" or that my "word isnt worth anything near as much as if it was printed out on used toilet paper" or that I am a Goofball, Wikipedia® and I are correct and the rest of you were wrong. Does it matter? No, although anybody in The World(tm) can read Usenet, nobody does.. Just fun to observe people twist and turn. I do see where you are coming from, as both myself and Larry made the obvious but incorrect assumption that a PV panel could be modelled adequately as a controlled voltage source. It was labelled as an assumption and an approximation, i.e. a simplification, NOT A FACT. Yes but it is not an approximation, it was totally wrong and useless not "useful" at all. As it happens, the only effect that correcting that has is to move the modelled MPP for the better panels above the charging voltage of a Lead acid battery. This means a small simplification in the topology of the switching converter. A closed loop converter based on the simplistic analysis would soon settle within a few percent of the MPP anyway so the results would be almost identical. The MPP is light and temperature sensitive. The quoted patent states that they sample the open circuit volage and apply an offset to arrive at the (instantaneous MPP) You get what you pay for on USENET, and neither of us were being offered any beer coupons :-) Now what point were you trying to make? "Shut up if you don't know the answer" ? Tying to stomp BS offseason just gets you covered in sh!t and sprays it all over the place. ;-) Lighten up. At least this isnt a political thread. Here is a new link for you: http://patft.uspto.gov/netacgi/nph-P...391&RS=6111391 or http://tinyurl.com/yobfz3 And of what use is that link? Well the OP wrote: "I am considering purchasing a Blue Sky Energy Solar Boost 2000E controller (regulator) to use with my solar panels. The manufacturer claims an increase in current power of 30%" Larry inferred that the claims were close to perpetual motion. Oh, the link is a link to a patent for that particular product which explains its operation and shows it is not pure snake oil or perpetual motion. See: http://www.blueskyenergyinc.com/pdf/...Ldatasheet.pdf If you can muster the patience to wade through their claims, you find there is nothing new under the sun there. They've tried to claim a unique application to gasoline powered motorhomes. The Saudis were installing MPPT panel arrays on a large scale back in the early 80's (lots of cash, lots of sun) so there is a hell of a lot of 'prior art' That patent *might* be usefull as toilet paper . . . The link I found has usable Spice models so if one grabs a copy of SwitcherCad (google it) the rest is just tedious engeneering . . . A diode is a diode. |
Solar panel controller
On Feb 9, 8:33 am, Jeff wrote:
Geoff Schultz wrote: Jeff wrote in : Geoff Schultz wrote: Get a controller that diverts voltage above the maximum charging voltage of the battery to a resistive load. In my case this is the water heater with 12V and 120V heater elements. 100% of the power of the solar panels will go to charging the panels up to that point. You can't produce more power than the panels are generating. I personally use a Morning Star TriStar controller to control both my wind generator and solar panels and it works great. -- Geoff So, are you saying that if the panels are putting out 17 volts and the battery is only taking 14, then 3 volts are applied to the heater? I don't think that's the way it works. That's exactly what I'm saying. It's called Diversion Mode and on the controller you set the maximum voltage which is allowed to be applied to the batteries. Anything above that is diverted to the load. The only time that this occurs is when the batteries are fully charged. The vast majority of the time the charging load of the batteries drops the output of the solar cells to a voltage less than the maximum allowable voltage and thus nothing is diverted. For details please see the manual: http://www.mrsolar.com/pdf/morningstar/TS_Manual.pdf Yes, this is how the tristar works. And for some people, it works fine. However, for those of us whose power usage far exceeds the charging ability, the diversion mode would rarely be turned on. In my case, it would only happen if I had just run the engine, and at that time the water tank is fully heated. The diversion mode is suited to boats with excess generating capability, such as trade wind passagemakers with wind or hydro generation. For systems where the solar panels will fall behind the load, the new MPPT (Maximum Power Point Tracking) systems will generate more power at the battery. Many panels will put out up to 17 Volts, and their Wattage will be rated at this level. A normal regulator will reduce this to an appropriate charging Voltage, perhaps 13.5 Volts if the battery is discharged. However, the current is not increased so the net Wattage will be reduced. A MPPT controller is a DC-DC converter that will drop the Voltage down without reducing the Wattage. An 85 Watt panel that can put out 5 Amps at 17V will put out 6.3 Amps at 13.5 and stay up at 85 Watts. A normal controller would only allow 67 Watts. Thus, the controller is not "creating more power than the panel outputs," its adjusting the Voltage so that 30% of the power isn't thrown away. As I've said, I've watched the current go from 8 to 10 Amps when the MPPT is turned on.- Hide quoted text - - Show quoted text - Yes, i agree. I want to add my support again for this explination and any negative comments (except maybe those negative comments against practical sailor's reliability) that followed my post early in this thread are unjustified. Let's face it, the affordable controllers that have historically been available are simple an did little more than keep the voltage at 12.6 volts, and if the voltage of the batteries exceed the voltage of the panels, the controller will prevent the batteries from draining. In this arrangement, the panels were setup with enough cells to insure that 12.6 volts would be reached in overcast days (or they would be useless), which means on sunny days you end up with 18 even 19v. New controllers can match the panels to the batteries better ... and without any snake oil, you get more bang out of your solar cells. In regards to practical sailor, they have demonstrated their independence and willingness to tell it like it is, perhaps that is a better description than reliable. If they measure a 25% increased output in AMPS with the new technology controllers, I can take that to the bank. However I will concede there are problems with some articles. When it comes to bottom paints, I realize as I read the articles the limits to their testing. To be really scientific and valid the tests would be repeated on a second set of samples by a different organization or employees, but it's amazing what they do for limited $. The article on winches was just way off the mark. Also they recently had an article on 2006 editions of two books in regards to 12V boat systems, that was extremely poor, one of the books in fact does not have such an edition. I could not get a response back from them when I pointed it out. Perhaps the loss of their star editor has a big influence, I don't think he would have let that article on Winches fly. But .. it is real refreshing to read their articles, especially boat reviews. I am getting tired of reading boat reviews in sail magazine that are absolutly meaningless, and really hate to read words such as "we only had light winds today, but judging from this boats design it will be a real performer" ... do meaningful journalism, go out and sail the boat again on a windy day would you ? In that light, Practical Sailor looks reliable to me, just not scientifically so. |
Solar panel controller
Goofball_star_dot_etal wrote:
I do see where you are coming from, as both myself and Larry made the obvious but incorrect assumption that a PV panel could be modelled adequately as a controlled voltage source. It was labelled as an assumption and an approximation, i.e. a simplification, NOT A FACT. Yes but it is not an approximation, it was totally wrong and useless not "useful" at all. As it happens, the only effect that correcting that has is to move the modelled MPP for the better panels above the charging voltage of a Lead acid battery. This means a small simplification in the topology of the switching converter. A closed loop converter based on the simplistic analysis would soon settle within a few percent of the MPP anyway so the results would be almost identical. The MPP is light and temperature sensitive. The quoted patent states that they sample the open circuit volage and apply an offset to arrive at the (instantaneous MPP) Leaving out any personal attacks *this* time, Mr Ball, Their approach is actually questionable *FOR A MARINE APPLICATION* as they make no provision for extracting power if the panel voltage is below that of the battery. This frequently happens if the panel is partially shaded and some cells bypass diodes are conducting. This wouuld be a not uncommon situation aboard an yacht at anchor, on a swinging mooring or underway. The panel has to deliver over 140ma at over 14V before *any* power is transferred. Elsewhere they say it is stable down to 0.8A and as it seems to be designed for 10A nominal output, what proportion of the time will it not operate? They seem to be excessively concerned about keeping the converter in continuous operation mode, *Probably* to avoid violating a competitor's patent. It looks like it would be advisable to disable their regulator and run a float regulator if layed up for the winter as the trickle charging capabilities are suspect to say the least. I suspect that the manufacturer the OP was considering were rather optimistic in their test conditions for a 30% efficiency boost, they probably tested it normal to the sun, totally clear sky and at 10 degrees C ambient temperatue into a very flat battery. At more normal insolation levels and temperatures, averaged over a normal battery charging cycle, the 10% to 15% improvement that most other sources claim is more plausible. After all, you CANNOT get more out than you can get at the MPP. -- Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED) ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk [at]=@, [dash]=- & [dot]=. *Warning* HTML & 32K emails -- NUL: 'Stingo' Albacore #1554 - 15' Early 60's, Uffa Fox designed, All varnished hot moulded wooden racing dinghy. |
Solar panel controller
On Fri, 09 Feb 2007 23:09:58 +0000, Ian Malcolm
wrote: Goofball_star_dot_etal wrote: I do see where you are coming from, as both myself and Larry made the obvious but incorrect assumption that a PV panel could be modelled adequately as a controlled voltage source. It was labelled as an assumption and an approximation, i.e. a simplification, NOT A FACT. Yes but it is not an approximation, it was totally wrong and useless not "useful" at all. As it happens, the only effect that correcting that has is to move the modelled MPP for the better panels above the charging voltage of a Lead acid battery. This means a small simplification in the topology of the switching converter. A closed loop converter based on the simplistic analysis would soon settle within a few percent of the MPP anyway so the results would be almost identical. The MPP is light and temperature sensitive. The quoted patent states that they sample the open circuit volage and apply an offset to arrive at the (instantaneous MPP) Leaving out any personal attacks *this* time, Mr Ball, Their approach is actually questionable *FOR A MARINE APPLICATION* as they make no provision for extracting power if the panel voltage is below that of the battery. This frequently happens if the panel is partially shaded and some cells bypass diodes are conducting. This wouuld be a not uncommon situation aboard an yacht at anchor, on a swinging mooring or underway. The panel has to deliver over 140ma at over 14V before *any* power is transferred. Elsewhere they say it is stable down to 0.8A and as it seems to be designed for 10A nominal output, what proportion of the time will it not operate? They seem to be excessively concerned about keeping the converter in continuous operation mode, *Probably* to avoid violating a competitor's patent. It looks like it would be advisable to disable their regulator and run a float regulator if layed up for the winter as the trickle charging capabilities are suspect to say the least. I suspect that the manufacturer the OP was considering were rather optimistic in their test conditions for a 30% efficiency boost, they probably tested it normal to the sun, totally clear sky and at 10 degrees C ambient temperatue into a very flat battery. At more normal insolation levels and temperatures, averaged over a normal battery charging cycle, the 10% to 15% improvement that most other sources claim is more plausible. After all, you CANNOT get more out than you can get at the MPP. Yes. http://www.blueskyenergyinc.com/pdf/...PSB2KErevE.pdf page 8 table 2 |
Solar panel controller
Ian Malcolm wrote:
.... Leaving out any personal attacks *this* time, Mr Ball, Their approach is actually questionable *FOR A MARINE APPLICATION* as they make no provision for extracting power if the panel voltage is below that of the battery. This frequently happens if the panel is partially shaded and some cells bypass diodes are conducting. This wouuld be a not uncommon situation aboard an yacht at anchor, on a swinging mooring or underway. The panel has to deliver over 140ma at over 14V before *any* power is transferred. Elsewhere they say it is stable down to 0.8A and as it seems to be designed for 10A nominal output, what proportion of the time will it not operate? They seem to be excessively concerned about keeping the converter in continuous operation mode, *Probably* to avoid violating a competitor's patent. It looks like it would be advisable to disable their regulator and run a float regulator if layed up for the winter as the trickle charging capabilities are suspect to say the least. I couldn't find anything on the Blue Sky or Outback sites that address the issue of raising the voltage from a partially shaded panel so the it is at the charging point for the battery. In theory, there's nothing to prevent this. But the situation is complicated because many installations have several panels in parallel (I have three) the shading would not be even. I suspect that the manufacturer the OP was considering were rather optimistic in their test conditions for a 30% efficiency boost, they probably tested it normal to the sun, totally clear sky and at 10 degrees C ambient temperatue into a very flat battery. At more normal insolation levels and temperatures, averaged over a normal battery charging cycle, the 10% to 15% improvement that most other sources claim is more plausible. After all, you CANNOT get more out than you can get at the MPP. The literature specifically says "up to 30%" gain; they certainly don't claim that will always be possible. In particular, it depends a lot on the temperature, since panels will put out a much higher voltage when cold. Thus, the gains would be less in the tropics, more in temperate zones in colder seasons. Also, gains are more with a depleted battery, less as the battery is charged. The web sites are pretty up front about these issues, admitting that gains might be only 10% in some scenarios. As I've said, the system I checked out had a 25% gain, which the owner said was typical. |
Solar panel controller
A question about bypass diodes:
"Jeff" wrote in message ... Ian Malcolm wrote: ... Leaving out any personal attacks *this* time, Mr Ball, Their approach is actually questionable *FOR A MARINE APPLICATION* as they make no provision for extracting power if the panel voltage is below that of the battery. This frequently happens if the panel is partially shaded and some cells bypass diodes are conducting. This wouuld be a not uncommon situation aboard an yacht at anchor, on a swinging mooring or underway. The panel has to deliver over 140ma at over 14V before *any* power is transferred. Elsewhere they say it is stable down to 0.8A and as it seems to be designed for 10A nominal output, what proportion of the time will it not operate? They seem to be excessively concerned about keeping the converter in continuous operation mode, *Probably* to avoid violating a competitor's patent. It looks like it would be advisable to disable their regulator and run a float regulator if layed up for the winter as the trickle charging capabilities are suspect to say the least. I couldn't find anything on the Blue Sky or Outback sites that address the issue of raising the voltage from a partially shaded panel so the it is at the charging point for the battery. In theory, there's nothing to prevent this. But the situation is complicated because many installations have several panels in parallel (I have three) the shading would not be even. I suspect that the manufacturer the OP was considering were rather optimistic in their test conditions for a 30% efficiency boost, they probably tested it normal to the sun, totally clear sky and at 10 degrees C ambient temperatue into a very flat battery. At more normal insolation levels and temperatures, averaged over a normal battery charging cycle, the 10% to 15% improvement that most other sources claim is more plausible. After all, you CANNOT get more out than you can get at the MPP. The literature specifically says "up to 30%" gain; they certainly don't claim that will always be possible. In particular, it depends a lot on the temperature, since panels will put out a much higher voltage when cold. Thus, the gains would be less in the tropics, more in temperate zones in colder seasons. Also, gains are more with a depleted battery, less as the battery is charged. The web sites are pretty up front about these issues, admitting that gains might be only 10% in some scenarios. As I've said, the system I checked out had a 25% gain, which the owner said was typical. Do most panels have the bypass diodes (to allow current flow through shaded cells)? The specs for my Shell 100W panels do not mention them. I'm not talking about the series reverse-current blocking diodes, but the per-cell bypass. I am considering an MPPT controller, and if the panels have these diodes, it should be better to connect the panels in series, rather than in parallel. My installation has three panels, and does have issues with panel shading. Currently I have the panels in parallel, and use a non-MPPT controller. I will probably do some V/I curves for the panels with varying types and degrees of shading, which should answer the bypass diode question, but until then any advice would be appreciated. Thanks, Paul |
Solar panel controller
Wayne.B wrote in
: So I guess you would disapprove of my 15 and 20kw generators? Not me. Dan's Hatteras 56 had two Onans on it with two transfer panels at the main helm. One was a two-cyl 8KW and the 4-cyl 20KW. You could shed the load from one to the other very neatly or to shore power for the 5 zone air conditioners under the galley deck, where I used to spend my weekends in the heat sweating like a pig on my hands and knees...(c; Someone would ask them where the hatch in the middle of the galley floor lead. They'd tell them, "That's Larry's Stateroom."....(c; Larry -- VIRUS ALERT! VISTA has been released! NOONE will be spared! |
Solar panel controller
Gordon wrote in news:12spkq9in9jgh88
@corp.supernews.com: So here you are cruising along with more wind then needed for hull speed, why not drag a surfboard with an alternator with big paddle wheels on each side to make electricity? Gordon Lionheart's free spinning shaft alternator produces over 20A at 6 knots. Her Aux diesel is a Perkins 4-108 powering a hydraulic transmission made to freewheel when off. The 3-bladed screw provides pretty nice power to the slow-spinning shaft alternator to run my toys. Larry -- VIRUS ALERT! VISTA has been released! NOONE will be spared! |
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