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Solar panels
Is anyone familiar with "self regulating solar panels"? I would like to
hear from someone who has installed one without a regulator and how well it keeps the batteries up. Thanks, Gary |
Solar panels
Gary wrote in news:uVSyg.273940$IK3.20678
@pd7tw1no: Is anyone familiar with "self regulating solar panels"? I would like to hear from someone who has installed one without a regulator and how well it keeps the batteries up. Thanks, Gary As long as the AH created by the solar panels is LESS than the AH needed to keep the batteries charged up full, you don't need a regulator. Ours puts out 5 A in bright sunshine, hardly a battery buster to two banks of L16H beasts who simply digest it and feed it to the pumps and lights... (c; The solar panels aren't "self regulating", per se. Their open circuit voltage is around 18V in bright sunshine. Their internal resistance, which makes the cells get hot when charging the batteries, drops the difference between 18V and what voltage the batteries are producing at the time, like 13V. 5V X 5A = 25W across the whole panel. You'll notice old panels that have been powering stuff for a few years turn brown on the part of the silicon that's producing the power because of the heat. Around the edge, they're still blue like new where it doesn't produce power. Silicon melts at a very high temperature, but you can damage the cells by causing migration of the doping across them if they get too hot. If any cell isn't in the sunshine, like a shadow from the boom/mast/rigging, output drops like a rock as that cells voltage, around ..3V to .6V depending on the sun, is lost. The stupid idiots who run South Carolina DOT put up solar power panels along the interstate to power the radars and traffic cams. Of course, true to their idiotic thought, they put the panels on the NORTH SIDE of the pole the radar/cams are on so the panel has a shadow that moves across it all day. Dumb, very dumb. |
Solar panels
Gary wrote in news:uVSyg.273940$IK3.20678@pd7tw1no:
Is anyone familiar with "self regulating solar panels"? I would like to hear from someone who has installed one without a regulator and how well it keeps the batteries up. Thanks, Gary I've never heard of a self-regulating solar panel, but I would suggest that you need one. The problem occurs when your boat is plugged into shore power and the batteies are fully charged. If there's nothing drawing any current, then the additional amperage will easily bring your batteries way above charging voltage What you need is a regulator that runs in diverter mode. In this mode it senses the voltage and when it goes above the level that you've set, it diverts some of the wattage to a resistive load (in my case, a water heater element in my hot water tank). There is absolutely no loss when running in this mode. This regulator controlls both my solar panels and my wind generator. I would suggest looking at charge controllers from MorningStar. I went through several Trace/Xantrex and finally scrapped it. It seems that once they started buulding the units in China that the reliability went to hell. I went with MorningStar TriStar unit and have been very happy with it. -- Geoff |
Solar panels
"Geoff Schultz" wrote What you need is a regulator that runs in diverter mode. In this mode it senses the voltage and when it goes above the level that you've set, it diverts some of the wattage to a resistive load (in my case, a water heater element in my hot water tank). There is absolutely no loss when running in this mode. This regulator controlls both my solar panels and my wind generator. I would suggest looking at charge controllers from MorningStar. I went through several Trace/Xantrex and finally scrapped it. It seems that once they started buulding the units in China that the reliability went to hell. I went with MorningStar TriStar unit and have been very happy with it. Geoff, I have been looking at the Tristar but couldn't figure out what to divert to. How did you wire up the water heater to isolate the Tristar from the AC shore power? -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com |
Solar panels
"Glenn Ashmore" wrote:
"Geoff Schultz" wrote What you need is a regulator that runs in diverter mode. In this mode it senses the voltage and when it goes above the level that you've set, it diverts some of the wattage to a resistive load (in my case, a water heater element in my hot water tank). There is absolutely no loss when running in this mode. This regulator controlls both my solar panels and my wind generator. I would suggest looking at charge controllers from MorningStar. I went through several Trace/Xantrex and finally scrapped it. It seems that once they started buulding the units in China that the reliability went to hell. I went with MorningStar TriStar unit and have been very happy with it. Geoff, I have been looking at the Tristar but couldn't figure out what to divert to. How did you wire up the water heater to isolate the Tristar from the AC shore power? We divert the excess solar power (and wind power) to little fans that run in the cabins and keep the air circulating. We can tell when the batteries are charged if the fans start to run. If the boat is on the hard and we aren't aboard, it helps to have the air circulate. YMMV |
Solar panels
Gary wrote: Is anyone familiar with "self regulating solar panels"? Quote from: http://www.solaronline.com.au/page/technical_notes.html "A self-regulating module has a limited number of cells connected in series, normally 30 or 32. This limited number allows the module to only produce a maximum of 14.5 Volts, thus making it difficult to overcharge the battery. Using a self-regulating module does not automatically assure that a PV system will be self-regulating. Battery capacity, use of the loads and temperature must be considered. Generally, self-regulating modules can be safely used when the battery capacity is large. If the capacity is small, there is still the possibility of overcharging the battery." That being said, self regulating panels are much less efficient in a battery charging application, as the charging voltage is considerably lower than a regular 36 cell module. |
Solar panels
Geoff Schultz wrote in
6: What you need is a regulator that runs in diverter mode. Naw.....What you need is a TOWEL to throw over the panel to keep it in the shade at the dock. What's that cost? $1.39?....(c; |
Solar panels
Mark wrote:
Gary wrote: Is anyone familiar with "self regulating solar panels"? Quote from: http://www.solaronline.com.au/page/technical_notes.html "A self-regulating module has a limited number of cells connected in series, normally 30 or 32. This limited number allows the module to only produce a maximum of 14.5 Volts, thus making it difficult to overcharge the battery. Using a self-regulating module does not automatically assure that a PV system will be self-regulating. Battery capacity, use of the loads and temperature must be considered. Generally, self-regulating modules can be safely used when the battery capacity is large. If the capacity is small, there is still the possibility of overcharging the battery." That being said, self regulating panels are much less efficient in a battery charging application, as the charging voltage is considerably lower than a regular 36 cell module. Thanks. What I am trying to find out here is if anyone has any first hand experience with self regulating solar panels. Gary |
Solar panels
Larry wrote:
Geoff Schultz wrote in 6: What you need is a regulator that runs in diverter mode. Naw.....What you need is a TOWEL to throw over the panel to keep it in the shade at the dock. What's that cost? $1.39?....(c; That is what the book says as well! Gary |
Solar panels
Gary wrote in
news:5Y7zg.278047$Mn5.49928@pd7tw3no: Naw.....What you need is a TOWEL to throw over the panel to keep it in the shade at the dock. What's that cost? $1.39?....(c; That is what the book says as well! Gary I suppose, in keeping with the "nautical motif", we should have a custom- made blue cover with a ship's wheel, anchors or flags boldly emblazoned on the cover with the boat's name underneath for, say, $350? Naw, belay my last.....that old towel that we found in the lazerette will do.... Just toss it over the panel and hold it down with a few "empties". After all, this IS the party boat, right? We must keep up appearances to maintain our status! |
Solar panels
Larry wrote in news:Xns98109EBC3AAC7noonehomecom@
208.49.80.253: Geoff Schultz wrote in 6: What you need is a regulator that runs in diverter mode. Naw.....What you need is a TOWEL to throw over the panel to keep it in the shade at the dock. What's that cost? $1.39?....(c; That's a good plan until you forget to do so or they blow off and you cook your batteries. Hey, those batteries only cost you...oh a lot, lot more than a controller. Send the bill to Larry! He told you that you don't need one...that's your choice. You're the captain and pay the bills. My water heater accepts 2 heating elements. Ones 120V and the other is 12V. I know other people who have large resistors that they divert power to. Of course they get hot, but it works. -- eoff |
Solar panels
"Glenn Ashmore" wrote I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com I like the idea of diverting to the water heater, but most of us do not have the option to add a second 12V element to our existing heaters. One thought, would be to add a second heater in an external loop around the water heater - something like the add-on heaters that are sold for cars in lieu of a block heater. This site has the elements: http://www.realgoods.com/renew/shop/...204/ts/1025078 But, if the solar panels put out, say 150 watts for 8 hours, what happens when the water becomes too hot? With a small boat type water heater say 6 or 10 gal, this could happen quite quickly. Maybe then we throw the towel? GBM |
Solar panels
"GBM" wrote in
: "Glenn Ashmore" wrote I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com I like the idea of diverting to the water heater, but most of us do not have the option to add a second 12V element to our existing heaters. One thought, would be to add a second heater in an external loop around the water heater - something like the add-on heaters that are sold for cars in lieu of a block heater. This site has the elements: http://www.realgoods.com/renew/shop/...1204/ts/102507 8 But, if the solar panels put out, say 150 watts for 8 hours, what happens when the water becomes too hot? With a small boat type water heater say 6 or 10 gal, this could happen quite quickly. Maybe then we throw the towel? GBM You can get elements that have both 120V AC and 12V DC feeds. See http://www.svhotwire.com/divert_loads.html -- Geoff |
Solar panels
I used diverted power from my solar regulator to run fans throughout the
boat. "Geoff Schultz" wrote in message 6... "GBM" wrote in : "Glenn Ashmore" wrote I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com I like the idea of diverting to the water heater, but most of us do not have the option to add a second 12V element to our existing heaters. One thought, would be to add a second heater in an external loop around the water heater - something like the add-on heaters that are sold for cars in lieu of a block heater. This site has the elements: http://www.realgoods.com/renew/shop/...1204/ts/102507 8 But, if the solar panels put out, say 150 watts for 8 hours, what happens when the water becomes too hot? With a small boat type water heater say 6 or 10 gal, this could happen quite quickly. Maybe then we throw the towel? GBM You can get elements that have both 120V AC and 12V DC feeds. See http://www.svhotwire.com/divert_loads.html -- Geoff |
Solar panels
"Gerald" wrote in
: I used diverted power from my solar regulator to run fans throughout the boat. Just how many watts do your fans draw? -- Geoff |
Solar panels
At initial outfitting time, I had a separate 12V fan curcuit installed with
outlets throughout over bunks, heads, galley, eating area, chart table. I installed HELLA fans primarilly because they would give a reasonable breeze ..... for a 12 V fan and have minimal current draw --- for an electric fan.. So when I wanted to operate on the cheap (electrically cheap) I could have my breeze without eating the batteries. When I installed solar panels, I discovered the controller I selected(morningstar) had the ability to divert as the batteries topped off. Rather than do nothng with all the free electrons, I hooked it up to the fan circuit. "Geoff Schultz" wrote in message 6... "Gerald" wrote in : I used diverted power from my solar regulator to run fans throughout the boat. Just how many watts do your fans draw? -- Geoff |
Solar panels
"Geoff Schultz" wrote You can get elements that have both 120V AC and 12V DC feeds. See http://www.svhotwire.com/divert_loads.html That's great, but: - how is the water temperature controlled? Temperature should not exceed 49C to prevent scalding (used to be 60C) - Once water reaches maximum temperature, what do you do then? Seems to be of limited value if engine is also used to heat water. Our hot water gets up to about 45C after an hour of motoring at low speed. It is self limiting because of engine thermostat. GBM |
Solar panels
"Geoff Schultz" wrote
You can get elements that have both 120V AC and 12V DC feeds. See http://www.svhotwire.com/divert_loads.html GBM wrote: That's great, but: - how is the water temperature controlled? Temperature should not exceed 49C to prevent scalding (used to be 60C) - Once water reaches maximum temperature, what do you do then? Seems to be of limited value if engine is also used to heat water. Our hot water gets up to about 45C after an hour of motoring at low speed. It is self limiting because of engine thermostat. Just curious because I'm not familiar that with them - do marine water heaters have any sort of provision whereby you can insert a temperature sensor, which can then be hooked up to a limiting circuit? |
Solar panels
Sailaway wrote:
"Geoff Schultz" wrote You can get elements that have both 120V AC and 12V DC feeds. See http://www.svhotwire.com/divert_loads.html GBM wrote: That's great, but: - how is the water temperature controlled? Temperature should not exceed 49C to prevent scalding (used to be 60C) - Once water reaches maximum temperature, what do you do then? Seems to be of limited value if engine is also used to heat water. Our hot water gets up to about 45C after an hour of motoring at low speed. It is self limiting because of engine thermostat. Just curious because I'm not familiar that with them - do marine water heaters have any sort of provision whereby you can insert a temperature sensor, which can then be hooked up to a limiting circuit? Marine water heaters typically have two heating devices in one package. The first is a standard 110V electrical heating element, connected thru a thermostat mounted on the tank, more or less just like your standard domestic water heater. The second heating device is a coil of tubing inside the tank thru which you can circulate your engine coolant. There is no thermostat in the water heater for this circuit. But the engine has a thermostat which controls the temperature of the engine coolant which is circulating in it. This means that the hot water temperature will approach the engine thermostat set temperature with prolonged engine run times. bob |
Solar panels
"GBM" wrote in news:5vvzg.53527$Uy1.48756
@read1.cgocable.net: "Geoff Schultz" wrote You can get elements that have both 120V AC and 12V DC feeds. See http://www.svhotwire.com/divert_loads.html That's great, but: - how is the water temperature controlled? Temperature should not exceed 49C to prevent scalding (used to be 60C) - Once water reaches maximum temperature, what do you do then? Seems to be of limited value if engine is also used to heat water. Our hot water gets up to about 45C after an hour of motoring at low speed. It is self limiting because of engine thermostat. GBM I would say that if you have large enough panels to worry about this, then you should use the controller in PWM mode. Solar panels don't require a load. Wind generators do. I use 1 controller for both. In real life I rarely have problems with the batteries being completely charged while cruising. I only have 2 panels that output 68W *peak* each. The only time that I have the luxary of fully charged batteries is when it's been blowing 15-20+ for a day or two and my wind generator is cranking. Remember, this is a boat and there's no one-size-fits-all solution. You can always buy a resistive load such as the one at http://www.svhotwire.com/divert_loads.html, but then you have to do something with all of that heat. I can always find something to do with my "extra" power such as making more water and washing down something on the boat. Don't go crazy solving a problem that probably doesn't exist in real world. -- Geoff |
Solar panels
bob wrote:
Marine water heaters typically have two heating devices in one package. The first is a standard 110V electrical heating element, connected thru a thermostat mounted on the tank, more or less just like your standard domestic water heater. The second heating device is a coil of tubing inside the tank thru which you can circulate your engine coolant. Hi Bob, Actually I was curious about the 12 volt heating device someone had mentioned they had in theirs - would that one come with, or have provision for inserting a thermostat or temperature sensor? Thanks |
Solar panels
Matt,
6hrs at 240watts or 8 hrs at 150 watts - either one would heat water by about 100F. But what was the water temperature when you started? If the engine had not been run, it might be say 80F, so we get 180F - not enough to boil, but enough to scald anyone opening a faucet. If the engine had been run, the batteries could very well be fully charged and the hot water tank hot - lets say 150F. Now we anchor and put 240 watts into the tank for the next 6 hrs. Now the water IS boiling! Whether or not this is a real world problem, depends on how the boat is used. For live-aboards or those on extended cruises, it is likely not an issue. But, for weekend cruisers it could be. Suppose we return from a long weekend cruise and the batteries are low. We don't have shore power and rely on the solar panels to recharge the batteries unattended during the week. We get 8hrs/day for 5 days of bright sunshine on our 2x75watt array - about 430 Amp hours and we have a 200AH bank plus starting battery that need a total of about 150AH to recharge. In a case like the above will the charge controller safely cut off current to the batteries? Or should we cover the array? GBM "Mark Borgerson" mborgerson.at.comcast.net wrote GBM wrote: But, if the solar panels put out, say 150 watts for 8 hours, what happens when the water becomes too hot? With a small boat type water heater say 6 or 10 gal, this could happen quite quickly. Maybe then we throw the towel? According to this handy calculator: http://chuck-wright.com/calculators/watts.html Heating 6 gallons of water by 100F will require about 240 Watts for 6 hours. You're not likely to boil the water in in the heater with that amount of input. With losses, 6 hours at 150Watts is probably just enough for a hot shower. OTOH, on a day sunny enough to give you 150 Watts for 6 hours, you probably don't need a HOT shower. ;-) Mark Borgerson |
Solar panels
First of all 150 watts of panels is not going to produce 430 AH. You would
be very lucky to get 300 or so. If you can produce 56 AH/day extra just leave the refrigerator running and have the cold beer ready and waiting for next weekend. A half way decent refrigeration system should keep cold without being opened on 50 AH a day. -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com "GBM" wrote in message ... Matt, 6hrs at 240watts or 8 hrs at 150 watts - either one would heat water by about 100F. But what was the water temperature when you started? If the engine had not been run, it might be say 80F, so we get 180F - not enough to boil, but enough to scald anyone opening a faucet. If the engine had been run, the batteries could very well be fully charged and the hot water tank hot - lets say 150F. Now we anchor and put 240 watts into the tank for the next 6 hrs. Now the water IS boiling! Whether or not this is a real world problem, depends on how the boat is used. For live-aboards or those on extended cruises, it is likely not an issue. But, for weekend cruisers it could be. Suppose we return from a long weekend cruise and the batteries are low. We don't have shore power and rely on the solar panels to recharge the batteries unattended during the week. We get 8hrs/day for 5 days of bright sunshine on our 2x75watt array - about 430 Amp hours and we have a 200AH bank plus starting battery that need a total of about 150AH to recharge. In a case like the above will the charge controller safely cut off current to the batteries? Or should we cover the array? GBM "Mark Borgerson" mborgerson.at.comcast.net wrote GBM wrote: But, if the solar panels put out, say 150 watts for 8 hours, what happens when the water becomes too hot? With a small boat type water heater say 6 or 10 gal, this could happen quite quickly. Maybe then we throw the towel? According to this handy calculator: http://chuck-wright.com/calculators/watts.html Heating 6 gallons of water by 100F will require about 240 Watts for 6 hours. You're not likely to boil the water in in the heater with that amount of input. With losses, 6 hours at 150Watts is probably just enough for a hot shower. OTOH, on a day sunny enough to give you 150 Watts for 6 hours, you probably don't need a HOT shower. ;-) Mark Borgerson |
Solar panels
"GBM" wrote in news:BeTzg.53656$Uy1.27051
@read1.cgocable.net: Matt, 6hrs at 240watts or 8 hrs at 150 watts - either one would heat water by about 100F. But what was the water temperature when you started? If the engine had not been run, it might be say 80F, so we get 180F - not enough to boil, but enough to scald anyone opening a faucet. If the engine had been run, the batteries could very well be fully charged and the hot water tank hot - lets say 150F. Now we anchor and put 240 watts into the tank for the next 6 hrs. Now the water IS boiling! Whether or not this is a real world problem, depends on how the boat is used. For live-aboards or those on extended cruises, it is likely not an issue. But, for weekend cruisers it could be. Suppose we return from a long weekend cruise and the batteries are low. We don't have shore power and rely on the solar panels to recharge the batteries unattended during the week. We get 8hrs/day for 5 days of bright sunshine on our 2x75watt array - about 430 Amp hours and we have a 200AH bank plus starting battery that need a total of about 150AH to recharge. In a case like the above will the charge controller safely cut off current to the batteries? Or should we cover the array? GBM Once again, use the controller in PWM mode. Solar panels don't need a load, only devices like wind generators do. -- Geoff |
Solar panels
Sailaway wrote:
bob wrote: Marine water heaters typically have two heating devices in one package. The first is a standard 110V electrical heating element, connected thru a thermostat mounted on the tank, more or less just like your standard domestic water heater. The second heating device is a coil of tubing inside the tank thru which you can circulate your engine coolant. Hi Bob, Actually I was curious about the 12 volt heating device someone had mentioned they had in theirs - would that one come with, or have provision for inserting a thermostat or temperature sensor? Thanks I followed the link posted by others and looked at the elements - they look more or less exactly like standard 110V or 220V elements do - that is, they do not have an integral thermostat. If your plan was to install the 12V element in addition to an existing 110V element, then you would need another thermostat as well. And perhaps even more importantly, you would need another threaded tank penetration into which to screw the element. bob |
Solar panels
"Glenn Ashmore" wrote First of all 150 watts of panels is not going to produce 430 AH. You would be very lucky to get 300 or so. If you can produce 56 AH/day extra just leave the refrigerator running and have the cold beer ready and waiting for next weekend. A half way decent refrigeration system should keep cold without being opened on 50 AH a day. You are right Glenn - 150 watt panels will probably not produce 430 AH. But, according to this link it should have been about 405 AH: http://www.qsl.net/ve3lgs/solarpnl.htm My neighbour at the marina has the problem I described and has recommended we either install just one 75 watt unit or more batteries. I don't like the idea of running the refrigeration just to consume power . It gets everything quite cold in about 2 hrs anyway, once we get to the boat. Can't the controller simply switch off the current from the solar panels when the batteries reach full charge? GBM |
Solar panels
In article uVSyg.273940$IK3.20678@pd7tw1no,
Gary wrote: Is anyone familiar with "self regulating solar panels"? I would like to hear from someone who has installed one without a regulator and how well it keeps the batteries up. Not sure what size you're talking, but we have a 12w panel on our 120AH (used one-at-a-time) banks. It keeps the active battery up quite well for mostly 3-day weekends with a few multi-week trips each season. We have full voltage after 4-5 days away, almost never start the engine to charge, and the panel will bring a flat battery up enough to start our Yanmar 2GM by mid-morning. In two seasons, it brought a weak battery back to life, yet I need to add much less water than I did before. We're quite happy with the system. Our demands are obviously light, so you mileage may vary. -- Jere Lull Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD) Xan's Pages: http://members.dca.net/jerelull/X-Main.html Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/ |
Solar panels
"Geoff Schultz" wrote Once again, use the controller in PWM mode. Solar panels don't need a load, only devices like wind generators do. Not all controllers have PWM. I am considering a marine kit made by Soltek in British Columbia. It comes with their own controller called a GPR-22 - also sold for RV use under Go Power name. The company packages this controller with their kits and presumably it is satisfactory for basic systems and presumably cuts out panels once batteries reach full charge and cuts back in at some lower voltage. GBM |
Solar panels
Jere Lull wrote:
In article uVSyg.273940$IK3.20678@pd7tw1no, Gary wrote: Is anyone familiar with "self regulating solar panels"? I would like to hear from someone who has installed one without a regulator and how well it keeps the batteries up. Not sure what size you're talking, but we have a 12w panel on our 120AH (used one-at-a-time) banks. It keeps the active battery up quite well for mostly 3-day weekends with a few multi-week trips each season. We have full voltage after 4-5 days away, almost never start the engine to charge, and the panel will bring a flat battery up enough to start our Yanmar 2GM by mid-morning. In two seasons, it brought a weak battery back to life, yet I need to add much less water than I did before. We're quite happy with the system. Our demands are obviously light, so you mileage may vary. Thanks for the on topic response. The panel I have is a 46 watt panel and I will be running it into two 100 amp batteries. It produces a maximum voltage of 14.6 and maximum of 3.6 amps. I was wondering just how self regulating it would be. Do you leave yours on all the time? Gary |
Solar panels
In article 2cfAg.306263$iF6.139599@pd7tw2no,
Gary wrote: The panel I have is a 46 watt panel and I will be running it into two 100 amp batteries. It produces a maximum voltage of 14.6 and maximum of 3.6 amps. I was wondering just how self regulating it would be. Do you leave yours on all the time? Ours is on full time. All indications are that it isn't overcharging the 120 AH battery. I no longer parallel even "identical" batteries for any length of time. If one of them is slightly weaker, it will likely go south. My preference would be to install an 8D or a couple of big 6v in series. Doubt that panel would hurt either of those. Of course, I'm talking without knowing anything about the self-regulation. If it actively limits the current at high voltage, you're safe. If it simply has a diode to keep from draining the battery at night (like ours), you are less protected, though a max of about 50 watts is easily dissipated. BTW, expect your panel to perform better than the numbers, as they rate for what they expect after a few years' service. As I think, with a max 15 volts, you probably have active regulation, since modern cells are designed to charge even when slightly shaded. Keep track of things for a bit. If you have to add water quickly, your panel is too big for the battery, so get a bigger battery. It's tough to have too many AH. -- Jere Lull Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD) Xan's Pages: http://members.dca.net/jerelull/X-Main.html Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/ |
Solar panels
Jere Lull wrote:
In article 2cfAg.306263$iF6.139599@pd7tw2no, Gary wrote: The panel I have is a 46 watt panel and I will be running it into two 100 amp batteries. It produces a maximum voltage of 14.6 and maximum of 3.6 amps. I was wondering just how self regulating it would be. Do you leave yours on all the time? Ours is on full time. All indications are that it isn't overcharging the 120 AH battery. I no longer parallel even "identical" batteries for any length of time. If one of them is slightly weaker, it will likely go south. My preference would be to install an 8D or a couple of big 6v in series. Doubt that panel would hurt either of those. Of course, I'm talking without knowing anything about the self-regulation. If it actively limits the current at high voltage, you're safe. If it simply has a diode to keep from draining the battery at night (like ours), you are less protected, though a max of about 50 watts is easily dissipated. BTW, expect your panel to perform better than the numbers, as they rate for what they expect after a few years' service. As I think, with a max 15 volts, you probably have active regulation, since modern cells are designed to charge even when slightly shaded. Keep track of things for a bit. If you have to add water quickly, your panel is too big for the battery, so get a bigger battery. It's tough to have too many AH. Thanks. I'll just wire it up and watch for a while. Too easy! |
Solar panels
Jere Lull wrote in news:jerelull-94DCFA.21000703082006
@news.verizon.net: In article 2cfAg.306263$iF6.139599@pd7tw2no, Gary wrote: The panel I have is a 46 watt panel and I will be running it into two 100 amp batteries. It produces a maximum voltage of 14.6 and maximum of 3.6 amps. I was wondering just how self regulating it would be. Do you leave yours on all the time? Ours is on full time. All indications are that it isn't overcharging the 120 AH battery. I no longer parallel even "identical" batteries for any length of time. If one of them is slightly weaker, it will likely go south. My preference would be to install an 8D or a couple of big 6v in series. Doubt that panel would hurt either of those. Of course, I'm talking without knowing anything about the self-regulation. If it actively limits the current at high voltage, you're safe. If it simply has a diode to keep from draining the battery at night (like ours), you are less protected, though a max of about 50 watts is easily dissipated. BTW, expect your panel to perform better than the numbers, as they rate for what they expect after a few years' service. As I think, with a max 15 volts, you probably have active regulation, since modern cells are designed to charge even when slightly shaded. Keep track of things for a bit. If you have to add water quickly, your panel is too big for the battery, so get a bigger battery. It's tough to have too many AH. I always hate that...along with having too much money! :-) -- Geoff |
Solar panels
My common knowledge, experience from other cruisers and other research
differs from the below: GBM wrote: "Glenn Ashmore" wrote First of all 150 watts of panels is not going to produce 430 AH. You would be very lucky to get 300 or so. If you can produce 56 AH/day extra just leave the refrigerator running and have the cold beer ready and waiting for next weekend. A half way decent refrigeration system should keep cold without being opened on 50 AH a day. You are right Glenn - 150 watt panels will probably not produce 430 AH. But, according to this link it should have been about 405 AH: http://www.qsl.net/ve3lgs/solarpnl.htm Everything I've heard suggest that you'll get 1/4 typical minimum, 1/3 usually, and about 1/2 AH/watt.. This was confirmed recently by someone who came to check out my wifi, whose 250W through an MPPT controller reliably gives an average of 80AH/day in St. Petersburg FL, for the last 8 months' experience. I expect my 360W bank to provide us minimum 90, and probably more like 180 given that we're in the tropics (well, will be when we get there), and on the order of 120 during our Bahamas winter time. During the day here in St. Pete, with my batteries typically full because it easily keeps up with our profligate use of electricity, but no electronics to speak of, I routinely get 15-20A mid-day, and from 7 on get 7 or more until the sun's up, or it's going down. If I have a 12 hour sunlight day (typical in the tropics) and the top is 20-25A in peak times, I see it as reasonable to get the above. However, I'd love to be proven wrong and get a full 300AH from our bank!! L8R Skip and Lydia, on the boat, over wifi while Lydia talks to her mother in England on Vonage, free with the unlimited package we buy... |
Solar panels
You could use a home water heater 120/240V AC thermostat on 12V DC. I just
needs contact with the inner tank. If the water heater has a 120V thermostat, disconnect all the 120V wires and use it for 12V. Lee Haefele "Sailaway" wrote in message ... "Geoff Schultz" wrote You can get elements that have both 120V AC and 12V DC feeds. See http://www.svhotwire.com/divert_loads.html GBM wrote: That's great, but: - how is the water temperature controlled? Temperature should not exceed 49C to prevent scalding (used to be 60C) - Once water reaches maximum temperature, what do you do then? Seems to be of limited value if engine is also used to heat water. Our hot water gets up to about 45C after an hour of motoring at low speed. It is self limiting because of engine thermostat. Just curious because I'm not familiar that with them - do marine water heaters have any sort of provision whereby you can insert a temperature sensor, which can then be hooked up to a limiting circuit? |
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