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Advice on refridgeration unit please
Herodotus wrote in
: That's what I admire about you Larry - a true lateral thinker. Seriously. I'd be interested to see what results you get. cheers Peter I like the idea of using those gel cold packs instead of the heat sinks. They probably will absorb much more Btu than just Aluminum. I have all kinds of crazy ideas I like to think is based on some basic knowledge of science, in this case thermodynamics. For many years, my electric bill with electric heat and for the last 4 years simple $100 but very efficient Korean window air conditioners has been less than half of my neighbors'. I wasn't too interested until the main heat pump failed and I thought I'd have to pay through the nose using simple electric heaters as it was in the winter, January, our coldest month. Oddly, the house didn't simply freeze up and I found that only 1800 watts of two "milkhouse" nichrome-wire warm air heaters kept the place as warm as toast for me and my parrots. They even cycled on and off quite regularly. I began to wonder why as some neighbors were over $400/month with electric strip heat in central heating systems in these cheap trailers. What I discovered was it was my crazy lifestyle as a pack rat that was the cause of the low bills! I'm quite a packrat. I collect 'things' I find fascinating or remotely useful, especially from thrift shops on the truly cheap. My 14x70 yacht is loaded to the gills with my collections, some useful, some forgotten. I'm a loner, most of the time, so who cares? I love my stuff. Some times I go through and find things I haven't seen in years. Every day is like Christmas morning...(c; It was this crazy obsession of mine that was causing the low bills! All the stuff piled up all over the house creates two phenomenon I could measure....THERMAL LAG merely from the Btu stored in the "stuff" during the day with the sun coming in the windows....and the "stuff" radiating it into the cooling house all night...into a much smaller airspace than the usual empty house beautiful's 8 acres of perfectly clean white carpet you aren't allowed to walk on in shoes has. The other phenomenon is INSULATION. If "stuff" is sitting on the floor, because there is no place else to put it left...(c;)...it creates a tremendous R-value of insulation as the heat can't simply escape through a tiny bit of clean white carpet noone is allowed to walk on in shoes plus a little fiberglass insulation under the floor. Hell, in some places, my floors have 3 feet of insulating "material" over the carpet...in addition to being a heat storage medium. Throwing away that "stuff" is a mistake! It lowers your power bill! I suppose (on topic) the same is true on boats. An empty boat being delivered to its new owner with nothing in it heats and cools off much faster than a properly fitted out cruiser with 3000 pounds of tools, oil, spare parts, insulating books, and all that stuff you've forgotten about stuffed into the storage space under the settee....keeping the boat cooler in the day and warmer at night. Well, the neatniks don't last long around here. My friends love to come by and just go exploring. "What's this?", they'll say, holding up something I probably haven't seen in 2 years. "I dunno. You want it? It's yours.", I reply turning back to my keyboard or Heineken's keg filling my glass. I love to give stuff away because I'm a packrat and can't stand to just throw stuff out! What a waste. Someone got curious about an Ionic Breeze high voltage ion generator they sold for big money here in the States. I paid $5 in a thrift shop. It's gone....I helped him load it because he was carrying other stuff I'd dumped on him earlier...(c; My friends' boats are full of cable I'd just dragged off spools in the shed out in the yard. Radio Shack was selling stuff in a store to get rid of it, and I bought the whole lot of cables for $100 cash. We could hardly carry it out to the van! At the rate I'm giving it to friends, I'll run out in June of 2284...(c; That R-12 fridge I bought this morning brings my count of small fridges up to 6 I know about, at the moment. Somebody's beer is gonna love the new cooler pretty soon. I gave 4 away last summer...(c; $1000 fridges my ass.... |
Advice on refridgeration unit please
On Jul 18, 9:28 pm, Larry wrote:
" wrote in news:7f8aa6de-0499-4d2c- .... Tom, how are you measuring these percentages? Are you using a hydrometer? Zen. Well, I have an Ample Power computer but it only gives a general feel. I've got AGM's so a hydrometer is out. Anyway, I didn't mean for the percentages to be taken very exactly. When the batteries are low I can throw a couple hundred amps at them for 15 minutes or so and the absorption drops off pretty slowly. I figure until the rate is down to 60 or so I'm saving charge time over what I'd be doing with a normal alternator. One of the joys few joys of lead acid is that you don't need to top them off each time you charge them. Every week or so is fine. My feeling is it takes much less time to get charge the bank to a 15 amp acceptance with the 110's over what it would with a sixty... -- Tom. |
Advice on refridgeration unit please
On Fri, 18 Jul 2008 18:18:33 -0700 (PDT), "
wrote: On Jul 18, 4:46*pm, Bruce in Bangkok ... In practice high output alternators make a big difference getting up to about 80% charge. *That can be very, very useful. *It may be that you have some logic and battery chemistry in your text books but I live on my boat and go voyaging a bit. *High output alternators are a good thing. So do Larry, Peter and myself. (Well, larry doesn't live on one, he just voyages). Frankly, in my experience a 110 amp alternator and a 440 A.H. battery bank is overkill, ... Well, I've got two 110 amp alternators on a 510 AH bank and I think that's about right. My experience is that I can bulk my batteries quickly with my 110's. Sometimes I top them off with solar and sometimes I work them in the 80%-50% range. Every week or so they get a full charge and that does take a long time, but still less time than it would with a 60 amp unit. YMMV. -- Tom. During your bulk charging stage what voltage are your batteries reading and how many amps are you charging at? Bruce-in-Bangkok (correct Address is bpaige125atgmaildotcom) |
Advice on refridgeration unit please
On Sat, 19 Jul 2008 09:46:57 +1000, Herodotus
wrote: On Fri, 18 Jul 2008 18:32:48 +0700, Bruce in Bangkok wrote: Thanks Bruce, This is the sort of information I am looking for. It's a pity about the wind in that area. I always have to smile when I see people hiring the Sunsail yachts out of Langkawi and then motoring everywhere. Still, not a bad place to motor around the Islands and then up to Siam. In Curacao the trades blow non-stop. Even disconnected from the mains and relying on the one 80 watt solar panel (16 years old) and the new Airex wind generator, it keeps the batteries charged no matter my usuage and the charging light goes off indicating a full charge quite often during the day. Need some of those trades back home. cheers Peter (A bunch cut) Following is information from the Catamaran Guy I mentioned. Boat - 35 ft. Cat. Engines - 2 X 3 cyl. Yanmar, standard Alternators (probably about 50 amp) Solar Panels - 2 X 68 Watt (new Japanese) measured output 10.2 amps at noon Wind Generator - none Fridge - Built in Eutetic, Fridge only Insulation - Approx 7-8 cm. insulation, believe standard closed cell foam Compressor - Isotherm Classic Compact 12VDC/220VAC (uses inverter) Condenser - Water cooled, 12VDC pump Inverter - CLD Inverter, powers fridge and also acts as controller for fridge system - owner says not used for boat power Batteries - 3 X 120 AH = 360 AH Water System - 12VDC pressure Lights - All LED ------------------------------ Service: 4 day sailing trip: Ran engines as required, probably average of 3 hours per day, no problems with maintaining batteries at 90% or higher. At anchor: One week at anchor, did not run engines, ran fridge, radio, lights, computer, etc., batteries never under 90% charge. Comments: Stephen, the fridge guy, feels that system is unduly complex with water cooled condenser and inverter. Feels that straight 12VDC, air cooled condenser, would be less trouble. Owner admits that had initial problems with system, mainly electrical (inverter/controller). Owner says on 4 day trip kept thermostat at 15 degrees C. Tries to keep fridge full and ice on cold plate. Frequently charters bare boat and says all charters have reported no problems with fridge. Suggestions: Think that Stephen is right. Seems senseless to run 12VDC through inverter to power 220 VAC compressor. Always some losses in this type of system. Believe that air cooled condenser makes more sense as personal experience shows that 12 VDC air cooled system works in tropical climate and eliminates all the problems associated with the water cooling system - pumps, clogging, etc. If you need any more data let me know and I'll go down to Stephen's shop and talk with him. Do note the ALL LED lighting. Bruce-in-Bangkok (correct Address is bpaige125atgmaildotcom) |
Advice on refridgeration unit please
On Sat, 19 Jul 2008 04:54:43 +0000, Larry wrote:
Herodotus wrote in : That's what I admire about you Larry - a true lateral thinker. Seriously. I'd be interested to see what results you get. cheers Peter I like the idea of using those gel cold packs instead of the heat sinks. They probably will absorb much more Btu than just Aluminum. I have all kinds of crazy ideas I like to think is based on some basic knowledge of science, in this case thermodynamics. For many years, my electric bill with electric heat and for the last 4 years simple $100 but very efficient Korean window air conditioners has been less than half of my neighbors'. I wasn't too interested until the main heat pump failed and I thought I'd have to pay through the nose using simple electric heaters as it was in the winter, January, our coldest month. Oddly, the house didn't simply freeze up and I found that only 1800 watts of two "milkhouse" nichrome-wire warm air heaters kept the place as warm as toast for me and my parrots. They even cycled on and off quite regularly. I began to wonder why as some neighbors were over $400/month with electric strip heat in central heating systems in these cheap trailers. What I discovered was it was my crazy lifestyle as a pack rat that was the cause of the low bills! I'm quite a packrat. I collect 'things' I find fascinating or remotely useful, especially from thrift shops on the truly cheap. My 14x70 yacht is loaded to the gills with my collections, some useful, some forgotten. I'm a loner, most of the time, so who cares? I love my stuff. Some times I go through and find things I haven't seen in years. Every day is like Christmas morning...(c; It was this crazy obsession of mine that was causing the low bills! All the stuff piled up all over the house creates two phenomenon I could measure....THERMAL LAG merely from the Btu stored in the "stuff" during the day with the sun coming in the windows....and the "stuff" radiating it into the cooling house all night...into a much smaller airspace than the usual empty house beautiful's 8 acres of perfectly clean white carpet you aren't allowed to walk on in shoes has. The other phenomenon is INSULATION. If "stuff" is sitting on the floor, because there is no place else to put it left...(c;)...it creates a tremendous R-value of insulation as the heat can't simply escape through a tiny bit of clean white carpet noone is allowed to walk on in shoes plus a little fiberglass insulation under the floor. Hell, in some places, my floors have 3 feet of insulating "material" over the carpet...in addition to being a heat storage medium. Throwing away that "stuff" is a mistake! It lowers your power bill! I suppose (on topic) the same is true on boats. An empty boat being delivered to its new owner with nothing in it heats and cools off much faster than a properly fitted out cruiser with 3000 pounds of tools, oil, spare parts, insulating books, and all that stuff you've forgotten about stuffed into the storage space under the settee....keeping the boat cooler in the day and warmer at night. Well, the neatniks don't last long around here. My friends love to come by and just go exploring. "What's this?", they'll say, holding up something I probably haven't seen in 2 years. "I dunno. You want it? It's yours.", I reply turning back to my keyboard or Heineken's keg filling my glass. I love to give stuff away because I'm a packrat and can't stand to just throw stuff out! What a waste. Someone got curious about an Ionic Breeze high voltage ion generator they sold for big money here in the States. I paid $5 in a thrift shop. It's gone....I helped him load it because he was carrying other stuff I'd dumped on him earlier...(c; My friends' boats are full of cable I'd just dragged off spools in the shed out in the yard. Radio Shack was selling stuff in a store to get rid of it, and I bought the whole lot of cables for $100 cash. We could hardly carry it out to the van! At the rate I'm giving it to friends, I'll run out in June of 2284...(c; That R-12 fridge I bought this morning brings my count of small fridges up to 6 I know about, at the moment. Somebody's beer is gonna love the new cooler pretty soon. I gave 4 away last summer...(c; $1000 fridges my ass.... If you don;t stop going on about R-12 the tree hugging gestapo is going to come calling and burn a cross on your lawn, or something. My God man, you are probably responsible for half the ozone hole all by yourself :-( Bruce-in-Bangkok (correct Address is bpaige125atgmaildotcom) |
Advice on refridgeration unit please
On Sat, 19 Jul 2008 06:46:33 +0700, Bruce in Bangkok
wrote: On Fri, 18 Jul 2008 11:36:32 -0700 (PDT), " wrote: On Jul 18, 8:42*am, Larry wrote: Bruce in Bangkok wrote : Well, first of all you need a "Larry Lesson" on how batteries charge as your 110 amp alternator is just a waste of money. No, no! *Everyone knows a boat battery can be charged in 3 minutes if you buy a big enough alternator! Don't let logic, battery chemistry and me upset it. In practice high output alternators make a big difference getting up to about 80% charge. That can be very, very useful. It may be that you have some logic and battery chemistry in your text books but I live on my boat and go voyaging a bit. High output alternators are a good thing. So do Larry, Peter and myself. (Well, larry doesn't live on one, he just voyages). Frankly, in my experience a 110 amp alternator and a 440 A.H. battery bank is overkill, \The reason why I have a Bosch 120 AMP alternator is that the Nanni 37 HP diesel came with a standard 55 AMP one. I got the larger alternator because I read that they never output their full power and it was a great price new. With the smart charge/fast charge system it only ever outputs a steady 80 amps before tapering down. Also, it seldom gets hot. The first one needed replacing in Europe so went to Bosch agents in Italy and Spain. They hunted the part numbers from the casing and even phoned Germany before receiving advice that Australian Bosch part numbers were different. Found a new Bosch 120 amp one with the same mounting in Spain in a catalogue - price 900 Euros - $1,500. Arrived back in Australia, went to the dealer and purchased a Bosch 120 amp one for $240 - new. Looked at the casing. It had a label "Made in Spain". That's capitalism for you. |
Advice on refridgeration unit please
On Sat, 19 Jul 2008 18:27:00 +1000, Herodotus
wrote: On Sat, 19 Jul 2008 06:46:33 +0700, Bruce in Bangkok wrote: On Fri, 18 Jul 2008 11:36:32 -0700 (PDT), " wrote: On Jul 18, 8:42*am, Larry wrote: Bruce in Bangkok wrote : Well, first of all you need a "Larry Lesson" on how batteries charge as your 110 amp alternator is just a waste of money. No, no! *Everyone knows a boat battery can be charged in 3 minutes if you buy a big enough alternator! Don't let logic, battery chemistry and me upset it. In practice high output alternators make a big difference getting up to about 80% charge. That can be very, very useful. It may be that you have some logic and battery chemistry in your text books but I live on my boat and go voyaging a bit. High output alternators are a good thing. So do Larry, Peter and myself. (Well, larry doesn't live on one, he just voyages). Frankly, in my experience a 110 amp alternator and a 440 A.H. battery bank is overkill, \The reason why I have a Bosch 120 AMP alternator is that the Nanni 37 HP diesel came with a standard 55 AMP one. I got the larger alternator because I read that they never output their full power and it was a great price new. With the smart charge/fast charge system it only ever outputs a steady 80 amps before tapering down. Also, it seldom gets hot. The first one needed replacing in Europe so went to Bosch agents in Italy and Spain. They hunted the part numbers from the casing and even phoned Germany before receiving advice that Australian Bosch part numbers were different. Found a new Bosch 120 amp one with the same mounting in Spain in a catalogue - price 900 Euros - $1,500. Arrived back in Australia, went to the dealer and purchased a Bosch 120 amp one for $240 - new. Looked at the casing. It had a label "Made in Spain". That's capitalism for you. Actually a XX amp alternator WILL produce XX power. The question is for how long, usually not very. Actually I should not needle you about a big alternator as I have one too (but I know I don't need it :-) I've also got a "auto - manual" selector which is a two way switch and a rheostat. Switches the alternator from regulator to manual control. Good for when the regulator fails :-( The auto/manual switch sounds like just the thing. Run the engine at low revs and crank up the field current and put out prodigious amperage at low revs but it doesn't work that way. If the battery is down even a little there is no difference between regulator and manual selections. Apparently a "smart" regulator runs wide open until you get to about 14 volts and then slows things down. By the way. The last alternator I bought cost me US$50, used. Took it to the rewind shop and had them check everything and test it - $7.00. Like new alternator $57.00. Cheap is good, as Larry says. But it failed the other day when I set off for the ship yard. Had only been down there under the floor for five years too -- they just don't build 'um like they used to :-( Talk about capitalism. When I was in Viet Nam fighting the communists and making the world safe for capitalism I ordered some parts. When they arrived each and every one had etched on the case "Made in Yugoslavia". Bruce-in-Bangkok (correct Address is bpaige125atgmaildotcom) |
Advice on refridgeration unit please
Bruce in Bangkok wrote:
$1000 fridges my ass.... If you don;t stop going on about R-12 the tree hugging gestapo is going to come calling and burn a cross on your lawn, or something. My God man, you are probably responsible for half the ozone hole all by yourself :-( Bruce-in-Bangkok (correct Address is bpaige125atgmaildotcom) Watching a greenie show on TV last night and it showed an illustration of the hole in the ozone layer. Their statement was that it was caused by man but luckily it healed itself! HUH? G |
Advice on refridgeration unit please
On Jul 19, 12:23*am, Bruce in Bangkok
wrote: ... During your bulk charging stage what voltage are your batteries reading and how many amps are you charging at? ... I generally cycle the batteries on passage where I try to get away with one hour of charging a day. We support two 12 volt, air cooled compressors (fridge and freezer) and the auto pilot and nav lights, RADAR, radios &c. Our solar array is usually partially shaded while under way so we have less input there. Keeping in mind that no two days are alike and I'm not working off of data logs or anything: In the morning we generally see ~12 volts or a little less on the batteries (they are always under load) and the acceptance rate plus load is more than 200 amps. The voltage rises slowly to 14.2~14.4 (depending on what the temp is). After about and hour I typically shut down the engine and the acceptance plus load at 14ish is in the low teens. For the first third or so of that the charge rate is greater than 50 amps. My take is that I'd kill standard sized alternators pretty fast asking them to go full out for half an hour (integessing the extra time to 50 amps) plus another 45 min of topping off and it would take more time to get to the same charge rate. Down the list a ways you mention a cat that charges its batteries 3 hours a day. I would find that intolerable. It seems to me that the trick to reducing charging time is to have a good sized alternator and know when to stop charging. It's unusual to be offshore for more than a week without a day of calms and on those days you can top the battery off while getting a propulsion boost form the motor. YMMV. -- Tom. |
Advice on refridgeration unit please
"Gordon" wrote in message
m... Bruce in Bangkok wrote: $1000 fridges my ass.... If you don;t stop going on about R-12 the tree hugging gestapo is going to come calling and burn a cross on your lawn, or something. My God man, you are probably responsible for half the ozone hole all by yourself :-( Bruce-in-Bangkok (correct Address is bpaige125atgmaildotcom) Watching a greenie show on TV last night and it showed an illustration of the hole in the ozone layer. Their statement was that it was caused by man but luckily it healed itself! HUH? G Not quite... didn't heal itself until after we stopped dumping the refrigerant into the atmosphere. http://www.livescience.com/environme...zone_hole.html http://www.techmonitor.net/techmon/0...zo_science.htm -- "j" ganz @@ www.sailnow.com |
Advice on refridgeration unit please
On Sat, 19 Jul 2008 02:33:54 +0000, Larry wrote:
/// I was cruising on of my thrift shops today and paid $10 for a Sears Kenmore 2.2 cu ft little bar fridge in nice condition. ///The little compressor is SO quiet you can't even hear it start! /// The wattmeter still sits on 71W when it's running, which I take to be about 15% duty cycle on my stopwatch after the initial cooldown and temperature stabilization to 38F on the top shelf away from the evap. The thermometer inside the little box evap sits on 8F at about 2/3 thermostat setting and should keep the icecream hard...(c; ...I think the nice door on this fridge will fit on my favorite old R-12 fridge, the one with the 40 watt vibrator compressor from Sweden. That's the most efficient little fridge I own ... I'll be in the lab with my Linux tablet running spreadsheets if Algore calls for advise.... Forget about the pleasures of sailing a fresh warm breeze, it's nice to see simple joy radiating off into the net: about finding a bargain, running tech checks, looking forward to icecream and chill beer afloat. Gotta love those dorm fridges. Brian W |
Advice on refridgeration unit please
On Jul 18, 8:00*pm, Larry wrote:
... Would you drive a Nano for $2500 that gets 70 mpg? Yup. I think the idea of saying that all vehicles below a certain weight are motorcycles is brilliant. Let's allow folks to drive them who have taken an extra course and are aware of the risks. I'm think that tiny cars would be very popular in the big urban centers particularly if they got HOV privileges & so on. What's the down side? -- Tom. |
Advice on refridgeration unit please
|
Advice on refridgeration unit please
Bruce in Bangkok wrote in
: Suggestions: Think that Stephen is right. Seems senseless to run 12VDC through inverter to power 220 VAC compressor. Always some losses in this type of system. Believe that air cooled condenser makes more sense as personal experience shows that 12 VDC air cooled system works in tropical climate and eliminates all the problems associated with the water cooling system - pumps, clogging, etc. Does someone make a 12VDC compressor? I've never seen one, here. I do see AC inverters built into fridges driving standard AC-powered compressors that have relays or electronics to switch to shore power if shore power is available to run the compressor straight off shore power, however. Inversion and synthsized AC power creation from battery power is now in the range of 98-99% efficient with switching power supply technology using pulse-width-modulation to accomplish a near-perfect sinewave output to drive loads. These powerful synthesizers are very cheaply constructed and very profitable. The AC compressors synchronize to power line frequency (50 or 60 Hz), which gives them a steady power output regardless of condensor pressure loading which would drive a DC motor crazy trying to maintain counter EMF. It makes little difference in efficiency running a switching inverter outside......or building one inside for another $1500 to sell at the boat store. The price difference is phenomenal! |
Advice on refridgeration unit please
Bruce in Bangkok wrote in
: half the ozone hole all by yourself :-( .....an ozone hole that hasn't varied one iota from all of man's activities since it was discovered? |
Advice on refridgeration unit please
" wrote in news:b2f93b8e-4554-434c-
: What's the down side? Oil company profits.....for my president's family. |
Advice on refridgeration unit please
On Jul 19, 2:32*pm, Larry wrote:
... 200A x 12V = 2,400 watts. No danger of overheating and warping AGM plates with only 2.4 kilowatts forced into them at all. *You should crank up the charging even further.. ... Just for the record, my electrical system was designed and installed by Gary Pacey of Outback Marine. He's an EE specializing in marine power systems. He's installed virtually the same system on lots of boats. In the small world category, the boat three down the dock from us was built in the same year in the same part of Oz and with the same power system as my boat. I know Gary did a lot of in house testing and had good relationships with the suppliers of the batteries and controllers. In short, this isn't something that I just threw together out of catalogs. Also, I don't follow you point. Are you saying 2.4Kw is too much power for any battery bank or were you making a specific point? -- Tom. |
Advice on refridgeration unit please
On Sat, 19 Jul 2008 09:43:01 -0700 (PDT), "
wrote: On Jul 19, 12:23*am, Bruce in Bangkok wrote: ... During your bulk charging stage what voltage are your batteries reading and how many amps are you charging at? ... I generally cycle the batteries on passage where I try to get away with one hour of charging a day. We support two 12 volt, air cooled compressors (fridge and freezer) and the auto pilot and nav lights, RADAR, radios &c. Our solar array is usually partially shaded while under way so we have less input there. Keeping in mind that no two days are alike and I'm not working off of data logs or anything: In the morning we generally see ~12 volts or a little less on the batteries (they are always under load) and the acceptance rate plus load is more than 200 amps. The voltage rises slowly to 14.2~14.4 (depending on what the temp is). After about and hour I typically shut down the engine and the acceptance plus load at 14ish is in the low teens. For the first third or so of that the charge rate is greater than 50 amps. My take is that I'd kill standard sized alternators pretty fast asking them to go full out for half an hour (integessing the extra time to 50 amps) plus another 45 min of topping off and it would take more time to get to the same charge rate. Down the list a ways you mention a cat that charges its batteries 3 hours a day. I would find that intolerable. It seems to me that the trick to reducing charging time is to have a good sized alternator and know when to stop charging. It's unusual to be offshore for more than a week without a day of calms and on those days you can top the battery off while getting a propulsion boost form the motor. YMMV. -- Tom. No, Perhaps I should have explained in more detail. On the 4 day trip because of having little wind the Cat motored between 3 - 4 hours a day. Bruce-in-Bangkok (correct Address is bpaige125atgmaildotcom) |
Advice on refridgeration unit please
On Sat, 19 Jul 2008 10:07:10 -0700, "Capt. JG"
wrote: "Gordon" wrote in message om... Bruce in Bangkok wrote: $1000 fridges my ass.... If you don;t stop going on about R-12 the tree hugging gestapo is going to come calling and burn a cross on your lawn, or something. My God man, you are probably responsible for half the ozone hole all by yourself :-( Bruce-in-Bangkok (correct Address is bpaige125atgmaildotcom) Watching a greenie show on TV last night and it showed an illustration of the hole in the ozone layer. Their statement was that it was caused by man but luckily it healed itself! HUH? G Not quite... didn't heal itself until after we stopped dumping the refrigerant into the atmosphere. http://www.livescience.com/environme...zone_hole.html http://www.techmonitor.net/techmon/0...zo_science.htm Since here in Thailand, and probably all over the third world, they are happily using R-12, and dumping it to atmosphere it probably goes to prove that the Americans were responsible. Damn, if the Indians hadn't sold Manhattan Island we wouldn't have had all these problems :-) Bruce-in-Bangkok (correct Address is bpaige125atgmaildotcom) |
Advice on refridgeration unit please
On Sat, 19 Jul 2008 21:42:34 +0000, Larry wrote:
Bruce in Bangkok wrote in : Suggestions: Think that Stephen is right. Seems senseless to run 12VDC through inverter to power 220 VAC compressor. Always some losses in this type of system. Believe that air cooled condenser makes more sense as personal experience shows that 12 VDC air cooled system works in tropical climate and eliminates all the problems associated with the water cooling system - pumps, clogging, etc. Does someone make a 12VDC compressor? I've never seen one, here. I do see AC inverters built into fridges driving standard AC-powered compressors that have relays or electronics to switch to shore power if shore power is available to run the compressor straight off shore power, however. Inversion and synthsized AC power creation from battery power is now in the range of 98-99% efficient with switching power supply technology using pulse-width-modulation to accomplish a near-perfect sinewave output to drive loads. These powerful synthesizers are very cheaply constructed and very profitable. The AC compressors synchronize to power line frequency (50 or 60 Hz), which gives them a steady power output regardless of condensor pressure loading which would drive a DC motor crazy trying to maintain counter EMF. It makes little difference in efficiency running a switching inverter outside......or building one inside for another $1500 to sell at the boat store. The price difference is phenomenal! I've got one. At least it says so on the can, Been tucked down under the cockpit floor for ten years or more. Bruce-in-Bangkok (correct Address is bpaige125atgmaildotcom) |
Advice on refridgeration unit please
On Sat, 19 Jul 2008 16:02:44 -0700 (PDT), "
wrote: On Jul 19, 2:32*pm, Larry wrote: ... 200A x 12V = 2,400 watts. No danger of overheating and warping AGM plates with only 2.4 kilowatts forced into them at all. *You should crank up the charging even further. ... Just for the record, my electrical system was designed and installed by Gary Pacey of Outback Marine. He's an EE specializing in marine power systems. He's installed virtually the same system on lots of boats. In the small world category, the boat three down the dock from us was built in the same year in the same part of Oz and with the same power system as my boat. I know Gary did a lot of in house testing and had good relationships with the suppliers of the batteries and controllers. In short, this isn't something that I just threw together out of catalogs. Also, I don't follow you point. Are you saying 2.4Kw is too much power for any battery bank or were you making a specific point? -- Tom. Not to disparage anyone but have a look at the battery manufacturer's specs and see whether they recommend that high a charging rate. I suspect you'll see something like 10 - 15% of rated capacity. Bruce-in-Bangkok (correct Address is bpaige125atgmaildotcom) |
Advice on refridgeration unit please
On Jul 18, 9:34*pm, Larry wrote:
Ryk wrote : You would be much better off filling the freezer with a phase change fluid that melts/freezes somewhere in the desired temperature range. Water, for instance... I have lots of freeze packets, both in plastic bags and hard plastic cooler packs made to go between the cans. *I'll try them, too, as a cold plate.. If you have two sets of the freezer packs you can freeze one during the night and morning, move it to the fridge compartment just prior to the hottest part of the day, simultaneously moving the other (thawed) bunch of freezer packs to the freezer. I've found it works wonders. |
Advice on refridgeration unit please
On Sat, 19 Jul 2008 21:42:34 +0000, Larry wrote:
The AC compressors synchronize to power line frequency (50 or 60 Hz), which gives them a steady power output regardless of condensor pressure loading which would drive a DC motor crazy trying to maintain counter EMF. I don't think so - they are integrated induction motors and compressors in a can. There's a capacitor that splits the phase, but they slip the rotating field depending on load - if I recall Brian W |
Advice on refridgeration unit please
On Sat, 19 Jul 2008 16:02:44 -0700 (PDT), "
wrote: On Jul 19, 2:32*pm, Larry wrote: ... 200A x 12V = 2,400 watts. No danger of overheating and warping AGM plates with only 2.4 kilowatts forced into them at all. *You should crank up the charging even further. ... Just for the record, my electrical system was designed and installed by Gary Pacey of Outback Marine. He's an EE specializing in marine power systems. He's installed virtually the same system on lots of boats. In the small world category, the boat three down the dock from us was built in the same year in the same part of Oz and with the same power system as my boat. I know Gary did a lot of in house testing and had good relationships with the suppliers of the batteries and controllers. In short, this isn't something that I just threw together out of catalogs. Also, I don't follow you point. Are you saying 2.4Kw is too much power for any battery bank or were you making a specific point? -- Tom. Larry is possibly supposing that the 50 ampere hours you are charging with will show up as 2.4 kW of heat - but he will remember that most of that energy goes to electrochemical storage. Still, give a person credit for gun-shyness from a battery fast-charge accident! Brian W |
Advice on refridgeration unit please
On Jul 19, 5:04*pm, Bruce in Bangkok
wrote: ... Not to disparage anyone but have a look at the battery manufacturer's specs and see whether they recommend that high a charging rate. I suspect you'll see something like 10 - 15% of rated capacity. ... Nope. My battery manufactuer recommends charging with a voltage regulated charger at 14.2-14.4 volts.* That's what I do. And as I say, many other boats are doing this, too. It has worked well for me for years and AFIK it works well for other folks also. Not to disparage anyone, but where are you getting your information? You sound very sure of yourself. However, what you are saying doesn't fit with my experience or with the advice I have taken from a pro. Do you have any sources or experience you can point to? -- Tom. *http://www.lifelinebatteries.com/mch...procedures.php |
Advice on refridgeration unit please
Larry wrote:
Does someone make a 12VDC compressor? I've never seen one, here. You're pretty much admitting that you've never seen a custom marine refrigeration system and know nothing about them. Most of the small boat systems in the last 20 years have used DC Danfoss hermetic compressors. The larger systems use a belt or direct drive from a DC motor. I do see AC inverters built into fridges driving standard AC-powered compressors that have relays or electronics to switch to shore power if shore power is available to run the compressor straight off shore power, however. Perhaps the AC/DC units on powerboats do it this way. Inversion and synthsized AC power creation from battery power is now in the range of 98-99% efficient with switching power supply technology using pulse-width-modulation to accomplish a near-perfect sinewave output to drive loads. These powerful synthesizers are very cheaply constructed and very profitable. It can be done, but if you buy a general purpose inverter it will likely run at about 80%, The AC compressors synchronize to power line frequency (50 or 60 Hz), which gives them a steady power output regardless of condensor pressure loading which would drive a DC motor crazy trying to maintain counter EMF. It makes little difference in efficiency running a switching inverter outside......or building one inside for another $1500 to sell at the boat store. The price difference is phenomenal! OK, I just checked the energy efficiency of a GE compact fridge, 5.7 feet with a tiny freezer. It uses 360 kWh's a year, or 1 kWh per day. Supplying this with an inverter would take over 100 AmpHours. However, a similar sized fridge built with a small Danfoss will only use about 35 Amp-hours. My system includes this size fridge (bigger, actually), plus a 5 foot deep freeze which keeps a summer's worth of burgers and steaks at about 5 degrees only uses 55-60 AmpHours in New England, maybe 75-80 in the tropics. (Mine is a belt driven 12V compressor with holding plates and water cooling. In the tropics, if I had to do it over, I'd be considering two small Danfoss air-cooled systems, one for the fridge, the other for the freezer.) I'm a fan of faster charging, either with a high output alternator or a Honda 2000i pushing a 100 Amp charger - either way I can do most of my charging at 75-95 Amps, even though its only a 440 AH bank. But still, adding 65 AH a day to save some money doesn't work, even assuming the GE fridge would fit in a boat. Frankly the cost is irrelavent; there's no way I would double my charging time to have less capacity. Since you're claiming you can't charge at over 25 Amps, running the commercial fridge would take an extra 2 and a half hours, and a system like mine would require even more hours. Of course, you're saying that a marine fridge *could be* built for on a few dollars more than a commercial unit. Possibly true, but the market is tiny by comparison, and that's what its all about. |
Advice on refridgeration unit please
On Jul 19, 5:22*pm, Brian Whatcott wrote:
.. Still, give a person credit for gun-shyness from a battery fast-charge accident! ... Oh yes. An exploding battery while offshore is a nightmare! I appreciate the concern. I think Larry is incorrect in his assertion, but I'm listening because if he convinces me that he isn't then I'm going to change my ways fast. -- Tom |
Advice on refridgeration unit please
On Jul 19, 2:42*pm, Larry wrote:
... Does someone make a 12VDC compressor? *I've never seen one, here. *I do see http://www.rparts.com/Catalog/Major_...ss/danfoss.asp (http://tinyurl.com/2tkja3). "Like the smaller BD35F and BD50F models (below), the BD80F uses an electronically commutated permanent magnet brushless DC motor." They're pretty much everywhere. I've got two. -- Tom. |
Advice on refridgeration unit please
On Sat, 19 Jul 2008 18:52:14 -0700 (PDT), "
wrote: On Jul 19, 5:04*pm, Bruce in Bangkok wrote: ... Not to disparage anyone but have a look at the battery manufacturer's specs and see whether they recommend that high a charging rate. I suspect you'll see something like 10 - 15% of rated capacity. ... Nope. My battery manufactuer recommends charging with a voltage regulated charger at 14.2-14.4 volts.* That's what I do. And as I say, many other boats are doing this, too. It has worked well for me for years and AFIK it works well for other folks also. My battery manufacturer recommends charging to 14.8 and then dropping back to 13.2, see: http://www.trojan-battery.com/Batter.../Charging.aspx If you stop when the batteries first reach 14.8 you never fully charge your batteries. Not to disparage anyone, but where are you getting your information? You sound very sure of yourself. However, what you are saying doesn't fit with my experience or with the advice I have taken from a pro. Do you have any sources or experience you can point to? Try http://www.trojan-battery.com/Batter...Selection.aspx Note that my figures were too low for some batteries. Trojan recommends 20% but other recommendations are in the 10 - 15% range see: http://www.solarnavigator.net/battery_charging.htm -- Tom. *http://www.lifelinebatteries.com/mch...procedures.php Bruce-in-Bangkok (correct Address is bpaige125atgmaildotcom) |
Advice on refridgeration unit please
Bruce in Bangkok wrote:
Not to disparage anyone but have a look at the battery manufacturer's specs and see whether they recommend that high a charging rate. I suspect you'll see something like 10 - 15% of rated capacity. That's what Trojan says for their wet cells, though I've done a lot of charging at more like 18-20% will no ill affects. My first set did die after 7 years (they might have gone another year or so if I had tended to them better over a harsh winter), but frankly, they are the cheapest part of the system. For their gel and AGM batteries, they say 20%. |
Advice on refridgeration unit please
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Advice on refridgeration unit please
Bruce in Bangkok wrote in
: Since here in Thailand, and probably all over the third world, they are happily using R-12, and dumping it to atmosphere it probably goes to prove that the Americans were responsible. Not to mention the extensive air pollution controls on all those thousands of 2-stroke little trucks running old motor oil at 15:1 premix.... It's those damned Americans....every time. They love to be blamed. |
Advice on refridgeration unit please
Brian Whatcott wrote in
: I don't think so - they are integrated induction motors and compressors in a can. There's a capacitor that splits the phase, but they slip the rotating field depending on load - if I recall B The capacitor lags the phase so you don't have to spin start them by hand....they do run at the power line frequency....minus a little phase slippage caused by the load. Listen to one that has just started up and note its musical note. Notice how the note hardly varies as the head pressure comes up to maximum, and only the running current increases to maintain it. Invented by Nikola Tesla, Father of Modern Electricity. (I'm a fanboi...(c;) If it had DC motors in it, those compressors would run like your universal series wound vacuum cleaner or a drill/saw motor....varying widely in speed as the load doubles/triples from idle. The smooth steady hum of a compressor reeks of an AC induction motor, capacitor start/capacitor run. |
Advice on refridgeration unit please
jeff wrote in
: 1 kWh per day. Supplying this with an inverter would take over 100 AmpHours. 1KWh at 13.8V = 72AH per day....1000/13.8V Not much of a problem for a 330AH golf cart pair.... |
Advice on refridgeration unit please
" wrote in
: http://www.rparts.com/Catalog/Major_...rs/Danfoss/dan f oss.asp Hmm..... Basic Specifications: bullet Refrigerant: HFC-134a, CFC-12 bullet Speed Range: 2,500 - 4,400 rpm Yep, it's DC allright... bullet Capacity: 934 Btu/hr (274 Watts) I don't understand how they get 274 watts of cooling with only 168 watts input. Must be physics magic! bullet Max Evap (2.5k rpm) +23F (-5C) bullet Max Evap (4.4k rpm) +23F (-5C) bullet Power Input (max): 168 Watts Arithmetic: 168W/13.8V=12.17 amps. In comparison, the bar fridges draw LESS POWER off AC motors. The 2.2 cuft I got yesterday draws 1.08A (measured) pumping hard on a hot box after 10 minutes of stabilzation...That's 120x1.08=129.6 watts/.95 (95% efficient inverter)+ 5 watts idling = 141.4W after conversion....still 20 watts less than the Danforth. My 4.4 cuft $129 Magic Chef draws 148 watts (measured) and through inverter would be about equal....but $850 cheaper. As it sits full of beer right next to my desk, I can estimate its duty cycle at 10% just sitting there after stabilization. Solid foam insulation form fitted leaves only the door seal, same as any marine fridge, magnetic strips with accordion folding pressure, as the leakage point. It doesn't leak much as the case is never wet and there's no doorseal heater strips in it....too cheap. I still contend the SMALL INVERTER/cheap AC fridge is very competitive without taking out a mortgage. For a 150W box, you need a 200-300W inverter....not that 4KW monster with the 4 fans from Waste Marine. The little inverters draw almost no idle power, unlike the big beast. It's insignificant, even for boat battery banks. You want it mounted...I use steel angle brackets and toggle bolts through the thin walled case CAREFULLY drilled away from where it gets hot (condensor coils buried under the skin). The old R12 I got yesterday has external coils out the back...MUCH MORE EFFICIENT but vulnerable to breakage. bullet Height: 5.39" (137 mm) bullet Weight: 9.5 lbs (4.3 kg) |
Advice on refridgeration unit please
On Jul 19, 7:34*pm, Larry wrote:
" wrote in news:b2e0cf11-1ba5-4e82- : Also, I don't follow you point. *Are you saying 2.4Kw is too much power for any battery bank or were you making a specific point? Think about the heat from 2,400 watts, about twice what comes out of an electric heater turned up full....but now confined really hard inside the rolled up lead and gauze of an AGM battery sealed inside a plastic tube. Seems to me that most of the energy must go into the chemical reaction. As the heat builds up the internal resistance will go up and the voltage will go up and the controller will reduce the amps... No? Anyway, there's no way that that much heat is being produced. The batteries are cool to the touch when charging, so there is something wrong with you analysis. Also, just so you know, my AGM are made of rectangles of lead and glass sandwiched together. No tubes. ... 2400 watts is a LOT of power! *It will also create a LOT of HYDROGEN GAS once the surface charge of all those amps insulates the plates from their SLOW CHEMICAL ACTION OF 14 HOUR NORMAL CHARGING! You're yelling, dude. Given how long my batteries have lasted I don't think they can be outgassing all that much hydrogen. I also think you need to look at a charging curve. Yes, getting to 100% charge takes a long time, but the curve is nowhere near linear. Most of the time involved is taken going from ~80-100% and the charge rates at that end are very small (ending at less than an amp). However, from ~50%-80% the charge rates are quite high particularly with AGMs which have low internal resistance. Yeah, I'm saying 2400 watts is WAY too much power.... Regardless of battery bank size? Pity the poor diesel-electric submarine boys, it must take them years to charge their batteries. same old crap a boater trying to recharge dead house batteries in an hour a day.....geez. I'm not trying to completely recharge them in an hour a day. I am getting a useful charge into them in an hour a day and fully recharging them periodically. This has been working well for me for some years now. I'm just reporting the facts, friend. There's no need to yell. I'm listening to you, but I haven't seen much signal in your noise yet. -- Tom. |
Advice on refridgeration unit please
On Jul 19, 7:27*pm, Bruce in Bangkok
wrote: ... http://www.trojan-battery.com/Batter.../Charging.aspx If you stop when the batteries first reach 14.8 you never fully charge your batteries. Good point. I use a three stage controller, too. ... Note that my figures were too low for some batteries. Trojan recommends 20% but other recommendations are in the 10 - 15% range see:http://www.solarnavigator.net/battery_charging.htm ... Yes. Interesting. Particularly the last link which says my Concorde AGMs can be charged at C times 4 (400%) of the 20 hour rate! I guess I need bigger alternators :) It isn't clear to me if some of the charger links are minimum size recommendations or limits on the charge rate. All the smart chargers I know of just assume that the battery will come up to voltage before it is damaged by the amperage. That is, they don't come with an amp setting, only a volt setting. But you point is good about RTFM. Thanks for the links. -- Tom. |
Advice on refridgeration unit please
On Jul 19, 7:37*pm, Larry wrote:
... I heard a noise about taking the VOLTAGE REGULATOR off the alternator and putting a manual current control on the field winding so it can be "cranked up" to whatever charging current some idiot wants. * That's just suicidal. I didn't see that suggestion, but it would be absolutely insane and I hope that I didn't write anything that would suggest otherwise. ... I'm in FULL AGREEMENT of 14.2 to 14.8V REGULATED VOLTAGE charging....the way the damned alternator was delivered. *BUT, alas, this will NOT recharge those batteries in an hour! *... Quite. But at lest with my batteries I do get a days worth of power out of an hours charging (to be fair we usually get some sun on at least some of the panels during the day, too). ... *Of course, in the wonderful AGM battery you cannot MEASURE the specific gravity of the soaked up gauze electrolyte so you have no idea of its charge condition. To be sure. But, what I do know is that I've got enough amps to run my stuff. Including the HF radio that demands voltage in excess of 12. ... Battery charging takes 14 hours......REALLY! *You cannot get 90% from 50% using a NORMAL, voltage regulated alternator in 60 minutes...CHEMISTRY won't allow it. ... I'm not claiming to get to 90% or even very exactly 80%. I am using a normal voltage regulated alternator (well they're regulated externally, but regulated none the less). I am able to put a substantial and useful charge into my batteries in an hour. That's just the way it is. Maybe it has something to do with the physical make up of the batteries, maybe I'm using a smaller percentage of them than I think I am (or than the controller is reporting). Whatever. I don't know the why's. I'm not an expert. I did hire an expert to put the system together and it works. ... This will soon change as we leave these 1885-era chemical monstrosities behind us. *A fantastic technology is coming. *You charge it at a thousand times its AH rating for SIXTY SECONDS to 80% charge and 3 minutes to 100%! *Read hehttp://www.physorg.com/news3539.html Man, that looks cool. Super-capcitor charge times with 1k cycle plus life span deep cycling. Yes, yes, yes. Only problem I can see is that it will cost more than my boat. :) -- Tom. |
Advice on refridgeration unit please
On Sat, 19 Jul 2008 19:03:33 -0700 (PDT), "
wrote: On Jul 19, 5:22*pm, Brian Whatcott wrote: .. Still, give a person credit for gun-shyness from a battery fast-charge accident! ... Oh yes. An exploding battery while offshore is a nightmare! I appreciate the concern. I think Larry is incorrect in his assertion, but I'm listening because if he convinces me that he isn't then I'm going to change my ways fast. -- Tom If you are charging a battery fast enough to make bubbles in the electrolyte you are venting hydrogen. I saw a Chinese bloke in Singapore disconnect a battery charger without turning the charger off. It made a spark and the whole shebang blew up. Had he not been on a dock so he could dive in the water I suspect he would have received severe acid burns. After he stopped shaking he commented, "Never had that happen before".... Bruce-in-Bangkok (correct Address is bpaige125atgmaildotcom) |
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