# 12V refrig units and power



## Dave_E (Aug 7, 2013)

Hi Cruisers,

Those of you who are pretty dedicated to the ball or hook, do you have refrigerator units and how are they powered? I just don't know, so I'm asking - do solar cells and/or wind generators make enough juice to supply the batteries while they are running a refrigeration unit? 

Dave


----------



## IStream (Dec 15, 2013)

Dave,

There are too many variables to answer this definitively. It depends on the size of the compressor (determined by the size of your box), the amount of insulation you have, whether you want/need a freezer, and the amount of solar panel area you have or can accommodate. 

If you've got an ice box already, as a starting point I'd go looking for fridge conversion kits and determine their current requirements. Assume a duty cycle of 75% to be safe and calculate how many amp hours that corresponds to in a 24 hour day. Then figure out how much solar area you can accommodate, divide the total panel rating by 2 given our latitude, shading, etc., assume a 6 hour day, and that'll tell you if you can cover the load. The devil will be in the details but this will give you an order of magnitude estimate.


----------



## Don L (Aug 8, 2008)

Dave_E said:


> Hi Cruisers,
> 
> Those of you who are pretty dedicated to the ball or hook, do you have refrigerator units and how are they powered? I just don't know, so I'm asking - do solar cells and/or wind generators make enough juice to supply the batteries while they are running a refrigeration unit?
> 
> Dave


My boat sits out on a mooring and the freezer/refrigerator (huge freezer with a spill over fan system) on it runs all the time from April splashing to Nov haulout. I have a 290W solar panel and 460 AH batteries and when I get to the boat Friday evening the batteries are normally 95+% state of charge. From the logging menu of my solar controller the system normally uses about 60 AH/day. I have never seen the batteries less than 90% SOC at the end of the week even with cloudy/raining days during the week.


----------



## Domknotty (Jun 1, 2011)

*good info*

I just got the frig in my Morgan 35 working today...yea! I plan on setting the DC up with a 240w solar panel and controller followed by 3 sets of 6v golf cart batteries. Our only other drain will be fans and lights and possibly an 110 ice maker. Does this sound feasible?


----------



## deniseO30 (Nov 27, 2006)

uh.. gentlemen please spell it Fridge or Refridge. not frig  

It would not sound quite so right to say something like: DIY frigging lol


----------



## heatobi1 (Jun 3, 2009)

We live aboard our Sabre 36 on a mooring. The refrigerator (adler barbour cold machine) is always switched on. We have two soliban 125w panels and 540a/h batteries. Fridge has been on 9 weeks straight with just solar powering the setup.


----------



## cranki (Jun 11, 2006)

heatobi1 said:


> We live aboard our Sabre 36 on a mooring. The refrigerator (adler barbour cold machine) is always switched on. We have two soliban 125w panels and 540a/h batteries. Fridge has been on 9 weeks straight with just solar powering the setup.


Where are you moored?

I have a solar panel and a wind generator that are connected to 2 batteries that are dedicated to just running the fridge/ice box. I am at the dock though, in Connecticut, and have the charger hooked up as well. I have been out for 2 weeks with no problems though. Wind generator works a lot better (most of the time) when off the dock and on the hook.


----------



## heatobi1 (Jun 3, 2009)

We are based out of Port Washington LI. We have a Honda 2000 onboard but have yet to use it


----------



## boatpoker (Jul 21, 2008)

*Re: good info*



Domknotty said:


> I just got the frig in my Morgan 35 working today...yea! I plan on setting the DC up with a 240w solar panel and controller followed by 3 sets of 6v golf cart batteries. Our only other drain will be fans and lights and possibly an 110 ice maker. Does this sound feasible?


A 110v icemaker (through an inverter) will suck your batteries dry very quickly.


----------



## newhaul (Feb 19, 2010)

It also depends on what type of system you install i just installed a system for a customer in tacoma pm me and I will sendreal world specs i have can't send crap on this tablet to the forum just thru email. Rob


----------



## TQA (Apr 4, 2009)

I have a small freezer box at the top of a large well insulated top loading fridge. Makes ice in 95f ambient..

Adler Barbor Super Cold Machine air cooled. 

I have 400 watts of tiltable solar feeding 6 golf cart batts.

Most days I am fully charged by mid day.


----------



## fallard (Nov 30, 2009)

Your ice box insulation could make a huge difference in the energy required to maintain temperature. Before we added refrigeration, we went to Maine in the company of an older Morgan 34. These folks used literally 10 times the ice we used in our boat over a two week period. 

These folks bought bulk ice at a commercial dock and had a strategy for recycling the melt water--but that's another story.

Since then, we've added an Isotherm refrigeration system with a thru-hull fitting that contains an in-water heat exchanger. It has proven to be a very energy-efficient setup. Normal engine operation (60+ minutes/day) is sufficient to keep the battery bank sufficiently charged when cruising.


----------



## cranki (Jun 11, 2006)

heatobi1 said:


> We are based out of Port Washington LI. We have a Honda 2000 onboard but have yet to use it


I am in Stamford - practically neighbors.


----------



## WGEwald (Jun 2, 2014)

I have a 12V cooler powered by battery and solar panel. Need it to store my insulin :-(


----------



## chucklesR (Sep 17, 2007)

I'm currently running a 12v only 27 year old unit that is air cooled (perhaps the most inefficient setup possible). I've got 280w of solar panels running through a MPPT controller and a Victon BMV600S monitor to tell me watts watt.
On hot days (over 90) I need around 75ah to satisfy the fridge, it's on the list for a air/keel replacement next haul out. 
My panels keep up the draw (about 110 on average daily) quiet easily, more often than not I'm showing 95% by early afternoon.


----------



## chef2sail (Nov 27, 2007)

We I replaced our refrigeration with wate cooled aldar barbour supercold5 years ago i took the oppertunity to blow foam isulation aorund the exhisting box. The average daily ah draw dropped from 48 to 22.

iNSULATION IS SO VERY IMPORTANT


----------



## norahs arc (Jan 23, 2013)

I use a Domatic cooler/freezer, it can be used as a deep freeze or cooler. For the summer I set it to 0 C (32 F) and leave it on all the time. I have two 100 ah batteries and a 64 watt (10 year old) solar panel. Two years now and never had a problem. A bonus is that because it runs on 12 or 24 vdc or 120vac I take it home and plug it in and set it for minus 18 C (0 F) and have an energy efficient extra deep freeze for the winter.


----------



## xort (Aug 4, 2006)

We have a very large freezer with spillover to a refer. 280 watts of solar and an Air Breeze wind gen.

Currently in the cold waters of Maine we're almost always 90% state of charge or higher. Even on cloudy windless days. But in Florida in the winter we need to run the gennie every 3 to 5 days to assist charging. 

I did add a bunch of insulation which helped a lot but warm water and warm air temps make a big diff.
BTW, solar does a lot more overall than wind gens.


----------



## Seafarer (Aug 26, 2012)

Engel has very efficient drop-in units. I'm planning to purchase one of these to replace my un-insulated ice-box, and power it with two 12v G27s, each fed by it's own 100Watt panel and WPM charge controller. I may add more batteries, or bigger batteries, at a later date, but other than lights (which will eventually all be LEDs) and fans, there is little other power consumption.

My previous boat had a similar setup, but aided by a wind generator for those stormy days that keep the sun hidden.


----------



## Alex W (Nov 1, 2012)

I'd be curious to see photos of smaller boats with large panels on them. A fridge could be handy, but the requirement to plug in makes it far less appealing. The 30w panel on my 28' boat already is large, I can't imagine finding room for 250w worth of panels.

Dave_E: We've always had an easy time finding ice on the Salish Sea, so a fridge conversion hasn't been a major consideration. Our icebox is well insulated and we can go 4-6 days on 2 blocks of ice (4 days if one is half melted when we start, 6 if both are intact).


----------



## deniseO30 (Nov 27, 2006)

Seafarer said:


> Engel has very efficient drop-in units. I'm planning to purchase one of these to replace my un-insulated ice-box, and power it with two 12v G27s, each fed by it's own 100Watt panel and WPM charge controller. I may add more batteries, or bigger batteries, at a later date, but other than lights (which will eventually all be LEDs) and fans, there is little other power consumption.
> 
> My previous boat had a similar setup, but aided by a wind generator for those stormy days that keep the sun hidden.


Engel and norcold use the "swing compressor" Amazing little salt shaker it is!


----------



## deniseO30 (Nov 27, 2006)

Alex I don't have large panels. All I have is 10 watts to maintain. The 200 amp hour bank for the house so far seems to handle the fridge (around 3.5 amps) for well over 24 hours but I've not really given it a full weekend test yet. I did rewire and use isolated circuits for the battery banks. and the 90 amp alt seems to do the trick with charging!


----------



## Alex W (Nov 1, 2012)

I'd need to go for 10 days without plugging in or using the engine to make a refrigerator an option (that's about how long we've gone between staying in marinas with power). For Puget Sound (where light wind is the norm) that means solar because we can't fit more than two group 24 batteries.

Ice has the advantage of not requiring a long stop at a marina and being silent in use, but the annoyance of dealing with your items eventually swimming in cold water. A fridge would be nice, but it's not a clear win for me.


----------



## newhaul (Feb 19, 2010)

Here is one of the other options I showed to my client . Not the cheapest however with good insulation will use the least power in a 24 hr period CoolBlue Marine Refrigerator System | Cruise RO Water & Power


----------



## Puddin'_Tain (Feb 14, 2014)

Alex W said:


> I'd be curious to see photos of smaller boats with large panels on them. A fridge could be handy, but the requirement to plug in makes it far less appealing. The 30w panel on my 28' boat already is large, I can't imagine finding room for 250w worth of panels....


I don't think you would need that much solar. For a small, well insulated, refrigerator the average draw should average one or two amps. Let's say it averages 2.0 amps, or 48 Ah/day. Solar panels should generate about 3.5 Ah/day per 10W of output. 48 Ah/3.5 Ah = 13.7 or about 140W of panels. That's still a bit of real estate on a 28' boat, but just a bit more than half of your estimate. And given that one could probably get away with a bit less than that (remember, I rounded up to 2.0 amps), and/or run the motor every few days to make up the difference, it's not all that bad. In fact, I would be willing to bet that for the size of refrigerator a 28' boat is likely to have the average draw would closer to 1.0 amps (if the box is well insulated), cutting the necessary solar panels down to about 70W.


----------



## Group9 (Oct 3, 2010)

chucklesR said:


> I'm currently running a 12v only 27 year old unit that is air cooled (perhaps the most inefficient setup possible). I've got 280w of solar panels running through a MPPT controller and a Victon BMV600S monitor to tell me watts watt.
> On hot days (over 90) I need around 75ah to satisfy the fridge, it's on the list for a air/keel replacement next haul out.
> My panels keep up the draw (about 110 on average daily) quiet easily, more often than not I'm showing 95% by early afternoon.


That's very close to the set up I have and that I was running 24/7 when I was cruising. A 12v only that is 24 years old, 280w of solar panel, and I have the same experience with my batteries being fully re- charged early to mid afternoon.


----------



## Alex W (Nov 1, 2012)

Puddin'_Tain said:


> I don't think you would need that much solar. For a small, well insulated, refrigerator the average draw should average one or two amps. Let's say it averages 2.0 amps, or 48 Ah/day.


This is a much lower estimate than I've heard in the past. I've heard 3-5 amps average.

The ice box on my Pearson is well insulated, but it is also larger than what you'll find on most 28' boats. It is 30" long, 11" wide tapering down to about 5" wide, and about 20-24" deep (the only measurement that I don't have handy), for about 2.5-3 cubic feet.

I did look up what a standalone Engel 80qt cooler needed power wise since it is close to the size of my cooler, and it does look like 48ah/day is reasonable. The performance graphs are here:
https://www.engel-usa.com/images/stories/pdfs/MT80F_performance_curve.gif



Puddin'_Tain said:


> and/or run the motor every few days to make up the difference, it's not all that bad.


Running a motor while on the hook or a mooring ball is simply not an option that I would ever consider. We often move when neighboring boats turn on their engines nearby. I sail for peace and quiet, and engines are not peaceful or quiet.

I'd still need my current solar to keep up with non-fridge loads, so with your estimates it looks like 150W of solar might do the job if I'm willing to plug in on non-sunny days. That is still a lot of solar to mount onto a small sailboat (especially if you can't allow any of it to get shaded).


----------



## newhaul (Feb 19, 2010)

Here's an idea I use to figure out the best place to put panels cut a piece of cardboard the size of the panels and mock it in various locations I found the renogy 100 watt panels will fit OK on my push pit on my islander 24 they are 4 ft long and 21 inches wide will put out well over the needed for a fridge or conversion unit at about 35 ah per panel 100W Solar Panel 30A Charge Controller MC4 Solar Adaptor Cable - Vegascart LLC


----------



## deniseO30 (Nov 27, 2006)

Alex, no one is trying to make you do anything. All the suggestions are just that; Suggestions, and what works for others. That is just you making it out to be some kind of blasphemy  there really is no need to argue against every suggestion anyone makes 

Running the motor in or out the anchorage should be enough charging for over night. It's certainly not a terrible thing to run it once or twice a day.


----------



## Alex W (Nov 1, 2012)

Sorry Denise, I'm not trying to argue against every suggestion. I did learn that the power draw is lower than I had assumed, which is great information. I was curious to see how people mount solar panels on a boat this size that are adequate to never use the engine to power the refrigerator. newhaul's suggestion to mock it up with cardboard is a good one -- one that I tried when picking my current small panel. I'd have to significantly change my boat's layout to put more than about 50w of panels on the stern pulpit however.

The only line that I'm drawing is that running the engine to charge batteries is never acceptable to me. I don't even like to run the engine to leave my anchor or mooring ball. The engine is a semi-necessary evil, but the less that it is powered on the better. I find the sound of the engine to be stressful. Other forum members (including Dave_E, who started the thread) may not.


----------



## deniseO30 (Nov 27, 2006)

What everyone forgets also; once the box is down to temp, the unit cycles just to maintain that temp. So the amp hours will be much much lower then anyone guesses.


----------



## Alex W (Nov 1, 2012)

The charts really do have the best power draw information that I've seen for a 12V refrigerator:
https://www.engel-usa.com/images/stories/pdfs/MT80F_performance_curve.gif

It shows % time that the compressor is running given an ambient temperature, a set point on the thermostat, and when the compressor goes from running full time to cycling over a 4.5 hour run time.

Engel has them for every model of standalone unit that they sell (except for the conversion kit, because they don't know the size of your cooler or the state of it's insulation). I found it useful to estimate what power draw would be on my own cooler by picking their cooler closest in size to mine, and assuming my power draw would be somewhere between the 25C and 35C numbers (ambient temp inside my boat is rarely above 25C, but my cooler may not be as well insulated as theirs).


----------



## Puddin'_Tain (Feb 14, 2014)

Alex W said:


> This is a much lower estimate than I've heard in the past. I've heard 3-5 amps average.
> ...


I was basing my estimates on this quote from the Engel site:


> ...The proven efficiency of the swing motor compressor calls for minimal power consumption, drawing between 0.7 and 2.5 amps per hour on 12.6V DC...


Two or three c.f. isn't very big. The Engel site states that their unit is good for up to 100 quarts, or a bit over 4 cubic feet. If the box rely is well insulated (more insulated than the Engel stand-alone unit), I would expect the draw to be somewhere toward the lower end of that range (i.e., ~1 to 1.5 amps).


----------



## newhaul (Feb 19, 2010)

deniseO30 said:


> What everyone forgets also; once the box is down to temp, the unit cycles just to maintain that temp. So the amp hours will be much much lower then anyone guesses.


You just hit the nail on the head my customers with these evaporator coil system are telling me they are averaging a 25%duty cycle in the middle attitudes with water temps around 60 deg in the summer here so would work out that like this the 48 ah number is actually more like 12 ah per twenty four once the unit is down to temp. And that equals so once down to cold would be able to maintain battery bank with a 50 watt panel leaving a little fudge room


----------



## deniseO30 (Nov 27, 2006)

thanks New! One does learn a few things after 50+ years in hvac even it it wasn't for "marine" LOL


----------



## SVAuspicious (Oct 31, 2006)

Puddin'_Tain said:


> I was basing my estimates on this quote from the Engel site:
> 
> 
> 
> ...


Please tell me that nowhere on the Engel web site do they say "amps per hour." There is no such thing.


----------



## Seafarer (Aug 26, 2012)

Newhaul- I bought two of those exact same panels for my Cal 29, with the intent to power the Engel, lights, and fans.

Alex W- if you can freeze things when you plug in, or find someone to let you use their freezer, you can freeze water in bottles to use in place of ice. It won't make a mess when it melts, and you can drink the cold water out of the bottles. This is what I currently do with my 110v "dorm fridge". I freeze water in bottles at home, and then put them in the fridge aboard when I unplug the boat.

Dave E- check out the prices on the Renology panels, and their kits with mounts and controllers, on Amazon.









For where to mount on small boats:
1) If you have a bimini, the panels can be placed above it, or even replace the bimini.
2) The panels can be mounted on stern "davits", either parallel to the stern or at an angle on either side
3) The panels can be mounted "outboard" on either side of the cockpit.

Cal 28 with 140watt panel mounted on a "sort-of davits" setup that could work on the Islander Bahama 24:


----------



## newhaul (Feb 19, 2010)

I am looking at mounting the panels in a similar manner to this but on the port and starboard sides of the pushpit http://4.bp.blogspot.com/-LsLxCh9YJ...A-g/62uK06L9knc/s1600/Solar+Panel+Small+2.jpg


----------



## Puddin'_Tain (Feb 14, 2014)

SVAuspicious said:


> Please tell me that nowhere on the Engel web site do they say "amps per hour." There is no such thing.


It's a direct quote from: https://www.engel-usa.com/products/fridge-freezers/ice-box-conversion-models/ice-box-conversion-kit-136(third paragraph under "Product Description")

I'll agree that "amps per hour" is not a valid unit. But that's what happens when the marketing folks don't get the engineers to proof-read their copy. In any case, it's pretty obvious that they mean that the draw is 0.7 to 2.5 amps over an hour's time.


----------



## SVAuspicious (Oct 31, 2006)

Puddin'_Tain said:


> It's a direct quote from: https://www.engel-usa.com/products/fridge-freezers/ice-box-conversion-models/ice-box-conversion-kit-136(third paragraph under "Product Description")
> 
> I'll agree that "amps per hour" is not a valid unit. But that's what happens when the marketing folks don't get the engineers to proof-read their copy. In any case, it's pretty obvious that they mean that the draw is 0.7 to 2.5 amps over an hour's time.


They should be horribly embarrassed.


----------



## lancelot9898 (Dec 30, 2008)

For me, amps per hour is a pretty good description unlike knots per hour.


----------



## deniseO30 (Nov 27, 2006)

In closing.. (if there is such a thing online LOL) Y'all really do get carried off in the topic. ANY of the 12/24 volt refrigeration units ARE a great solution that was not even addressed back in the day! 

It wasn't that long ago when boats only had engine driven or belt drive compressors with 12/24 volt motors! 

If you asked me to cool a box on less then 5 amps 12 volt DC 30 years ago I may have looked at you like you were quite insane. 

So split hairs all you want, but again ANY of the new generation 12/24 volt units are nothing short of amazing. But then amazing has a price....


----------



## Panope (Jul 18, 2014)

Smallest Engel (md14) set at just above freezing.
LED lights.
300 watt inverter for gadget charging.

Single 100 amp solar panel and 200 amp battery bank provides more than enough power for the above during PNW summer.

Steve


----------



## Alex W (Nov 1, 2012)

Do you mean a 100 watt panel? A 100 amp panel would be 1200-1800 watts (depending on panel voltage) and would be huge.

I'm not interested in making the compromise that newhaul is with 100 watt panels mounted to the sides of the stern pulpit. That is a lot of windage when sailing and would get in the way when docking or rafting up the boat. That's a compromise decision that everyone will need to make for themselves.


----------



## Panope (Jul 18, 2014)

Oops. Yes, 100 WATT panel.

Panel is mounted on top of pilot house so no extra windage. Of course the house itself is a hell of a lot of windage.

Steve


----------



## Alex W (Nov 1, 2012)

Yeah, a pilothouse or davits or a permanent bimini all give good places to mount panels on larger cruising boats.

My boat has no pilot house or davits (and in my opinion a 28' boat is too small for them). It has a dodger and bimini, but I often remove one or the other or both to reduce windage.


----------



## Capt Len (Oct 9, 2011)

There few problems that can't be solve by getting a bigger boat


----------



## newhaul (Feb 19, 2010)

Alex W said:


> Do you mean a 100 watt panel? A 100 amp panel would be 1200-1800 watts (depending on panel voltage) and would be huge.
> 
> I'm not interested in making the compromise that newhaul is with 100 watt panels mounted to the sides of the stern pulpit. That is a lot of windage when sailing and would get in the way when docking or rafting up the boat. That's a compromise decision that everyone will need to make for themselves.


My boat has a phrf of 267 so a little extra windage won't make any difference and they would be horizontal in use but vertical folded down against the legs of the pulpit in line with the sheer when docking or not in use definitely not an install for a day racing vessel I will try to post pictures of my mock up when I do the prefitting.


----------



## Alex W (Nov 1, 2012)

I'm also curious to see what mounting hardware you make to have them fold down when not in use.

"Horizontal in use" doesn't mean anything on sailboats which heel 25 degrees from side to side in regular use. They are healed the most and windage matters the most when beating upwind. That is more than half of my sailing time.


----------



## newhaul (Feb 19, 2010)

Alex W said:


> I'm also curious to see what mounting hardware you make to have them fold down when not in use.


Some of these units will work just great also would make them almost instantly adjustable to any angle needed using small adjustable poles and bungee cord to keep them at the sun best angle also would allow vertical positioning when docking/in a marina. http://cdn3.volusion.com/ltuea.ukvqh/v/vspfiles/photos/2039-2.jpg?1403825223


----------



## SVAuspicious (Oct 31, 2006)

lancelot9898 said:


> For me, amps per hour is a pretty good description unlike knots per hour.


They are equally bad: amps are coulombs (charge) per sec (time); knots are nautical miles (distance) per hour (time). Amps per hour is a meaningless measure of increasing current draw, analogous to knots per hour which is a ridiculous measure of acceleration.



Alex W said:


> My boat has no pilot house or davits (and in my opinion a 28' boat is too small for them). It has a dodger and bimini, but I often remove one or the other or both to reduce windage.


I have the same challenge. For now I have two hard 36 watt panels I put on the aft deck (center cockpit boat) on the mooring or at anchor. When we're sailing they get stowed. Not very elegant solution and definitely not permanent. We don't have davits and I don't plan to get any. We get on and off the boat over the side so I may put fold-down panels across the pushpit - maybe. Fold-down panels aft of the lifeline gates are possible but like you I worry about damage during docking and rafting.


----------



## deniseO30 (Nov 27, 2006)

Ever test the output on a panel in partial the shade? You may be mildly surprised.


----------



## Night_Sailor (May 27, 2012)

Dave_E said:


> Hi Cruisers,
> 
> Those of you who are pretty dedicated to the ball or hook, do you have refrigerator units and how are they powered? I just don't know, so I'm asking - do solar cells and/or wind generators make enough juice to supply the batteries while they are running a refrigeration unit?
> 
> Dave


You definitely can run a DC refrigeration system on a combo solar/battery bank. You would need excellent insulation, probably at least 200 watts of solar panel and 200AH or more of storage--just for the fridge/freezer. More is better obviously.

I'm a huge fan of photo-voltaic solar panels. These things are as addictive as heroin. You want as many solar panels as possible. Plan for adding more later. I got mine at Home Depot with a military discount. $132 per 100 watts.

Some rules of thumb.

A solar panel will generate about 3/10 of an amp-hour per watt of panel. A 100 watt panel would generate about 30 amp-hours.

Another rule is that a panel will generate about 5 hours of power for it's rating per day. A 100 watt panel will generate about 500 watts of power. Which works out to 41 amp-hours--close to the other rule.

Finally, the warmer it is the lower the output of a panel. So this tends to equalize. In cold weather we usually have shorter days, and the long summer days are hotter and we get less out of our panels. My panels still produce more power on the longer days than the shorter cooler days.

A good PCM charge controller can also divert surplus power to heat water.


----------



## Group9 (Oct 3, 2010)

deniseO30 said:


> Ever test the output on a panel in partial the shade? You may be mildly surprised.


I'm always amazed at how dark it can get, with mine (2 Kyocera 140's) still making some power.


----------



## Night_Sailor (May 27, 2012)

deniseO30 said:


> Ever test the output on a panel in partial the shade? You may be mildly surprised.


This is a complex subject. Panels wired in parallel will produce more if one is in shade or partial shade. If you put them in series, the voltage goes up but they partial shade on one will degrade both. But if in the clear, the voltages are higher so they can charge in less light.

I have 6 mono-crystalline panels on my camper (mounted flat) and they are set up as pairs in series times 3 sets in parallel. They produce power on cloudy days, and I even get 1 AH when it is very dark and raining hard during the day. I started with four panels and added the last two panels because I wanted to be able to fully recharge a typical 65AH deficit on an overcast day (not a dark overcast, but a bright overcast). On a clear day I can recover 180AH or more out of 620 watts of panels. It is a bit of overkill for the summer, but works great when I have 5-6 days of overcast in the spring, fall or winter. These feed 400AH batteries and I rarely drop below 75%. Once I forgot and left the fridge on AC through the inverter and took it down to 28%. I'd like to replace the fridge with a DC powered unit, but the cost is fairly high and my present unit works well. It will run off the inverter during the day, ok despite the high draw.

On my boat I have two 6 volt amorphous panels in series and they seem to work pretty well also. These go into a 400AH bank also. I'd like to have more panels, but space constrains me. I don't know the wattage of the panels. I'll guess about 200 watts.

The most important thing, IMHO for those who live-aboard, is to use a smart charge controller that will maximize the power produced and feed it to the batteries at voltages and currents it can best accept. This results in 35% more output from your panels. If you are not living-aboard or cruising, a cheap tapered controller is fine. A wind generator is a fine supplement to this, and as we all know in the trades- a wind generator is all you need.


----------

