Solor again

Would that be an Engel fridge with their famous 'swing' compressor? I found them a poor performer when running on battery power. Generator or car power, yes, battery power, no good.
Get a fridge with a ROTARY compressor if you want reliable battery operation.

As long as your battery gets charged up reasonably soon it should cope with draining down to 12.3V

Klaus

i thought you could safely go down to 11.2volts if you only drop to 12.3 over night thats excellent.

Brian,

There's something going wrong somewhere. Even allowing for 80% efficiency from your panels in that heat (assuming they're polycrystalline panels) you still should have been getting about 16 amps in full sun. Your 40L Engels should only draw a max of 2.7 amps each when running so you should have been well ahead.

Were your fridges in the sun? A 40L Engel on full blast should easily get down to neg 12 to 15. My 39L, older and less efficient, would easily hold neg 15 in any conditions (out of the sun) and neg 21 in cooler conditions.

12.3 volts is fine, indicates about 70% charge. This is OK first thing in the morning after running all night with no solar input.

Cheers,

Jim.

Hi Jim. Maybe I was expecting more as I don't seem to be any bettar than
last year when I was using just 2x80 panels.for the same result. The 2 engels are only a couple of yrs old. they were in the back of the wagon I had the doors up
as I said the daily thermometer readings were 38-40 (1.00pm)maybe just to hot.The multimeter readings
at 7.00am ranged from12.24-12.44.Going again mid june see what happens then.
Been into a metel frabrication shop. getting a new frame made to get bettar angles
for the sun. cheers brian

Brian
A few points to consider;
- "Engels were cycling continuous" - does this mean running continuously or cycling on/off? In 40deg heat, the Engel will probably be running nearly continuously as a freezer. At fridge temps, it should be doing a lot better.
- In practice, 155 watts of panels translates to about 10-11A of current into the battery, as the wattage is quoted at somewhat higher volts than 12v - more like 14-15v.
Was there any cloud? Panel output drops by several magnitudes with cloud cover; ie, 10A full sun can be 2-3A with cloud cover.
- Temperature - Output is generally quoted at about 20degC. Many solar panels drop their output by up to 20% in high temps.
- The low quoted current on the latest Engels seems to be offset by longer running time; On a trip a not long ago, a friend's Engel was observed running much longer than my Autofridge for the same internal and external temps.
- From previous postings and from some suppliers, people seem to quote using about 150w of panels for a single 40L fridge for a long-term stay; ie, no other charging; I get by with about 120w. This is more than enough on hot sunny days, but can be borderline on warm cloudy days.
Gerry

(Quote)2x80and1x75watt = 225 watt, the engels were cycling continuous. In the morning the battery was down to about 12.30v (end quote)

IMO the batteries are realistically getting 11 a/h x 9 hours daily, up north, from the 3 solar panels and the fridge should be using ~10 a/h…… if cycling continuous, according to the advertising blurb from Engel. They quote a low 2.8a/h for perfect conditions and cycling on/off, at +4 degrees, in the real world and in extreme outback temps as mentioned 36-40 deg, the Engel would be running flat out and using power to the max.
11 amps X 9 hours = 99 amps into the battery.
10 amps X 12 hours = 120 amps MINIUM out of the battery…. (realistically 180amp)

Will it do damage to the battery.. depends on the battery, is it a quality DC battery?
designed to be deep cycled or a cranking battery designed to start a vehicle?

Well my maths might not be the best but if your 2x80+1x75 cant run 2x 40lt engles you have a major f/up going on,,, I scored a 64watt unisolar dirt cheap so decided to go whole hogg on solar, bought a 120watt kyocera for a total of 184watts ,, run thru a plasmatronics pl20 regulator , the unisolar puts out at best 3.8amp , add the kyocera at 7.1amps = 10.9 amps per hr in "perfect" conditions,,
ANZAC day w/end camping started on solar saturday am with AGM batts reading 13.42 unrested[driving to camp] ,,,ran 80lt waeco + 15lt engle [on paper draw 7amp per hr] ,, leaving campsite 2pm monday batts reading 12.42 ,, w/end had overcast,rain,and full sun ,,,, I would be checking all your wiring and connections.