Solar power under load

[jxoco]

Mike have you checked the water level in your batteries?
If low add distilled water.
While the battery box is open give a little tug on each wire right at the crimped on connector that attaches it to the battery.
I had a crimp on connector that had corrosion up inside the plastic sleeve and a bit of a pull popped it right off, had to re-strip the wire and re-crimp a new connector.
My Go Power lets the charge go up to 14.4 volts for two hours each morning. then trickle 13.7
My old Morningstar lets the charge go up to 14.4 for three hours each morning. then trickle 13.7
Of course that expects that the panel is actually producing that much.
The 'Solar Bob' guy that others are telling you about makes reference to this when he says that a simple dumb Morningstar SunSaver can do a better job of charging then a fancy Go Power controller.
If you put a thousand watts of solar panels on your roof you couldn't charge the batteries in 15 minutes because the batteries can't accept that rate of charge.
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( VooDoo and black magic starts here )
manufacturers recommend that the batteries can be charged at C/5 from 10% to 85% of their charge
C/10 from 85% to 95% of their charge
and
C/20 from 95% to 100% of their charge

C is capacity, and 6 volt batteries are 230 amp capacity

I don't know if solar controllers use a less sophisticated method but that would mean to me that the controller would only allow 11 amps to flow into the battery when it was between 95% to 110% even when your panels are capable of 17Amps.

And I'll stop the mumbo jumbo here, because there are just too many variables.

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Like someone else mentioned (StarvingHyena) , your normal consumption may just put you in need of more battery(s) capacity.
I think you have enough panel capacity.

[Mike Lewis]

I started the thread to report real-world experience using the solar panels with a high draw on the system; I wasn't really complaining about a problem other than to express mild disappointment that I couldn't keep the Coleman cooler going on my 12V system alone. I was hoping I could, but nope.

Thanks for all the feedback-- it reinforces my belief that there is nothing really wrong with my 12V system; it's just not robust enough to do what I want. At some point in the future I will need to replace my batteries. When I do, I will try to increase my battery capacity. In the immediate future I need to get my $#*(*@! refrigerator fixed.

The bright spot is that the Coleman cooler works better than expected; it will stay in the mid-30s with ambient temps in the mid-80s, a bit better than advertised. It just sucks down a lot of power to do so.

[Defenestrator]

Might be worth looking into a dorm or marine compressor-based fridge instead of the Coleman if you have room. Thermoelectric coolers are drastically less power-efficient than compressor-based ones.