Wednesday, Mar 03, 2010 at 16:20
Hello Jo and Steve,
I reckon Steve is on the money in terms of battery capacity recommendations, but the solar panel of 100W won't go very far either.
Here are my calcs, pls correct me if I'm wrong:
80W times 4.5h equals 360Wh per day, equals 26Ah @ 13.8V. Add 30% to this output if you are constantly adjusting the panels to point to the sun.
So in average you'd think that you may get some 34Ah into your battery, every day.
But because you're not going to adjust your panels constantly and due to losses of your regulator, and panel (max power point at 17.5V instead of 13.8V) this figure will be lower, say around 30 Ah.
Now if according to Steve, the fridge requires 40 to 50Ah, your 80W panel isn't going to be sufficient.
And if your battery has to power the fridge for 16 hrs while there is no or little sun, it'll have to provide 67% of this daily Ah requirement, or 45Ah before it slowly gets recharged.
Your 24Ah battery is not sufficient for this, you want at least a 60Ah deep cycle battery, which you then will deplete to around 80% every day before it gets fully recharged by f.e. 2x80W panels.
A 100Ah deep cycle VRLA AGM battery's even better because it'll give longer service life compared to the 60Ah battery (plus you've got some leeway in case it's a cloudy morning...)
Hope this clears it up?
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