HANS HENRICO ASKED US: I’m from sunny SA and battle to get my solar setup arranged. Re batteries: what type should be used at what rating – I have 6 x Arco 12v panels (at 22 Watt per panel) and wish to drive an 3000 watt inverter for 240 AC output for a common household. We have appr. 8 hours strong sunshine here in Messina, Northern Transvaal, RSA.

There are so many types of batteries available. What deep cycle type should I get?

Some say wet cell, others Gel-cell and others MG types. I think Gell-cells are supposed to perform better at high temperatures (our summer could go to 35-40 Celsius).

There’s so much conflicting advice regarding batteries. Please help!

Hope to hear from you soon.

Hans Henrico

STEVE SPENCE REPLIES:

Let’s be conservative, and say you have 6 full sun hours.

6hrs x (6 x 22) = 792 wh’s daily.
792wh / 12v = 66ah

Considering what you have for panels, two 225ah 6vdc deep cycle lead acid (trojan T105) or one 255ah 12vdc AGM (lifeline/concorde gpl-8d) would do the trick. This would run your inverter at full load for 20 minutes or so. Now, If you let those batteries charge for a few days without using any power (it would take 4 days for full charge, 2 days to bring up from 50% discharge), you could run that inverter at full load for 30 minutes. It really looks like you need more panels, or don’t even think of pulling 3000 watts. Pull 1500 watts of load and you double the above run times.

Let’s look at your individual loads first. I look forward to hearing from you.

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2 Responses to “What type of batteries for cheap electricity?”

  1. Derek

    Has anyone tried the lithium phosphate batteries from Valence? I don’t know how much they cost, but it seems like combination of deep cycle, long life and no lead is a win.

    Reply
  2. Steve Spence

    Don’t even consider the Gel Cells. Go Lifelines if you can afford it ($300 or so USD), or the Trojans if you can’t ($75 or so USD).

    Reply

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