How to discharge a 2V cell?

[thomasdenmark]

I have a few 2V lead acid deep cycle cells, each of 1080Ah, when discharged over 10 hours. I would like to discharge them, one by one, to test their behavior (health). How do I discharge a 2V cell?

So I imagine discharging at app. 200A, for maybe three hours. 200A at 2V is 400W.

So I guess I need a load, with a resistance of R = V/I = 2V/200A = 10microohm.

How can I find / build such a load?

 

[ScottyUK]

Check your maths - 10m[Ω], not 10[μ][Ω].

A length of heavy cable in a large drum of water?

 

[IRstuff]

Note that your connectors will also contribute to the series resistance. Note also, the battery's internal resistance will have significant impact at such high currents. Typically, they are intended to be discharged at C100, not C5 as you intend. At C5, you'll only get about 70% of the rated capacity, which means that your battery will barely make it to 3 hrs.

TTFN
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[thomasdenmark]

Oops, it should be 10miliohm, not microohm. Is it not possible to edit my post... I can't see a way

 

[IRstuff]

No, there is no edit function. In any case, you'd need something like a chunk of battery jumper cable, but still short, and a good way to attach to the battery to minimize parasitic resistances. Sort sort of current meter is necessary to ensure that you are discharging at the rate you think you are.

TTFN
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