Batterys too cold to charge???

pnichols wrote:

Chris Bryant wrote:
So it is fine to charge a battery that is frozen?

Chris ....

Your comment gives rise to a thought sequence with a possible interesting conclusion:

1. Does ice and/or frozen electrolyte conduct electricity?
You can find out by putting a body part on ice and connecting a circuit across it. Prepare to be shocked.

2. If so, does a charging voltage applied to a frozen battery still result in some current flow between positive and negative areas inside the battery?
yes

3. If so, will this current flow - even though small at first - slowly begin to unthraw the frozen liquid due to warming from the current flow?
No, usually there is intense heat in one or more cells, aggravated by connector breakage from the freezing.

4. If so, will this current flow gradually increase and consequently the warming increase?See answer to #3

5. Hence, is it possible to eventually unthraw a frozen battery by trying long enough to charge it (assuming it didn't freeze so bad as to burst it's case from expansion of frozen liquid)?

[COLOR=]You may be able to "unthaw" the electrolyte by applying small amount of current at intervals but the end result will probably be an inoperable battery

When a battery totally freezes, there is expansion within the total case area and also withing the cell spaces. This tends to push plates and separators around and also causes connections to break. This is why it is unwise to try charging a frozen battery, it usually results in electrolyte expulsion and/or case failure.