I'd never heard of them at all, Joe.

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Re cold and batteries, following Foolestroupe's comments, I tried to do a little searching on lead acid batteries and temperature. While I guess there must be a low limit (when the electrolyte freezes???), it seems that in contrast to the battery capacity decreasing as temperature gets lower, battery life actually increases!

I guess the shorter life if harsh conditions is simply due to the batteries getting flattened too much (and lead acids, particularly "engine" starter types hate that - deep cycle ones take a lot more discharging) because of reduced capacity?