BA flat battery question
My friend left his BA XR6's lights on up at the snow and the engine wouldn't even crank, no central unlocking, no lights, nothing. We left it and planned to get some help when we were to leave, but when we came back later we had lights. We let it be for a little while longer before starting and idling the engine for a while to recharge the battery. Everything turned out fine.
My question is, what recharged the battery? And I wouldn't have expected that up at the snow.
Sarge, get a load of my tie.