Yep that all makes sense what you said CW, explains some problems I had getting batteries to charge and with them not lasting as long outside. Mind we were working in -3 for 8-hours so you can't complain (about the batteries at least!)
Lectrician wrote on Dec 13th, 2010, 9:53pm:My Makita 18v charger shows "Temperature Fault" when trying to chrge a battery early on a cod morning.
Yep, that's what the Bosch 36V charger said too with a red light, so had to leave the battery disconnected for an hour or so then tried again and it was fine.