Put a mains electric blanket under them (ideally separated by a thin sheet of ply or aluminium) and put it on a timer. Cheap & easy. If you can work some insulation into the mix, so much the better - the foil bubble wrap stuff is very space efficient. MW
On 20 Feb 2015, at 20:25, Danpatgal via EV <ev@lists.evdl.org> wrote: > Reviving this thread as we're having another very cold stretch here in the > Eastern US. > > My batteries (SE130 CALBs) are still going, but boy do they sag when it's > cold like this. It's annoying. > > I've been charging when my BMS sensors (atop each cell) are over 0C, which > they have generally remained over the past few weeks despite the cold > (thankfully my garage generally stays above 0C). > > But, my follow-up question on all this is if the BMS measurement is good > enough. For example, I guess there is resistive heat that gets generated > upon charge/discharge/shunting that probably make the sensors read higher > than the cells themselves. How much, I don't know. > > Does anybody have any thoughts, experience on this? We've gotten down to > -20C with a HIGH today of only -10C ... yet I'm charging. I didn't really > want to do it, but I was dragging so much on the road with low SOC%, I had > to, or risk having to really limp home. > _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
