> Large batteries are constructed different from the small tool and > computer > batteries. My guess is that the lack of a good charger/battery > management > in the computers and tools killed the batteries. NiMH don't like heat. > Will be interesting to see how the Li-ion batteries hold up.
I'm pretty much convinced that this is the case. I have a couple of sets of NiMH batteries for a digital camera; they haven't held up that well, and I suspect it's because the charger (supposedly designed for NiMH) doesn't do anything to monitor the temperature during charging. I have a set of Saft NiCDs in my Solectria Force, and they are doing very well so far. They are liquid cooled and it's very interesting to see how efficiently my cooling system works. If I'm driving on a warm day, the cooling system will kick on after I've driven some distance (typically about 20 miles). I believe the cooling system kicks on when the battery temperature hits 30C (86F). One day, I pulled into the garage after a drive where the batteries warmed sufficiently to turn on the cooling system, and before I plugged in the car (I was unloading some stuff I bought) the cooling system turned itself off. That surprised me. The cooling system also runs any time the charger is operating to keep the temperature down. I know NiCDs are like NiMH in that neither like to be too hot. With properly designed liquid cooling systems, I think both of these battery systems will be very practical. And how tough was the cooling system to set up? Not bad. I grabbed a new radiator from radiator.com, a matching fan/shroud from a salvage yard, and a 12V pump, hooked it up with various sizes of hose and a lot of spring hose clamps, and it works just fine. -Tom Thomas Hudson http://portdistrict5.org -- 5th District Aldermanic Website http://portev.org -- Electric Vehicles, Solar Power & More http://portgardenclub.org -- Port Washington Garden Club http://portlightstation.org -- Light Station Restoration
