Is there an available Lithium battery that fits into the space under the
driver's seat in our van?
   One might be far superior to the older generation batteries...Do they
even make deep cycle lithium battery s?
   I swapped in a lithium battery to save weight in my track car, did the
same job at about 3-4lbs that the standard battery (20lbs?) did, and tiny.
One could probably go 12v refrigeration, more than a day