They were Deep-Cycle Gel Cells (Marine Type) as far as I know,the chair is a Jazzy 1100..very reliable even if somewhat heavy 300 lbs!Are they Lithium Ion do you know?
The chair itself uses 2 batteries in series...with a range of 24 miles so it says in the literature..ive only taken it 12 at most,what with steady runs up inclines etc.