Gem gel batteries losing power quickly

I just got a 2002 gem e825 and finished rebuilding it. My mechanic tested the batteries and said they hold a good charge, but when they get down to about 70% reading on the meter, the cart slows down significantly. It will go about 10 miles from full charge to 70% and will run 30-40mph during this time. Anything under 70% is will get 20-22mph at best and has a hard time to get going from a stopped position. Any thoughts on this? The cart is currently running on gel batteries.

Thanks!

Sounds about right. Are you expecting more range?
See what others get for range. I’d be happy with that in my Gems.