Guv Bob wrote:
Got a dumb question.... I have an electric mower that uses two 12V lead acid batteries wired in series to give 24V. The batteries are marked 18Ah. Cost is around $100 for one 12v, or $140 for 2 in series, including shipping.

For the same money or less, I can get two std 12v car batteries and end up with more amp hours to boot, which would be good for a mower. Heavier to push around, but that's not a problem.

I don't know nuthin about how amp-hours work - reckon this would be a good idea? Anyone had experience with this kind of thing before?

Bob

Car start batteries are not meant for repeated deep discharge.
It will damage them.
Google for deep discharge batteries.