"Guv Bob" wrote in message
m...
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


There are two basic kinds of batteries like that. One is for starting cars
and gas lawn mowers. This is for a short usage of high curret. The other is
for long rime running such as your mower. While you may be able to use one
in the place of the other, it is not recommended dfor long battery life.

The amp hour rating is very simple. It is the ammount of current in amps
that you are using multiplied by the number of hours the battery can be
expected to deliver that current. If you look at the motor , it will state
how many amps it will use. Say it says 3 amps. That means that if you have
an 18 amp hour battery you should be able to run it abour 6 hours. If the
mower takes 9 amps, then you can use it for 2 hours. While the math is
exact, the more amps you use, often the shorter the real usage becomes.

Often the long usage batteries are called marine batteries. That is for
running the electric trolling motors. For your usage, ask about them.