I think pretty much all the AH meters nowadays reset themselves. I
have have an e-meter, Link, and Ample Power and they all reset
themselves when the charge rate falls below a certain point. That
setpoint can usually be adjusted if desired. Where the problem comes
in is when you cruise for long periods of time without connecting to
shorepower. When at anchor we don't normally charge the batteries up
enough to cause the reset so an error of up to several AH will accumulate.

Doug
s/v Callista

"Ric" wrote in message
...

"Joakim Majander" wrote in message
m...

How can you accurately use an Ah-meter? How do you know what is the
starting point (after few hours loading capacity could be anywhere
between 70 and 100%)?

The smarter Ah meters detect when the battery is fully recharged, then
reset
themselves to zero automatically. They also use the ratio of
Ah-out/Ah-recharge to give an indication of the state of your batteries
and
charging system. If the percentage is low, you are having to put back in a
lot more Ah than you took out, meaning your batteries are old
(alternatively
it could mean you have a bad charging system which is boiling your
batteries).

The Rolls-Royce of Ah counters is the Victron model which is very
sophisticated and expensive. I have one by Thira which automatically
resets
itself and gives a charging coefficient which is all I need.