"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.