On Thu, 10 Sep 2020 11:38:54 +0100, Max Demian
wrote:

On 10/09/2020 10:46, Chris Green wrote:
In uk.d-i-y williamwright wrote:
I'm trying to find a digital voltmeter/ammeter that will read both the
charge and the discharge of a battery. The vast majority of the products
available will only read current 'in one direction'. I need something
that will indicate discharge by showing a minus sign, and will display
the value thereof.

Huh!? Just about every digital meter I have ever come across works
'both ways', you just get a number (for +ve) or a number with a - sign
in front (for -ve).

That's what I thought. (I've never actually tried it out for current
with my little Sinometer from Maplin though.)

I think Bill is conflating battery current charge / discharge with
capacity (or has two different projects).

I have a similar issue in that I have an 'in-line' power meter that
logs watts and monitors volts and amps that I want to use on a
mobility scooter but it seems to be unidirectional, in that it has a
'Source' and 'Load'.

So, whilst it will log the power drawn from the battery, I think it's
a cumulative thing till reset and wouldn't monitor any power being put
back into the battery.

I have (somewhere) something I bought a while ago that is in two
parts, with the base part being a shunt and a remote (wired or
wireless) that shows all the data. I think they were designed to be
used on the likes of narrow boats with solar panels so you could both
monitor / log the energy in / out the battery and do so remotely.

I believe that also 'learns' the battery capacity (an issue I believe
I've been seeing when charging the scooter batteries (two scooters) on
the bench rather than though the scooters themselves.

Cheers, T i m