On 19 Jun 2018 13:05:54 GMT, David wrote:

snip

Ah! Sun has just come out and 15.8V showing for the vehicle battery. Now
that can't be right, Shirley?

Just OOI, where and with what are you reading these voltages?

I ask because if it's the display on the controller itself and it's on
fairly long / thin leads between that and the batteries, it could be a
metering thing or just a non calibrated meter etc?

I would be interested to see (if it's not what you have already done)
is put a known / calibrated meter across the batteries themselves and
see what they actually read in comparison to the controller display?

FWIW I have a fairly wide range of ages and chemistry of LA batteries
here and I wouldn't like to set a specific voltage (down to two DP
especially) on any of them! ;-)

Cheers, T i m