The battery was successfully charged up using the mains charger overnight.
But when we tested the solar charger, we discovered that there was only
4volts coming out! Oops!
But after chasing down the wires and switches and relays, and not
discovering what the problem was. There was a mysterious drain of 150mAfrom
the battery and there wasn’t nothing wrong with the solar cell (it produced
24V in the bright sunshine we were having).
We slowly realised that an old keylock switch we don’t use any more, was in
the “heating” position, for warming up the engine when it is freezing out
there, and we suddenly remembered that we used the heater last week for that
exact reason .. it was blooming cold!!
But it seems that the switch was left in that position all this time – oh
xxxx!!
So the problem is now solved – because there wasn’t any in the first place!