charging and maintaining batteries

[Chris]

I did Dave. That's how I tested it. There is nothing going through the alternator that I can see. All the loss was in the other lead going to the terminal on the changeover. I tried various combinations just to see. Including unplugging the alternator and it didn't change the drain. It's still a very small drain but there shouldn't be anything going from the battery like that. I guess that indicates some sort of earthing issue? There has to be a difference in potential for current to flow and as nothing is running, the smoke must be going somewhere.

 

[Dave2000]

The amount you are talking about is very small, try unplugging the relay that triggers the 24v changeover, IIRC it is on the inner wing UK passenger side, notorious for taking in water and shorting.

regards

Dave

 

[Towpack]

The lead from the batt to the changeover relay feeds power only to the starter solenoid so the drain must be in either of these two. There's no way the drain you've measured so far will flatten good batteries in a week IMO. If it's due to shorting due to water ingress/corrosion then obviously the drain will decrease as it dries out. The drain across my heater relay was down purely to corrosion bridging the main contacts and flowing current to the heater element. The relay itself had long since stopped operating.
I guess the starter solenoid is more prone to water ingress than the changeover relay but it should be easy enough to prove now you've narrowed it down. The relay that fires the changeover relay is 12v so should be fed from the driver's side battery.

 

[Chris]

All I need is some time.

Yes the relay is definitely fired from the driver battery. Interesting that there is a little drain on both batteries. It could be that this is all through the starter.