Battery Drainage

[jack Old member in all senses Find all posts View Profile Close jack]

My leisure battery in my C15 seems to have drained the car battery.
I think one battery is just connected directly to the other. Should there be some sort of intermediate connection to prevent this drainage.?
Any ideas?

[Yamaha Gold Poster Find all posts View Profile Close Yamaha]

I'm sure Ant will be able to comment better on the C15 - but no, they shouldn't be just connected together - for that very reason.

The ZIG unit usually takes charge of vehicle / leisure batteries - if you haven't got one, then there should at least be a split-charge relay, which is designed to alternatly charge each battery - but seperate them with the engine off, so you don't drain the vehicle battery with leisure use.

Mike

[ant Diamond Poster Find all posts View Profile Close ant]

Jack.
Mike has answered the question really, but the early C15s ( not sure how old yours is) came as very basic spec and often had retro fit bits fitted by either dealers or customers, many of these fits were a bit basic and I suspect someone has thought if they put two batteries in the van they would get away with never flattening the larger capacity. Sadly if one battery goes a bit sick ( as in your case) it will be constantly topped up by the other until eventually they are both flat. You need to have a relay fitted between the batteries switched by the alternator light feed from the back of the alternator. This only switches the relay once the red battery light on the dash has gone out therefor never having the batteries connected together until the engine is actually running.
Ant

[Shubberdog VW Campavan+Extention Find all posts View Profile Close Shubberdog]

Just a thought but I have had this happen even with a relay fitted, the problem was the contacts on the relay had stuck in the closed position, giving rise to the same problem. Hope you get it sorted, there is nothing worse than a flat battery.

[MartinW Silver Poster Find all posts View Profile Close MartinW]

This only switches the relay once the red battery light on the dash has gone out therefor never having the batteries connected together until the engine is actually running.
Ant

Hi Ant

My relay is ignition controlled and not the correct way, and thought, as you discribe, this was the right way to do it, but thinking more about it I had the idea that when the battery light went out the wire would then be dead and so not energise the relay. As yet I havn't tried it, what am I thinking wrong?

[ant Diamond Poster Find all posts View Profile Close ant]

Hi Martin.
The battery light wire becomes live once the light has gone out and the altenator is charging, so your logic actually is not the case.
Thanks
Ant

[MartinW Silver Poster Find all posts View Profile Close MartinW]

Thanks very much Ant, a rewire job then, when the weather get a bit warmer

[Yamaha Gold Poster Find all posts View Profile Close Yamaha]

Hi Martin.

It does take a bit of getting your head round how the alternator light works.

Basically, one side of the lamp gets a positive from turning on the key - before you actually start the engine. The other side of the lamp connects to the aternator, as you know. Now, with the engine, and therefore the alternator, not turning, this wire is earthed through the alternator - therefore the lamp lights.

When you start the engine, the alternator starts charging - and that wire that was earthed now receives a live feed from the alternator.

As you know - a lamp needs a live AND an earth to operate - this one now has a positive feed on BOTH sides of it - so it goes out, as it's now lacking it's earth path.

Hope this helps a bit.

Mike

[MartinW Silver Poster Find all posts View Profile Close MartinW]

Earth and positive, earth then CHANGES to positive

Thanks very much for fixing my brain Mike, I now can fully understand how it all works, I just couldn't get my head round that one.

Nice and sunny here today, I might have a go at it later.

Thanks again

[MartinW Silver Poster Find all posts View Profile Close MartinW]

All fixed,rewired and working OK

Thanks to everyone