Flat battery again ...split charge?

[kathyshack]

Wonder if any of you can help? Got a flat battery again! Put this latest one on 2 weeks ago, drove 50 miles ish, no lights or wipers needed. Parked up and now flat.... Don't think it's alternator as it seems to be charging looking at voltmeter. How would I know if my split charge was knackered? Lb not charging great but has been stood for ages. Both lb and main battery had same Reading yesterday when I checked. Could it be lb zapping main battery do you think?
From +ve terminal on battery I have big fat cable, a red cable and a green cable. Green cable has a fuse on it, and I think this is poss lb cable to split charge. Presumably if I remove this fuse the split charge will stop getting power? Still will be left waiting to see if this is prob though and going on first proper hol in van with both kids since last year, so don't really want to get stuck. Is there any tests I can do to see if it is this, and if not this, then any ideas hhow to find what could be draining it?
Thanks in advance
kathy x

[CovKid]

How long did you leave it before it went flat?

[kathyshack]

I left it 11 days and when I came to drive it yesterday, nothing....

[last redstar]

hi try disconecteing the main alternater lead the red one from the battery , there are dioads in the alternater which will if faulty let the batter go flat . buy disconecting the red lead it will tell you if its the alternater . but put it back on if you drive the bus . if you leave the wire of the the next time you leave the bus for more than two days and check what voltage is in the flattery

[CovKid]

For 11 days it could well be your stereo (if you have one). The stereo issue is associated with the memory function being wired permanently and after a time it flattens the battery. If you have a second battery, wire the stereo to that or disconnect the memory wire (which helps store stations and/or last track played). I was plagued with that for MONTHS and moving stereo to leisure battery cured it.

Also, some stereos seem to consume power even when 'allegedly' switched off. Some have also fitted switches to cut all power to the stereo but moving it to leisure is the best solution if you want to retain the memory.

[kathyshack]

Thanks guys. Stereo is wired to leisure battery.
Is there a way to check if split charge relay is knackered?

[VWCamperfan]

Disconnect live terminal from leisure battery. Check to see if you still have power at the connection (not the battery terminal). If you do it means the split charge relay has stuck shut and is keeping the two batteries permanently connected. If not then start the engine making sure the battery terminal doesn't touck any metalwork and check for voltage again. If you have charging voltage there then the relay should be working ok. Check again with engine off and you should have no voltage at terminal.

[kathyshack]

Brill thanks x

[kathyshack]

Disconnect live terminal from leisure battery. Check to see if you still have power at the connection (not the battery terminal). If you do it means the split charge relay has stuck shut and is keeping the two batteries permanently connected. If not then start the engine making sure the battery terminal doesn't touck any metalwork and check for voltage again. If you have charging voltage there then the relay should be working ok. Check again with engine off and you should have no voltage at terminal.

Thanks again for the advice. We tested this again today, but I didn't have your exact words with me, so this is what we did. Disconnected the main battery and checked the live terminal, and it was showing 11.3 on voltmeter. When I disconnected leisure battery (removed earth) this voltage was nothing. I took the fuse out of the green wire to the split charge to disconnect it and then put the earth strap back on leisure battery, but it was still showing 11.3. We concluded that the red wire from main battery mist be somehow connected to splitcharge relay, as when battery disconnected, no power. I then traced a red wire from my leisure battery to the relay. Once I removed this it seemed to work in disconnecting the two batteries. Once reconnecting the earth to l.batt this meant I could still use my lights with what little charge was in the battery.
Were hoping it was the splitcharge relay sticking like you said. I forgot to mention also, that when van wouldn't start, the voltage on the main battery and leisure battery were exactly the same. Would this happen if one was sucking power from the other? Ie share the power between the 2?
Also, even though I had disconnected my main battery my click continued to work, which makes me wonder if they were connected together and l.batt powering it. It stopped working when both batteries were disconnected, and is back working from main battery now l.batt removed from loop.
Now got to try and find a same type of relay to replace mine easily like for like so to speak......

Many thanks again everyone for you help and advice. Here's hoping for a hassle free first proper family camping holiday with zeke in tow. Shell island here we come! X

[kathyshack]

That should read clock continued to work, not click!

[VWCamperfan]

Yeah, sounds like relay if you disconnected main (starter battery) and the clock still ran from the leisure battery. That shouldn't happen!
Grab yourself a new relay, wang it in and try that test again for the clock. As you have guessed, it shouldnt run with main battery disconnected.
The two batteries showing the same voltage is very unlikely if seperated. Another indication they were connected through the relay when it should have been off.

[Cruz]

Take the relay out and take it with you when purchasing a new one from a motor factors.