Club 80-90 Forums

Hi all,

I've replaced my faulty BBB with Irish Dave's 3 stage charger mod and I know the wiring for this is working properly as I've tested with a multimeter and the new relay is switching fine with 240V applied and the charger turned on. The leisure battery is reading the correct voltage but the starter battery isn't showing any increase in voltage. I've spend a while understanding how the split charge relay system works and how all this is wired in relation to the 240V charger and I'm confused over one thing. There is a red/black cable for the starter battery by the 240V charger that goes to the split charge relay (87a) and then my understanding is the cable in pin 30 goes to the battery (multimeter reading confirms this). These are then connected electrically when the split charge relay is energised when the engine is running. How can the mains hook up charge the starter battery at all if this is the case as wouldn't the split charge relay have to be energised in order for the pins 30 and 87a be connected together to link the charger to the starter battery? Really confused as this would only seem to happen when the engine is running? This must work somehow as Irish Dave confirmed that with the original BBB both batteries charge when on 240V hook up and the wiring also would imply this happens too.

Another odd thing I noticed was I was getting a short on my multimeter between the two relay pins on the new relay for the charger I have put in (as per Dave's post, one which goes to the starter battery and the other to the leisure battery) even when the relay wasn't energised. I unplugged the two spade connectors and confirmed the relay was still open therefore operating correctly so the short must be from elsewhere. Maybe a red herring and could be normal? I replaced the split charge relay lat year but that's not to say it's not faulty.

I ran out of time last night but going to investigate the following later on, any more suggestions/pointers much appreciated!
- Take new relay setup out of the equation and plug new batttery charger straight to main battery connection to see if that works
- Check wiring and take readings on all pins on the split charge relay (did this last night and everything seemed ok but want to double check)
- Check split relay operating correctly

Thanks,
Simon

A traditional split charge relay does not charge the starter battery, it opens a circuit to allow the leisure battery to be connected in series to the starter battery and through that receive a charge, but only when the engine is running.

The newer voltage sensing relay can I believe allow the starter battery to be charged from the leisure battery / battery charger.

That makes sense and understand that from my studying of split charge relay circuit diagrams but not sure how the 240V battery charger can charge the starter battery if it is wired through the split charge relay? In a Westy it must have worked originally with the standard wiring/split charge relay as there is a connection for the main battery to the 240V charger?

In that case I assume the Westy must have had two outputs from the charger, so capable of charging two batteries in series at the same time.

Do you have a wiring diagram to verify ?

Been trying to find one for the west charger. There is one in the wiki but there's a comment that it's not correct for all vehicles and doesn't follow what I have in my van. It has two outputs on the BBB and Irish Dave's mod is works similar to the split charge as in only connects the two outputs to the batteries when there is 240V present AND the charger is turned on.

You're going beyond my knowledge then, so you probably need help from someone with experience of a Westy setup, sorry.

si macc wrote:There is a red/black cable for the starter battery by the 240V charger that goes to the split charge relay (87a) and then my understanding is the cable in pin 30 goes to the battery (multimeter reading confirms this).

It sounds like you have the wrong kind of split charge relay for the OEM Westy wiring. If you're replacing the split charge relay in a Westy then you need a make/break twin terminal relay - it has two 87 terminals but no 87a.

Search on eBay for a Durite 0-727-32.



If you have a look at the excerpt below from the Westy wiring diagram (courtesy of westfaliat3.info) it shows the split charge relay (C1) for an 1985 Joker / Club Joker highlighted in the centre. The labels are a bit hard to read (that's down to the original file I'm afraid) but the relay type is clear.



A - 12V Secondary battery, driver's seat box
A1 - Battery charger, bench seat
B - Connection to the switch box, VW schematic
C1 - Secondary battery isolation relay, driver's seat box - the split charge relay

That's a good idea. Two ouputs from the charger, one direct to the leisure battery and an internal connection on the relay charges starter battery from mains. Normal split charge relay function to charge the leisure battery when the engine is running.

I might see if I can adapt this idea on my AutoSleeper one day.

That's really helpful, thanks. I can see that this is correct as per my wiring (pretty sure from the top of my head). The 87a is probably just odd labelling on the replacement relay I have, I believe it works the same from memory but will double check tonight. In the diagram for the connection between the 87 on the split charge relay and the battery charger it looks like there is a fuse (guessing the break in the line with what looks like a number above it 25A maybe)? I suspected there might be a fuse blown somewhere so that I will find later on if it is indeed a fuse there.

It could be that either myself or the previous owner have incorrectly wired the split charge relay therefore preventing the main battery from charging correctly on 240V hook up. I think the red/white cable goes to the leisure battery from the split charge (on my van connected to pin 87) where as on the diagram below looks like it's connected to pin 30. I then have red/black which goes to the battery charger on pin 87a (or the other 87 pin). FInally I have a thick red cable which I think goes to the starter battery via the switch box? I suspect this could be my problem but will have to investigate further.

Thanks for the help so far!

Ok, so based on the links everyone has posted (thanks) and a bit more digging I’ve identified the split charge relay I have and how it works. At least I now know how everything works that’s in my van so when testing later I know where I am.

Clift, you were spot on. I had replaced the split charge relay with the wrong one. I had been thrown by differing reports of wiring. The original relay I had is definitely faulty as the pole isn’t switched when the ignition on but I proved both batteries charge when the engine is not running. I will purchase the one you mentioned above and that will sort it. Thanks for the pointers.

clift_d wrote:

si macc wrote:There is a red/black cable for the starter battery by the 240V charger that goes to the split charge relay (87a) and then my understanding is the cable in pin 30 goes to the battery (multimeter reading confirms this).

It sounds like you have the wrong kind of split charge relay for the OEM Westy wiring. If you're replacing the split charge relay in a Westy then you need a make/break twin terminal relay - it has two 87 terminals but no 87a.

Search on eBay for a Durite 0-727-32.



If you have a look at the excerpt below from the Westy wiring diagram (courtesy of westfaliat3.info) it shows the split charge relay (C1) for an 1985 Joker / Club Joker highlighted in the centre. The labels are a bit hard to read (that's down to the original file I'm afraid) but the relay type is clear.



A - 12V Secondary battery, driver's seat box
A1 - Battery charger, bench seat
B - Connection to the switch box, VW schematic
C1 - Secondary battery isolation relay, driver's seat box - the split charge relay

Could this maybe be added to the 8090 wiki?