# Split Charge Problems - Update



## navigator (Aug 31, 2006)

For those who can help me! Refer to previous post for further info. Here is an update.

I started the Motorhome today and the leisure batteries were still not charging, engine battery charging normally though. Left it running and noticed after 15 minutes that it HAD started charging the leisure batteries at 14.2V 5.5A. 

I stopped the engine and changed the 30A relays to Hella 40A (these are all my local garage had in stock), and checked the fuse (30A), which was fine. The terminals marked 30 on both original relays were warm to touch on the lips, others were cool to the touch.

I restarted the engine and all was still fine, charging the leisure side at 14.2V 8.8A, settling to 6.2A after a few minutes.

Checked again after a further 15 mins and it had stopped charging again. Engine battery still charging fine. I ran a test between the +ve terminal on the engine battery and the +ve terminal on one of the leisure batteries, there was no continuity. Checked the relays (swapped the originals back) and fuses, all fine. Checked the relay terminals which were all cool to the touch.

Still with the engine running, I checked two connectors which come from the relay area (wiring hidden behind the engine battery). There is a single wire connector (Red/Yellow) which I think supplies the fridge, and I assume one of the relays provides power for this. Also a pair of wires in the second connector (Brown/Blue and Brown/Green). The voltage reading at the R/Y was 0V, the Br/Gr 14.5V and the Br/Bl 12.6V. From this, I reckoned that zero voltage was coming out of either of the relays?


I guess that the Br/Bl powers the leisure batteries, and was reading their standing voltage, which I did check and I guess that the Br/Gr is the cable from the engine battery which provides alternative power in the living area?

I'm not too sure what direction to go now. In a way, I'm glad it failed while I was standing over it, as I do know that there is definitely a fault somewhere. Any ideas anyone?

I attach a few photos.


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## rayc (Jun 3, 2008)

Well you are almost there. You know that the positive terminals of the two batteries are not "connected" when the habitation battery is not being charged. The voltage is coming from the same place, i.e the alterrnator output so the problem has got to be someting to do with the relay for the battery charging or its wiring. I would guess that one of the relays is to provide power for the fridge and the other is to provide habitation battery charging. The fridge one appears to be working as you have 14+ volts at its output. 
Can you check with your meter the voltage across the operating coil of the habitation relay? Is the alternator output on one side of the operating contact of the relay? 
Ray


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## navigator (Aug 31, 2006)

Hi Ray,

Thanks, I'll check that tomorrow. Not too easy to get to the underside of the relays, but I have replaced them with new ones, and then back again without effect. Actually I got zero voltage at the red/yellow for the fridge.

Ian


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## DABurleigh (May 9, 2005)

I'd employ that irritating Haynes Manual diagnostic technique of "test by substitution", with the split-charge relay being first on my list 

Dave


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## rayc (Jun 3, 2008)

navigator said:


> Hi Ray,
> 
> Thanks, I'll check that tomorrow. Not too easy to get to the underside of the relays, but I have replaced them with new ones, and then back again without effect. Actually I got zero voltage at the red/yellow for the fridge.
> 
> Ian


I have sent you a pm. ray


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## Sargent (Feb 1, 2008)

Hi Navigator, sorry i have just seen this thread, my apologies for being slow??? 
The fact that neither relay is working does suggest that the relays are not being energised. The black thin cable is the negative and should be connected to a local negative (check continuity to the negative battery terminal) The thin blue cable is the positive which is connected to the alternator warning light cable, this connection can be followed back though the black PVC sleeving to the connection to the vehicle wiring (unfortunately the colour of the cable that it connects to does vary due engine differences and base vehicle model) 

I hope this helps but if you are struggling then please send me a PM or give our technical people a call tomorrow 01482 678981 and we will try to assist further.

Best regards

Ian Sargent


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## navigator (Aug 31, 2006)

Thanks everyone for your help and advice. Hopefully I'll be posting a 'good news' reply tomorrow.

Cheers,

Ian


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