# Split Charge Problems



## navigator (Aug 31, 2006)

Hi All.

I have a 2000 Bessacarr E745 motorhome which originally came with one 85Ah leisure battery under the drivers seat when I bought it in 2005.

I added two further 85Ah batteries under a bench seat in 2008, then last year a fourth 85Ah battery under the drivers seat.

I believe I have the capacity correct now for our use, and the installation was done by me following lots of research into positioning, ventilation, cable sizes and fusing.

Here is the problem: A single fuse (from the split charge relay) located under the drivers seat next to the original leisure battery started to blow occasionally last year just after I started the engine. It was rated at 15A I think, and I worked out that it was blowing when the leisure battery capacity dropped, so the charge required from the engine alternator increased beyond its capacity.

I changed the fuse for a 20A which blew a little later, then a 25A to try and cure the problem - which it did. I know, now you're worried!

I started the engine yesterday and the leisure batteries were charging fine. I have a voltage/current/capacity meter installed in the leisure system, and it showed a charging current in excess of 10 amps, and the battery capacity started to increase from 65% to 80%. Then the charge stopped, and I went straight to the fuse. It was fine, but I changed it anyway, but still no charge to the leisure side. I checked the engine battery and it was charging normally at 13.7 volts.

I don't know what a split charge relay looks like, but there are two identical relays fitted side by side in the engine compartment, next to the 12 volt battery. I swapped these over, but no change, still no charge to the leisure batteries.

I am guessing that my additional batteries have taken the split charge system past its capacity, and the blowing fuses were an indicator of the problem which I duly ignored!

Can any of you clever people enlighten me please?

Regards,


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## Fatalhud (Mar 3, 2006)

On my 2004 the split charge relays are under a black cover under the bonnet
next to them are fuses protecting them

Alan H


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## sallytrafic (Jan 17, 2006)

The relay is probably rated at 30A and the alternator at least 90A so its not likely to be there that the trouble lies. I would have expected the fuse to blow in the installation you describe (but its never good practice just to change a fuse without finding out why).

Are the wires to your battery fused at both ends - they should be.

or perhaps there is a fuse upstream of your relay.

Is the relay changing over


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## navigator (Aug 31, 2006)

Thanks for the quick reply. I don't have a picture under the bonnet just now, but can post one tomorrow (v impressed that you have one to hand).

I can tell you, however, that the relays are black in colour, with four spade terminals underneath, just like this picture.


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## navigator (Aug 31, 2006)

Hi Frank,

I rather hoped you would post a reply. Your information on this site is legendary in my household, quote " if in doubt, search for a sallytrafic reply to a post"!

I will check more thoroughly tomorrow. I have fuses at each end of each battery installation, but never thought of checking them! I've checked all other fuses under the bonnet.


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## sallytrafic (Jan 17, 2006)

Thanks for that

if you need any help identifying the relay contacts here is good link for all car relay circuits

>http://www.bcae1.com/relays.htm<

and specifically for split charge I recommend >Clive Motts split charging<


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## navigator (Aug 31, 2006)

Thanks so much. Bedtime reading for me. Will report further tomorrow or Thursday.

Cheers.


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## Spooky_b329 (Jan 24, 2009)

Firstly, I would go back to the pitiful 15 amp fuse, it will have been chosen to protect either the split charge relay or the wiring. If the wiring is only suited to 15 amps, the wire could act as a fuse if there is a short circuit, and catch fire...

Its not hard to setup a heavy duty split charge system, mine is an 80amp system, charge cables are the same size as the main alternator/battery/starter cables  The lower voltage drop from a heavy duty system will allow your batterys to charge faster for longer as well, though still not as good as a battery to battery charger.

Finally, even if your alternator is a 90 amp, when the split charge kicks in, you could get significantly more current flow as the flat leisure battery will draw huge current from the starter battery as they equalize.


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## DABurleigh (May 9, 2005)

With the engine running, simply check for continuity between vehicle and leisure battery positive terminals using a multimeter. That will soon isolate exactly where your problem is, whether fuse or relay.

Dave


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## DJP (May 9, 2005)

You may find more than one fuse in the circuit
See Dual charge relay wiring diagram


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## MYindServe (Oct 21, 2012)

I have a Fiat bessicarr E790 and it is driving me insane. It has 4 batteries that consist of a vehicle battery and 3 leisure batteries. There is a split charger in place that has a unit inside a wardrobe and im guessing a small sealed block that has a gree/red led on it.

My problem is that when the engine is running and i switch the headlamps on, it cuts out and the temp, rev dials start flicking up n down as does the side lights and other lights. All the batteries are fully charged and all the fuses work. However the 2 yellow 920a fuses under the splt charger panel have blown several times. The other day i was on the motorway at night and flashed in a lorry. Instantly i lost engine, lights the lot and even the AA were baffled. Does anyone have any ideas please????


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