# Electrical query on hymer b544



## guitarman59 (Oct 30, 2011)

Hi there, I have just purchased a Hymer B544 2003 and I was wondering about the electrics.

a) Does the alternator charge the leisure battery as well.

b) Can you drive with the fridge on 12v.

Because I was driving the other day with the fridge on 12v and the 12v alarm came on for the leisure battery, and I thought that the fridge would run off the alternator one way or another. Can some one please enlighten me about the functioning of that side of the electrics.

Thank you


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## patp (Apr 30, 2007)

On our 1991 model the fridge runs off the 12 v and the leisure battery charges too when the engine is running.


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## Bob45 (Jan 22, 2007)

a) Does the alternator charge the leisure battery as well. 
Yes 

b) Can you drive with the fridge on 12v. 
Yes
You should switch the fridge onto 12v before you start to drive.
If we intend stopping for a while I usually turn it back onto gas and try to remember to turn it back on our return.

Bob


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## 747 (Oct 2, 2009)

Yes to both questions.

On a Fiat Ducato base for 2003, there should be a couple of fuses right next to the van battery. A 2 amp and 40 amp (from memory). Check them first.

You probably have an Elektroblok 99. Check the fuses on that as well.

Under the bonnet, probably somewhere in the middle (possibly hidden behind a plastic cover) should be some relays. One is for relaying power to the fridge from the alternator. They can fail. If the same relay also feeds charge to your leisure batteries, that would account for the 2 problems.

Hook up to the mains and check the voltage with a meter at the leisure batteries. If that is OK then the EBL 99 is OK. Do the same check without hookup but with the engine running. If the leisure battery (ies) are being charged the voltage should be 13 to 14.4 volts. Anything else means there is a fault.

Hope that helps.


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## sebastiand (Jan 1, 2010)

Hi, I have a 2002 Hymer B544 based on a Fiat 2.8JTD.

In my van there are 2* 80 amphour leisure batteries under both front seats.

While driving the alternator charges the engine battery and the 2 leisure batteries.

The fridge should be switched to the 12volts position (battery symbol) while driving and the rectifier and charger unit will ensure that the alternator will also supply enough power to run the fridge. There should be NO 12volt alarm.

When the engine is off then no 12v is delivered to the fridge ( too much power required) and can only be run on a mains connection or gas.


I suggest that you check if the fridge is running on gas and mains first of all. Then check the fuse for the 12v running of the fridge in the rectifier charger unit (mine is next to the driver).

To make sure that your leisure batteries are charging and in good condition disconnect from the mains and switch off the engine. Does everything work ie steps, water pump, lights, heating, toilet flush? Leisure batteries should last 2 or 3 days without mains connection or any other form of charging. Leisure batteries will cut out at about 11 volts.

I have just come back from Toulouse and had tremendous problems with my electrics. I had to buy 2 new batteries at a cost of over £400 but all the strange problems have disappeared. Let me know if your problems continue and I'll give what help I can.

Regards.. Sebastiand


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## Bryansdad (Aug 24, 2010)

I also have a 2002 B544 and concur with Sebastian.
Good luck.


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## guitarman59 (Oct 30, 2011)

Thanks every one for your advice.

I have checked out the leisure battery and it is only charging on hook up and not when the engine is running, all fuses appear to be ok. I guess this points to the relay, I can't tell which relay is for the battery -as you pointed out there are two, is there any way of checking the relay or do I have to take it to a garage.

Thank you once again.


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## clive1821 (Mar 27, 2010)

Hi on the control pannel (the right hand meter) it will show you a good current charge, both on hook up and when the engine is running, is this ok? if not check at the back of the elb 99 for the main battery volts and also the leasure volts, or simpley just check the volts on the control panel it should be indicating 12 volts in both possitions (main and leasure batteries), then if thats ok you'll need to check the volts on the relay which then supplies the fridge, the way the relay works is that the volts from the feild winding of the altenator supplies that relay and thus switches on that relay to provide high current supply from the main battery (and NOT the leasure batteries), to the fridge and other needs like ones satelite dish auto shut down etc... it will need a volt meter and a little time to investigate.... sorry cant be more help as I would need to be there to help further... best of luck


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## guitarman59 (Oct 30, 2011)

Thanks Clive,

I do remember that the meter only shows charging on hook up and not when the motor in running, the same on the battery terminals. It looks like there are two relays, but I do not know they do, is one for the fridge and the other for the leisure battery or some other combination.

Thanks


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