# Sequel, split charging , leisure battery and fridge feed.



## 117720 (Oct 25, 2008)

Hi again. I have installed the Waeco battery charger (plus trickle charge to starter battery) and wired it up as per instructions; hard negative wire to both leisure and starter battery, single positive trickle feed to starter battery positive, etc. I have installed the Halfords split charge relay and inserted the appropriate fuses as per kind advice from this forum.

I have disconnected the dometic fridge feed from the leisure battery fuse block (where original owner had it running directly off of the leisure battery!) I have taken one 12 volt feed from the split charge relay to the fridge feed, via a fuse, and similarly the other 12 volt feed from the relay to the leisure battery, and I have a small but annoying problem!

With the split charge relay wires connected as above, I started the engine, and am getting the charge to the leisure battery ok. The fridge works fine as well BUT the fridge STILL works when the engine is stopped, and is drawing current from the leisure battery,(the voltage drop can clearly be seen on the panel meter when switched on/off) which is not what I want, obviously. I must be thick, or am missing something obvious here. Even when I disconnect the feed from the relay to the fridge, with the engine running, the fridge is still able to be powered up, so is obviously deriving its power somehow, either via the battery charger in circuit (but with no mains connected) OR in some way via the split charge relay, although the leisure battery only charges when the engine is running, which is what I intended for the fridge.

Having looked at some diagrams of split charge systems, am I missing an isolation relay somewhere? Can anyone help? I have spent a long time installing this system with the correct grade wires, even putting them into a protective sheath under the wagon, correctly fusing, etc, but cannot charge the fridge when mobile, separately, because there is already a 12 volt feed on its terminals before starting the engine. Where there was no proper vehicle earth for the leisure battery and mains input, I have now put one, and even tied the gas pipes to earth. At present I CAN have the fridge on, when mobile, BUT, it is taking power from the leisure battery, which although in itself is being recharged from the engine, is not able to charge efficiently as it has the fridge load on it!! I must have a blindspot, any advice welcome!! :?


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## DABurleigh (May 9, 2005)

Can you not trace back the wires from the fridge? Sounds like you've got one you don't want! :-(

Dave


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## 117720 (Oct 25, 2008)

*Sequel, split charging , leisure battery and fridge feed*

Hi again Dave, well I have tried as much as possible to check what is connected the fridge end, but apart from pulling the fridge out, I can only see so much with the ventilation panels removed. It does sound as if its bridged somewhere back to the LB. Not sure if it was you, but it was suggested that since there is already a tow ball fitted, there may be a charging relay already installed, but I never found one! This is the problem when dealing with other peoples wiring. With the wires I have installed, they are all clearly labelled with destination and source. Of course I could go ahead and just pretend there is no current present on the fridge feed, and reconnect the relay feed which definately gives the 12 volts, but having two separate incoming voltage sources to the fridge leaves me concerned that something has to give somewhere! Cheers


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## sallytrafic (Jan 17, 2006)

I have been trying to compose a useful reply but keep getting stuck because I'm not sure how your mains charger is connected does it have a leisure battery connection as well as a vehicle battery one?


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## DABurleigh (May 9, 2005)

Was the fridge operating off mains before, on only via 12V when plugged into mains? Can't recall history.

Dave


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## 117720 (Oct 25, 2008)

*Sequel, split charging , leisure battery and fridge feed*

:? Hi Dave and Frank. Frank, the Waeco charger I have installed gives 14 volts plus to the LB and about 1 amp trickle to the vehicle(starter) battery, if that helps you. 
.
Dave, when I got the vehicle, prev owner used to run the fridge directly off 12 volt LB for some reason. He seemed to think that this was fine, but then perhaps it had something to do with his coming from Chester, I really don't know! 
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If it helps, I isolated the fridge from the LB fuse block by taking the link fuse out which left the fridge positive connection in place on the empty fuse terminal. I ran the fused split relay cable feed to this terminal. The earth of the fridge feed was taken to the main earth point where all the other 12 volts accessory wires meet. It was never wired via the zig control panel, so operates independently. I thought when checking the wiring for one awful moment that the fridge was running off of the starter battery! Basically, even when the engine is not running, the fridge is finding a 12 volt feed but yet is not directly connected in my wiring to the LB. There must be an extra wire in there somewhere, but I was wondering whether in some way the Waeco battery charger was providing a path, and needs to be isolated when the engine is started. Brain starting to hurt now, my 57 years is beginnig to tell on me!! Thanks guys for your time - Paul


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## CullodenMuir (Dec 11, 2005)

You need TWO split charge relays.

One to supply the battery charge and the other to supply the fridge.

Then when the engine is not running both relays will not be operated and there will be no interconnection between the fridge and the leisure battery.

When engine is running both relays will operate and supply power to leisure battery and to the fridge.


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## short-stick (Jul 23, 2007)

hi Paul,
Dou you have a test meter you can use, or a 12v bulb and some wire...
I'd check that the supply from the relay to the fridge is working properly, i.e. only on with the engine running...


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## short-stick (Jul 23, 2007)

Ah yes I concur with Jlough... I just "assumed" you had two separate circuits!
Never assume, you make an ass out of you and me!


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## pieterv (Feb 3, 2009)

Yes, Jlough is right. If your relay connects both LB and fridge to charge from alternator, that basically means that fridge and LB are connected and the relay (when closed) makes the connection to the alternator (or starter battery, which has the same effect). How otherwise could two connections (LB and fridge) be switched by one relay.


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## DABurleigh (May 9, 2005)

I had thought a double pole relay, but, yes, the norm is two relays. That's the answer, no question.

Dave


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## 117720 (Oct 25, 2008)

Hi Guys, sorry I have not been able to access internet for a while so unable to say thanks for your suggestions. 
.
Firstly, I know you can obtain double relay units, but the Halfords one I bought was described as being perfect for my needs!! Obviously it is not. The interaction between the fridge output and LB output woulod, indeed , appear to be as a result of using one relay to try and do two relay's work. I appreciate all advice given, and will seek out a double relay unit and replace my current one. Thanks to all again, for your time, advice and thoughts, God Bless. Paul


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## CliveMott (Mar 10, 2008)

Yes,
You need TWO relays.
Like this
http://www.motts.org/SPLIT CHARGING SYSTEM.htm
C.


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## 117720 (Oct 25, 2008)

Hi, Dave, Pieter and Clive. I think the proverbial nail has been well and truly struck on the head, and talking of heads, mine needs a bashing, should have seen my error and known better (thats what comes of believing someone who sells you the wrong relay!!)
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Clive, mni tnx fer diagram, fantastic to hear from you again, its been years. You may not have realised but we have chatted through the four marks repeater (SN?) years ago, I used to run GX0LAW, and you aimed some good advice at me in 2005 when I retired, as I needed some help installing my FT857D and Yaesu ATAS120 - what fun I had with that one with a non metallic motorhome body, hehe. Eventually mounted the ATAS on the bonnet and got brilliant results on our European tour. Back now on UK soil.

God Bless you all, really appreciate you being there, and your time, great site, this!!

Paul - G0FUS


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