Help needed with leisure battery wiring

[California Dreamin]

Hi there
6mm2 'standard' cable is rated at 42amps continuous.....most two battery setups (a 64 amp starter with a 80 amp leisure) are know to initial 'surge charge' (after a weekends camping) in the region of 30 - 40 amps but only for a short period ( under 15 seconds). After this point, dropping below 30 amps and eventually settling in the low 20's.

I know this is all pretty much dependant on battery size, how many and how discharged those batteries are and of course the output of your alternator but having said all of this......there is only a relatively short run of cable between the two batteries and the maximum current flowing is below the cables rating and then only for 10 - 15 seconds.
You should be fine
As a side note and for overall protecting, you might want to fit strip fuse holders (say 40amp blow) close to each of the batteries on this connecting wire.

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Martin

[kevtherev]

One should also consider the loss of voltage over the distance of the wire, which is unusually long on a T25.
I changed my cabling to a 70 amp capability (10mm) to negate any such loss

I currently enjoy 14.2V at the battery terminals.

[Fande t25]

Thanks for the advice guys.

Yes I have fit two 40 amp fuses on each battery about 7cm from the positive terminals. I'll upgrade to 10mm wiring as a precaution. The van's bare at the moment so it makes sense.

On another point, should the fridge be wired to the main or leisure battery for 12 volt operation when driving. It's a 3 way so will be on gas or hook up when camped. It's just that a colleague at work has put doubts in my mind. Previously the fridge, wired through the autosleeper control unit and as I've changed the units connections to the leisure the fridge is now on leisure battery. Is this ok ?

Eric

[California Dreamin]

You could, but normally it is a switched feed very much like the split charge relay itself, so there is only a 12volt feed when the engine is running.
Some fridges have their own relay, which is switched from a seperate 'fridge output' on a dedicated split charge relay.
On the other hand, if you are using a normal heavy duty 4 pin relay, you could extend the trigger wire from the alternators charge light circuitry to switch the fridge relay.

There are several ways you can do this.....

Martin

[Fande t25]

Martin

The fridge is an Electrolux RM212,F.

Am I right in saying the switching will be done manually using the selector switch at the front therefore not requiring a separate relay? Or is that me being dumb

Eric

[California Dreamin]

Hi
Sorry mate.....you will have to download the RM212F PDF and read it for yourself, it's not one I'm familiar with.
Of course when you select the 12 volt setting from the front of the fridge that's what it runs on however, an additional relay just ensures the fridge only receives that power when the engine is running...you will have to do some research yourself mate.

Martin

[Fande t25]

Thanks mate I'll get on with the research

Eric