Another leisure battery wiring thread

[robp]

Hi

Sorry to jump in with a leisure battery question as my first post to the forum. I've done my best to figure this out (on this forum and jk) for myself but want some reassurance I'm doing the right thing.

We became the proud owners of Gertie the 1989 T25 earlier this year. I've just started looking into wiring in a new leisure battery.

After figuring out what goes where, I'm just waiting on delivery of the battery. I should add that other than fitting the dab stereo in the van, this is a brave new world for me.

The attached diagram shows what i can see in and around the starter battery. My starting point is as you can see on the attached, but minus the leisure battery. There are 3 loose wires, 1 red which runs to the leisure electrics, 1 red to the switch relay and a fat blue one to the negative terminal on the starter battery.

I have 2 questions for anyone that's made it this far down my post.

1.
Most of the wiring diagrams I've found online suggest in-line fuses between the batteries and the switch relay. My setup does not have these, are they essential?

2.
Should the earth from the leisure battery run to the chassis itself, or is it ok to connect to the negative terminal on the starter battery?

Thanks for reading, my next problem will be securing the leisure battery to something. One step at a time.

This is my first van, looking forward to figuring it all out eventually.

Rob

IMG_20160809_173637.jpg

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[moospop]

Have a look in the wiki (on the top banner of the page) you will find what you are looking for there, from your diagram, you might want to start with searching "split charge relay" in the camper electrics section (16.2)

[MidLifeCrisis]

1.
Most of the wiring diagrams I've found online suggest in-line fuses between the batteries and the switch relay. My setup does not have these, are they essential?

In short 'yes' you need them both - without them any damage to the wires that run between the two batteries could short to the chassis and suddenly the wires get very hot and you risk creating a lot of unwanted smoke/fire!!!
Ideally there should be a fuse at the positive terminal of each battery as close to the battery as possible (so that as little wire as possible is unprotected by the fuse!

2.
Should the earth from the leisure battery run to the chassis itself, or is it ok to connect to the negative terminal on the starter battery?

The leisure battery earth can run to the starter battery earth (because the starter battery earth is connected to chassis) - it's usually just easier to ground the leisure battery to chassis near where you fit the battery rather than running a heavy cable back to the starter?!? And again that additional wire is another potential fault point that can be eliminated by just grounding to chassis at the battery installation location.

Also make sure that the wire running between the two batteries is of a decent size/gauge - there can be 20+ amps running through it when a depleted leisure battery is being charged.

Good luck!!

[robp]

Thanks, very helpful.

I could probably benefit from some kind of basic electrics for dummies book.

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