Mk7 2008 single battery want to fit leisure

[jacksonator]

Hey guys,

only me I have a pretty simple question,

Can I buy a leisure battery and put it in where the second battery should go? will it have a vent hole or would I need to make one?

I will use an aftermarket split charger so I don't have to have anything updated. So a fused live from my main battery to the new battery then ground the split sensor and the negative battery terminal to the chassis.

My thinking of putting it where the second battery should go is to keep the job tidy and then there isn't any wires running anywhere.

Has anyone does this here before?

Thank you in advance - I did use the search function but not specific to my question i have seen peoples camper conversions putting a battery in the rear or adding a second battery to a single battery mk7 and updating the software for it to charge 2 batteries.

[knobby1]

The "second battery" was a factory option in the FWD machines, so some of the hardware may be there already, just a matter of sorting what else you need. RWD's came from the factory with twin batteries as standard.

Lord Knobrot

[Cider Andy]

I've done something very similar, although I had a donor van too so I could use its battery cables. Battery itself is located in the front of the seat base (original battery clamp does both batteries). The positive cable is connected to the same shunt as the original battery in the seat base fusebox. I fiited a 200A isolator in the seat base that disconnects this wire. In parallel with the isolator I wired a TEC3M caravan towing relay, designed to operate a fridge en route and charge the caravan battery whenever the towing vehicle is charging. Basically it is used as a 30A voltage sensing relay which automatically connects and charges the auxiliary battery when there is alternator output. The reason for the isolator (which is normally open) is I can connect the two batteries directly together if needed (eg. if the van battery was low and it needed a jump start).

[jacksonator]

Evening Guys,

Thank you for the reply guys

Andy that sounds exactly like I am after! So you still fitted your leisure battery under your seat next to your singular battery then did all the sense relay etc?

Did you place and earth the sensor and leisure battery to the body under the seat?

[Cider Andy]

Yes the whole lot goes under the seat, in the seat base. The original battery main earth to chassis is done at the front corner mounting bolt of the seat base. I fitted the second battery ground cable on the other front corner of the seat base.

I didn't put the TEC3M in there but that's only because I'd done some other wiring jobs at the same time and the relay was fitted with the other stuff. Had I just done it as a project like yours I'd have mounted it in the seat base. It's a small unit, there's plenty of space for it and it minimises the wiring.

[jacksonator]

Ah fantastic! That's filled me with confidence to get on it and get it done. Been doing a few other bits to it fitted an awning rail, black out curtains all round and some other little bits.

Would I be able to use the same earth as the main battery or do I need to put in a secondary earth?

Do you have any pictures of your install?

Thank you

[Altransit]

If you get a factory twin batt earth lead, it has a clamp for each battery in the correct position, and bolts to the same seat bolt as the original. You can also buy a twin pipe to dispel the vapour to the original outlet.