Twin Batteries

[tony&kasia]

Hey guys i bought a custom to do a camper conversion.
It's a 2016 2.2 white in colour and has 86.000 miles.
I am at the stage to buy a leisure battery. I have noticed that there are 2 batteries already in the van.
Can i replace any of the existing batteries with a new leisure battery or do i keep the new leisure battery seperate.

Thanks in advance.

Tony

[Altransit]

It's probably best to leave the two batteries as they are, and fit your leisure battery elsewhere, and charge it via a B2B charger.
That's my advice, anyway

[dumper]

It's probably best to leave the two batteries as they are, and fit your leisure battery elsewhere, and charge it via a B2B charger.
That's my advice, anyway

That’s what I have done a Sterling b2b and two 125 amp leisure batteries I’ve kept the camper side separate from the van side electrics the only connection to the van is to the sterling unit.

[bortaf]

It's probably best to leave the two batteries as they are, and fit your leisure battery elsewhere, and charge it via a B2B charger.
That's my advice, anyway

That’s what I have done a Sterling b2b and two 125 amp leisure batteries I’ve kept the camper side separate from the van side electrics the only connection to the van is to the sterling unit.

Same here

[drivetheglobe]

Hi,

I would say you could also replace if there would be enough space to do so. As both are under the seat, space is an issue.

I ve gto a camper based on a 2007 2,4l that has twin batteries and I have a 3rd one of 110Ah that is loaded when driving ( Relais on D+), with solar or land-line.
I would like to change this to have the 2nd batt combined with the leisure to have more capacity. But I heard the electronic that connects the both is a littel bit strange: its said it also combines the 2 batts during starting. This would potentially give raise to heavy currents to the 3rd batt - so did not dare yet.
HAs anybody a clear statement on how the connection of the 2 batts works?

My doughter has also a Custom - seems like yours. She is using just the second batt as it is for camping. As in such a small car, you dont usually have so much of power consumption.
Actually what costs the most in my case is the heating-vent in the winter the whole day long. And with a custom usually you do no camp in the winter with a heating. Do you? Lights are LED nowadays. REst is usually done with gas or is short term usage.

br

[dumper]

On my set up (see below )but on my mk6 that didn’t have a smart alternator all I used was a standard split charger the one that they used for powering a fridge when the engine is running I only charged to a B2B for the mk8 it charges a lot faster so if not doing a lot of running about it is a plus but the Sterling is not cheap.

[bluebottle]

drivetheglobe - I wouldn't try combining batteries 2 and 3, starter batteries and leisure batteries are designed for fundamentally different output, and putting your leisure battery into a system where it has to spike out a lot of amps will not be good for it

[marcrbarker]

starter batteries and leisure batteries are designed for fundamentally different output

To add a bit, a starting battery is optimised to deliver insane amount of current for a second or two, totalling a small fraction of 1 Ahr of discharge. Soon as engine starts the starting battery is hammer-charged with up to 90 Amps to put that <1Ahr back again as rapidly as possible. The way the factory 'pastes' a starting battery's plates is more to compete in a 'cold cranking amps war' than for survivability, which means the plates 'shed' like crazy when using any more than single-digit Ahrs of discharge. That's why the "A-hrs rating" is dissappearing from specs and replaced with [one-time-only] "reserve capacity".

So a leisure battery being the complete opposite to that, in order to survive needs the appropriate kind of charging while in motion. I've heard of people in past getting away with just using a series-ballast headlight bulb with a simple relay,but today two decades into the 21st century there must better!