Why are there two batteries?

[Totalnewb]

So I bought a 2005 12 seater mini bus. I want to make it a day van. Under the seat is 2 batteries but they are connected in parallel, when I watch a DVD player through the cigarette lighter; both batteries start depleting?
The front batter is only connected to the rear battery, and the rear batter has 3 red cables connected to it (one thin wire with 02 or 20 amp fuse. A larger cable with a 70 amp fuse inline and a third/thickest cable that disappears under the chassis (guess going to the fuse box under the bonnet.
I want one battery to be for the starter and the other to run electrics but this doesn’t seem to be the case. Any help?

[dumper]

Your better off fitting a split change relay and a separate leisure battery and leave the van batteries to look after the van .

[bortaf]

So I bought a 2005 12 seater mini bus. I want to make it a day van. Under the seat is 2 batteries but they are connected in parallel, when I watch a DVD player through the cigarette lighter; both batteries start depleting?
The front batter is only connected to the rear battery, and the rear batter has 3 red cables connected to it (one thin wire with 02 or 20 amp fuse. A larger cable with a 70 amp fuse inline and a third/thickest cable that disappears under the chassis (guess going to the fuse box under the bonnet.
I want one battery to be for the starter and the other to run electrics but this doesn’t seem to be the case. Any help?

That's not factory? they should be sperate not directly connected you sure somone hasn'y just added in a 2nd battery ?
I that is the cae i'd just fit a VSR in the live cable that joins the 2, i prefer BtoB battery chargers but for a simple instal just to watch a dvd player a VSR is ok.

[Jim Archer]

Mk7 RWD set-up is a easy retro fit.

I just got a complete Mk7 seat base, my 02 Jumbo had a spare switched live in the fusebox that I plugged the relay sensing feed into.

Then you have a connection on the busbar to connect your split charge set-up to.

Jim

[quirkycampervan]

Rejuvenating this thread nearly 9 years later!!

I have a 2013 Transit (100 T280), not sure what Mk, and the identical problem so this was incredibly useful. The front battery is well down in capacity so I think I will replace both.

I had two options from a battery company, a 2 year warranty on an unnamed brand or a 4 year warranty on a Duracell. The Duracells are about 30% more expensive. Which should I go for. I believe the battery company is pretty reputable and not selling rebranded rubbish.

Also I am really curious about the noise that Laserbee noted coming from behind the dash, probably right between the rev counter and speedo. It sounds like a moter turning briefly when the ignition is turned or off and only occurs when the van has been left for a while. Anyone know what it might be?

Thanks

[Altransit]

I have a 2013 Transit (100 T280), not sure what Mk, and the identical problem so this was incredibly useful. The front battery is well down in capacity so I think I will replace both.

I had two options from a battery company, a 2 year warranty on an unnamed brand or a 4 year warranty on a Duracell. The Duracells are about 30% more expensive. Which should I go for. I believe the battery company is pretty reputable and not selling rebranded rubbish.

In all probability, you have a late registered Mk7, (probably again) fitted with a Euro5 2.2 engine. In all likeleyhood (as you have two batteries) it's a rear wheel drive.
Personally, I wouldn't entertain unbranded batteries, as the Transit is hard on its batteries, and again, personally, I would only buy Bosch or Varta silver calcium, allegedly, both made by Varta, anyway

If your motorhome stands about a lot, or mainly does short journeys, I would either rig up some sort of solar charging, or connect some fly leads for trickle charging with a smart charger.
Make sure that your drivers door lock works (unlocks) with the physical key, because if your front/aux battery goes flat, the central locking won't work

[quirkycampervan]

Thanks for reply and info.

It is a 2.2 engine but is actually front wheel drive and you are right it does tend to stand around a lot. Solar charging is a good idea but I understand there are other reasons for taking it for a spin a bit more regularly, eg air conditioning and brakes. I just hate using diesel unnecessarily.

Bosch S4010 seem to be a drop in replacement for the ones in the van (Quinton Hazell QBT1103) and are available at pretty reasonable price.

Unfortunately I spent quite a lot of money with an auto electrician to diagnose this and another problem. Should have come here first!! At least I understand it all now.

[Altransit]

It is a 2.2 engine but is actually front wheel drive and you are right it does tend to stand around a lot. Solar charging is a good idea but I understand there are other reasons for taking it for a spin a bit more regularly, eg air conditioning and brakes. I just hate using diesel unnecessarily.

All E5 Mk7s are 2.2, earlier E4 RWD were 2.4.
It's unusual for a FWD to have two batteries, mine has, but it's not standard
It's good to take it out for a short run about once a week to keep the brakes clean and the A/C seals lubricated, but the batteries would need a much longer run to replenish the losses through standing, unlocking and starting. Just unlocking the door powers up many circuits which take about 20 mins to power down again, so some sort of auxiliary charging is essential to the upkeep of the batteries. Allowing them to drop below 12v will potentially damage them in no time at all, complete discharge will ruin them permanently.

[quirkycampervan]

Thanks Altransit, all good advice. The guy who did the conversion installed internal batteries and a solar panel. I think he knew what he was doing, perhaps he put in a second vehicle battery.