Dual to single battery

[marcuswarehan]

Hello, I have a 2011 transit which I have converted to a campervan, It has the ford dual battery set up under the driver's seat. I have installed an additional leisure battery (3rd battery) which is connected via a relay so it is only connected to the other batteries when the alternator is charging.

This is all working perfectly however I would like to add an additional leisure battery in parallel to add more capacity (4th battery), the snag is I don't have space or a suitable location for it.

So I was wondering whether I could convert the van to start and run on 1 battery instead of the 2 batteries under the driver's seat, and then get rid of the cab/aux battery and replace it with a deep cycle leisure battery in parallel with the existing leisure battery, I would connect this using the relay which closes when the alternator is charging rather than using the factory ford relay, because as far as I understand it the transit connects both batteries when the ignition is on so is cranking the engine from both batteries (not a good idea for a deep cycle leisure battery)

So the question is, can this be done, can a mk7 MWB Medium height 2.2Litre function fine with a single battery does it really need the extra glow plug/cranking power from the 2 batteries, also what drawbacks would changing to having one 1 engine battery have.

Many Thanks

Marcus

[dumper]

As I understand it the auxiliary battery runs the systems that are live when the engine is not running and if it goes flat the centre locking doesn’t work and if the door lock is not acceptable due to parking at the side of a wall or not working you will be locked out.But if it’s one battery running every thing then using the jump point under the bonnet would get round this unlike the standard set up which you can not power up a flat auxiliary battery from out side the van and also when a auxiliary battery is getting weak it gives all sorts of running problems.
Me not being a electrician is just my thoughts on this someone with more experience will be along to correct me if this is wrong.

[Brettbear63]

I think some of them do have a single battery , ? so it must be possible

[knobby1]

I think some of them do have a single battery , ? so it must be possible

All Mk7 RWD's have twin batteries from the factory. On the FWD's it was a factory option.

Lord Knobrot

[Altransit]

Personally, I would leave the van batteries as they are, and find another location for your leisure battery, but if you really want to do it, you need to locate and remove the big relay in the battery fuse box:-

Battery_Fuse_Box (8).JPG

Battery_Fuse_Box (1).JPG

Then replace it with this solid link bar, which effectively connects the main (starter) battery to the aux battery wiring ...........

Battery_Fuse_Box (5).JPG

Then remove the two front battery cables and front battery which are no longer needed, you may need to modify the dual battery retainer to make sure that the single one is secure.

You *should* alter the configuration in the BCM to tell it that there's only one battery, but I'm not sure how important that is
Check that the "now" single battery is the larger 110 type battery, as some twin battery vans have 2 smaller batteries, which may struggle when used as a single battery.

[Brettbear63]

I think some of them do have a single battery , ? so it must be possible

All Mk7 RWD's have twin batteries from the factory. On the FWD's it was a factory option.

Lord Knobrot

so it must be possible to reverse engineer a double to a single

[dumper]

What passenger seat have you got if you have a single you could fit two leisure batteries under it or if you have not fitted a double swivel you could maybe fit them in it cannot remember what they look like never looked in mine when I removed it and fitted a single I know it’s been done on a mk8.

[knobby1]

I think some of them do have a single battery , ? so it must be possible

All Mk7 RWD's have twin batteries from the factory. On the FWD's it was a factory option.

Lord Knobrot

so it must be possible to reverse engineer a double to a single

Yes you can...but I wouldn't....The twin battery setup will still allow you to start the van even if the front battery has failed....which happens often as it runs 95% of the electrics on the van...the rear battery basically just connects for starting...then essentially goes along for the ride.

Lord Knobrot

[Brettbear63]

Thats a good point , on my 2.4 rwd , one Battery was dead and the other was " walking towards the light " it barely started at all , yet i still bought it lol , 2 new Batteries and its a good one , , plus tyres , egr , maf , air filter , bulbs , windscreen sealant , fan belt , rear brakes , and the removal of 2 buckets of mud from the floor

[marcuswarehan]

Personally, I would leave the van batteries as they are, and find another location for your leisure battery, but if you really want to do it, you need to locate and remove the big relay in the battery fuse box:-

Battery_Fuse_Box (8).JPG

Battery_Fuse_Box (1).JPG

Then replace it with this solid link bar, which effectively connects the main (starter) battery to the aux battery wiring ...........

Battery_Fuse_Box (5).JPG

Then remove the two front battery cables and front battery which are no longer needed, you may need to modify the dual battery retainer to make sure that the single one is secure.

You *should* alter the configuration in the BCM to tell it that there's only one battery, but I'm not sure how important that is
Check that the "now" single battery is the larger 110 type battery, as some twin battery vans have 2 smaller batteries, which may struggle when used as a single battery.

Thanks for that, very informative

[marcuswarehan]

[/quote]

Yes you can...but I wouldn't....The twin battery setup will still allow you to start the van even if the front battery has failed....which happens often as it runs 95% of the electrics on the van...the rear battery basically just connects for starting...then essentially goes along for the ride.

Lord Knobrot[/quote]

In most cars even with same sized diesel engine thats in the van you have a single battery running all of the electrics and often more electrics and it's fine, If the van can be sold and run fine with a single battery i dont understand the worry. I understand having the second aux battery to run electrics with the engine off (when builders are sitting in the van with the radio on, fans and lights on while eating there lunch) having the second battery makes sure you can always start, but i will have 2 leisure batteries for running all the stuff in the van for when staying somewhere so its kind of like the same thing

[Brettbear63]

presumably two batteries were fitted to cope with the demands on a "works " vehicle ,however as you now use it for leisure pursuits its less likely to run down the primary battery , in my swb 330 there is room if i wanted to fit a 3rd battery under the passenger seat .

[dumper]

presumably two batteries were fitted to cope with the demands on a "works " vehicle ,however as you now use it for leisure pursuits its less likely to run down the primary battery , in my swb 330 there is room if i wanted to fit a 3rd battery under the passenger seat .

I’d disagree with a camper you will be parked up longer without running the engine not sure on a mk7 but if the same as on my mk8 it turn on ignition or open a front door and it activates different systems

[Altransit]

I’d disagree with a camper you will be parked up longer without running the engine not sure on a mk7 but if the same as on my mk8 it turn on ignition or open a front door and it activates different systems

Same on a Mk7, it powers up some of the running systems for 20 minutes or so, which is why I fitted two batteries. Mine spends a lot of time parked up, and not much time with the engine running, and I often access the load space during the day. Do this several times a day, leaving the doors open for 15-30 minutes, and there's not enough juice left in the battery to turn the engine over fast enough to start

[Brettbear63]

It does sound like a Ford mishmash , lots of vehicles only have one battery ,and lots of electrical systems , yet they still manage to start , is the 2.4 engine such a battery drain that it requires a 2nd battery to kick it into life ? , mine has , in comparison to my previous japanese 3.5 V6 mpv , hardly any electrical gizmos yet my japanese mpv only needed one battery , and we used that as a camper with doors being opened and closed or left open all day , we just switched off the courtesy lights to stop the bulbs boiling . the Mondeo with the diesel engine doesnt have 2 batteries .