Extra Storage For Three Batteries In A Ford Transit Based Mh (1 Viewer)

[Andi968]

I am not sure how many owners of Ford Transit based motorhomes know this but there is built in storage for three yes three extra batteries!
As owners should already know the vehicle battery is located in a compartment under the drivers seat and on inspection you will find it is designed for two batteries but most manufacturers only install one to save money and payload. It is a simple job to install a second battery with two short lengths of 30a rated twin wall cable with in-line fuse of 10a and connecting live to live and earth to earth. The reason for the in-line fuse is in case either battery develops a dead cell and in simple terms there is an attempt by the othr to equalise voltage and amperage.
Now if you look under the passenger seat you will see there is more storage for another two batteries, you will need to get down to your local Ford dealer for a battery clamp (around £6) How you wire these up is down to choice as long as it is in parallel , my choice was to wire them into the leisure circuit. Again use 30a rated twin wall cable and in-line fuse.
As I have a 250w and 2 x 150w solar panels each going to a 20a MPPT controller I have done away with the leisure battery completely and depend on the four batteries under the seats and have a grands total of 440Ah of capacity.
I know perhaps I will get comments about using commercial vehicle batteries instead of leisure batteries but these have now been in use three years with not one problem.
When you stop to think about it when a battery is been smart charged by the MPPT charger it is more or less doing the same as a modern smart alternator does whilst driving around.

Hope this is of help to other Ford owners who like myself prefer to be off grid, our longest session off grid so far is 17 days without a problem or anywhere near a flat battery, I have even charged up someone's mobility scooter for them .

Please excuse the dog hairs in the pictures, you can guess who the culprits are !

 

[Welsh girl]

We had the dealer put another battery under our passenger seat.,can't see under the driver seat so presume that there's just the starter battery under it.

 

[robrace]

I fitted another leisure battery in parallel to our existing one under dinette only to discover that I already had a second battery under the drivers seat in front of the main battery.it was dead so I replaced it!!So now we have 4 batteries!!!

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[Wildman]

an inline fuse will not stop the batteries equalising in the event of ONE BATTERY WORKING HARDER THAN THE OTHER, A FUSE IS NOT A DIODE IT IS A 2 WAY DEVICE.

 

[daveandsan]

We had the dealer put another battery under our passenger seat.,can't see under the driver seat so presume that there's just the starter battery under it.

Our Mk 7 Transit has 2 batteries under the drivers seat, one is the starter battery and the other one is a auxiliary for radio and cab 12v sockets.

 

[Andi968]

an inline fuse will not stop the batteries equalising in the event of ONE BATTERY WORKING HARDER THAN THE OTHER, A FUSE IS NOT A DIODE IT IS A 2 WAY DEVICE.

Yes it will if a 10a fuse is used, if a cell dies in one it results in that battery having a lower voltage and lower current and a rush of power from the other causing the fuse to blow!.
If a schottky diode for example is used you either have a battery that charges but can not discharge due to the blocking diode or a battery that only discharges and receives no charge .
If you doubt this try the following
Get two batteries one fully charged and one totally discharged connect the two together using jumper cables in parallel - to - and + to + wait 10 seconds or so and remove one of the cables, you will find the cables have got very hot in a short time due to the amount of current the discharged battery has drawn from the charged battery.
Now repeat with a diode, depending on which way round the diode is fitted either nothing will happen as the diode has blocked the flow or the discharged battery will draw the current again and cables will get red hot. The diode will only protect one direction.
Now repeat a final time with a inline fuse more or less immediately the fuse will blow ! The cables will not get hot and no risk of fire.

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[jonandshell]

Why not utilise the Ford dual battery wiring solution?
Fit the optional battery splitter onto the bus bars in the battery compartment fuse board and then connect the passenger seat batteries via the customer connections on the rear corner of the drivers seat box?
I would use 16mm cable for that to minimise volt drop and ensure efficient charging.
It would be a more robust and reliable system, already field tested in transit tippers and cherry pickers across the world.
The voltage drop across those thin cables must be massive. No wonder such a small fuse is sufficient.

 

[Andi968]

Why not utilise the Ford dual battery wiring solution?
Fit the optional battery splitter onto the bus bars in the battery compartment fuse board and then connect the passenger seat batteries via the customer connections on the rear corner of the drivers seat box?
I would use 16mm cable for that to minimise volt drop and ensure efficient charging.
It would be a more robust and reliable system, already field tested in transit tippers and cherry pickers across the world.
The voltage drop across those thin cables must be massive. No wonder such a small fuse is sufficient.

Thanks for the heads up never thought of using the bus.
The only problem I see above is using the customer connections is that all batteries would be connected to the vehicle side leaving nothing for the leisure circuit. Or have I misunderstood?

 

[andy63]

got a mk 7 transit panel van conversion... it has two vehicle batteries ie the start battery and the auxiliary which runs the vehicle electrics like cent locking , alarm , radio ,sockets etc when the ignition is off.. the start battery is just that and is isolated from the other when ignition is off.
I put in another single seat and put two batteries under there to run the habitation side of the van..
the only thing I would say is I have two cut rubber mats which I use to cover the batteries under each seat to avoid any accidental contact with the terminals when removing and replacing the seats...
the single seat that I got came with the electrical bits left in, (very kind of the salvage folk.) and I used that as well as adding a shunt for the power management panel..pic attached.
ta andy.

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[Andi968]

got a mk 7 transit panel van conversion... it has two vehicle batteries ie the start battery and the auxiliary which runs the vehicle electrics like cent locking , alarm , radio ,sockets etc when the ignition is off.. the start battery is just that and is isolated from the other when ignition is off.
I put in another single seat and put two batteries under there to run the habitation side of the van..
the only thing I would say is I have two cut rubber mats which I use to cover the batteries under each seat to avoid any accidental contact with the terminals when removing and replacing the seats...
the single seat that I got came with the electrical bits left in, (very kind of the salvage folk.) and I used that as well as adding a shunt for the power management panel..pic attached.
ta andy.
View attachment 68300

On my 2012 Transit which is based on the tipper chassis there are holes under the batteries for the breather pipes And have thought about using these to run cables.

Why don't manufacturers offer extra battery capacity instead of go faster stripes?
My old leisure battery was in a battery box cut out of the habitation area floor, amazing when they could have utilised the compartments under the seats. Have to mention mine is a coach built 6 berth factory converted to 4 berth opposed to conversion where space is tight.

 

[jonandshell]

Thanks for the heads up never thought of using the bus.
The only problem I see above is using the customer connections is that all batteries would be connected to the vehicle side leaving nothing for the leisure circuit. Or have I misunderstood?

The Ford twin battery setup isolates the starter battery with the ign off.
The 'aux' battery (to which you parallel your extra leisure batteries) will run your radio, lights, 12v sockets and the rest of your hab area without draining the isolated starter battery.
The work has all been done by Ford already.
Once the splitter is fitted, and the cabling revised to suit, the three 60 amp fused posts on the rear of the seat box become effectively a habitation supply. You connect your extra batteries to these and any charging source.
It can be all very much simplified. Catch up with me at a show and I will happily whip the seat off and show you the original Ford wiring setup for dual batteries.

 

[andy63]

as jon said , that was my solution and as I mentioned above the kind salvage folk left everything in the single seat I bought to replace the double..
I chose not to link the vehicle aux battery directly with the habitation batteries, but did install a large 120 amp voltage sensing relay between them so the habitation batteries do get some charge off the alternator when engine is running..
andy

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[Andi968]

The Ford twin battery setup isolates the starter battery with the ign off.
The 'aux' battery (to which you parallel your extra leisure batteries) will run your radio, lights, 12v sockets and the rest of your hab area without draining the isolated starter battery.
The work has all been done by Ford already.
Once the splitter is fitted, and the cabling revised to suit, the three 60 amp fused posts on the rear of the seat box become effectively a habitation supply. You connect your extra batteries to these and any charging source.
It can be all very much simplified. Catch up with me at a show and I will happily whip the seat off and show you the original Ford wiring setup for dual batteries.

That would actually be my preferred route, the main reason for not touching the bus in the first place was when I asked polar Ford during annual service the guy said it would void the warranty! Now going off base we had a lot of problems with polar ford the main one been a fuel leak from a cracked tank ! It went in for its service we mentioned when filling up to the top fuel came out underneath. When we picked the van up we asked if this was solved to which the answer was yes. So we took the van home and a couple of weeks later we set off on our way calling at Morrisons to fill up. We didn't just fill the van up but also the forecourt, it was that bad the fire brigade had to attend. We have AA COVER and bless them they took us to our destination on the back of a low loader. The smell of diesel in the habitation area was that bad we had to stay in a hotel for three nights while the smell disbursed and stoneacre ford replaced the tank. It would appear polar ford hadn't even looked at the problem. I did however get £1000 out of polar ford for this, what makes this even worse was the fact during the service the van had its first MOT and should have failed due to fuel leak, I was shown underneath by stoneacre and you could see where diesel had been vaporising all down the full 24' of the van.
Right back to the thread !!!
Since the event above we have changed our service contract to Evans Halshaw Ford and the van goes in next week for its annual and I think I will be asking them about the split charger and connecting directly to the bus and terminals.
Do you happen to have a picture you could post to show them exactly what I want to do ?
Thanks in advance

 

[Welsh girl]

so can you tell me what this is for ,ringed in yellow please?

 

[Wildman]

Yes it will if a 10a fuse is used, if a cell dies in one it results in that battery having a lower voltage and lower current and a rush of power from the other causing the fuse to blow!.
If a schottky diode for example is used you either have a battery that charges but can not discharge due to the blocking diode or a battery that only discharges and receives no charge .
If you doubt this try the following
Get two batteries one fully charged and one totally discharged connect the two together using jumper cables in parallel - to - and + to + wait 10 seconds or so and remove one of the cables, you will find the cables have got very hot in a short time due to the amount of current the discharged battery has drawn from the charged battery.
Now repeat with a diode, depending on which way round the diode is fitted either nothing will happen as the diode has blocked the flow or the discharged battery will draw the current again and cables will get red hot. The diode will only protect one direction.
Now repeat a final time with a inline fuse more or less immediately the fuse will blow ! The cables will not get hot and no risk of fire.

It does not quite work like that a cell does not decide to fail right away, it does so gradually, hence the batteries will equalise gradually and no inrush of current. They will charge at a constant rate to keep the batteries equalised albeit at a lower voltage.

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[andy63]

View attachment 68305
so can you tell me what this is for ,ringed in yellow please?

That is the customer take off point Jon mentioned in his post.. It has 3 connection points each fused at 60 amps..
If you look at the other seat I got from salvage you will see the same set up which I used for my habitation side
Ta andy

 

[Andi968]

][l


'

It does not quite work like that a cell does not decide to fail right away, it does so gradually, hence the batteries will equalise gradually and no inrush of current. They will charge at a constant rate to keep the batteries equalised albeit at a lower voltage.

Sorry to disagree with you there, a cell can fail wholly at anytime from for example a faulty alternator over charging it. The other point been the secondary battery is there for extra capacity when parked up, but say for example I didn't have all the solar panels and MPPT chargers connected and the main battery develops a fault and I turn the ignition on. The dash will still light up fine but when I turn the key You are then trying to draw 2-300 amps through a 30amp cable !
That's the reason for the 10amp fuse I don't like the smell of burning insulation.

 

[Wildman]

][l


'

Sorry to disagree with you there, a cell can fail wholly at anytime from for example a faulty alternator over charging it. The other point been the secondary battery is there for extra capacity when parked up, but say for example I didn't have all the solar panels and MPPT chargers connected and the main battery develops a fault and I turn the ignition on. The dash will still light up fine but when I turn the key You are then trying to draw 2-300 amps through a 30amp cable !
That's the reason for the 10amp fuse I don't like the smell of burning insulation.

that will not happen if the leisure batteries are charged via a relay, ah well you are obviously an automotive electrician and my HNC in electrical and electronic engineering doesn't quite cover the topic so will bow out, no wish to argue.

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[Andi968]

Nor does my BEng hons
Pissing contest aside always have a fuse within 6" of the live terminal.
What happens if something shorts to earth ?
What happens if wire gets damaged?
The simple solution would be a single battery that fits the space two presently take up, but I couldn't find one so am stuck with two wired in parallel and FUSED
This set up has been in location just over three years without a single problem not even a blown fuse, the batteries charge and hold charge fine and power the whole van which is totally 12v (even the 24" smart TV in the front and 20" in the bedroom along with two satellite receivers )

 

[Seajay]

I have a 96 smiley faced Transit with 2 batteries under the bonnet. I'm still not sure which one is for the starter and which for the habitation as there is yet one more in a tray under the stern!!.I guess CI the motorhome manufacturer was responsible for that odd arrangement, & I have been searching for a wiring diagram without much luck..

 

[Andi968]

I have a 96 smiley faced Transit with 2 batteries under the bonnet. I'm still not sure which one is for the starter and which for the habitation as there is yet one more in a tray under the stern!!.I guess CI the motorhome manufacturer was responsible for that odd arrangement, & I have been searching for a wiring diagram without much luck..

You should be able to get the original wiring diagram here http://www.ford.co.uk/OwnerServices/Owners-Manual
Hope this is of help to you

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