2nd battery does NOT charge

[travelbear]

Hi!
I have a Transit 1999 with dual batteries in front. I cannot find an electrical diagram on the in internet ( does someone know where I can get a (free ) electrical diagram?) . My problem is the 2nd battery does not charge ...(the first one does charge)) I traced the wires as best I could. So far I found that the positives of BOTH batteries are connected! But the Grounds are NOT. It SEEMS the 2nd batteries ground is connected to the chassis! SOOOOOO ... it seems the MAIN batteries ground is isolated from the rest of the van. Question: Where is the relay that connects the 2nd battery ground to the altenator? Where is the fuse?

Thanks
Attila

[JactoDrifter]

I have the same problem in my van!

The second battery isn't charging as well, and i'm thinking of connecting 2 or 3 extra ground cables from the chassis to other places in the engine, and see if it works!!
I think it will be enough, but next week i'll try, and then i'll put the updates in here!!
Cheers

[JactoDrifter]

Oh, i've just remembered that i have the wire diagram!!
I'll post it tomorrow!!

Cheers!!

[travelbear]

Super! cannot wait for the diagram!
At least your battery is charging (although not well)

There is a 20Amp fuse at the 2nd battery. I just checked it and it is good. Are there any other fuses that would prevent the 2nd battery from charging?

cheers

[Altransit]

First thing to check, is that the battery is good and can hold a charge Have you tried charging it from a seperate battery charger

[JactoDrifter]

You don't have to fear...the diagrams are here!!
















Sure hope they are helpfull

Cheers M8

[MrMPuk]

Going from the fact the positives are connected then it has a standard twin battery setup. There is no separate fuse or relay. If it's not charging then it's probably that it's not holding charge and needs replacing.

[travelbear]

Thanks for the diagrams! Unfortunately my 1999 transit is DIFFERENT ... The 2 batteries are NOT connected. The positive of both batteries ARE connected BUT the Negatives are NOT ... The main starter battery runs the starter motor and is connected to the altenator. I have connected the grounds of the 2 batteries together using a booster cable and everything works ... meaning the 2nd battery gets charged. I think a will wire a circuit which has a relay that would connect the main battery ground to the body of the van (the 2nd battery ground is connected to the body) ... I am almost sure Ford would have done this already .... anybody know?

cheers

[bigbad mothertrucker]

as mpuk says if the positives are connected all you need to do is ground the earths .

[MrMPuk]

The negatives don't need to be connected, they are just grounded to the body.

[JactoDrifter]

Yes, i think that's my problem too!!

Try to mesure the amps of either batteries, because when you say that "everything works when you conect both negatives" is because the battery that is discharged is pulling "juice" from the good one, just like my case!
so your conclusion may probably be misleading! In my opinion i think that you have a bad ground case, and i think you can solve it by making new ground conections and a shunt between both positives and negatives.
And i have to do the same!!

Keep posting the news!

[Cheese Monkey]

Please dont try to measure the amps of either battery, I think you might blow them up if you dont know how to do it. Check the voltage!

Both batteries should be connected to the chassis. There is no need to connect the negatives directly to each other, the chassis is one single large lump of metal, no different to a cable running between the two batteries.

If your main battery works fine etc, theres no problem there with it or any of its connections. If the 2nd battery works fine with a cable running between its negative and the main battery negative then you need to check the negative connection to the chassis. Check its connected to the battery properly, no breaks, connected to the chassis properly. Clean all of the connections. Possibly change the point on the chassis it is connected to. Make sure its connected to bare metal, not paint.

[travelbear]

Connecting the main battery to the body will solve the problem. I read somewhere that Ford made versions where the 2 battery systems where separate i.e. main battery for starter and running motor. 2nd battery for lights and other non-essential stuff. There must be some fuse or relay to connect the 2nd battery to the charging system. My van was modified to be able to use a wheelchair lift in the back ... I must have blown a fuse or disconnected something in the back ...

thanks all ...
If anybody has a different wiring diagram please post ...