Not purchased one yet but thats the route iv'e decided to go, keep the second battery up to scratch rather than messing around charging it via mains or swapping the 2 batterys around, so.......

my question is, what too look for and how too wire it in,

Jon,

Try here for a cheap alternative.


http://www.kampenwagen.co.uk/Split%20Charge.htm

Cheers, looks easy enough to do.

Can't make head nor tail of that wiring diagram, but alternators can chuck out about 55 amps max depending on size. A 10 amp fuse would last no time at all if the batteries were only parcialy flat.

Or is the diagram nothing to do with the answer to Jons question. I don't like pages full of text, I find diagrams far easier to read.

[Edited on 26/2/05 by clbarclay]

Have been modeling a soulution but have come to an underlying problem, to acive 24v the batteries must be connected in series.

However batteries should be chargein parellel or you risk seriously damaging the batteries, especially if batteries are not equally discharged as in this case. Both are used to run the reverse motor but only the first runs the rest of the car.


My solution would be to have thew batterys wire in parallel most of the time so that they can both be charged and then switch the batteries to series when you need 24v the reversing motor.

To achive this though would need three seperate switches being worked by one or more relay.

[Edited on 26/2/05 by clbarclay]

All very well running them in parallel, except the internal resistances are not likely to be the same (even in supposedly identicle batteries), leading to the batteries discharging themselves over time. I know this from experience with my van. I'd use a split charger to charge the batteries.

The split charger just disconects the batterys + terminals when the alternator is not running.

Family range rover has does not split chargeing and that never has problems with flat batteries.
Having said that look at early range rover maual for a 12/24v system, they used them for a 24v supply to a caravan etc.

[Edited on 27/2/05 by clbarclay]

That's what I mean. The batteries discharge when the vehicle is not running. The van was used only for towing a monoposto car to meetings and was not used daily, but if left for more than a week or so the batteries would be dead. Both batteries were fine in isolation though.

Sorry my last post had a major typo, the bold was wat i ment to say.

Checked all tractors on farm and not a single one has split charging, some even had some very miss matched batteries.

Gazza285 did you ever try just a single battery on your van, might just be low current short circuit.

Now runs one battery without trouble.