How To Charge 3 Seperate Batteries...Advice needed please

[Leeday]

Hi all,
I currently have 1 starter battery and 1 auxilliary battery under the bonnet, using Ford original fitment split charge relay and wiring (Fitted by Ford when new).. Had to add fuses though as there were none...
However, I want to know the best way to fit 2nd auxilliary battery in the rear of the van.....all 3 batteries need to be isolated from each other, so 1st option is remove Fords split charge and fit a Sterling Pro-split Diode:
http://www.force4.co.uk/1023/Sterling-- ... gn=pid1023
or keep Ford split charge and add a 2nd split charge relay for the 3rd battery.
Adding the 2nd split charge relay set up is easy enough but am not to sure on the implications, ... the Ford system takes its relay trigger from the alternator and if I add a 2nd relay trigger to this connection will it cause problems with the ignition light and alternator operation.
I can`t see any initial problems with 2 split charge relays working side by side... but someone may know different.
I know the Sterling diodes work well as I had one on my narrowboat and it done a "Sterling" job
Alternator fitted to van is 70amp.
Thanks....

[MrMPuk]

You get massive voltage drop across these split charge diodes, I'd fit a second relay.

[Leeday]

Excellant... thanks MrMPuk... I was inclined to go in that direction, just wanted confirmation the 2 relays would work together ok...
Many thanks.

[MrMPuk]

I'm guessing that your current relay is operated when the alternator is charging, if you wire the new one the same way then you don't really need a new one and could just wire into the current one. I used a voltage sensing relay that only operates once the primary battery is fully charged.

[Leeday]

I'm guessing that your current relay is operated when the alternator is charging, if you wire the new one the same way then you don't really need a new one and could just wire into the current one. I used a voltage sensing relay that only operates once the primary battery is fully charged.

Not sure I quite understand this bit "you don't really need a new one and could just wire into the current one" .. do you mean wire new relay into exsisting relay so that new one is tripped by existing relay, or do you mean wire new battery into exsisting relay?
If I connect new battery to existing relay, then the two auxilliary batterys will not be isolated from each other and if I apply a heavy load to the rear battery then I will end up with many amps surging down the "Not Capable of carrying extreme amps" connecting cables would warm the van up though
I have seen the voltage sensing relay you mention, but have never as yet used one (have fitted them for others)... I tend to stick to the relay set up using:http://cgi.ebay.co.uk/Heavy-Duty-Relay- ... 5d2ae43779.

[mbev51]

hi
my transit mk6 day van has from new 2 engine batteries and one liesure battery. The original ford split charge relay had a problem with one of its screw terminals in that some idiot had cross threaded the nut on the power out so a good connection had never been made, probably from new. I bought a new generic relay from ebay, similar to the one you refer to and banged it in. I found that ford used a switched earth to trigger the existing relay so just used that set up.

For your application if its the same as mine, buy that relay and use the switched earth going to the orginal relay to power the new one, together with a permanent live. Why place the battery in the rear, its a long run for the main live cable? Can you not put it under one of the front seats and run the cables to power watever from there. I'm not an electrical person, just an old diyer, some technical person might find fault with my suggestions.

[Leeday]

hi
my transit mk6 day van has from new 2 engine batteries and one liesure battery. The original ford split charge relay had a problem with one of its screw terminals in that some idiot had cross threaded the nut on the power out so a good connection had never been made, probably from new. I bought a new generic relay from ebay, similar to the one you refer to and banged it in. I found that ford used a switched earth to trigger the existing relay so just used that set up.

For your application if its the same as mine, buy that relay and use the switched earth going to the orginal relay to power the new one, together with a permanent live. Why place the battery in the rear, its a long run for the main live cable? Can you not put it under one of the front seats and run the cables to power watever from there. I'm not an electrical person, just an old diyer, some technical person might find fault with my suggestions.

Thanks for that...haven`t even tested the Ford relay to see how it works just a quick look
Yes will stick to the relay (I have 5 of them in my toolbox buy them in bulk). Need the battery in the back (4 captain seats and work area right at the rear) as the captain seats have swivel bases, so nowhere to put the battery under the seat. Also the battery will be powering invertors and 12v items in the work area so these cables need to be short... shouldn`t be an issue as to how far the battery is from the charge source (same principle as a car and caravan set up with battery in van charging) as long as you compensate cable size/voltage drop over distance etc, van is in for MOT today, so when I get it back I can crack on with the wiring (or do repairs for the MOT )
Thanks again, Lee.

[mbev51]

hi
how have you got on with mot and wiring?

[Leeday]

hi
how have you got on with mot and wiring?

Van failed on O/S steering rack gaitor (split) and both front windscreen wipers ineffective in clearing windscreen..... New windscreen wipers fitted, new o/s steering rack gaitor fitted (took me about an hour altogether) van re-tested this morning .. 12 months MOT Not bad for 21 year old van... very happy..
2nd leisure battery is installed in the rear, vented through floor, 2nd relay fitted under bonnet, connected to trip with 1st relay, 50amp cable running under van to charge 2nd leisure battery, fused at both ends.
All works well

[alexthecheese]

Could you set this up with a leisure battery, or would it knacker it in? We've got a zig charger unit in ours, but it only charges at 3 amps on the move. Would be nice if it could get a huge charge each time we're moving.

[Leeday]

Could you set this up with a leisure battery, or would it knacker it in? We've got a zig charger unit in ours, but it only charges at 3 amps on the move. Would be nice if it could get a huge charge each time we're moving.

My starter battery is standard battery, my other 2 batteries are leisure batteries, won`t knacker the batteries as alternator regulates what charge it puts into the batteries.
Starter battery is designed to give loads of output quickly (to start vehicle) and then be recharged,
Leisure battery is designed to give out lower outputs over a longer period of time but still be recharged,
The only real thing that damages batteries is the "quick boost" chargers (140 amp etc), a vehicle alternator will not significantly reduce a leisure batterys life.

[solarman]

Another alternative is to have the 2nd leisure battery solar charged thus keeping it isolated,
Solarman

[Leeday]

Another alternative is to have the 2nd leisure battery solar charged thus keeping it isolated,
Solarman

Hmm, problem there is that in order to get a decent charge you need a decent solar panel (£££`s) and sunlight, most of the smaller solar panels actually drain the battery when there is no sunlight

[solarman]

Another alternative is to have the 2nd leisure battery solar charged thus keeping it isolated,
Solarman

Hmm, problem there is that in order to get a decent charge you need a decent solar panel (£££`s) and sunlight, most of the smaller solar panels actually drain the battery when there is no sunlight

the smaller panels are too small anyway and some don't have a diode fitted hence the drain,larger panels do and you would need a decent size panel 80 watt mininum would be a good sized panel.

[Leeday]

Very true... used to sell the elevating tracker solar panels, would follow the sun ... when it was out.
However, I think for the cost involved in purchasing a decent solar panel, a split charge set-up is the easiest and cheapest option