AuthorTopic: twin alternator wiring  (Read 2334 times)

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Offline westy 90

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twin alternator wiring
« on: April 20, 2013, 18:16:33 »
hi i am planing on fitting a 2nd alternator to my defender 90 300 tdi and would like it to work so i can switch between the two battery's on which on i use to start the truck. As the 2nd alternator will charge the 2nd battery no need to worry about running the other one flat. Just need some some to explain to me the best way to wire it up. Would like a switch on the dash so i can switch between them, easily. A diagram would be great it anybody got one thanks

Offline lambert

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Re: twin alternator wiring
« Reply #1 on: April 21, 2013, 07:07:23 »
Drop wizard a pm he knows his stuff on this.
Lambert Coverdale.

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Offline Budgie

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Re: twin alternator wiring
« Reply #2 on: April 21, 2013, 10:10:32 »
Wouldn't a split charge system be easier to fit & use?
I had one battery used for running & starting my old Disco and the second one for running the winch, spot lights (including the roof mounted ones), rear power socket and inverter.
The winch was run direct off the battery and I installed a separate fuse box for everything else.

Both batteries were deep cycle batteries of the same size & capacity so I could swap them around if needed.  :wink:

I found this photo of it:

The fuse box & two light relays are fitted to the inner wing, behind the air filter. The split charge relay was on the other side of the engine bay.
« Last Edit: April 21, 2013, 10:18:32 by Budgie »

Offline Range Rover Blues

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Re: twin alternator wiring
« Reply #3 on: May 28, 2013, 03:03:23 »
You can get switches for this from marine equipment suppliers as it's popular on boats.

I'd go split charge TBH, unless you need redundancy in your charging system I can't imagine you needing 200 amps unless you plan to do a bit of welding :huh:

You can make a split charge system in a number of ways, from a big relay wired into the charge light to a voltage sensitive relay that is fully automatic.


Done it both ways in the past.
Blue,  1988  Range Rover 3.5 EFi with plenty of toys bolted on
Chuggaboom, 1995 Range Rover Classic
1995 Range Rover Classic Vogue LSE with 5 big sticks of Blackpool rock under the bonnet.