Which colour

[Andy Walker]

I've tried searching on here but can't find which colour wire to/from the alternator to use for the "trigger" wire for a split charge unit.
I'm sure it's mentioned elsewhere, but very well hidden. No luck with the google either.

 

[Gary Stockton]

I ran mine from the same terminal on the battery the alternator connects to. Is there a specific reason to go direct to the alternator (in case I've got it all wrong?). All the docs / diagrams I've seen from, for e.g. National Luna show that type of connection. Mine seems to be working fine?

Cheers, from paranoid in Edinburgh!!

 

[Jon Wildsmith]

For a standard relay type split charge system you should just connect to the battery. You should only need to intercept the alternator voltage sense wire for systems that trick the alternator into generating a higher voltage to overcome losses in the diodes they use for the split charging. In that case the alternator B+ wire would also be going to the unit for splitting, rather than direct to the battery.

 

[Andy Walker]

This http://www.x-eng.co.uk/X-Charge.asp is the split charge relay I intend to use.... It suggests that the thinner wire is connected to the wire that goes between the alternator and the charge light on the dash....... Or can anyone suggest a better place to wire to?

 

[Gary Stockton]

I attached the voltage-sense relay trigger wire on the battery positive terminal too. Interesting to find out why they want it to go to the alternator light wire?

The 120 has an ecu-controlled alternator, don't know if that makes any difference int he set-up?

 

[Jon Wildsmith]

You're after the charge warning light in that diagram then not the voltage sense wire. Most of us are using an intelligent controller to switch the split charge relay whereas the version in that diagram will only link the batteries when the engine is running (which might be all you want). Have you looked at the EWD in the FSM?

 

[Jon Wildsmith]

I attached the voltage-sense relay trigger wire on the battery positive terminal too. Interesting to find out why they want it to go to the alternator light wire?

Saves having an intelligent controller, just piggy backs the warning light which will only power the relay coil if the alternator thinks it is producing charge.

 

[Andy Walker]

Looks like it maybe better/easier to get one of the cyrix ones I've heard about on here. Is the 120a one OK, or do I need the 400a one......Bit expensive though.

 

[Jon Wildsmith]

You could just use a T-Max controller with what you have and it will give you crude voltage readouts as well. What rating you need depends on your usage requirements? If you want the aux battery to contribute to powering your winch then you need a fairly high rating. If it's just for powering a fridge etc then the X-Eng is plenty, and their method of controlling it will work, it just lacks a few of the benefits of using an intelligent controller but you may not want or need those benefits ...

 

[Andy Walker]

Thanks - I'll try putting the trigger wire to the posative on the main battery like Gary did and see what happens.

 

[Jon Wildsmith]

Should be yellow with a white stripe. Just check it is +13.8 volts ish when the engine is running and near enough 0 volts when it isn't to double check.

 

[Jon Wildsmith]

Thanks - I'll try putting the trigger wire to the posative on the main battery like Gary did and see what happens.

The relay will always be powered, so the batteries will always be linked, until the voltage drops so low on the main battery that the relay drops out. Gary is using an intelligent controller, so his equivalent of your wire goes to the intelligent controller which then monitors the voltage on that wire and decides from that if it should power the split charge relay or not.

 

[Andy Walker]

OK - I'll look for a yellow with white stripe wire

 

[Gary Stockton]

I have an older version of this:

Raw Components

Which may not handle a winch load though.

Cheers

 

[Gary Stockton]

And I'm sure you've got this covered off, but don't forget to put a mega-fuse either end of the cables to the batteries

 

[AndyCook]

I have an older version of this:

Raw Components

Which may not handle a winch load though.

Cheers

some of us got the Cyrix 400amp units for not much more than that

 

[Gary Stockton]

From where, Andy? I only use mine to charge the leisure battery, but if there's a better alternative, let's have it

EDIT: found it

and £187.25 from here

 

[AndyCook]

this was original thread where the ebay bargain was spotted

viewtopic.php?f=29&t=7550&hilit=relay+split+charge

got the 400amp one for £65 from ebay, Chris, Rob and I put offers in that were accepted