split charge voltages

[Team28crew]

Hello all
I have just fitted the RAW componants 100amp split charge kit to my 1986 1.9 DF. both the cranking batt and the leisure batt have a voltage of around 12.6v when the engine is off. When I start up the engine it only increases very slightly on the LB and drops a little on the cranking battery. I have measured between the large terminals on the relay and there is no reading when the engine is off and around 0.65v when the engine is running. This does not sound quite right to me ( Im no expert though). Could it be a duff relay/battery or altenator.

Ive got to go out to the shops now on the orders of the Mrs but will check back in later.

Thanks in advance, Mark

[kevtherev]

your right it's wrong.

recheck that the relay is operating, by putting a good current across the trigger terminals. then check that the big terminals are a curcuit.

if this is all good.
Check and make good all connections

What have you wired the trigger to?
what is the Alternator output like? put the Voltage meter accross the big terminal on the alt and a good earth (should read 14V + - 2V)

[Oldiebut goodie]

You won't get any potential difference across the large terminals on the relay with the engine running (except for that occasioned by the resistance of the contacts). Check the potential difference between the output and earth!

[bigherb]

If the voltage is not increasing to the starter battery then the alternator is not charging, first check the wiring to the alternator, have you dislodged something.

[Team28crew]

Thanks for the the tips and things to check. The trigger is from the blue wire that runs from the altenator to the red light on the dash as shown in the instructions supplied with the kit the fridge relay is also connected to this wire, a scotch lock was provided but I ditched this and soldered the wires together so that connection is good. The the LB is grounded to the chassis (paint all removed from the area to make sure a good earth connection is made) I have also connected the relays GND to this point. I will check the alt output in the morning and the test the relays as you guys have said and I'll check for anything I may have disturbed also.

I'll report back in the morning, thanks again guys.

[CovKid]

I think it was Mocki that first raised this, but I had probs getting a trigger from the dash end but once I'd run a small wire directly to the alternator (blue wire) all was OK. Also you may well have to give the engine a rev to trigger the charging.

[Team28crew]

Also you may well have to give the engine a rev to trigger the charging.

Yep thats all it needed a wee rev I noticed that the red batt light on the dash had stayed on after I started it up this morning so as you say a little rev light goes out and then checked all the voltages.

Engine running (after a rev)
Cranking batt: 14.31v
LB: 14.30v

Engine off
Cranking batt: 13.33v
LB 13.32v

I also disconnected the LB side of the relay when the engine is off and got a reading of 0.015v from the LB side terminal to earth and with the engine running 14.32v again so looks like everything is ok.

Thanks for the help and now I know how to test the split charge system.

Mark

[1664]

Just as a point of interest, I upgraded my split charge system a while ago (100A relay, 10mm cables). Although I upgraded the cables for the batteries/relay, I re-used the trigger wire from the original split charge fitted by Autohomes which triggered both the split charge and the fridge relays. I noticed that the trigger wire ran not to the dash but to the glovebox which of course contains the vehicle fusebox. 'Uh-oh', I thought, 'don't like the look of that' so I traced the wire to the rear of the fusebox where it was attached to a spade connection on the back. I decided to check out how exactly this spade connection switched so disconnected the trigger wire and attached my Avometer to it instead.

Key out - 0v
Key in, steering lock off - 0v
Key in, ignition on - 12v
Key in, cranking engine - 0v
Key in, engine running 12v

As I understand it, this is also how it works using the alternator blue wire at the dash. Frankly, I personally avoid going within 50 yds of that dash wiring loom and flexi-connector as it's so prone to problems and am wondering why nobody has mentioned this rather convenient alternative before? Or am I missing something?

[Cruz]

you may well have to give the engine a rev to trigger the charging.

I have to do this even with a new regulator fitted. Dash lights stays on until I give the throttle a little love tap

[CovKid]

love tap