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Split charging help

Posted: 28 Dec 2016, 11:38
by quattrodave
Whilst checking the leisure battery today I noticed the voltage was only 11.75v and doesn't appear to be charging .
The relay has the number 30 on it, part number 165 906 381 which appears to be a fuel pump or general relay - is this man enough for the job?
It has 2 large wires going to it, leisure battery + and main battery +
The other 2 are black/red and blue, these go to smaller terminals on the alternator, the blue one to a post near the battery main cable, the black/red to a spade terminal higher up.
With the engine running, the battery +wire is reading 14.2v which seems to be fine, the leisure battery still reads 11.75v, blue wire reads 14.05v, black/red wire reads 0.05v.
Both large cables on the relay appear to have overheated at some point, slightly melted :(
The questions are, is this relay suitable?
Are these wires going to the right places?
The battery is a 75ah normal battery, Not leisure, is this ok?
Would this have been retro fitted or factory (1990 diesel multivan, eberspacher fitted)
Thanks

Re: Split charging help

Posted: 28 Dec 2016, 12:00
by MidLifeCrisis
Sounds like the relay is no longer working;
The blue wire is the one that should power the relay on - and you are seeing 14v on that so that's fine.
And you have you seen you are not seeing the same voltage at the leisure as you are at the starter battery - which you would if the relay was working and connecting those two together.
I can't see any specs on that relay but I would suggest any relay that can handle 40A would be a good choice - and it will need to have the same terminal layout as your current relay (assuming the relay is mounted into a holder and is not just connected by spade connectors;
I'd suggest taking the relay to an auto supply shop and seeing if you can find one that has the same pin layout (they should be marked)

Re: Split charging help

Posted: 28 Dec 2016, 12:21
by a1winchester
A proper leisure battery is best if you want it to do it's job properly. The charge / discharge curves are different, which makes a leisure battery the better choice.
Do you know the age of your battery. It may need to be replaced now anyway.
(Note to self - check age of mine - must be 7 or 8 years old at least.)

Re: Split charging help

Posted: 28 Dec 2016, 12:26
by Oldiebut goodie
11.75v - the battery is on its way to battery heaven. ~ Melted wires say inadequate wiring for the demand placed on it. An LVD would have saved you running the battery so flat to begin with.

Re: Split charging help

Posted: 28 Dec 2016, 12:36
by nicq
Have you any fuses in line. There should be at least one inline that should be the value of the max current the relay can Handle.

Re: Split charging help

Posted: 28 Dec 2016, 12:48
by quattrodave
The battery is a decent exide one 12-18 months old at a guess, certainly no older.
The relay is just hanging in mid air on spade connectors so not ideal !
Both main battery wires are pretty heavy so I'm certain there're ok
I can't see any fuses after a quick look, what's recommended and on what wire would you say?

Re: Split charging help

Posted: 28 Dec 2016, 13:14
by Smiffo
MidLifeCrisis wrote:Sounds like the relay is no longer working;
The blue wire is the one that should power the relay on - and you are seeing 14v on that so that's fine.
And you have you seen you are not seeing the same voltage at the leisure as you are at the starter battery - which you would if the relay was working and connecting those two together.
I can't see any specs on that relay but I would suggest any relay that can handle 40A would be a good choice - and it will need to have the same terminal layout as your current relay (assuming the relay is mounted into a holder and is not just connected by spade connectors;
I'd suggest taking the relay to an auto supply shop and seeing if you can find one that has the same pin layout (they should be marked)

What this man says ^^

Sounds like relay faulty as voltage is different on each battery when engine running.

Here is a WIKI link that specifies fuse ratings and locations that you should consider.
( I think I put 30A in mine as my holdsworth wasn't fused when I acquired it. )

https://club8090.co.uk/wiki/Ca ... it_charger" onclick="window.open(this.href);return false;

You will notice some of the WIKI content is from MidLifeCrisis too :wink:

Re: Split charging help

Posted: 28 Dec 2016, 17:56
by quattrodave
Thanks for that link skiffs, spot on!
Will get another relay ordered up.
Not sure where to put the fuse on the main battery + wire though (thick red/white wire), it s in the loom and goes to the glowplug relay black box in the engine bay, any suggestions or is it fused anyway?

Re: Split charging help

Posted: 28 Dec 2016, 19:21
by MGP
The best thing to do would be to put the feed to the split charge relay direct to the battery positive terminal, you are aiming for the shortest possible route with the least amount of connections.
Fuses need to be as close to the power source as possible and rated lower that the rated amperage of the cable, no exceptions, you also need to put a fuse at the leisure battery end.

Sent from my SM-G920F using Tapatalk

Re: Split charging help

Posted: 28 Dec 2016, 19:53
by nicq
MGP wrote:The best thing to do would be to put the feed to the split charge relay direct to the battery positive terminal, you are aiming for the shortest possible route with the least amount of connections.
Fuses need to be as close to the power source as possible and rated lower that the rated amperage of the cable, no exceptions, you also need to put a fuse at the leisure battery end.

Sent from my SM-G920F using Tapatalk

And rated lower or equal to the current value of the relay (don't go larger even if you use big cable)

Re: Split charging help

Posted: 29 Dec 2016, 13:03
by quattrodave
New relay ordered from brickwerks, need to sort out fuses now
Just another job to add to the list.........

Re: Split charging help

Posted: 29 Dec 2016, 13:21
by nicq
These are quite handy for the job http://www.ebay.co.uk/itm/2x-Standard-B ... SwX~dWoNBN" onclick="window.open(this.href);return false;