split charge fuse keeps melting

[djhammy]

Hi there folks

I had a JK split charge relay fitted 3 years back when i purchased a leisure battery. All was well until last autumn but since then I have had a problem where the fuse in the relay keeps blowing or melting so that some charge still gets through but my 12 volt lights etc running off the leisure battery are very dim and a meter showed just 7 volts coming out of the said battery so it wasn't charging properly. I haven't had a problem or so i thought with the main battery.

I took the van in to an auto electrician 3 weeks ago and he changed the voltage regulator on the alternator saying that should solve the problem. He also said i had the correct 15 amp fuse fitted.

Off i went and a few days later my lights were working a treat again and i noticed my headlamps etc were brighter running off the normal battery. Then when loading my dj gear into the van over xmas i noticed my lights running off the leisure battery were deadly dull again. I checked the fuse and as before it had a melted area though the fuse metal though burned through was just touching

I am taking it back tomorrow to the auto elctrician to check over but wondered if any one has any ideas why this is happening?

Many thanks

Dave/Hammy

[R0B]

im pretty certain my split charge relay has a 30 amp fuse.i remember an inline fuse holder on my van was melting.until i noticed it only had a couple of strands of wire going to it.i re crimped another one on using all the strands.and everything has been fine since.worth a look methinks...

[djhammy]

Hi it came with a 15 amp fuse and the tech man said that's right? don't want to do any damage but something can't be right here. I hope it's that simple as i have plenty of 30 amp fuses.

[R0B]

soz fella dont know about the jk split charger.was this the same tech guy who told you your problem was your regulator

and the tech man said that's right?

[djhammy]

This is the duel charging kit

http://www.justkampers.com/shop/type_2_ ... 10520.html" onclick="window.open(this.href);return false;

tech man is well respected has a well established business ??

Dave

[nenenaiad]

Hi,

The split charge relay should be only making a connection between the positive output of the alternator
and the positive terminal of the leisure battery when your ignition switch is on. This allows the leisure battery to charge as the vehicle battery charges.

When the ignition is switched off, the relay contacts open breaking the connection between the alternator and the leisure battery.

Any lights or whatever connected to the leisure battery under these circumstances ONLY discharge the leisure battery and NOT the main vehicle battery.

Please advise me where this large fuse is and I may be able to advise you further.


Regards


Dave

[R0B]

ahh right.he was correct about the regulator then.sorry i read it that he was wrong?

tech man is well respected has a well established business ??

[nenenaiad]

Hi,

As a final comment - if the Leisure battery is very low in voltage and 7 Volts is pretty dead.

Under these circumstances a large current would flow into the leisure battery and through the fuse in an
attempt to recharge it. Ask the man to test the leisure battery for you.

Regards


Dave

[Red Westie]

Trust me.....the JK setup is far to weak, the fuse, wiring and relay are all just borderline and what you are experiencing is a result of an overloaded circuit that just cannot cope with the amount of current TRYING to flow.
Pull out this cheap nasty wiring and upgrade. Looking at the JK wiring in the picture it looks like the wire itself is very thin 20amp or less and the relay probably 30amp....the fuse holder is an obvious weak point if it is melting and only fitted with a 15amp fuse.
To put things into perspective....Westfalia conversions use a 25amp fuse which also blows occasionally and this wiring is heavier than the JK kit but still considered weak.
Relay should be 40amp minimum (70amp recommended)
Wiring, fuse holder and terminals also need to be rated 40amps minimum (again 50-70amps recommended)
The fuse itself.....you could try a 30amp and see how you go..it may need to be slightly higher but never exceed the rating of the circuit.

I would also advise first charging the leisure battery (slow 2-4amps for 48 hours) then having it checked with a hydrometer (not drop tester) several hours after charge..if the cells give a level specific gravity and overall 12.6 volts or higher.. it's fine.

Don't try to soldier on with the JK setup...this is really the core problem and needs changing wether or not the leisure battery proves to be up the swanny as well.

Martin

[jed the spread]

In my limited experiance anything from JK is shizer...

jed

[CovKid]

To be fair,the JK set up works providing both batteries in good condition but agree, if theres a problem it may well let you down. I bought a heavy duty relay and sourced my own cable for the job. I have to confess I run with no fuse at all at mo but its a heavier duty circuit than most and can handle around 80amps. I may fit a fuse when I do all my Spring maintenance stuff but a split charge relay is pretty easy to fit and in my view it makes more sense to use quality parts you've selected yourself. Its generally cheaper that way too. The challenge really is getting cables into spade terminals that are secure, particularly when using thicker cable. Its all about having good connections and ones that meet demand.

[djhammy]

HI guys many thanks for your advice i shall first slow charge the leisure battery back to full charge. Then refit a new fuse and see what happens. My guess is this started after a non electric hook up rally where i ran the leisure battery down a lot.

This is a great forum for sure.

Dave/Hammy

[Red Westie]

You are spot on

My guess is this started after a non electric hook up rally where i ran the leisure battery down a lot

but this only goes to highlight how weak the JK setup is, afterall, it should be able to handle any situation and charging from nearly flat isn't that unusual after a 2-3 day camp.
Martin

[Mr Bean]

HI guys many thanks for your advice i shall first slow charge the leisure battery back to full charge. Then refit a new fuse and see what happens. My guess is this started after a non electric hook up rally where i ran the leisure battery down a lot.

This is a great forum for sure.

Dave/Hammy

I have to say that the modern aftermarket kit you buy in you local - even Halford - car spares shop is barely adequate in design and construction. Old kit can weaken and become slack. I had exactly that problem and in one case found the plastic from the thirty amp fuse in a solid blob under the fuse holder. My fuze and holder was the flying lead blade type and I hunted for one with a thicker lead and a good firm grip on the fuze. The quality of the fuzes is variable between makes and in some cases the plastic can easily be misplaced leaving the thin fusible link subject to damage or maybe even short circuit. While the actual materials are of sufficient conductivity any electrical resistance at a joint/interface will produce destructive heat when a heavy current flows such as after a longish stop using the liesure battery. As already suggested if you do flatten the liesure battery it is best to bring it up to some kind of charged state with a battery charger.
Cheers
Wolfie

[AngeloEvs]

I agree - 15A is too small a rating - Minimum 30A.