Starter battery drained - Split Charge?

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kezza87
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Starter battery drained - Split Charge?

Post by kezza87 »

Hi, I am still in the process of fitting interior .etc in my van but have finished installing all the split charge stuff but have no load connected at all. the van is parked up and has not been driven or even ignition turned on. went to it today and the Starter battery (Brand New) was completely drained to the point voltage was undetectable.
Im not sure but im thinking I have a faulty relay that is not disconnecting when ignition is off. so basically my Leisure (also Brand New) and starter battery are connected to each other at all times when van is parked. would this completely drain the starter battery?

or anyone have any idea whats happening?

The relay is clicking on and off with the ignition now that i have charged the starter battery so it hasn't seized or anything.
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Re: Starter battery drained - Split Charge?

Post by nevill3 »

Normally the relay is only triggered once the engine is running and the alternator is charging, usually by means of a blue wire that comes from a separate connector on the alternator to the relay. Basically the relay remains in the open (off position) until it is energised by a 12 volt feed (blue wire). that is if it is one of the old types, I do not know how the newfangled voltage sensing relays work.

If your relay is clicking when the ignition is merely switched on and it is the older type then I would suggest that it is wired incorrectly
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kezza87
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Re: Starter battery drained - Split Charge?

Post by kezza87 »

Ok thanks for your reply. The van was an autohomes conversion and I just used the original cable that they had going to the zigg relay under the driver seat.
I'm not totally sure where it comes from but it's wired to the fuse box somewhere. It seems to engage on the turn of the key so I am assuming they have wired it off the ignition.
I just don't understand how the battery has completely discharged itself though.

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Mocki
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Re: Starter battery drained - Split Charge?

Post by Mocki »

is the leisure battery flat also ?

all a split charge relay does is join the two batteries together ,
dont beleive the old myth that it charges one then the other !
they will equalise to whichever battery has the lower voltage,
so if your leisure wasnt flat too, its not the relay joining them together.

it is either the trigger wire at fault, or something else left on
most factory conversions are too lazy to wire the interior lighting from the leisure battery,
you may find that they are powered by the main battery
did you leave a light on, or a door open?
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kezza87
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Re: Starter battery drained - Split Charge?

Post by kezza87 »

Both batteries were fully charged and the leisure battery still seems to be charged although I haven't checked how much. There is literally nothing connected as the van has been gutted. So I'm wondering now if I have a leakage to ground somewhere? Maybe I just bought a faulty starter battery...
I'll investigate more this evening after work and see what I can find.

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Re: Starter battery drained - Split Charge?

Post by Mocki »

simple test time!
test 1
fully charge the suspect battery on a mains charger ( if it will)
take a volatge reading one hour after disconnecting from charger
leave disconnected for 24 hours, then take a voltage reading.
if the voltage is any more than 0.5v less than the first reading, its toast!

test2
take your battery you just fully charged and tested, and connect it back up to the van
positive only, and get a 21w ( brake light bulb ) and connect the neg through the bulb to chassis.
if the bulb lights there is a drain, the brighter it lights the bigger the drain

using a bulb is easier than a meter, it either lights or it doesn't

do this before you return the battery if its duff, no point killing a replacement battery !
Steve
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kezza87
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Re: Starter battery drained - Split Charge?

Post by kezza87 »

Thanks for your help mockingbird, I've put the battery back on charge now. I had to use the "old fashioned" charger as the smart charger would only detect 5 volts.

I'll let you know how I get on after the tests.

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Re: Starter battery drained - Split Charge?

Post by Mocki »

kezza87 wrote:Thanks for your help mockingbird,

Looks like your nem-l51 battery is not too charged either
Steve
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kezza87
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Re: Starter battery drained - Split Charge?

Post by kezza87 »

Haha oh dear.... Auto correct! Or my phone is making up code names!

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Re: Starter battery drained - Split Charge?

Post by kevtherev »

Unfortunately that flattened battery is now no longer 100%
It will never recover from that state fully.
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kezza87
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Re: Starter battery drained - Split Charge?

Post by kezza87 »

I thought it might be and it seems your right, I managed to get the smart charger to recognise it so left it on over night and it's still in the red so is barely getting past about 20% charged but is showing 12.5v.

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Re: Starter battery drained - Split Charge?

Post by Mocki »

Unfortunately the 12.5v you are seeing is not the battery voltage, but the voltage the charger is applying .....
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kezza87
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Re: Starter battery drained - Split Charge?

Post by kezza87 »

Ah ok I didn't think about that. I did the battery tests.
Test number 1, the voltage dropped from 13.33v down to 13.18v in 24 hours. So is it definitely toast?

Test number 2, I couldn't find any kind of drain to ground from either battery so I'm assuming the problem must simply be the battery is a dud.

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Re: Starter battery drained - Split Charge?

Post by AngeloEvs »

Drain current is a problem, not in your case it seems but for anyone reading this worth bearing mind that some car radios and alarms will drain the main battery if the van is not used regularly or left standing. You can ft an isolating switch or disconnect the battery to prevent any form of leakage. Recommend fitting an isolating switch simply to rapidly disconnect the battery in the event of an electrical short circuit. Seen T25's go up in smoke and total write offs because of electrical faults on this forum.
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Re: Starter battery drained - Split Charge?

Post by Dubworth »

Apologies for resurrecting an old thread, but it seems to make more sense than starting new in this case.

My wife yesterday left a cig-lighter powered cool box on in the van, this was fed from the leisure battery. Now I'm actually about to replace the leisure battery as I know it to be old and probably down a cell or few, as recently it has been 'gassing' with the lovely sulphur smell that goes with it. The van runs on a split charge, and the leisure battery is also topped up by a 100W solar panel and PWM controller (certainly not enough to power a coolbox, I know this).

I have the same issue as the original Poster, not only is my leisure battery now well and truly dead(I was actually bringing the van in to have it replaced today), it has also drained my starter (much to my chagrin, my boost pack...also was without charge as I forgot to charge it...d'oh)! Should a split charge relay stop this from happening, ie one battery dying then draining the other, or is this fairly normal behaviour when a battery is failing in a split charge system?

Thank you for your knowledge on this, I'm still learning on this side of things :)
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