# Battery Drain Help



## Mossup (Jun 30, 2016)

Noticed the LB on my motorhome is going flat after 4 days or less when not being used. 
Checked for any current drain with a meter and noticed about 0.5A being used. I traced it to a circuit protected by the 7.5A fuse shown here. It's the 2nd fuse from the right. 
Anyone know what the symbol above it denotes? Looks like a spark of sorts so I'm guessing its possibly gas ignition?? 

Any suggestions on how to diagnose exactly what's causing this please? 

Currently got the battery fully charged from the EHU and have disconnected for the night to see there's an issue with the battery itself also.

Thanks


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## Mossup (Jun 30, 2016)

Better pic here.,.


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## gaspode (May 9, 2005)

A quiescent current drain of 500ma could certainly flatten a battery within 4 days, How low is the battery voltage going? I'd expect a good condition 100a/h battery to be at 12v (no-load) or just under after 4 days of 500ma drain, if it's well under 12v then it's likely that the battery is well past its best. You also have to consider that there may be an additional internal current drain if the battery is a few years old.
The only way to check is to connect an ammeter in series with the battery and isolate different circuits in turn until you locate the cause. Maybe you've already done this to be suspicious of the 7.5 amp fuse circuit?
If so, you need to remove the fuse and see if the battery still goes flat as quickly. If it doesn't then you'll need to trace all the wiring from that fuse to see what it feeds. As you say, the symbol looks like a spark ignition but there may also be other things connected, either from new or more likely that have been added by previous owners. I've never heard of a spark ignition causing this sort of problem but anything is possible.

Good luck in your search.


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## Mossup (Jun 30, 2016)

gaspode said:


> A quiescent current drain of 500ma could certainly flatten a battery within 4 days, How low is the battery voltage going? I'd expect a good condition 100a/h battery to be at 12v (no-load) or just under after 4 days of 500ma drain, if it's well under 12v then it's likely that the battery is well past its best. You also have to consider that there may be an additional internal current drain if the battery is a few years old.
> The only way to check is to connect an ammeter in series with the battery and isolate different circuits in turn until you locate the cause. Maybe you've already done this to be suspicious of the 7.5 amp fuse circuit?
> If so, you need to remove the fuse and see if the battery still goes flat as quickly. If it doesn't then you'll need to trace all the wiring from that fuse to see what it feeds. As you say, the symbol looks like a spark ignition but there may also be other things connected, either from new or more likely that have been added by previous owners. I've never heard of a spark ignition causing this sort of problem but anything is possible.
> 
> Good luck in your search.


I haven't checked how low the voltage is going. I'll check that next.
Yes, I connected an ammeter in series as you suggested to track down the 7.5A fuse. I don't fancy tracing all the wiring ... I'll end up stripping the whole van ! :frown2: But I guess there's not much choice... I suppose I could pull the fuse and see what doesn't work any more and start from there.
Thanks for you help...


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## cabby (May 14, 2005)

So lets consider what you have on 12v in the Leisure side, are there any bulbs left on in the bathroom say,Is there a clock that runs off the battery,is the radio connected to the LB rather than the engine battery, or an extra radio in the back, maybe the TV left on standby..
Have you left the awning light on.
With the battery fully charged wander round checking. It is bound to be something we take for granted.Do you have a microwave that has a clock.
Do let us know what it was when you find out.

cabby


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## siggie (Oct 2, 2010)

Take the fuse out and try to discover what no longer works ;-)


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## gaspode (May 9, 2005)

Thinking about it, a 500ma current draw suggests to me a 5 or 6 watt incandescent bulb so the first port of call would be a fridge or wardrobe light that is remaining on when the door is closed.


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## Mossup (Jun 30, 2016)

Further to this, the drain is happening when the main control panel switch is Off. Therefore no lights etc are on... On further examination the 7.5A fuse circuit is indeed controlling spark ignition. The fridge gas ignition and water heater ignition for a start. I haven't found any more circuits it's controlling just yet. 
I'll keep you posted..!


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## siggie (Oct 2, 2010)

Does the drain still occur with the 7.5A fuse removed?

Is it possible there is another feed straight from the battery, avoiding the control panel, for any other custom fitted circuit (power/USB socket, tracker, etc)?


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## Mossup (Jun 30, 2016)

The drain reduces to around 200mA with the fuse removed... Haven't found anything obvious yet..


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## Pudsey_Bear (Sep 25, 2008)

Not sure if it a helps or muddies the water, but from the charger, (see below) there is a grey wire along side the red & black, which is only 5v, this goes to the back of the fuse board, but no idea what it powers.


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## raynipper (Aug 4, 2008)

Is there a clock somewhere? Fridge control even when in the off position can still consume. Maybe the radio unless it's on the engine battery.
Just thoughts.

Ray.


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## dghr272 (Jun 14, 2012)

raynipper said:


> Is there a clock somewhere? Fridge control even when in the off position can still consume. Maybe the radio unless it's on the engine battery.
> Just thoughts.
> 
> Ray.


Good point Ray, I only discovered this year that my fridge display panel has a permanent live feed.

Terry


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## cabby (May 14, 2005)

Silly thought, if you turn the control back on and check everything is turned off, what drainage do you get then.It really sounds like a sensor or something similar.

cabby


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## Mossup (Jun 30, 2016)

Drain is the same whether panel is on or off. 
For now I've pulled the 7.5A fuse while its not in use. Not got chance for any more problem solving this weekend.... 
Thanks all


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## WildThingsKev (Dec 29, 2009)

Kev_n_Liz said:


> Not sure if it a helps or muddies the water, but from the charger, (see below) there is a grey wire along side the red & black, which is only 5v, this goes to the back of the fuse board, but no idea what it powers.


The grey wire is probably a control wire to close the relay that feeds the vehicle battery when the charger is powered up. The relay would be normally open so the vehicle battery is isolated.


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## Pudsey_Bear (Sep 25, 2008)

WildThingsKev said:


> The grey wire is probably a control wire to close the relay that feeds the vehicle battery when the charger is powered up. The relay would be normally open so the vehicle battery is isolated.


Cheers Kev, sparky stuff not really in my repertoire.


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## Mossup (Jun 30, 2016)

Just had a thought. The electric steps always have power regardless of the control panel switch. Could be a fault on those.....Maybe....


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## cabby (May 14, 2005)

I thought about that, but I assumed that it worked off the cab battery, via the relay.

unplug it at the step end.

cabby


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## Glandwr (Jun 12, 2006)

You don't have a battery master fitted do you? The gizmo that trickle charges the vehicle battery from the LBs if the vehicle battery falls below a critical voltage. If you do maybe your vehicle battery is buggered but you don't know it.

http://www.campervanstuff.com/shop_stuff/index.php?mod=product&id_prd=976

Dick


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## Pudsey_Bear (Sep 25, 2008)

Glandwr said:


> You don't have a battery master fitted do you? The gizmo that trickle charges the vehicle battery from the LBs if the vehicle battery falls below a critical voltage. If you do maybe your vehicle battery is buggered but you don't know it.
> 
> http://www.campervanstuff.com/shop_stuff/index.php?mod=product&id_prd=976
> 
> Dick


Don't they shut down if the LB drops too low Dick.


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## Mossup (Jun 30, 2016)

Glandwr said:


> You don't have a battery master fitted do you? The gizmo that trickle charges the vehicle battery from the LBs if the vehicle battery falls below a critical voltage. If you do maybe your vehicle battery is buggered but you don't know it.
> 
> http://www.campervanstuff.com/shop_stuff/index.php?mod=product&id_prd=976
> 
> Dick


Don't think so Dick but I'll take a look. Presumably this would be wired close to either of the batteries?


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## Pudsey_Bear (Sep 25, 2008)

I think if you plug in the vans EHU, and the Vb starts to charge, then you have a link of some sort twixt LB & VB, but I think you will need to get the LBs above 12v at least for it to turn on and possibly the VB below that, to demand supply.

But I could be talking out of my posterior


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## Mossup (Jun 30, 2016)

I know that when I start the van the alternator is charging both batteries as I get a voltage reading of over 13v at both. So I guess, at very least there's some sort of split-charge relay set-up, although as I understand it , that doesn't mean I have a Battery Master fitted.
Correct me if I'm wrong but the Battery Master sounds like a split-charge relay that only kicks-in when the VB voltage drops below that of the LB.


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## raynipper (Aug 4, 2008)

Ironically I went to start my van to give it a little run and lube.
The engine battery was flat as a pancake.!! 
Seems the Ctek built in charger that keeps the engine or chassis battery topped up had switched off.
All OK again after resetting charger and going for a little ride out. But now of course the chassis battery will be suspect.
It's only 3 years old and has not really been used in earnest just kept topped up by the Ctek.

Another thing to worry about.

Ray.


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## Pudsey_Bear (Sep 25, 2008)

Mossup said:


> I know that when I start the van the alternator is charging both batteries as I get a voltage reading of over 13v at both. So I guess, at very least there's some sort of split-charge relay set-up, although as I understand it , that doesn't mean I have a Battery Master fitted.
> Correct me if I'm wrong but the Battery Master sounds like a split-charge relay that only kicks-in when the VB voltage drops below that of the LB.


Yup, the split charge relay seem to be working okay at least, I'm not sure how the B2B type work TBH.


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## Mossup (Jun 30, 2016)

UPDATE 

Havent had much time over the last week or so to revisit this but managed a quick look yesterday. 
Since tracing the drain to the 7.5A fuse I removed it 2 weeks ago. Since then the battery has maintained charge. 
The only things I can figure out are attached to this fuse are the Fridge ignition and Water heater ignition. Neither seem to be continuously sparking when the fuse is in so still a bit of a mystery...
Definitely no clocks or car radio etc on this circuit either


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## Pudsey_Bear (Sep 25, 2008)

I jsut looked for a wiring diagram but didn't find one


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## Mossup (Jun 30, 2016)

Thanks for lookin Kev


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## philoaks (Sep 2, 2008)

Mossup said:


> UPDATE
> 
> Havent had much time over the last week or so to revisit this but managed a quick look yesterday.
> Since tracing the drain to the 7.5A fuse I removed it 2 weeks ago. Since then the battery has maintained charge.
> ...


Are you able to access the 12v connections to the water heater and fridge? If so I'd disconnect them and see what (if any) drain there is through that 7.5A fuse with them both disconnected. If the drain is still there then there must be something else connected to that same circuit. If not then reconnect one at a time and see when the drain returns.

Just as an afterthought..........there isn't a fan fitted at the back of the fridge to improve air flow during hot times is there?


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## Mossup (Jun 30, 2016)

philoaks said:


> Are you able to access the 12v connections to the water heater and fridge? If so I'd disconnect them and see what (if any) drain there is through that 7.5A fuse with them both disconnected. If the drain is still there then there must be something else connected to that same circuit. If not then reconnect one at a time and see when the drain returns.
> 
> Just as an afterthought..........there isn't a fan fitted at the back of the fridge to improve air flow during hot times is there?


Good idea but I don't think I can access (easily) either the fridge or water heater. I'll have to take a look when I've got more time.my
As for a fridge fan.I don't think there is. At least I haven't heard one, and I've listened quite a lot for things that may be running and causing a drain...
Thank you.


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## Pudsey_Bear (Sep 25, 2008)

Fridge access is via the bottom vent mainly, fan would be in the top one but would be a retro fit not original, water heater is under the long sofa??? but is gas only I think except for the igniter which you would hear anyway.


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