Battery going flat Twice in fortnight

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Aybesea
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Battery going flat Twice in fortnight

Post by Aybesea »

It seems that since we had that heatwave my battery has been going flat or rather down to 11.5 volts.it has done this twice.This morning i got in the car to start and zilch not enough to turn the starter.I had a spare Vartar battery so swapped them over and all ok went out and returned.i checked the volt charge and it came up as engine idle 14.2 volts ,with lights and rear heater etc all on showed 13.9 volts.so seems car is getting enough charge.but the 14.2 volts seems to be on the high side.what i did notice is that when i tried to start the car this morning i could hear the CD changer working ,like trying to find a disc even though the player was not switched on so pulled the cd cassette out.
I now got the Excide battery on charge which i took out two years old the one that replaced it is a vartar and that has been holding it's charge for 18 months now and worked straight away.
If it starts the car in about five days time at least i know it was the excide battery that is kaput if not then i have a leakage somewhere.Anybody have any suggestions as where i can start looking? Earth connection to chassis looks good.
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alexperkins
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Re: Battery going flat Twice in fortnight

Post by alexperkins »

14.2 is absolutely fine

The cd changer running when the car starts is also normal

You need to do a leakage test with a multimeter
Aybesea
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Re: Battery going flat Twice in fortnight

Post by Aybesea »

Thanks for that info,never heard the cd changer before but then the car always has started, so this time its why i have heard it as no engine running
Aybesea
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Re: Battery going flat Twice in fortnight

Post by Aybesea »

Well the car has been okay since my last post on this subject,i wondered if the electronic steering pump was playing up so i havent been turning full circle in the road now only 3point turn .I know VW say in the hand book you should not have the steering on full lock for more than 15seconds but it wasn't taking that long to turn car round.
Is there any electrics etc in the pump itself out of interest?
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Re: Battery going flat Twice in fortnight

Post by RUM4MO »

The power steering pump is electric and it needs a lot of power to keep it happy when you are turning the steering wheel. It is probably the highest of all the car's electrical consumers.
Aybesea
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Re: Battery going flat Twice in fortnight

Post by Aybesea »

Well after pulling all fuses etc which took a long time with checking everything my second battery ended up kaput after so many swaps with discharges and recharging.Took car to vw said needed new battery cranking amp was down also alternator was on its way out,so fitted new battery and alternator.Have now done another leakage test came out at 1.5mamps same as before,then by accident the day after found that the radio was not turning off even though nothing showed in the lcd panel that it was on .Pulled fuse and went down to .005mamps. will leave it a few days and check for leakage again.
Out of interest and not wanting to damage anything can a neg drain leakage test be found with out diconnecting battery neg but just going from neg battery to body earth? or has it got to be diconnected from battery.
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Re: Battery going flat Twice in fortnight

Post by RUM4MO »

No, you will need to break the circuit to the battery to measure leakage current, though I always do this by using the -Negative lead.

What I do is:- open bonnet > close all doors and lock car up > wait maybe 30 minutes to make sure all supplies have gone to sleep > what I do then is, using a DMM set on current - fit a crock clip lead to one side of the meter and fit a long thin spike probe lead to the other, connect the crock clip to the car body end of the earth lead and then press the spike probe lead down onto the top of the -VE battery terminal, then with a spanner in the other hand slacken off the -VE battery clamp and ease that lead up over the spike probe lead - then read off the measured current, then refit the earth lead and remove the spike probe from the -VE battery post. By doing that you have not done anything to waken up sleeping power supply controllers.
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Re: Battery going flat Twice in fortnight

Post by Aybesea »

Last time i checked it i opened bonnet locked everything up flicked shut the bonnet lock and took neg cable off and connected the DMM red to neg on battery and black to earth cable,i tried your way but had problems pulling the connector off the battery neg to lift it.Also found out that if the radio is on and the engine is turned off with the key there is power to the radio for 1hr then switches auto off to save battery,read it in VW Polo user manual.( i have not had radio on)
It's a pain not having a garage so its done outside weather permiting.
I have been out in the car this morning got back plugged in a ciggy LED volt metre and dropped from 12.6 to 12.4 volts after 40 mins.Have pulled the fuse for the radio so when i drive it next time and come back will see if it drops again to that voltage and how long it will take.Obviously im going to have some leak through clock and imobilizer,but that is not going to show 1.50mamps.Before i fitted the new battery the car started in the morning but by lunch time went to start and it was down to 11.30 volts.If it is not the radio,then it seems it is something like a micro switch somewhere or faulty ign switch that does not quite turn off hence leekage.
Are the micro switches sold seperatly or have to be sold with say a lock eg central locking or boot lock etc
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Re: Battery going flat Twice in fortnight

Post by RUM4MO »

Yes, with earlier cars the radio does stay on longer, though if it worked as intended, if you switched the radio off, its current draw would be minimal/zeroish. My wife's 2015 Polo switches its radio off after about 15 minutes and all the controllers shut down very quickly like they do on my 2011 Audi S4, so battery drain is being treated seriously nowadays.

I had considered tripping the bonnet lock but found with my cars, including the late 2009 Ibiza, that that made no difference.

Removing the battery earth lead, I suppose that initially I made sure that I could remove it easily while making sure it was able to keep good contact while it was still fitted, all trial and error stuff.

I think that the limit for "sleeping" level drain is 50milliamps, though I would expect that you could see less than that when everything is working as it should.

My issue was the late 2009 Ibiza was a slightly known software issue as later cars have a BCM to handle shutting down all unnecessary power loads. (Body Control Module)

Edit:- another clue to when all supplies have shut down is that the measured voltage across the battery rises slightly as the current draw has dropped to a very low level.
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Re: Battery going flat Twice in fortnight

Post by Aybesea »

Well it seems that it is the audio unit, drove the car for a 7 miles to the shops and back and parked up at 20.15pm with the 15 amp fuse taken out. Checked it this morning at 7.30 ish and it was reading 12.62v.
Does anybody know if a short somewhere in the wiring could cause this beside a faulty radio unit,or could the 6 cd changer in the boot be the problem?Which i cant see it being the cause as it should be off when unit switched off.
I supose it will be a case of disconecting the cd changer to find out .
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Re: Battery going flat Twice in fortnight

Post by alexperkins »

Unlikely to be in the wiring. My advice would be change the radio to something more modern and be done with it
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Re: Battery going flat Twice in fortnight

Post by Aybesea »

I have come to the same conclusion,had a look at Halfords web site but i would like to keep it VW if possible,are there any newer models that fit for eg. RCD 310 or something like that.Don't mind loosing cd changer.Shal i put a post in the ICE forum asking this Question.
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Re: Battery going flat Twice in fortnight

Post by alexperkins »

A newer RCD200 would work providing is it the earlier ISO plug model and not the later Quadlock model - from a 9N/9N3 polo.
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Re: Battery going flat Twice in fortnight

Post by Aybesea »

Okay thanks for that info will take a look on EBay .
Thanks
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Re: Battery going flat Twice in fortnight

Post by RUM4MO »

It was Gamma that I fitted to my wife's previous Polo, though as it was an SE it would have had the extra speakers already in it, as an import it was not fitted with ICE.

In case you do not know, be very careful when you buy a used Beta/Gamma/etc from ebay as if it does not come with the correct security key code, you will not be able to get that from VW as they stopped handing these codes out many years ago to anyone, now you need the original "mother car" VIN before they will help you - obviously this is to reduce theft from cars. Also, don't believe anyone that tells you that you stuff the serial number of a VW radio into a "code generator software package" - I have been caught by that lie. As far as I now, there is only one way to retrieve a missing code and that is by reading the stored "lock code" using special software and a clip to mount onto the correct chip, then feed that into some other software to convert that code into a usable series of numbers.
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