Do car batteries die overnight?

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Nuro

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Hi All

I have a 2003 Polo, and suddenly the battery has started running down overnight, to the point where the engine won't turn over, and all the lights dim when I try and start the car.

I jump started the car, and drove her around for the day, and she started without hassle every time, but as soon as she stands for about 12 hours, dead again. I measured the current while switched off and locked, and it came to 0.05A after about a minute (cabin light switching off, etc) so I don't think there is a short. I did a proper test with my multimeter in a series connection, between the negative terminal and the battery.

Now, the battery was replaced after a bumper bashing about 1.5 years ago (the battery was stolen somewhere during the tow and the panel beating shop getting the car), so it's a bit early for the battery to die. I suppose it could just be a bad battery, or they gave me a 2nd hand battery.

I don't mind replacing the battery, just don't want to fix the wrong problem.
 
I had to replace my battery on Saturday. After 4 years it decided to let go if standing for more than a day. Especially with the colder starting temperatures it might start dying overnight.
 
Nuro said:
Hi All

I have a 2003 Polo, and suddenly the battery has started running down overnight, to the point where the engine won't turn over, and all the lights dim when I try and start the car.

I jump started the car, and drove her around for the day, and she started without hassle every time, but as soon as she stands for about 12 hours, dead again. I measured the current while switched off and locked, and it came to 0.05A after about a minute (cabin light switching off, etc) so I don't think there is a short. I did a proper test with my multimeter in a series connection, between the negative terminal and the battery.

Now, the battery was replaced after a bumper bashing about 1.5 years ago (the battery was stolen somewhere during the tow and the panel beating shop getting the car), so it's a bit early for the battery to die. I suppose it could just be a bad battery, or they gave me a 2nd hand battery.

I don't mind replacing the battery, just don't want to fix the wrong problem.
Click to expand...

go and have your tracking unit tested...
If they go wonky, they can bleed your battery dry overnight.

I had the same issue with my car. Wanted to have the battery tested but it was one of those "maintenance free" batteries. Guy at the auto-elec workshop suggested I have my tracker unit tested because he's seen plenty cars come in with the same problem.

So check the tracker unit first before replacing the battery... because it would just bleed the new battery dead too.
 
If you have a multimeter hook it up in series and check how much current is being drawn when the car is off (with lights/radio etc off) - it should only be drawing a few milliamps. If its drawing lots then you have something in the car that is shot (tracker), if nothing is drawing major current then the battery is kaput.
 
gregmcc said:
If you have a multimeter hook it up in series and check how much current is being drawn when the car is off (with lights/radio etc off) - it should only be drawing a few milliamps. If its drawing lots then you have something in the car that is shot (tracker), if nothing is drawing major current then the battery is kaput.
Click to expand...

Yup, mentioned in OP, did a test, only drawing 0.05A, so not much at all. I'll get the tracking unit tested anyway, was fitted a month ago when I switched insurance companies.
 
Well if they supplied you with a 2nd hand battery or a very cheap battery I would say 18 months was good and I would go and get another battery.
 
I think it would be a good idea to get the alternator tested before you put in the new battery just to be sure that the voltage regulator is working correctly. The one on my alternator went bad and damaged my battery. It would have also damaged the new one if the battery place didn't test it first. In hindsight I had noticed that the fan was making a different sound from time to time but didn't realise the cause until it was too late.
 
What make of battery did they fit?... From the sound of it, I would also say its the battery
 
Nuro said:
Hi All

I have a 2003 Polo, and suddenly the battery has started running down overnight, to the point where the engine won't turn over, and all the lights dim when I try and start the car.
Click to expand...

Sounds suspiciously like a dead cell. They tend to show up when the nights are cold.

Have one of the battery places do a load test: if it is a dead cell you'll know immediately.
 
rrh said:
Sounds suspiciously like a dead cell. They tend to show up when the nights are cold.

Have one of the battery places do a load test: if it is a dead cell you'll know immediately.
Click to expand...



I agree. Up until a few years ago, was working in my dad's motor spares, so have sold/tested many batteries in my lifetime. (Was helping out from age 8 till 29, all part of growing up, so no slave labour :-)). Definitely sounds like a dead cell. Yes, they normally run down overnight, but once you have it started, it will run all day just fine. Definitely doesn't sound like alternator/voltage regulator. If it were, you would not be able to drive all day as the battery would not be able to charge.

Also, most battery manufacturers give you a 12 month guarantee and on some occasions a 24 month guarantee. If your battery lasts longer than this, its a bonus, so don't be too disappointed. Sometimes batteries can last up to 5 years, but this is the exception rather than the rule.

Back in the old days when things were made to last, it would not be uncommon for a battery to last 5 years, however in this day and age, the least we can expect is to last the warranty period.

Good luck with that.
 
Thanks guys. Took it to battery centre this morning, and they did a bunch of tests for me. They only problem they could find was the battery, so forked out for a new one. It's one of those exide silver calcium maintenance free ones.

I did a trickle charge on the old battery yesterday, and left it disconnected overnight to see what would happen. The voltage was only 10.45V this morning (12.88V when disconnected), so was probably poked.
 
Nuro said:
Thanks guys. Took it to battery centre this morning, and they did a bunch of tests for me. They only problem they could find was the battery, so forked out for a new one. It's one of those exide silver calcium maintenance free ones.

I did a trickle charge on the old battery yesterday, and left it disconnected overnight to see what would happen. The voltage was only 10.45V this morning (12.88V when disconnected), so was probably poked.
Click to expand...

Yip, that sounds too low. My SO also had/has an Excide battery in her car, and I think it's also on it's way out.
 
Just replaced mine too. After 4 years, my Varta was still holding full charge, but it just couldn't crank my diesel engine in the mornings due to the colder temperatures.
 
My battery is doing the same thing. Over the last few years i noticed that during winter the car struggles to start. I wonder if if has any thing to do with the cold weather affecting the battery
 
So my battery died the other night. Same thing... fine one day, and dead the next (as in central locking wouldn't work, never mind starting the engine dead).

Took it to a battery place nearby, and the battery was poked. On the car, they checked that the charging voltage was fine (just above 14v) with the car on, and that the battery drain with the car off was only a few milliampere. So there was nothing on the car that was draining the battery.

So to answer your question, yes it happens, they do seem to die overnight.

Paid R750 cash for a new 55Ah battery.
 
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