I have a vauxhall agila 03 I have a test on battery and alternator which are both working fine,I dont leave any electrics on including interior light but after about 2 weeks it's gone flat again?
Battery keep going flat
- Thread starter romario2
- Start date
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Quite a common problem on modern vehicles, the most likely cause is that current is being drawn by something while the car is parked.
Disconnect the + battery terminal with everything turned off and connect an amp meter between the battery and the lead you have removed, it will show a small discharge but it shouldn't be more than say 50m/a, that rate of discharge would run a good say 50ah battery flat in 1000 hours, if it is much more than that firstly make sure there are no lights staying on, in the boot for instance, if not remove the fuses one by one until the load drops, then find out what that fuse powers.
If the battery is not in very good condition it could go flat in two weeks left standing with normal current draw.
Peter
Disconnect the + battery terminal with everything turned off and connect an amp meter between the battery and the lead you have removed, it will show a small discharge but it shouldn't be more than say 50m/a, that rate of discharge would run a good say 50ah battery flat in 1000 hours, if it is much more than that firstly make sure there are no lights staying on, in the boot for instance, if not remove the fuses one by one until the load drops, then find out what that fuse powers.
If the battery is not in very good condition it could go flat in two weeks left standing with normal current draw.
Peter
Obviously the battery is slowly discharging somehow.
This can be due to an internal fault in the battery itself or a small current drain within the car such as the alarm/immobiliser circuit, a boot or glove box lamp not switching off, or more rarely an alternator fault.
The big check is to fully charge the battery and then disconnect one of the battery leads to see if it holds its charge.
John
This can be due to an internal fault in the battery itself or a small current drain within the car such as the alarm/immobiliser circuit, a boot or glove box lamp not switching off, or more rarely an alternator fault.
The big check is to fully charge the battery and then disconnect one of the battery leads to see if it holds its charge.
John
Great minds, etc Peter - and a very good morning to you!
John
John
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As an ex battery laboratory technician, testing automotive batteries under ALL conditions, I can tell you that.......
whatever your problem (about which, you have received several good suggestions) if your battery goes below 10.5 volts when it's discharged, then the chances are, that whatever the problem, even if cured, you are unlikely to ever recover the battery.
If charged IMMEDIATELY it gets to 10.5 volts, you stand a chance; if left at, or below this for any time, your battery is shot.
You can recharge it, but you are likely to have a battery which WAS say 40Ah when new, will now have a capacity of something like 1Ah, and you will be lucky to even start the car.
The plates sulphate (the paste drops off them, and sinks to the bottom of the battery, and shorts out many of them, leaving one or two un-shorted plates to perform the function of many plates.
New battery is the only answer.
AFTER......you have cured the fault that caused the problem of course.
whatever your problem (about which, you have received several good suggestions) if your battery goes below 10.5 volts when it's discharged, then the chances are, that whatever the problem, even if cured, you are unlikely to ever recover the battery.
If charged IMMEDIATELY it gets to 10.5 volts, you stand a chance; if left at, or below this for any time, your battery is shot.
You can recharge it, but you are likely to have a battery which WAS say 40Ah when new, will now have a capacity of something like 1Ah, and you will be lucky to even start the car.
The plates sulphate (the paste drops off them, and sinks to the bottom of the battery, and shorts out many of them, leaving one or two un-shorted plates to perform the function of many plates.
New battery is the only answer.
AFTER......you have cured the fault that caused the problem of course.
