Month old 055 battery, had to jump start this morning after weekend of no use, parked up at work (8hrs) and had to jump start again. (Had spare battery and leads in car from morning)

Voltage at Idle after 15 Miles/35 min journey home- 13.85V
Voltage at Idle with 250W of lights on - 13.58V
Voltage with car off after above - 12.82V
Current draw, with doors locked and alarm on - 0.05A / 50 milliamps

Voltage 5 mins later - 12.59V
Voltage an hour later - 12.52V


Tried to crank it with the fuel pump off, voltage drops to 7 volts after 2 secs, starter motor disengages and clicks.

Jump start and Voltage reads 13.99V


Seems to suggest that the alternator is ok, and battery has lost capacity.

Sure does, still got the receipt ?

Yes it does sound like a duff cell in the battery..

Does sound like the battery.

Have you done an ignition off draw down test to see if something is drawing from the battery whilst the ignition is off ?
Just thinking it seems strange for a new battery to fail so early ?

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Originally posted by perksy
Does sound like the battery.

Have you done an ignition off draw down test to see if something is drawing from the battery whilst the ignition is off ?
Just thinking it seems strange for a new battery to fail so early ?

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Almost certainly a dead cell but to be a 100% sure it should be charged off the car for a few hours at a low current rated, rested for a couple of hours then tested with a proper load tester.

The other thing it could be is leaking diode n the alternator but if that were the case you would see the current draw.

quote:

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Originally posted by britishtridentThe other thing it could be is leaking diode n the alternator but if that were the case you would see the current draw.

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