Battery Flat
Posted: Fri May 16, 2014 8:19 am
Hi,
I recently have been experiencing flats on my (12 year old) battery for my Mk6 '02 Fiesta. The first time was afetr I accidentally left the cabin light on for a couple of days. Remarkably the car still started but the next time it was left in the driveway for a few days the batt was flat and it required jump starting. The battery will charge off the alternator (I measured 14V across battery while idling). With everything off including the engine I could watch the voltage on the battery drop from 12.20V by about 0.01V every couple of seconds.
At first I tried to measure a current draw with everything off using a magnetic loop ammeter on the positive batter wire, it was showing -7A but I didn't know whether to believe this figure. I disconnected the positive connection on the alternator but it made no difference to the reading.
After some YouTube-ing I tried to measure for any current draw with everything off using an inline ammeter between the negative battery terminal and the negative wire which I had disconnected but the value seemed to be just noise? Around 6mA??? I turned on the cabin light and it drew about 0.5A so I think I had the ammeter connected correctly?
Does this sound like the battery itself is gubbed or have I missed something else?
Thanks
I recently have been experiencing flats on my (12 year old) battery for my Mk6 '02 Fiesta. The first time was afetr I accidentally left the cabin light on for a couple of days. Remarkably the car still started but the next time it was left in the driveway for a few days the batt was flat and it required jump starting. The battery will charge off the alternator (I measured 14V across battery while idling). With everything off including the engine I could watch the voltage on the battery drop from 12.20V by about 0.01V every couple of seconds.
At first I tried to measure a current draw with everything off using a magnetic loop ammeter on the positive batter wire, it was showing -7A but I didn't know whether to believe this figure. I disconnected the positive connection on the alternator but it made no difference to the reading.
After some YouTube-ing I tried to measure for any current draw with everything off using an inline ammeter between the negative battery terminal and the negative wire which I had disconnected but the value seemed to be just noise? Around 6mA??? I turned on the cabin light and it drew about 0.5A so I think I had the ammeter connected correctly?
Does this sound like the battery itself is gubbed or have I missed something else?
Thanks