windowlicker
New member
I have a 2009 JKU CRD here in the UK.
On a long trip last summer I noticed a strong sulphur smell, and found the original 6 year old Optima yellow top battery was swelled up and hissing. I replaced it with an identical new battery, and checked the charging voltage with a multi meter: 14.5V at all engine speeds. I thought this was a bit high, but the Optima battery label says it is within limits (<15.0V).
No problems since, but I recently installed a constant voltage monitor in the cigar lighter socket. It reads 14.3-14.5V at all engine speeds when the engine/battery is cold, but once warmed up it varies between 14.8 and 15.0V. Even flashed 15.1 briefly on a longer trip. Doesn't seem to make much difference whether I have lights/wipers etc on or not. I haven't had any more issues with the new battery for 6 months, but can't help wondering if I'm shortening its life.
My understanding is that voltage is regulated via the PCM, and I read that it can be re-flashed to lower the charging voltage, but the thought of taking it to the only Jeep dealer within 100 miles fills me with dread, based on previous experience of them.
Any thoughts?
On a long trip last summer I noticed a strong sulphur smell, and found the original 6 year old Optima yellow top battery was swelled up and hissing. I replaced it with an identical new battery, and checked the charging voltage with a multi meter: 14.5V at all engine speeds. I thought this was a bit high, but the Optima battery label says it is within limits (<15.0V).
No problems since, but I recently installed a constant voltage monitor in the cigar lighter socket. It reads 14.3-14.5V at all engine speeds when the engine/battery is cold, but once warmed up it varies between 14.8 and 15.0V. Even flashed 15.1 briefly on a longer trip. Doesn't seem to make much difference whether I have lights/wipers etc on or not. I haven't had any more issues with the new battery for 6 months, but can't help wondering if I'm shortening its life.
My understanding is that voltage is regulated via the PCM, and I read that it can be re-flashed to lower the charging voltage, but the thought of taking it to the only Jeep dealer within 100 miles fills me with dread, based on previous experience of them.
Any thoughts?
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