Charging voltage too high?

[windowlicker]

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?

 

[jeeeep]

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?

When the car is running and charging,14-15v is normal. When not running, a full battery is around 12.5v.

What you experienced with the Optima is not unusual, the quality of Optima has gone down significantly over the last few years. Not sure where they are manufactured now.

 

[USMMA11NC]

When the car is running and charging,14-15v is normal. When not running, a full battery is around 12.5v.

What you experienced with the Optima is not unusual, the quality of Optima has gone down significantly over the last few years. Not sure where they are manufactured now.

What jeeeep said! Your new battery appears to be acting normally. It's a shame that the yellow top quality had dropped off.

Pro tip: Your battery is dead when it reads this :

 

[windowlicker]

Thanks for the reassurance guys.

I'm old skool, and thought charging voltage should be in the range 13.2-14.2, but I guess modern vehicles (and batteries) are designed to operate with higher voltages. I may have to remove the plug in voltmeter - it makes me sweat when it flashes 15.1

The replacement Optima cost me around $300, so I hope it lasts! Is there a better alternative, if it craps out again? Bearing in mind that a US battery may not be available in the UK. Choice of AGM batteries seems to be quite limited here.