Hi Guys

i have my xf battery on charge, it was very low when i bought it must of been on dealership yard for a while

just want to know if Theres anything i should be worried about other than recalibrating windows and parking brake ?

Thanks
Dan

 

Other than reset your radio stations/clock, no.


But if the battery is very low, it might not come all the way back and be reliable.


If you start having small drivability issues or electric gremlins, replace it with a fresh unit.

 

Welcome to the forum Dan,

You don't mention Model Year so I can't tell if your vehicle has BMS (Battery Monitoring System) fitted. If so, you may get odd messages or DTC's set but it should recalibrate itself. BMS usually only needs calibration with Jaguar diagnostics after a disconnect and a new battery is fitted.

Please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST forum and post some information about yourself and your vehicle for all members to see. In return you'll get a proper welcome and some useful advice about posting to the forum.

Graham

 

thanks for the info

sorry about that - i have a jaguar xf 2012 2.2D premium Luxury, i think it does have the BMS i noticed a cable coming off the negative lead so i take it that's to to with the monitoring

hoping a full charge will fix it all

thanks for the welcome!

 

Modern Jaguars are very sensitive to battery condition. Partially discharged or failing batteries cause all kinds of weird error messages.

If it's not going to be driven regularly, a battery tender is a good plan. Most members use one of the CTEK range.

Graham

Graham

 

ill keep an eye out, there were no weird messages to be fair - the start stop wasnt working, checked voltage on battery it was only at 12.05 when disconnected so i think thats quite low, leaving it on charge overnight, will reconnect tomorrow

 

Another quick question can the car be driven without the auxiliary battery connected? Thanks

 

As I understand it, the “auxillery” battery is the smaller 16volt unit that runs the start-stop ECO system and does not need to be hooked up, but of coarse that kills the start-stop system from working.

And will probably give a warning indicator.

 

Well it all went well, no warning messeges at all, just the parking brake and windows needed recalibration, it let me run the car without the auxiliary battery just says eco stop start unavailable, ive now fully charged and fitted the auxiliary battery and the stop start started working.

So case closed, thanks for the help all

 

I own a 2015 XF 3.9SC AWD which I purchased new and the car now has approximately 18,000 miles on it. I use it every day but only put on about 20 miles per day. Every couple of weeks or so I plug the car into a Battery Tender Plus to bring it up to full charge.

recently had a problem where the Start/Stop function stopped working. I was also under the impression that this feature was controlled by the smaller battery in trunk. When I brought the car into dealer, the service advisor also said that the smaller battery controls the Start/Stop function. I told him that I was not so sure about this.

After about an hour the service advisor called me over to his desk and said that he had apparently given me incorrect information because my small battery tests fine but the larger battery was defective.

They changed the larger battery to an Interstate AGM 900 CCA battery under warranty and I have not had the problem since. This was done a few months ago.

So.....it appears to me that a defective larger battery can cause problems with the start/stop function and I am still not certain what the smaller battery does except to run auxiliary functions when the car is in the STOP position. In your case, I would not rule out a defective larger battery as the culprit.

 

Yes that's correct.
We need to understand how the system works.
The big battery does all the starting and stopping. The little battery is to power the rest of the car when the engine is off. So if the big battery gets weak then the car will shut off the ECO mode. Same as if the little battery gets weak ECO mode is shut off.
.
.
.

 

That would make sense. On all the older cars I've ever worked on with a traditional ignition switch (was just replacing a Chevy switch yesterday), the start position disables most of the car's electrical systems in order to devote as many amps as possible to spinning the starter motor. If the starter is going to be spun every one or two city blocks, then it probably needs every bit of the biggest battery they could fit and it will probably still get down to 50% of capacity sometimes before the car gets back on a freeway for long enough to recharge. With Jaguars so sensitive to low battery power, they probably figured the best way to keep the computers from freaking out after ten city blocks was to put in a second backup battery. But I'm just theorizing.....

 

Your theory sounds solid.

I was told a few years ago that the smaller battery was a 16v unit to spin the starter over very fast to get it to fire fast at the light.

Now that we know that the battery is the Exide 151 battery, it is 12v and is way to small to spin the starter over effectively.