My wife's 13 XF started throwing low battery codes a few weeks ago. Comes on at start up says shut down in 3 or 1 minute and is gone before you can read it all. Battery was a Deka 800 CCA and was in for nearly 3.5 years. Took it to my local starter/alt rebuilder who also sold the battery. Tested out at about 790cca but I did note that the volts seemed to be a little low resting (around 12.3/12.4 after sitting for a few hours so I replaced it with a new Deka same 800cca which tested out at 890cca. Same thing after a few days of limited use. Did a parasitc draw test and after a few minutes with the vehicle locked the amp draw dropped to .01 so not a huge draw on it. Took it back in today to have him do a bit more testing and he also tested the small run/start which came back at 378 cca. He gave me another battery to throw in just to be sure there wasn't a fault with the few day old one that wasn't showing. It also throws low battery codes. Charging wise at an idle I'm getting a 14.8 reading at both batteries which I thought seemed a bit high until I checked on my 15 and it was 14.7. Cables look new in the trunk and just fine under the hood.

Any thoughts, or advice as I'm stumped. I wouldn't necessarily care if it was mine but the heat goes off when this happens. Never had this code show up in either car before. I really am not wanting to pull the one out of my car to try it in there as it is the really heavy Jag one so a PITA to angle in and out.

Thanks!

 

Hi TreVoRTasmin, Just out of curiosity have you replaced a starter or alternator on the vehicle with a rebuilt? The reason I ask is that I just recently rebuilt the starter on my 2010 and found draw issues which I had to keep a trickle charger on it daily. The other factor was that my daughter used it for short runs (10-15 minute drives that did not allow decent charging). The car will throw the low voltage warning on start up but go away within a minute of running, I replaced the battery in July with no issues until I had the started rebuilt.

I took it to a local mechanic who specialized with European vehicles (I was going to take it to my local dealership but there was a major shake up there and the staff all left so things are a bit confusing there right now) He replaced my rebuild with a new Bosch starter and no more issues. His explanation was that many rebuilds do not change out the electronics which could have been an issue in the first place and can do more damage to the electronics of the car over time. He also explained that Jaguars a very sensitive to voltage and amperage so even if the component works on the table, it might not pair properly with the vehicle. I was under the impression that there was just the solenoid and motor so I never thought of any electronic parts to ask about when I took the old one in for rebuild.

Wither this was the issue or not, all I know is that, in my case, it was eliminated with the new starter.

As for the stop/go battery, I looked at the 2014 XF and it has the JDE32902 which only has 200A and we have not had issues with it to date. I'm guessing the cca you outlined is derived from stress test which do not look bad to me. Not sure if this helps but it is what I experienced.

 

The battery negative cable has the battery monitor electronics in it and could be dropping some voltage. Check voltage between battery negative and the car ground i.e. engine. Voltage should around zero even with ignition on. If it is not zero then you are losing volts across the device. You could try connecting battery negative to ground directly with a jumper cable and see if things act normally.

 

This is a common misunderstanding about the two battery stop/start system, the smaller 200 CCA battery does NOT restart the car / power the starter motor, it's too weak for that and the main 800 or 850 CCA battery still does that job.
The small battery is used only to power the peripherals - lights, HVAC, infotainment etc - during the brief time that the "start" phase of the stop/start system is triggered, so that the starter motor gets the full whack of amps from the main battery. Then once the engine has restarted the main battery takes over again and the secondary battery goes back to sleep/stand by.

 

Thanks OzXFR for clarification as I always wondered about the amps of the stop/go battery.

 

Would it be possible to add the smaller battery to cars without the two battery system? And is it even worth doing it?

 

Why would you ever in your wildest dreams consider doing that?????
I can't see what it could possibly achieve or how you could wire it in.
Even if you could figure out a way to wire it in you still wouldn't get a working stop/start system without spending squillions on other modifications, and even then I somehow doubt it is possible.

 

lol good to know I’m on missing out on anything. Thanks for the info.

 

Thanks for the replys. Let me clarify that when I put the 2nd new battery in which just tested above 850ccas before we put it in immediately resulted in the 3 min low battery warnng light coming on for a split second on the second start up 5 minutes later. Battery was fully charged with a manufacture date of 11/20 (Dekas are made a few miles from where I live). Nothing else has changed on the car, starter and alternator are originals at 90k.

 

Well problem solved. After 3 different batteries did the same thing my wife decided to trade it in on an i pace. Seriously on the 3rd battery it stopped the warning after a day. Why I can’t say as the 2nd battery actually had a few more cca when tested.