Hello all. I have a 2013 XF Supercharged with the ECO system. After replacing both batteries and the alternator, and monitoring the main voltage with a volt meter while driving, I noticed the car is only charging during de-acceleration and braking. I have read a factory paper on the system, but it did not specifically address this issue. As well, when I unplug the single wire on the alternator feeding information to the ECM, the alternator will charge as needed like an older system does, but the battery not charging message illuminates. Has anyone heard of this? Thanks, Brandon

 

Wrong forum (you want x250) but the answer should still be the same. Today's "smart charging" changes the parameters of when the battery is charged. It reserves X% of the battery for regenerative (braking, slowing down) charging. Until your battery gets below the threshold (75%?) it won't charge it from the alternator unless the car is in slow down or brake mode. Consequently you are constantly with a depleted battery that sulfates more and shortens its' life. But it saves gas .... not enough to make a difference to the cost of the premature battery replacement IMO .... and definitely not good for people that live in extremely cold climates where batteries have a perilous life. But it helps the MPG stats and makes the Eco fascists happy. That's my understanding and I'm open to correction. Interesting though .... my X260 with a single battery doesn't seem to follow that pattern as it's usually fully charged after a long drive.

 

Thanks for your reply. I will repost any changes as I work through this. Brandon