I have reposted the following from another thread because I thought it might generate more attention.

It was suggested I charge my battery to see if it would resolve problems with BSM and rear cross detection..
8 hours charging on the CTEK 5.0 to get to green status did not solve those issues.

However, it did raise a question about battery charging while driving.
I went back to look at my trips over the past few months on the Jaguar Remote app.
Most were over 20 miles, many over 50 miles, with relatively few under 5 miles.
So even averaging 1,000 miles/month the battery still needed charging.
So, I am curious why a new 2021 battery would need so much attention given the way I have been driving.
Does this suggest a bad battery or a defective charging system?

 

CTEK and similar systems require a battery to be absolutely full before they go green. Even after a long drive, batteries lose a bit. You lock the car, which draws current, and then the battery carries on draining for up to 10 minutes. Not by a lot, but enough to take the top off the charge. The alarm is then on which takes some. The CTEK doesn't charge at a high rate, so it takes time to bring the battery back to "Green"
On most cars I have, batteries which I think are fully charged will take a while on my CTEK equivalent to go green.
If you don't have battery problems, I wouldn't worry. If you do, and the battery goes flat over time, then you need to look again

 

Make sure your key fob remote is not kept in or near your car. Battery drainage problems have been reported. Also when I bought my 16R I don't think dealer followed the correct OBD tool removal and battery died in driveway in less than a week. indie mechanic did the same when I had to get an inspection. Not sure if any of above applies to 2021.

 

Thanks, jaguny.
I already pay attention to those points from following information learned on this forum.
Since buying the car, this forum has provided a wealth of info. Thanks all.

 

We talked about charging years ago here. My memory of that is it didn’t seem the F-type charging system always charged to 100%. Or perhaps the battery maintainers don’t have the same 100% voltage as the car’s charging system. I think SLA vs. AGM also have slightly different voltages at 100% charge, though I could be wrong.

There’s also the concept of float charge, though I don’t know if that would factor in here.

 

Since most locations now use OBD's for smog testing, I've wondered why we don't hear more about problem drainage issues from the annual process. Cars are exempt for the first few years, and my county no longer is required to test, but there was a period in the middle and I didn't have an issue.

Is it only some OBD devices that create a problem?

 

That seems to be the case.

 

Interesting point and there could be a flood coming. Here in California, which has some of the most brutal smog rules anywhere, cars are exempt for the first 8 years unless you sell them, then they are required at transfer if they are older than 4 years old. I've seen a huge amount of cars sold when the 3 year lease is up, which would not require a smog check. None of the cars out here have yet to hit that all important 8 year mark, but it is coming soon. This could be a bit of a **** show when it does happen.

 

Hi CJS - just posted on your other thread

On my XF V8 I also have the ctek with that plug in red/amber/green socket. Sometimes after a 2+ hour highway drive it can still show red on ctek socket. But a multimeter shows it plenty charged. I've concluded the ctek lights are v sensitive and treat fully charged as really fully charged. Think having interior lights and trunk light on once parked puts enough drain to make it show red. Strangely if I park, go away for a couple of hours and come back, it can show green without any further charging

So, check with a multimeter but it doesn't sound like you have any battery or charging issue.

And yes / the OBD port issue is some cars only, and some devices only. I never have issues after a dealer visit or with my code reader. But the MA state annual inspection trips it every time and I have to disconnect and reconnect the battery
Car came from CA (where it didn't need to be tested) so the dealer and prior owner never experienced the issue.

 

I understood that if the OBD tool was disconnected before the car was shut down that the issue wouldn't occur, Could be wrong.

 

No - for the MA service they unplug the OBD while the car is still running. But when I shut down I still have the issue
It seems that some OBD devices correctly end the session and stop this issue. Others leave some module(s) running indefinitely
But - only an issue on some cars

It's an easy fix to disconnect and reconnect the battery once a year at state inspection. So I just live with it.