Following on from my earlier post:
I have a 2015 V6 S, although possibly the 2016 model
It is permanently hooked up to a ctek, and on locking, the red triangle extinguishes so no ongoing battery drain from OBD II issues. Battery shows fully charged on CTEK, but car warns "low battery", and yesterday morning "power management shutting down system in 2 minutes"
I thought maybe a duff battery, or fault on the warning system.
My garage asked me where I connect the Ctek. I connect it directly to the positive battery terminal and the floor earth connection in the trunk. The technician said that was the problem. He said I am bypassing the battery management system so it doesn't understand it's being charged and shows the warnings. He said I need to connect directly to the poles under the hood. He confirmed the battery is fully charged and fine.
He re-set the system to understand the battery is charged.
Is he right?
I have read of connections for Ctek being made in the boot but not directly to the battery - would this avoid confusing the system?
Advice would be much appreciated, as the under hood connection isn't ideal for my set up.

 

I connect my CTEK to the positive bus bar in the floor "box of wires" and to the negative post that the negative battery wire attaches to, and never had any issues with "low battery". I guess it depends where the BMS sits in the scheme of things.

 

I've now re done my connections, and connected through the bus bar as per a previous post on the subject, and like you SCM, so I'll see how it goes now!

 

Here's an excellent tutorial on connection a CTEK to the bus bar terminals:

https://howtune.com/articles/548-ins...-jaguar-f-type

 

Thanks Dwight - that's actually the tutorial I found and followed! Nice and clear, for simple people like me.

 

Have a my2017 base Premium coupe. I asked my JLR tech the best way to connect it and he said to pos battery post and to ground post on floor of the trunk. So it has been that way since fall of 2020 when the new battery went in. The Ctek fires up and goes through all its testing & conditioning when the F is stored over our Wisconsin winter. Interesting that your tech advised a different means of connection.

 

Yes, my Ctek ran well and did it's business, but the car just showed all these warnings. I've checked, and jaguar accessories say don't connect direct to the battery so I've now gone to the bus bar - easy enough as it happens

 

To simplify things any current across the battery terminals will charge the battery so either scenario will stop your battery going flat if you continuously use the ctek. Connecting directly to the battery removes the BCM from the loop so the car doesn’t know the real state of the battery. This could cause issues with charging from the alternator once the battery gets a bit older and increases the potential for electrical gremlins to occur. This is similar to pumping up your tyres twice a week but never calibrating the tpms sensors . You will probably never have an issue from a slow leak but the car is in the dark about the true state of your tyre pressure and everything will fine for 99% of the time until you have a bigger leak.

 

Just to expand a little on Borbor's spot on statement regarding removing the Battery Monitor (BM) from the charging loop and to clear up the confusion regarding where to wire in a CTEK, or any other charger for that matter. The BM acts as a minuture ammeter, measuring the current flow through the battery. It is placed between the battery grounding strap and the battery negative post "in series", as you would when connecting any ammeter to a circuit to measure current flow. It's difficult to see clearly in our F-Types as it is tucked under the rear boot panel. You can see it clearly in this F-Pace install, which uses the same BM.

If you connect a battery charger directly across the battery terminals, you bypass the BM, removing it from the charge circuit. As the charge current does not flow through the BM, it cannot monitor the current flow through the battery. By connecting the negative charge cable to the battery grounding strap, the BM remains in the charging circuit and can monitor the charge current. You can connect the negative charge cable to ANY ground point on the car (including the jump start earth stud on front wing), as the current flow will always return to the battery via the battery grounding strap. Likewise you can connect the positive charge cable to ANY battery positive terminal, from the battery postive post, boot/trunk main fuse box bus bar, or the engine bay fuse box/jump start terminal. Any and all of these connection methods will keep the BM in the charging circuit and able to monitor the charge current. The ONLY method you should NOT adopt is to connect directly across the battery terminals.

 

If the battery is original, it might actually BE the problem, and at 8 years it is on borrowed time. Try checking the voltage with a meter after leaving the charger off for a few days, or bite the bullet preemptively.

 

Stumbled upon thsi video, which seems to imply that the BMS is required to implement stop/start (among a lot of other thngs). Every day's a school day!

 

I was hoping somebody could shine some color:

If CTEK max 5.0 stays on stage 7 or 8, and after you have come back from a long drive and CTEK starts from Stage 4 again, what does it mean? The battery lost power? Wouldn’t it start from Stage 7? Doesn’t long drives help the battery instead of reducing its voltage?

 

It always starts like before increasing later so there is no problem. It has no reflection of the state of discharge from the battery. A long drive is the same as connecting to a battery charger as the alternator will be charging the car as you drive

 

It does a bit of battery checking at the earlier stages, but if your battery is pretty fully charged already it shouldn't take long to get to 7.

 

Also remember that after a long period of no use, the Ctek will go from stage 8 back to stage 7. This is to maintain 95% charge rather than 100%, so the battery isn't being continually charged

 

This may help understand the process

https://smartercharger.com/blogs/new...arging-process

 

A big "thank you" to all who contributed to this thread. I installed my CTek 5.0 charger pigtail as described to the busbar yesterday (it took all of 10 minutes) and charged my battery - this morning, the battery charger showed full charge. During the week, I only drive the car a total of 4 miles to work and back -- not enough to really charge the battery. I replaced the battery about 3 months ago and it had become pretty flat as of yesterday - I can tell that the battery is low when driving because the start/stop feature stops working. After a full charge, the car is eager to start/stop at every light (gotta start using the disable button now). I am quite sure that had I not invested in the CTek I would've burned through my new battery fairly quickly ..... it will now become a weekly routine to maintain battery health. Again, thank you for all the advice on this subject.

 

Thanks for all the input! Mine’s been sitting on Stage 7 and got there after couple of hours. Online search tells me stage 8 comes after 10 days and will stay there.

 

I seem to recall that Stage 8 didn't come on for about a week after putting my car in hibernation. Even if you unplug the CTEK unit after the car has been connected for several days or more, go for a short drive and reconnect it, it always goes back to step # 4 or 5 and then goes to # 6 and 7 again within a couple of hours. The owners manual says if it doesn't go to Step 7 within 50 hours, there is some sort of malfunction.

Dillweed, disconnecting the Start/Stop function is extremely simple. It takes more time to remove the storage compartment components than to pull the connector. Here's a tutorial if you haven't seen it.

 

Thanks, Dwight. I don't really mind the start/stop feature all that much, as my FTR is a daily driver and I spend a lot of time in the stop 'n go of Los Angeles gridlock. If it ever annoys me, the solution is just a button away ....