Because I have a AntiGravity Lithium Ion Battery I don't want the F-Type BMS to do repetitive battery draining down to 12 volts as desired for the standard AGM battery. Anyone tried to modify or bypass the BMS short of unplugging it?

 

FYI—BMS Stands for battery management system, which is initiated by the little black box device mounted between the negative ground cable and battery neg. post. This is where I want to disrupt the discharge process.

 

If you think we don't know what BMS is, I wonder why you think anyone here can answer your question. Comes across as a bit patronising.

 

I believe you can remove the BMS module from the battery lead/terminal, BUT I have no idea whether that will simply deactivate the BMS without any problems or side effects or it will cause all sorts of insurmountable problems.

 

good point not meant to be. By the way, found this.
https://www.avaq.com/technology/-sol...or-2023#header
However, it makes no sense in specifics.

 

@chasers03 I understand your reasoning as it is an expensive battery with its own internal BMS, and the Jaguar BMS may conflict. I am fascinated by the myriad electrical issues in these cars as detailed in the forum (OBD2 drain, etc), and the BMS is often a suspect in the crime scene investigation.

You could be a Vanguard here and disconnect the BMS to see what happens.

Since it is a circuit with the ECU it may result in a fault, but that should be reversible by reconnecting and clearing the code if it does occur.

Many other forum members have made the successful switch to the Antigravity battery. A search will reveal their prior posts. Perhaps they could chime in? Are these lithium batteries OK with potential overcharging from the alternator with BMS disconnected versus the BMS-induced drain.

Otherwise it may be "a solution looking for a problem."

 

Good ideas I did try disconnecting the BMS wires and got the charging system not working alert and monitored the charging. It seemed to continue to be full 13.49v charging but I didn’t like that dashboard alert so I plugged it back in.
Antigravity FOLKS say charging all the time to full is non-detrimental to their battery.
Like the idea of unplugging it and using my code reader to clear the display alert.
Will give that a try thanks for your help.

 

Give that a try, but I suspect the next time you start up it will reappear! Can you report back?

 

I see the OBD2 issue as a software defect, not an electrical problem. The system fails to go to sleep.

On the original question, I don't recall hearing of any issues with the AntiGravity battery. I was not aware of any "repetitive draining of the battery down to 12V" but it's not something I've investigated at all. My current battery (pun intended) is about eight years old now, but I'm not sure I'm ready to spend the extra for the AntiGravity. A far cheaper way to save weight would be to just ditch the emergency kit in the trunk. Still, I can't say it's not tempting so I am interested in the outcome of any experiments here.

 

I have had an AntiGravity battery in my 2014 V8S for 2 years now with out any problems. I usually keep a Lithium Ion charger on the car when I'm not using it. BUT I have also had it sit for a couple of months while I was on vacation unplugged because I wanted to see what it would do and it held the charge and started just fine. Plus being 50-60 Lbs lighter is nice when you're replacing it.

 

Having run the Anti Gravity Battery for 3+ years my experience is that on a cyclical basis the Jaguar BMS prevents charging and allows the Lithium Battery to deplete to about 12 volts before starting the charging process back up to about 13.5 volts. If not driven and while sitting at a voltage about 12.2 V or less the AG Lithium Batteries BMS disconnects to save it from a possible total drainage. I then have to use the Anti Gravity remote fob to reengage the battery in order to unlock and start the Jaguar. Then soon after the charge process starts as dictated by the Jag BMS. Trouble is I have to reset the clock and windows, a pain in B....
My latest attempt at interrupting this charge and no charge cycling is to connect a wire from the neg. post to the one wire coming from the Jag BMS module which is not positive charged. So far the charging system wants to keep the AG battery at about 12.7 volts or 60% full constantly as read by my Anti Gravity Battery Tracker. We'll see if this stays and doesn't repeat the usual discharging process?

 

Simply double click your remote and it will fully shutdown, my battery is going on almost 10 years ,january first ill replace it with the same interstate agm battery

 

Double click what button on the remote, Dennis? And what will fully shutdown? I did remember some saying back years ago that double locking did resolve but it wasn't conclusive...

 

Wouldn't parking the vehicle with a NOCO Genius One solve this problem?

 

When you get out of your it takes 30mins to shut down, because it your still in the area and wants to be ready when you get back in the car so when you press the lock on your remote twice it shut the car down dead

 

This has been the topic of some debate but I'm fairly sure North American (NAS) cars don't have double locking.
Easy enough to check - get out of the car, shut all doors etc, then press the lock button on the remote twice within three seconds (or push the door handle in twice within three seconds) - if double locking has worked the auto fold mirrors will stop and pause for around half a second then continue on until fully folded, if no double locking there will be no pause in the fold action.
Of course this test will only work if the car has auto fold mirrors and the fold function is turned on (I know on my car there is no way to turn it off but I believe a dealership can do so).

 

My 2018 F-Type and my 2015 XF both have double locking. Yes, it works and is denoted by the beep. It can be confirmed by noting the behavior of the dashboard at the moment of double locking.

 

The 2017 premium Coupe that I have (built late 2016) has single-press to lock both doors and double press to unlock the driver's then the passenger's doors. The mirrors fold in on single press to lock.

 

This is incorrect. On US cars, the second press only activates the audible confirmation of locking with the beep. To prove it, unroll your driver's window and then lock the car with the fob from the outside. Press the fob again to 'double lock.' Then reach inside the open window and grab the door handle and open the door. It will unlock and open (and may set off the alarm). If it was truly double-locked, the interior handle would be disabled and you would not be able to use the inner door handle to open the door (one of the characteristics of double-locking).

 

Sorry Matt but it is correct. My F-Type is a convertible and one of the things which I checked soon after I got it was the double locking (which is described in the handbook). With the top down I exited the car, double locked the doors and then attempted to open them from the inside. They were locked. I have previously done a similar test with my XF, as you described, and they do double lock.