@chasers03 I have a LiFePO4 battery (PowerTex) and I don't have any issue with the battery being constantly discharged. It works as if OEM, I've had it for a year now. I have never reset the BMS either, although I just ordered the Jaguar SDD clone connector + software so I will perform the reset when it comes and see if that re-enables my eco start stop.

 

My antigravity battery doesn’t need cycling to discharge. But when the Jaguar BMS did it, it also caused the Antigravity BMS to disconnect for protective purposes. Then I had to reengage it by getting the remote out of it storage place on the car aggravating to me.
I didn’t know the BMS could be reset. I wonder what the purpose of it resetting would be.?
Can you tell us more about what this Jaguar SDD clone connector + software can do?

 

Both the primary and auxiliary batteries in my 2015 are the originals (i.e. 10 years old for those of us who aren't engineers). The primary is maintained on a CTEK 5.0 tender but the auxiliary battery is left to its own devices during winter storage. It takes a few drives before the start-stop feature activates along with cornering lights and the passenger temperature controls. Sometimes the infotainment system also goes silent and dark until after a long drive.

Dave -

You replaced your infotainment system? With what? The nav/infotainment system in our 2018 F-Type has gone wonky. Sometimes it takes as much as 30-minutes and a stop-start for the screen to light up. But 3-5 minutes to boot up is awfully common. Could it be time to replace the original battery? 95% of my driving is interstate during daylight hours. And I use a CTEK 5.0 battery tender anytime the car sits idle for a week or more.

 

Hi Frank,
No, I didn’t replace the entertainment system. I did replace the battery on my ‘18 XE this winter, it was appearing a bit weak. Yours could be due. Start/
stop came back to life, I haven’t been bothered enough yet to permanently disconnect it.

The entertainment system (ICTP) on my XE was quite buggy when I first got it, but Scarborough Jag upgraded it to CarPlay (no charge), and since whenever it was last updated (OTA), it’s been pretty stable.

 

@Ichi Ban That is a new record - 10 years! Well done.

I think a brand new battery will solve your issues. I replaced mine with an Interstate H8/900 CCA 1624801 (~ $200 at Costco). Just charge it fully with your CTEK before installing. You can let the BMS know it's a new battery via the OBD2 but many have skipped this step. You might as well replace the smaller battery too.

The ECU has a battery-preserving feature that disables the infotainment system from booting up if the battery SOC is too low. The screen will remain dark and no sound until the SOC is sufficient. I know this from replacing the Meridian stereo system and initially not using a maintainer during my work tuning my new speakers and DSP. Now I always use a maintainer if I do any work that requires >2 minutes.

Even charging an old battery with a CTEK is not enough - as soon as you unlock the car or open the door the BMS will discharge the battery down at least 0.5V. This may be enough to put an old battery into a perilously low SOC. Another issue I have found is just driving the car and expecting the alternator to charge up an old battery is also not enough. Perhaps this might explain your symptoms.

Good luck and please report back with your findings after installing the new battery!

 

Thanks, guys! New batteries are on my priority list. That is, after replacing the pinion seal on the e-diff.

 

Frank, let me know if you need an OBD2 reader to reset the BMS when you replace the battery.

 

Naw. I'm good. Thanks for all the help, Dave.

Remember the days when we could drive a vehicle with a dead battery or alternator once we got the engine running? No lights but we could limp along to our destination with a map on our lap and flashlight in hand. Not so anymore.

 

Yes! and with the manual transmission just get 'er rolling and pop the clutch to start the engine...

 

I don't think it's a new record, I am sure I have read somewhere on this forum or maybe another forum that at least one owner has gone 11 or 12 years on the original F-Type battery before replacing it.
I went 10 years and 3 months on my original F-Type battery (battery built Sep 2014, replaced Dec 2024).
The secret as we have learned is to hook the car up to a battery maintainer such as a CTEK whenever it is not in use.

 

Short term parking results (1 week) with the car locked (one click):

The battery drops about 0.1V every 48 hours. This is with two active BT devices (the Ancel BM300Pro and Veepeak OBD2 dongle actively transmitting) and JLR telematics unit running in the background. No red triangle illumination.

So based on this I plan to use a battery charger if it is parked for more than a week (assuming you have a relatively new battery). For older batteries like @OzXFR mentions, I would charge if parked for more than 2 days.

Thanks to @chasers03 and @s3yang for confirming there is a solution to the OBD2 drain red triangle illumination problem!

https://www.jaguarforums.com/forum/f...2/#post2834921

 

SDD is the software used by the dealer up until MY2017. Theoretically it has every function (the clone may not) that the dealer can perform, among them resetting the BMS. The reset is standard procedure after replacing a battery, it resets the parameters learned over the lifetime of the previous battery as it degraded.

 

Yes...and not just on JLR vehicles.


TOPIC DRIFT ALERT: THIS is why "right to repair" laws are being considered.

But hey, I just read that battery-powered hand tools might have a universal, one-size-fits-all configuration. It's a start.

 

An update for this thread:

I left the windows down overnight to air out the toxic smell of the freshly applied 303 fabric protector on the convertible top, locked the car (ironically to prevent battery drain), but left the key fob in the garage 5 feet away from the car. No illuminated red triangle.

This morning I have a low battery warning - it went from 13.8V 100% SOC to 11.6V 20% SOC overnight with the low battery warning. Having the keys near the car even when locked drained my battery!

I can only surmise that the close proximity of the keys kept the car in a semi-ready state that drained the battery.

I will fully charge it again then conduct the experiment under the same conditions but with the key fob far away.

 

Yes, this is a known issue we used to talk about. You’re right, having the fob near the car stops it from going to sleep.

Once, I was in the yard, talking on my cell phone. I had my XE fob in my pocket, and when I walked by the XE in the garage, the car woke up and transferred the call to the car, which I hadn’t touched. I was rather confused, until I heard the other party’s voice coming out of the closed car.

 

Did not want to start a new thread, but in the context of all of the above, would I be nuts got get a Braille/Deka 21 lb battery.....550cca supposedly.

Reason - weight mostly. My car did not tolerate the AntiGravity battery (with their tech support being flummoxed too....so not just a "me" issue).
Saves 38 lbs. If safe to use.

Thanks!

jeff

 

Jag specs 850CCA and 90AHr. I’d check capacity (AHr) in addition to CCA. If you don’t drive it in the winter, maybe you’d get away with the 550CCA, but I wouldn’t recommend it. Travel with a jump pack if you do. If the DEKA battery is smaller capacity, then I suppose it’s possible the F-type charging system might charge it too hard (higher current than it’s rated for) which could damage it.

In my opinion, not a great idea. But maybe it would work OK.

 

Thanks. I think I'll leave things as is and just stay stock size/AGM.

 

Update:
I performed the BMS reset using SDD. Good news: auto start stop is working. Bad news: everything else

The old settings in my BMS must have had more conservative ranges for the battery due to declining battery health of my old battery. Now, the BMS lets my battery completely discharge to 0. This somdwhat makes sense as the voltage range for LiFeP04 definitely cannot go under 12V, while an AGM can. It seems the BMS cycles the battery to a low voltage then allows it to charge fully.

My car quite literally died (completely off, no power) a few times after coming to a stop and turning the engine off (or start-stop engaging). This is even after a long highway drive of 30+ mins. Thankfully it wasn't anywhere dangerous, like at an intersection. I've had to resort to disconnecting the current sensor on the negative battery post, and living with the BMS fault as noted earlier in this thread. This keeps the battery at 13.7V always.

I'm looking into solutions for this (tricking the sensor to read a slightly lower voltage, etc), but am close to admitting defeat on the lithium ion experiment. Will update if I make any progress.

 

@takeapieandrun thank you for the update. That is vexing to say the least - especially being potentially stranded out on the road. Do you really need the auto start-stop? I would pull the plug in the trunk and permanently disable it.

The JLR BMS is, as Churchill once said, "a riddle wrapped in a mystery inside an enigma."

I just finished installing a new Helix DSP and have been fighting my BMS during the entire testing and tuning process. The BMS shuts the stereo off after a few minutes, and it can't be restarted even with a maintainer hooked up. On top of this I had the "Voltage low, please start engine" message pop up even though the battery was at 13.2V and 100% SOC. Starting the engine and running for a few minutes did nothing. I had to reset the BMS via the OBD2 scanner to eliminate the message and be able to get back to work on the stereo project. I ended up clamping the ground of my maintainer to a bare metal (not painted) part of the chassis and soldiered on.

As a result of these shenanigans, I was looking at buying a lithium battery like yours. The problem is the JLR BMS drops voltage immediately by 0.5V even with just unlocking the car or opening a door. As @DJS mentions this is likely surface discharge which is transient, but it messes with anything that reads real-time voltage in the ECU or the antigravity battery's own built-in BMS.

This may be a golden opportunity to get a small boat with electric motor and use your lithium battery for hours of pleasure on the lake!