When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I have a 2022 SL55 that had battery issues last fall. For last 8 months I have kept keys in a faraday box about 30 feet from garage and double click to lock. No battery issues. I only use tender to recharge battery after driving a few short distances. Tender will take hours to get back to full charge after short trip even if tender was showing full charge when disconnected. Since using faraday box I have left car sitting in garage for up to two weeks without the tender and have had no battery warnings. Only time recently that I had a battery alarm on app was when I took to dealer for annual maintenance and they let car sit with key fob in car. They returned car charged and I drove it home 40 miles. No issues since. Faraday box on Amazon about $15. Hope this helps.
I have a 2022 SL55 that had battery issues last fall. For last 8 months I have kept keys in a faraday box about 30 feet from garage and double click to lock. No battery issues. I only use tender to recharge battery after driving a few short distances. Tender will take hours to get back to full charge after short trip even if tender was showing full charge when disconnected. Since using faraday box I have left car sitting in garage for up to two weeks without the tender and have had no battery warnings. Only time recently that I had a battery alarm on app was when I took to dealer for annual maintenance and they let car sit with key fob in car. They returned car charged and I drove it home 40 miles. No issues since. Faraday box on Amazon about $15. Hope this helps.
I am astonished at how many hoops R232 owners will jump through to keep these cars on the road. I couldn’t do it.
speaking for myself it is only one “hoop” ie keeping my battery charged with a battery tender. So not so bad as I have done this with other cars that I have not driven enough to keep it charged. It really is a great car to drive. The big tablet is great and unlike anything I have driven before. Plus I don’t need it as a daily driver so any time in the shop is OK. MB gives a loaner if you need it so I think a lot of the frustration is not being able to drive a great car. Plus isolated incidents reported on this forum blow the whole thing out of proportion. I love the car one hoop and all. Lol
My 22 SL63 just turned 2,000 miles, has had all updates, kept on MB battery maintainer connected in the engine compartment when not in use (have many cars so this is normal procedure for my collection), have had zero problems fantastic car!
2019 SL450, 2019 E450 Luxury Trim Wagon, 2024 BMW I7 xDrive60
Originally Posted by FirstBenz@62
speaking for myself it is only one “hoop” ie keeping my battery charged with a battery tender. So not so bad as I have done this with other cars that I have not driven enough to keep it charged. It really is a great car to drive. The big tablet is great and unlike anything I have driven before. Plus I don’t need it as a daily driver so any time in the shop is OK. MB gives a loaner if you need it so I think a lot of the frustration is not being able to drive a great car. Plus isolated incidents reported on this forum blow the whole thing out of proportion. I love the car one hoop and all. Lol
Well, we are all different and I am very happy for you. Enjoy your car!
Wife just ordered these for $9.99. We will see if it helps. Battery still not charged past 3/4.
I have something similar. Takes care of it. When I put my keys on the kitchen counter they merely go inside the bag rather than on the counter itself. I'd rather not have to do this but it is not burdensome in the least.
Hmmm, I don't understand, the key is supposed to go to sleep if it senses no movement after a time of inactivity unless the car senses the key because it is too close-by and then commands/signals the key to not go to sleep? Is that why?
I am taking the car in today so will try to find out what is causing my battery drain to the point of sending a “critical” alert. I have been following the “double click” and 20 ft away procedure but my 20 feet might have been only 10 feet due to my key storage in kitchen above garage. Dunno. Will let everyone know if and when I find out.
Just checked battery tender which has been attached since last Friday and it has gone down to 1/2 charge. Something is definitely draining the battery while the car is in the garage and I don’t think faraday bag is helping.
One of the recalls is that MB gives you the battery tender, as well as rewires(?) the cigarette adapter in the trunk so you can connect your trickle charger there (rather than under the hood). I also had many critical battery warnings, but have since had none and have been very pleased. I do leave the car sitting for weeks at a time and I am used to connecting up a tender, so none of this bothers me like it does to some. Good luck, KH
Did they charge you labor for battery tender hook up?
Battery tender was hot when unplugged this am. Left melted paint marks on the stool I had it resting on. Can’t be a good sign. Both service manager and shop manager perplexed. Hopefully will find out the problem by Friday.
Last edited by FirstBenz@62; Sep 11, 2024 at 11:35 AM.
Reason: Word correction
Did they charge you labor for battery tender hook up?
In my case the service department tried to charge. When I picked up the car the paperwork said I owed $250.00. I pointed out this is a warranty issue and they waved the charge.
My problem? Bad battery, starter battery failure and replaced under warranty. Also door handle update performed. Hopefully that was it but do not know what caused the battery to fail.
My problem? Bad battery, starter battery failure and replaced under warranty. Also door handle update performed. Hopefully that was it but do not know what caused the battery to fail.
Thinking it was caused by remaining discharged when the vehicle was sitting in the lot or port back then when MBUSA didn't approve the release of the vehicle from VMI, if I recalled correctly, it took months, sitting there?
Found these reasons for “battery drain”. Wonder if my problem was connected to my door locks that were working sporadically. I would often walk up to my car and the door locks wouldn’t work even though I was passing my hand over the handle. They seem to be working fine now after the door handle update. Anyone else experience sporadic door locks? If so get the update.
Faulty Door Light Switch
Faulty Door lock actuator (integrated light switch)
Trunk lock switch
Faulty car stereo or the wirings to it.
Any aftermarket electrical parts were installed incorrectly.
I am following the exact procedure, with the same exact (MB branded) trickle charger. I hooked up negative to ground post, opened hinged plastic door to reaveal positive battery connector, slid the positive post door cover(inboard) then attached the positive clamp to the positive battery post(in engine compartment. Then I plug into wall outlet(reverse procedure to disconnect). When the charger completed a full cycle( amber 1/4 amber 1/2 amber 3/4 amber 4/4 then green led full charge indicator), I pushed the reset button to restart the cycle.
Then I found out that with AGM batteries, they suffer from being overcharged. So now I only go through 1 complete cycle, every other day. I don’t know if that charger is set up to provide current equal to the parasitic draw, or if there is excess that overcharges the starter battery.
I am following the exact procedure, with the same exact (MB branded) trickle charger. I hooked up negative to ground post, opened hinged plastic door to reaveal positive battery connector, slid the positive post door cover(inboard) then attached the positive clamp to the positive battery post(in engine compartment. Then I plug into wall outlet(reverse procedure to disconnect). When the charger completed a full cycle( amber 1/4 amber 1/2 amber 3/4 amber 4/4 then green led full charge indicator), I pushed the reset button to restart the cycle.
Then I found out that with AGM batteries, they suffer from being overcharged. So now I only go through 1 complete cycle, every other day. I don’t know if that charger is set up to provide current equal to the parasitic draw, or if there is excess that overcharges the starter battery.
my experience after the critical starter battery msg and hooking up MB tender was 3/4 amber down to 1/2 amber after 24 hrs and tender getting very hot which may indicate tender over charging battery. My original starter battery initially checked out OK while being serviced but later after electrical diagnostics were performed it failed and was replaced. Currently following the double click hide the key fob in a faraday bag procedure. Plan to get a battery tester to check periodically the charge status of new battery.
I am following the exact procedure, with the same exact (MB branded) trickle charger. I hooked up negative to ground post, opened hinged plastic door to reaveal positive battery connector, slid the positive post door cover(inboard) then attached the positive clamp to the positive battery post(in engine compartment. Then I plug into wall outlet(reverse procedure to disconnect). When the charger completed a full cycle( amber 1/4 amber 1/2 amber 3/4 amber 4/4 then green led full charge indicator), I pushed the reset button to restart the cycle.
Then I found out that with AGM batteries, they suffer from being overcharged. So now I only go through 1 complete cycle, every other day. I don’t know if that charger is set up to provide current equal to the parasitic draw, or if there is excess that overcharges the starter battery.
The manual that comes with the MB trickle charger says to connect the red lead first - then the black to the ground post. And reverse when disconnecting. Don't know if it will make a difference.
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
