Never thought about the 12V battery. Does anyone know if sitting idle and watching netflix while waiting, drains the 12V like a regular car, or is it running off the main batteries? Probably silly, but what about a redundant second 12V battery? I added a second Optima Red Top battery to my FJ.
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12 Volt Battery
- Thread starter Peg_
- Start date
No idea for sure, but I'd assume that since the car is awake, it will actively monitor and charge the 12V from its HV battery in this scenario. I do not have schematics or source code, just an assumption. I think most 12V issues will be from the car parked, idle, and not plugged into a charger.
so then why are they using an automotive battery...just use a deep cycle marine battery. doesn't that seem link an obvious solution?
Cost. Availability. Size. Contracts. Focusing on the bigger picture.
Obvious solution may not be so obvious or a solution. Install one when yours fails and let us know.
As with every problem reported, what percentage of owners out there have had their 12V battery last 4-5 years? My 1999 VW Beetle battery failed at like 26 months, 2 months out of warranty. Yeah... I was pissed.
DFibRL8R
Active Member
I just got the "12 V battery must be replaced soon" warning message on my 4 month old Model Y with 2750 miles on it. That's pretty pitiful. Hopefully just a one-off "bad battery" issue and not something more.
Even my early build (Feb '13) Models S got 8 months before my first 12v Change!
My Model 3 has 2.5 years, 33k miles and no 12v replaced yet (hasn't had a single service visit since delivery despite being a very early build).
That said the warning feature is helpful and I have yet to have any of my Teslas leave me stranded for 12v issues (or any other).
Even my early build (Feb '13) Models S got 8 months before my first 12v Change!
My Model 3 has 2.5 years, 33k miles and no 12v replaced yet (hasn't had a single service visit since delivery despite being a very early build).
That said the warning feature is helpful and I have yet to have any of my Teslas leave me stranded for 12v issues (or any other).
Funny how there is no rhyme or reason as I believe the Model 3 and Y use the same AtlasBx battery. AtlasBx is owned by Hankook and makes ACDelco batteries in Korea as well.
I'm hoping the added volume for the battery with the 3 and Y will get a lot of other 12v battery manufacturers interested in making alternatives so we can just pick these up anywhere. If it's ubiquitous and cheap, then I wouldn't care if it fails. (If only Tesla could use an off the shelf 12v battery that is common with other vehicles.)
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I have read opposite things on this forum and wonder if others have direct input from Tesla. My Model Y does not get used often, it sits in a semi-heated garage (fortunately there is a Supercharger in the garage, but obviously I can't leave it plugged in there) and loses about 0.7 to 0.8 Rated Miles of charge per day.
Some say not to worry about the 12 volt battery, because even when idle the main battery will top it up when necessary. Others say that the 12 Volt battery is only charged when the car is driven or when the main battery is being charged.
How long can the car sit idle before the 12 volt battery goes dead and the car will not start? The longest I've gone is 43 days.
Do you remember your Tesla's state of charge (SOC) when you initially parked, and the SOC after 43 days? The Tesla vehicle monitors the 12V battery and will power on the 12V DC-to-DC inverter that keeps the 12V battery charged whenever the 12V voltage drops, keeps the 12V battery between 12.0V and 12.5V. If you charge the Tesla to 80 to 90% SOC and park and lose ~1% per day after 60 to 70 days the SOC of the Tesla's battery pack would have dropped to ~20%. The Tesla would have maintained the charge of the 12V battery all during this time and it would be advisable to then charge the Tesla. (Note: This assumes that you have Sentry Mode turned off. If you leave Sentry mode active then the Tesla vehicle will not go into sleep mode. In that case you would need to charge the Tesla battery much sooner than if Sentry Mode is turned off.)
I don't charge my Model Y every day, I know precisely when the Model Y's 12V systems are powered up because I receive a text message from the Alexa app whenever the Echo Auto device that is plugged into the front accessory power port powers on. This happens approximately every 24 to 36 hours. I have no idea what the Model Y is doing during these events, perhaps beaming data back to the mother ship but I also believe that the Model Y is also charging the 12V battery during these times. (The Alexa app only texts me when it is activated, not when the Echo Auto is powered off.)
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I’m confident that the BMS is constantly topping up the 12v battery, whether or not it’s driving/charging, especially when you consider how necessary this is to do with any lead acid battery due to its high self discharge rate. Add on the parasitic loads on top of the high self discharge rate and your MY wouldn’t have responded to anything after 43 days of storage due to a dead 12v if the BMS wasn’t maintaining it constantly.
Yes, It was at 234 Rated Miles the last time it was driven, and now it is at 185 Rated Miles 43 days later. That's 1.14 RM per day, and is higher than the 0.8 RM per day I quoted for the past 3 months, probably because during those 43 days I authorized three firmware updates. Also I checked on the iOS app more often than usual, which must consume energy.
OutofPocket
Member
Just picked up my white/white mid-2020 build 14XXX MY from Tesla Service. I brought it in to have them match the blotchy drivers door to the body. (By the way, they only painted the driver’s door and the match was flawless!)
When I saw the invoice I noticed that they also replaced the 12v battery ((Part ASY,12V BATT AND VENT PLUG,M3(1129182-00-B) 1.0 ). I had received no warning. I popped the frunk panel to check and there was the newly minted battery! I wonder if there was an issue with the earlier MY builds. Never had an issue with my M3.
When I saw the invoice I noticed that they also replaced the 12v battery ((Part ASY,12V BATT AND VENT PLUG,M3(1129182-00-B) 1.0 ). I had received no warning. I popped the frunk panel to check and there was the newly minted battery! I wonder if there was an issue with the earlier MY builds. Never had an issue with my M3.
If you change from displaying estimated miles to state of charge (SOC) percentage for the battery status under the Tesla display settings you will be get a more accurate assessment of the battery's charge status. I try and keep my Model Y's battery SOC between 40% and 80%. You want to maintain the battery SOC above 20% and no higher than 90% to maintain the best performance of the battery.
Interesting. I got my car mid-2020 as well and haven't had any 12V warnings either.
One month old Model Y delivered the day after Christmas and the dreaded 12 volt battery issue bit me with less than 500 miles! Trouble began yesterday when I jumped in the car and got the '"reduced power" error, rebooted the screen a couple of times, did a power down/power up, nope didn't clear the issue. Scheduled a service appointment and drove the wife's car to work.
By lunchtime the car was dead! Good thing I had it inside my garage at home. Escalated the service appointment by email at night, then the Service Center called me in the morning as they noted the 12 volt battery was drained and there also appears to be some sort of fault which probably caused the battery to drain.
They sent the roadside service tow truck and the driver did pop open the frunk using the two small 12 volt wires behind the round plug in the bumper but he noticed the two leads were touching each other instead of being separated which was odd. We jumped the actual 12 volt battery with his jump pack to unlock and wake up the car so I could drive it to the Service Center with the two truck following just in case.
Got a loaner and let them run their diagnostics so I don't get stranded again by just replacing the 12 volt battery.
So you never know when this bug will rear it's ugly head and bite your behind!
By lunchtime the car was dead! Good thing I had it inside my garage at home. Escalated the service appointment by email at night, then the Service Center called me in the morning as they noted the 12 volt battery was drained and there also appears to be some sort of fault which probably caused the battery to drain.
They sent the roadside service tow truck and the driver did pop open the frunk using the two small 12 volt wires behind the round plug in the bumper but he noticed the two leads were touching each other instead of being separated which was odd. We jumped the actual 12 volt battery with his jump pack to unlock and wake up the car so I could drive it to the Service Center with the two truck following just in case.
Got a loaner and let them run their diagnostics so I don't get stranded again by just replacing the 12 volt battery.
So you never know when this bug will rear it's ugly head and bite your behind!
Side note, the refreshed MS/MX have apparently changed its 12V lead acid battery and now have a Li-Ion 12V battery instead. So perhaps a future version of the MY will also make the move, or maybe we will get a retrofit option.
Tesla's new Model S and Model X get rid of lead-acid 12v battery, move to Li-ion - Electrek
Tesla's new Model S and Model X get rid of lead-acid 12v battery, move to Li-ion - Electrek
He just reiterated this in his interview with Sandy Monroe. He also said he would like to go to 48V at some point because you can make the wires a lot smaller.
I have been reading about the automotive industry moving to a 48V electrical system as a better way to power all of the accessories in a modern automobile for 30 years. Still waiting. Large trucks do have 24V electrical systems.
