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12volt Battery Replacement - NAPA Auto Parts

Hey yall. I know this has been discussed at length on here, but I wanted to provide a different perspective. So my 12v alarm went off 2 weeks ago, with the earliest appointment being yesterday. The service center was impossible to reach by phone. Batteries were apparently not in stock. There is very limited info on here about replacement batteries other than the stock Atlas battery. I was able to locate a battery at Napa Auto Parts. The sales tech sized it in the 51R category, negative terminal on the right. This fit right in my 2018 Tesla Model 3 Long Range, and worked fine. I was worried because some people on here expressed that installing a non-Tesla battery may void other warranties or cause issues, so I installed the Atlas back in the car before the service tech arrived. While he was there, I confirmed that there is NO PROBLEM with you sizing this battery up from Napa or wherever, and changing it yourself. I see some of you have your Tesla waiting in a service center for a battery!? You can do this in a parking lot in 10 minutes yourself. Just FYI, trying to share some info. Good luck!

-C
 

iwannam3

Active Member
Aug 8, 2016
1,025
1,412
Washington
Hey yall. I know this has been discussed at length on here, but I wanted to provide a different perspective. So my 12v alarm went off 2 weeks ago, with the earliest appointment being yesterday. The service center was impossible to reach by phone. Batteries were apparently not in stock. There is very limited info on here about replacement batteries other than the stock Atlas battery. I was able to locate a battery at Napa Auto Parts. The sales tech sized it in the 51R category, negative terminal on the right. This fit right in my 2018 Tesla Model 3 Long Range, and worked fine. I was worried because some people on here expressed that installing a non-Tesla battery may void other warranties or cause issues, so I installed the Atlas back in the car before the service tech arrived. While he was there, I confirmed that there is NO PROBLEM with you sizing this battery up from Napa or wherever, and changing it yourself. I see some of you have your Tesla waiting in a service center for a battery!? You can do this in a parking lot in 10 minutes yourself. Just FYI, trying to share some info. Good luck!

-C
Did the replacement battery have a vent hose fitting? How much did it cost?
 
My battery went about a month ago and I couldnt find one anywhere. I eventually caved and had to have Tesla come out as they seemed to be the only source of them. I got lucky and they did it next day but it was an interesting call to work that I couldn't come in because my battery died and I needed to wait at home for a mobile service tech.
 
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Did the replacement battery have a vent hose fitting? How much did it cost?
No, the Napa Auto battery did not need a vent. It was around $120.

The mobile service from Tesla, replacing the Atlas, was also $120 including labor. That is obviously the preferred method, but no bueno if your car is going to be down for days
 
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My battery went about a month ago and I couldnt find one anywhere. I eventually caved and had to have Tesla come out as they seemed to be the only source of them. I got lucky and they did it next day but it was an interesting call to work that I couldn't come in because my battery died and I needed to wait at home for a mobile service tech.
Yeah I couldnt, still cant, find a replacement for the Atlas brand. There is the $500 Ohmmu lith-ion option, but not worth it imo. But my point was, you dont need the Tesla brand battery. Just get any 12volt in the 51R size family and throw it in there if you have to
 

iwannam3

Active Member
Aug 8, 2016
1,025
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Washington
No, the Napa Auto battery did not need a vent. It was around $120.

The mobile service from Tesla, replacing the Atlas, was also $120 including labor. That is obviously the preferred method, but no bueno if your car is going to be down for days
Good thing Tesla replaced it, some my use it as the final solution. The Atlas battery will vent Hydrogen gas and sulfuric acid fumes in your frunk area. I assume you have seen corroded battery posts and rusted out battery supports? That happens under an ICE hood with all the air flow, imagine that corrosion in the frunk area.
 
Good thing Tesla replaced it, some my use it as the final solution. The Atlas battery will vent Hydrogen gas and sulfuric acid fumes in your frunk area. I assume you have seen corroded battery posts and rusted out battery supports? That happens under an ICE hood with all the air flow, imagine that corrosion in the frunk area.
Im just sharing information here. Do with it as you wish. A regular Auto Parts battery will not vent acid fumes into the frunk. Its a standard battery.
 
Good thing Tesla replaced it, some my use it as the final solution. The Atlas battery will vent Hydrogen gas and sulfuric acid fumes in your frunk area. I assume you have seen corroded battery posts and rusted out battery supports? That happens under an ICE hood with all the air flow, imagine that corrosion in the frunk area.
So what is different about the Atlas battery that it requires the vent hose? I assume most 51R batteries from an auto parts store don’t require a vent hose?
 
So what is different about the Atlas battery that it requires the vent hose? I assume most 51R batteries from an auto parts store don’t require a vent hose?
Im not an expert in battery construction. The Tesla service tech told me any 12v battery is fine to swap out yourself. Yeah its just a normal battery like in your regular gas car. Again, I will continue to attempt to use Tesla service to swap the battery, because its the same price anyways. But I was nearly in a bind, and have seen others on here that actually cant drive there Tesla because of this. Its worth putting in a standard battery until Tesla takes care of it. Rental cars arent cheap!
 

KenC

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Sep 4, 2018
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Tesla uses AGM batteries rather than Lead Acid. You'll never buy another Lead Acid battery once you've had a single leak! Most AGM batteries from Kragen, etc, are much more than the $85 Tesla charges. But it's a option if battery is dead.
When has Tesla ever charged less than market price? The part listed by the OEM shows it's not an AGM, but a MF, maintenance-free one.
by default 2021-04-20 at 3.12.11 PM.jpg
 
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SteelClouds

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Nov 12, 2021
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CA
I just went through all this with my Hybrid van.. there is a 12 volt battery in the passenger compartment in the very back. The OEM has a vent hose.. the replacement AGM doesn't have the vent so the tube is gone unused. Chrysler wanted 600 for a 12 volt battery replacement. I had a local franchise battery shop do it for 200 installed. But I did have to walk the tech through the process since he had never done one :/ But it's under warranty for 4 years.. no pro-rated replacement. Its either good or it's not and if not, it will be replaced :)

I can't imagine the Tesla 12 is any different. Everything I have seen so far is that it's a "battery".. just a 12 volt battery. So if the size fits, the contacts fit and its AGM.. good to go. Even normal battery would probably work fine 95% of the time. I plan to get mine M3 replaced soon. Its the original 2019 and in March I am road tripping to Tombstone and back.. I dont trust the OEM battery to make it so I will replace it. I'll give Tesla first crack it but if they have excuses, I will just do this and call it a day :). thanks for sharing the data sheet. Good stuff
 
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iwannam3

Active Member
Aug 8, 2016
1,025
1,412
Washington
I just went through all this with my Hybrid van.. there is a 12 volt battery in the passenger compartment in the very back. The OEM has a vent hose.. the replacement AGM doesn't have the vent so the tube is gone unused. Chrysler wanted 600 for a 12 volt battery replacement. I had a local franchise battery shop do it for 200 installed. But I did have to walk the tech through the process since he had never done one :/ But it's under warranty for 4 years.. no pro-rated replacement. Its either good or it's not and if not, it will be replaced :)

I can't imagine the Tesla 12 is any different. Everything I have seen so far is that it's a "battery".. just a 12 volt battery. So if the size fits, the contacts fit and its AGM.. good to go. Even normal battery would probably work fine 95% of the time. I plan to get mine M3 replaced soon. Its the original 2019 and in March I am road tripping to Tombstone and back.. I dont trust the OEM battery to make it so I will replace it. I'll give Tesla first crack it but if they have excuses, I will just do this and call it a day :). thanks for sharing the data sheet. Good stuff
NOT AGM, it is a vented conventional battery. AGMs are SEALED, no vent, can be mounted upside down! Why does that keep coming up? There is so much misinformation on the 12 volt battery. AGM may give you errors like the $500 Ohmuu each time Tesla updates the BMS for the conventional battery since the AGM has different charging and maintenance voltages. Ohmuu scrambles every time they causes errors (twice at least) to update their battery BMS. Why pay more than $85 from Tesla for the WRONG battery? Don't expect to slap a LI battery from revised X and S either without a new BMS and more. From the new Model S owner’s manual, the low voltage battery has a rating of 6.9 amp hours, with a voltage of 15.5v.
 

iwannam3

Active Member
Aug 8, 2016
1,025
1,412
Washington
So what is different about the Atlas battery that it requires the vent hose? I assume most 51R batteries from an auto parts store don’t require a vent hose?
Tesla does not want acid fumes and hydrogen in the frunk area. All standard lead acid batteries release them through the VENTED caps on the top of the battery. I watched a battery blow its caps off when a guy yanked the charger leads of a charging battery and the sparks ignited the hydrogen and all 6 caps blew off! Tesla directs them out of the frunk area with the vent hose. My Mini Cooper S had an AGM battery in the rear behind the back seat because it was in the passenger compartment and they didn't want hydrogen and acid fumes inside the car, same on my Prius. Lots of web discussion about using a std. battery instead of the $AGM, but the BMS was designed for AGM with different internal resistance and charging and maintenance voltages.
 

iwannam3

Active Member
Aug 8, 2016
1,025
1,412
Washington
Im just sharing information here. Do with it as you wish. A regular Auto Parts battery will not vent acid fumes into the frunk. Its a standard battery.
A standard battery has vents for each shell otherwise they would pop off due to hydrogen gas generation. When you put a std battery on a charger you should remove the caps so the hydrogen doesn't accumulate. You can see it bubbling on the lead. When you add water to top off the battery , the missing water H2O had been turned into into hydrogen gas H2 previously.
 
I didnt really post this to start a debate on what battery to use. The answer to your question “why pay for the wrong battery” is the reason for this post. Tesla recently has not had the right battery in stock, leaving the car stranded for some people in this forum. I felt like I was pretty close to that situation myself. This is an alternative option to keep the car on the road until the Tesla is serviceable. Rental cars are expensive. Some people dont have extra cars to drive in the mean time. This was more aimed at that individual saying “what do I do?”. You stop in Napa, put a $100 battery in it and go down the road.
 
NOT AGM, it is a vented conventional battery. AGMs are SEALED, no vent, can be mounted upside down! Why does that keep coming up? There is so much misinformation on the 12 volt battery. AGM may give you errors like the $500 Ohmuu each time Tesla updates the BMS for the conventional battery since the AGM has different charging and maintenance voltages. Ohmuu scrambles every time they causes errors (twice at least) to update their battery BMS. Why pay more than $85 from Tesla for the WRONG battery? Don't expect to slap a LI battery from revised X and S either without a new BMS and more. From the new Model S owner’s manual, the low voltage battery has a rating of 6.9 amp hours, with a voltage of 15.5v.
I was considering getting an Ohmmu 12V LFP battery before I did some more research and found out about the couple times they have had to "update" their battery in order to work properly. There are a lot of threads on this that I read through. Happened in mid/late 2020 and just happened again a few months ago. They shipped everyone a new "V2" battery in late 2020 and now they are working on a new "V3" battery that will be released soon per their website. So I think just buying any old battery that "fits" for the Tesla is not a good idea due to the same potential issue as Ohmmu has/had, but is fine if you just need something ASAP. The BMS and Tesla software is only calibrated for a certain 12V battery and I imagine the software is different for the new 2022 models with the Tesla lithium 12V.

I like the idea of having a 12V lithium or LFP battery. However, every time Tesla updates the software that has to do with the 12V battery it messes things up, making the situation untenable for aftermarket parts. So I essentially would be trading one problem for another. Since I live 100 minutes from the closest Tesla dealership, my new plan is to proactively replace my 12V battery via mobile service every 2 years. $100 every 2 years is nothing. I also leave Sentry mode on at work every day during the week for 9-10 hours, which is cycling my 12V battery constantly. I imagine I will need one every 2 years for sure.
 
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FYI- I don’t think it needs to be a reversed polarity battery… the cables are long enough to connect regardless of R or non-R spec. Just install with the positive towards the passenger side.

*my battery is the bottom pic. Top battery is from a YouTube video.
 

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FYI- I don’t think it needs to be a reversed polarity battery… the cables are long enough to connect regardless of R or non-R spec. Just install with the positive towards the passenger side.

*my battery is the bottom pic. Top battery is from a YouTube video.

I think you may be correct. However, if it IS a vented battery you'd need to see what side the vent is and if the hose will reach. It would be good to confirm as it appears the plain Group 51 battery is generally more available and cheaper.
 
Auto parts stores do sell group size 51R batteries that have a hole for the vent tube, and I would but one of those even though they are a bit more expensive. But in a pinch, a normally vented one will get you going. And 51R batteries can be found anywhere, but your have to look for them as such. You will not find a replacement battery for the Tesla by looking it up in the battery catalog or computer. Your have to know the size your are looking for.
 
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