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Has Anyone Tried the Diehard 12V Battery ?

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Price is $240 US. Why would you choose this over the OE Tesla 12V?

REQUIRES PROFESSIONAL INSTALLATION: DO NOT attempt to install batteries in this vehicle.; Non-BCI group size.; Battery is vented to outside of vehicle.; Call service specialist before changing battery; Battery specifically desgined for EV/HEV auxilary applications; Must use a 8mm to 5.8mm vent tube adapter; Installation may take up to 60 minutes.​


Comments on the AdvanceAutoParts web page:

Was worried about the vent hose adapter and the terminal size. The vent hole in this new battery came with that adapter attached. Then the terminals where the correct size. Model 3 2018 LR RWD. Don't forget to disconnect the 12v from the high voltage main battery, switch located under the rear seat under a foam triangle.

Bottom Line Yes, I would recommend to a friend

I'm sure this is a great battery, but the terminals are much smaller than the Tesla OEM equipment, which means if you plan on using it, you're going to need to replace the cable connectors (along with some kind of adapter for the 8mm vent instead of the 6mm vent. This made it a hard pass for me. I wanted a drop-in replacement, not a project.

Bottom Line No, I would not recommend to a friend
 
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Price is $240 US. Why would you choose this over the OE Tesla 12V?

REQUIRES PROFESSIONAL INSTALLATION: DO NOT attempt to install batteries in this vehicle.; Non-BCI group size.; Battery is vented to outside of vehicle.; Call service specialist before changing battery; Battery specifically desgined for EV/HEV auxilary applications; Must use a 8mm to 5.8mm vent tube adapter; Installation may take up to 60 minutes.​


Comments on the AdvanceAutoParts web page:

Was worried about the vent hose adapter and the terminal size. The vent hole in this new battery came with that adapter attached. Then the terminals where the correct size. Model 3 2018 LR RWD. Don't forget to disconnect the 12v from the high voltage main battery, switch located under the rear seat under a foam triangle.

Bottom Line Yes, I would recommend to a friend

I'm sure this is a great battery, but the terminals are much smaller than the Tesla OEM equipment, which means if you plan on using it, you're going to need to replace the cable connectors (along with some kind of adapter for the 8mm vent instead of the 6mm vent. This made it a hard pass for me. I wanted a drop-in replacement, not a project.

Bottom Line No, I would not recommend to a friend
Honestly, I have no clue how much the OE battery is from Tesla, or if they even have them in stock. I was considering buying one to just have on hand for when it needs to be replaced. I have a 2020 MYP with about 25K miles.
 
OEM battery only has 1 year warranty from Tesla. Diehard EV has a 3 year free replacement from Advance Auto Parts
The Tesla OEM Hankook manufactured 12V lead-acid battery is covered by the 48 month/50k miles Tesla basic vehicle limited warranty. If the 12V battery fails during that period/miles Tesla will replace the 12V battery under the warranty at no cost. Experience has shown that the Hankook 12V battery can be expected to last 2 to 3 years under most conditions. The first replacement 12V battery is likely to be covered under the warranty. The second replacement and beyond you will pay ~$135 US for each occurrence to have a new 12V battery installed by Tesla.
 
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My first OEM 12V battery lasted 2 years and was replaced for free under warranty. My 12V battery needs replacing again and the warranty on my Model 3 expired last month!

Mobile Service will replace it for $85 plus $28 labor! Great price but the OEM 12V battery is on backorder.

So I decided to get the Diehard instead. I think an AGM battery best suits my needs anyways.
 
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AGM batteries need a different charging program than conventional lead acid batteries.
That is true but some AGM batteries can apparently tolerate conventional lead-acid charging parameters without issue. I started using Optima AGM batteries in my Saab 95 vehicle and this extended the life of the 12V battery in the Saab from 1 year to 3 years (probably due to the Optima battery's superior resistance to vibration and heat.)
 
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My first OEM 12V battery lasted 2 years and was replaced for free under warranty. My 12V battery needs replacing again and the warranty on my Model 3 expired last month!

Mobile Service will replace it for $85 plus $28 labor! Great price but the OEM 12V battery is on backorder.

So I decided to get the Diehard instead. I think an AGM battery best suits my needs anyways.
UPDATE: Tesla service just called to let me know the OEM battery is back in stock. The Mobile tech is coming tomorrow. So in the end the Mobile tech is coming on the day Tesla had originally scheduled!

I bought the Diehard mainly because Tesla told me the OEM battery would not be in stock for over a week. At least Advanced Auto had the Diehard in stock online. Several posts indicate an AGM battery improves electrical performance but my M3 is out of warranty and I worry about any unintended consequences of using a non-OEM 12V battery. I can return the Diehard for a full refund within 45 days so I have some time to make my final decision.
 
My first OEM 12V battery lasted 2 years and was replaced for free under warranty. My 12V battery needs replacing again and the warranty on my Model 3 expired last month!

Mobile Service will replace it for $85 plus $28 labor! Great price but the OEM 12V battery is on backorder.

So I decided to get the Diehard instead. I think an AGM battery best suits my needs anyways.

tesla came to my job and replace mine yesterday
had car for 2 years and 10 months before the message its dying came up. Tesla replaced under warranty
a month later, the message to replace came up again. They tried to blame it on the subwoofer I'm using ,but that was in the car for 2 years and 9 months with no problem. They replaced it again free under warranty