Best 12V Battery for Tesla Model 3 (Li-Ion vs. Lead-Acid vs. Aftermarket Options)

By Zac Ludicrous •  Updated: 07/31/22 •  8 min read

Lead-acid, lithium-ion, aftermarket options such as Ohmmu… It’s hard to decide which 12V battery to get for your Model 3.

It’s all about chemistry, you know. All you have to do is find out what 12V battery has got the best chemistry with your electric car.

Don’t worry, I’ve saved you all the hassle. 

This buying guide will guide you through everything you need to know about the best Tesla Model 3 12V batteries and which one you should get according to the community.

Let’s hop into it.

Best Model 3 OEM Battery Overall: Lithium-Ion 12V Battery

best 12v battery for tesla model 3
Credit to Charged EVs

It’s common knowledge that Tesla introduced li-ion batteries as an improvement over its lead-acid batteries which were failing quite frequently.

Per recent studies, li-ion batteries have definitely shown themselves as a better and more efficient alternative to lead-acid batteries, so as far as which is best, li-ion definitely steals the show.

We’ve already published a detailed comparison of both batteries, but for the sake of this article, I’ll share a brief comparison here too.

Starting with the cost, lithium-ion battery appears to be a more viable option because of its longer life span, even though its initial cost is higher than that of the lead-acid battery.

Then we have the weight. The lightweight lithium-ion battery enhances your car’s efficiency by three to four times, which is a significant improvement over the heavier lead-acid batteries.

Finally, li-ion batteries are literally maintenance-free, while lead-acid batteries have to be looked after quite often.

By all means, Tesla’s li-ion battery is better than the lead-acid battery and all the aftermarket options for that matter.


✅ Cost effective
✅ Lasts longer (5000 lifetime cycles to be precise)
✅ Lightweight


❌ High initial cost

Tesla Model 3 12V Battery: Aftermarket Options

#1: Ohmmu 12V Li-Ion Battery

Ohmuu is a renowned name in the Tesla community when it comes to 12V batteries. 

Any Tesla owner who isn’t satisfied with the OEM batteries for some reason always goes to Ohmmu.

As far as the product is concerned, it’s definitely commendable. The 12V battery is durable and has higher capacity and better efficiency.

Everything is great, but still, for some reason, Tesla has been creating obstacles that mess with the Ohmmu battery and create issues for users. It almost seems planned!

To better understand this matter further, let’s hear it from the victims themselves:

I installed the Ohmmu 12v battery about 4 weeks ago. Today, I got the “replace low voltage battery” and associated warnings before ever leaving the house. Did some quick reading, and was preparing to contact Ohmmu with details, when I came across their support document outlining how this error might come about with a few recent software updates from Tesla. I’m on 2021.44.30 but it covers a couple other versions preceding that. Ohmmu’s support article says they are working on a fix and it will involve some kind of hardware fix/replacement. In the meantime, the article implies that the 12v is most likely fine (I’m surmising mine is fine, as it’s only been in service for 4 weeks). For anyone else that is seeing this issue with the Ohmmu and the recent software updates… are you more or less continuing to drive like normal until the fix is available? I see the USB ports and heated seats don’t work in this condition, and I’m fine with that, but wondering if anyone in the same situation is going about business as usual until the fix is ready?


Thanks for sharing. We’ve been here before with the 1st gen Ohmmu batteries for the 3 about 2-2.5years ago. At the time Tesla also changed something in their diagnostics and/or 12v monitoring and charging logic which caused issues and false positive alerts pre or post MCU software updates.

Now they’ve done it again and are bound to do it again after the fleet of 3/Ys switch to the 18v for the 2022 refresh.

Now Ohmuu is indeed great, but this game of cat and mouse with Tesla is changing things (diagnostics, CAN bus messaging, v8/9/10/11 GUI, etc.).

It’s just a matter of time until old aftermarket auto frunk/trunk and self presenting doors start to malfunction depending on what Tesla does?


So here’s how it’s going:

Ohmmu makes a 12V Battery for the Model 3 >> Tesla releases a new software upgrade that somehow messes with the Ohmmu battery’s functionality >> Ohmmu carries out changes >> Tesla again releases new software >> and it goes on and on…

To counter Tesla on this issue, Ohmmu has started a petition, hoping that if enough Tesla owners participate, Tesla will let them sell 12V batteries in peace.

Meanwhile, they’re also upgrading their battery to adjust with the new software, and it’ll be out in a few months as of this writing.

One thing I can say for sure, if Tesla and Ohmmu make things up, don’t hesitate a second to invest in this battery if you prefer aftermarket options.

#2: EarthX ETX900 Lithium-Ion Battery

As discussed earlier, Tesla does have some personal beef with aftermarket 12V batteries. 

However, per a few Tesla owners, the ETX900 12V battery has some good terms with Tesla as no software update resulted in countless error messages.

12V super lightweight lithium with built in BMS for the Tesla Model 3 installed using Taner Bosnali’s 3D printed tray.

Easy 5-10 min. installation using factory hardware. No messing with aftermarket nuts, bolts or hold-downs. 23 lbs lighter.

No error code so far. The install was actually done back in July, 2021. I wanted to give it some time before my post to make sure I don’t experience any issues.


I found a few more such posts that verified this owner’s claim, so yes, there’s a good chance that this battery can work flawlessly with your Tesla.

However, there were some concerns that the OEM battery is 45 Ah while the ETX900 is 15 Ah (about one-third of the capacity).

Another owner clarified this issue in a very elaborate way:

The EarthX battery does not actually have less usable capacity. A lithium iron phosphate (LiFePO4) battery’s capacity is almost 100% usable. Let’s say it’s 90% usable because you don’t want to discharge it all the way. Then the EarthX has 13.5Ah usable capacity.

A lead acid battery capacity is not anywhere near 100% usable unless you want to permanently damage the battery. On a deep cycle battery, you could possibly use up to 80% of the capacity with a reduced life or up to 50% of the capacity for increased life. That would be 22.5Ah to 36Ah of usable capacity in the OEM Tesla battery if it were deep cycle, but I’m pretty sure it’s not. For a regular lead acid battery, you do not want to use more than about 30% of its capacity or it will decrease its lifespan by a lot. On the OEM Tesla battery that would be about 13.5Ah of usable capacity. See how that matches exactly with the EarthX’s usable capacity as explained above?


To summarize, if you really want to replace your Tesla Model 3 12V battery, I’d suggest you give the ETX900 a shot.

Other Tesla Model 3 12V Battery Products to Consider

Jumper Cables: Energizer

15,000+ reviews, 4.7 out of 5 stars rating, happy customers… This jumper cable surely ticks all the boxes for customers. 

Energizer is a proven brand that sells a wide range of cables, including this best-selling jumper cable, which is more than enough to jump-start your Model 3. 

The best thing is you can use it with any type of vehicle, including sedans, SUVs, and trucks.

Power Starter Bank: NOCO Boost Plus GB40

NOCO is a well-known brand that is popular among Tesla and other EV owners, as well as those who own ICE vehicles. On Amazon, it has almost 50,000 reviews!

This smart battery charger includes heavy-duty jumper cables or battery clamps, eliminating the need to purchase them separately.

It will make it simple to jump-start a depleted battery by pushing and holding the manual override to engage boost mode.

Here’s Anthony Dyer using this power starter bank to jump-start his Model 3 on his YouTube channel:

Super informative and helpful!

Final Thoughts: Best Tesla Model 3 12V Battery

As expressed earlier, the safest path is to go with the Tesla OEM 12V battery. 

But if you’re determined to go with the aftermarket options, I’d encourage you to prefer ETX900 over ohmmu.

Not that ohmmu isn’t a great brand, it of course is. The problem lies with the company’s issue with Tesla. If in the future, this problem resolves then ohmmu will absolutely be a better option than ETX900.

Zac Ludicrous

Mechanical engineer by profession. TSLA shareholder before the hype. EV enthusiast all day long. Zac enjoys learning about the future of battery technology, autonomy, and EVs. He considers Tesla Model 3 the most important vehicle of the 21st century -- and is in a quest to improve the ownership experience of every Model 3 owner he possibly can.

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