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12v Battery Options - Which is best?

Ostrichsak

Active Member
Sep 6, 2018
3,325
3,283
Colorado, USA
Chill buddy... Just a discussion of opinions... and you know what those are like!
Your stance on the topic is an opinion. Mine is a statement of fact. From where I sit, I'm as "chill" as I can be because I didn't waste nearly $500 on snake oil.

I bet your windshield wipers work 15% better. lol
 

Kaveman

Member
Oct 27, 2020
23
9
FL
BTW: You are right the one that lasted only one year may be an outlier... But I am also interested in working/trying newer technologies...
BTWII: It's my money, so I can waste it where I see fit... If it lasts 3-4 years I'll be at the same cost, with less aggravation changing batteries.
BTWIII: I got Math... LOL
 

Ostrichsak

Active Member
Sep 6, 2018
3,325
3,283
Colorado, USA
BTW: You are right the one that lasted only one year may be an outlier... But I am also interested in working/trying newer technologies...
BTWII: It's my money, so I can waste it where I see fit... If it lasts 3-4 years I'll be at the same cost, with less aggravation changing batteries.
BTWIII: I got Math... LOL
We're in agreement there. You can light your money on fire if you want because it's your money. Just don't come on here trying to convince us all that it's the most effective way to keep warm which is what all of these Ohmmu evangelists are doing.

How is it your math is not even close to accurate based on your OWN numbers and then you punctuate your statement that your math is accurate as if you just stuck the dismount?

If your $420 (plus tax shipping) battery lasts 3-4 years that's most likely the exact same amount of time your OME battery would have lasted and it costs only $140. Tell me how that's the same cost. It's literally 3x more for the same service life. This couldn't be any more obvious.

Acting like you're somehow advancing "newer tech" is just silly. Lithium is nothing new and it's been around for quite some time now. In fact, the only reason we still use Lead Acid and AGM (which is just a form of lead acid, BTW) like in the OEM Tesla battery is because they're FAR more stable in the wider temperature swings seen in normal operation in North America. Lithium is NOT the right choice unless you're able to keep the cells in a very specific temperature range which is why the HV packs on these cars have such advanced thermal management systems and the cars are worthless if it goes down.

Remind me again, what specifically is the thermal management system in your Ohmmu lithium cell 12v battery?
 
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Kaveman

Member
Oct 27, 2020
23
9
FL
Uncle!
The original poster wanted OPINIONS on 12V batteries and peoples experiences.
That's what we both did.
Have a good rest of your day.
 

IchDochNicht

Member
Sep 4, 2016
300
210
Bay Area, CA
Thanks, everybody, for the insight you provided! I really appreciate it - regardless of which side of the fence you're on.

Based on what was said, I have definitely ruled out the Ohmmu battery. I was skeptical before, but now it's clear that I'm not going to spend the extra money.

So, it's between calling mobile service and the Gruber battery. The latter could take a week to get here,

One thing I had not considered was warranty. My car is past the 4-year warranty, even though I only have 42k miles on the odometer. I'm not sure, if and how warranty may play into my situation.

Is there any data on the minimum of how long the old battery lasts, once the warning comes-up? I saw the message first on Friday, February 12. It has been sitting since. As stated, the car is used once or maybe twice a week for getting groceries or running errands (no commute).
 
Last edited:

Ostrichsak

Active Member
Sep 6, 2018
3,325
3,283
Colorado, USA
Thanks, everybody, for the insight you provided! I really appreciate it - regardless of which side of the fence you're on.

Based on what was said, I have definitely ruled out the Ohmmu battery. I was skeptical before, but now it's clear that I'm not going to spend the extra money.

So, it's between calling mobile service and the Gruber battery. The latter could take a week to get here,

One thing I had not considered was warranty. My car is past the 4-year warranty, even though I only have 42k miles on the odometer. I'm not sure, if and how warranty may play into my situation.

Is there any data on the minimum of how long the old battery lasts, once the warning comes-up? I saw the message first on Friday, February 12. It has been sitting since. As stated, the car is used once or maybe twice a week for getting groceries or running errands (no commute).
Why wait? Just because it could last several weeks once the warning pops up I sure wouldn't tempt fate.
 
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random155

Member
Mar 18, 2019
876
450
NJ
Thanks, everybody, for the insight you provided! I really appreciate it - regardless of which side of the fence you're on.

Based on what was said, I have definitely ruled out the Ohmmu battery. I was skeptical before, but now it's clear that I'm not going to spend the extra money.

So, it's between calling mobile service and the Gruber battery. The latter could take a week to get here,

One thing I had not considered was warranty. My car is past the 4-year warranty, even though I only have 42k miles on the odometer. I'm not sure, if and how warranty may play into my situation.

Is there any data on the minimum of how long the old battery lasts, once the warning comes-up? I saw the message first on Friday, February 12. It has been sitting since. As stated, the car is used once or maybe twice a week for getting groceries or running errands (no commute).
I'm a DIY person and after reading some stories about issues after people changed their own batteries, I'm definitely just going to pay the price and let Tesla change mine, when the time comes. If you search you will find some of these stories.
 

IchDochNicht

Member
Sep 4, 2016
300
210
Bay Area, CA
I'm a DIY person and after reading some stories about issues after people changed their own batteries, I'm definitely just going to pay the price and let Tesla change mine, when the time comes. If you search you will find some of these stories.
Thats what I ended-up doing today. I had a little time and swung by the local service center. They had the battery in stock and took it in pretty quickly. The best of all: it cost less than $200!

I’m happy.

Thanks again for the guidance. Sometimes I find it hard to extract the right information from an endless thread. This was great help!
 

Kandiru

Active Member
Oct 20, 2014
1,169
374
USA
Reading the average croak time of Tesla batteries I paid the SC to replace mine at 4yo. I also keep a starter permanently plugged into the cigaretter lighter adapter along with tools to remove nosecone (MS classic) and terminals in trunk.
 

sorka

Well-Known Member
Feb 28, 2015
7,867
5,780
Merced, CA
Keep in mind Tesla recently made a change that goes from killing batteries way faster than typical autos to making them last longer than typical autos.

If you take a brand new 12v lead acid battery and keep it topped off with a tender on a shelf, it will last for many years.
Using a battery tender, I've had batteries last for 12 years.

Until recently, the way Tesla used it's 12 volt battery was to run the vehicle systems with main HV contactors open. The system will draw 60 to 70 watts continuously from the 12v battery. Every 4 to 6 hours, the contactors will close and recharge the battery which has been drawn down 50%. It does so quite quickly at high amperage over several minutes and then the contactors open and the cycle starts all over again. This is murder on lead acid batteries.

With the MCU2 upgrade, the standby inverter is now active on any car made after March 2015 so that the contactors are engaged all of the time and the battery is constantly maintained at 100% SOC. Basically the vehicle systems now run off the main HV battery and those contactors only close for non typical situations.

Even without this, I'd still replace the battery with the standard OEM lead acid, but if you have a newer car with MCU2 or an older car after March 2015 with the MCU2 upgrade, your 12v lead acid should last much longer than regular ICE car unless you're comparing it to an ICE car that lives on a tender it's whole life.
 
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ElectricLove

Member
May 28, 2013
554
314
This has been covered ad nauseum and never has concrete evidence been presented that Lithium 12v batteries last any longer let alone the 3x longer required just to break even. Nor do they provide any advantages during their operational life over the $138 OEM battery. To the contrary, if you end up with issues with your 12v system while using an aftermarket 12v battery Tesla can void the warranty of related components citing the battery as the cause.

In a Tesla, all a 12v battery does is run small accessory devices like the MCU, headlights, interior lights, turn signals, etc. Compared to what the 12v battery is required to do in an ICE car (think starting the engine at very cold temps) to say this is "light duty" doesn't even fully capture the difference between these two applications.

Not to mention the Tesla keeps the battery at optimal SoC even when not running whereas an ICE car requires the engine be running to charge the battery via the alternator. Whenever this accessory isn't spinning the battery is discharging all-the-while. They sit for days sometimes discharging and then (in minus zero temps sometimes) are expected to provide an absurd amount of instant amperage draw to physically turn over a large internal combustion engine.

This is why the Cold Cranking Amps (CCA) is probably the most important metric when shopping for a new 12v battery... especially in cold climates. This metric means absolutely nothing in a Tesla to give you an idea how different of an application we're talking.

In an ICE car, there is no way to predict when that battery will suddenly not be able to provide the necessary juice to make the car run and it generally fails in the coldest and most dangerous of scenarios. There's too many variables and the ability to provide CCA tends to drop off rapidly once it nears the end of it's life. This isn't the case with a Tesla. The amps required to power headlights or a stereo are fractional by comparison and the car can monitor the health of the battery at a finite level. This battery health monitoring algorithm tends to err on the side of safety when it comes to warning of an impending failure and most can go weeks or even months once that warning has been issued. It's all-but-eliminated the potential for becoming stranded due to a 12v battery failure so for a few rare outlier cases.

Naturally, people are fearful of being "stranded" in the middle of the night, in the dead of winter and in the most inconvenient time possible. This is a good fear to have and it's based largely on our experience with ICE cars in which this fear is founded in reality. Manufacturers of 12v Lithium batteries prey on this fear since it's unrealistic in a Tesla. They try to get you to pay for something that will do you zero good in a Tesla and, if your fear is being stranded, could potentially even increase the odds of this happening due to the system not being able to properly monitor & manage the health of your 12v battery they way it was designed to do with the OEM chemistry.

The new cars will come with a lithium-based 12v battery but it will include thermal management & cell health management technology that was created for their battery packs. It will be properly engineered and accounted for within the Tesla electronics ecosystem unlike these Band-Aid slapped on Li-Ion 12v aftermarket "solutions" but I'm sure we'll see more and more people asking about it once the new cars start rolling out. Just know that there is a LOT of engineering resourced going into making that an OEM solution so it's silly to think you can just slap one in something as complex as a Tesla w/o any accounting for it via the firmware.

My last warranty replacement 12v battery (I'm still amazed Tesla will replace these under warranty when every other car manufacturer treats them as a "wear item" like the brake pads... I digress) they had a "newer & better version" which was similar in overall chemistry but from a new supplier. This required a change to my car's firmware to properly account for what was the same basic battery. Think about that for a minute. Do you seriously think that if changing to something as different as a lithium chemistry 12v battery you wouldn't need to account for a change that extreme in the car's management system if one is required for what basically amounts to the same battery? When I saw that even going from previous versions of the OEM battery to the newer versions required a firmware change to account for even these minor differences within the system it shed some light on how bad of an idea going with something as different in chemistry as a lithium battery for the 12v system is at any cost.

In short, anyone who says that a $400+ lithium 12v battery is an "upgrade" in any way for a Tesla is selling you snake oil. Don't fall for it.

tl;dr Stick with the OEM and file this conversation under crap not even worth wasting your time considering.

Why did Tesla say they are now using 12V LFP in the new S and X? Along with “we should have been doing that long ago”... weird, they sure are dumb not understanding batteries as well as you do...
 

Ostrichsak

Active Member
Sep 6, 2018
3,325
3,283
Colorado, USA
Why did Tesla say they are now using 12V LFP in the new S and X? Along with “we should have been doing that long ago”... weird, they sure are dumb not understanding batteries as well as you do...
The same as ripping out your LEDs or HIDs and hot-gluing a bunch of laser pointers in their place would now give you better lighting performance at night because it's what Tesla does in the new cars because... ya know... lasers!

It cracks me up when people see ONE WORD and assume all else is equal. Much like when I talk to someone who says EVs are crap and their ONLY data is from a Leaf.

Lasers.
 
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