What's with the Ohmmu 12V battery?

[camalaio]

Lots of people get batteries from the car manufacturer. My views might be colored a bit because of my long history with BMWs, but BMW has used AGM batteries for quite a while, AND a battery change also required "re registering" the battery with the car with a specific process that required either a computer with an ODB to ethernet cable and specific BMW software, or later, a wireless ODB adapter and specific iPhone apps.

"Regular" BMW AGM batteries (for lowly 4 series) are like 500-600 installed at the dealer, but the battery itself is like 300 ish even if you go after market, and then spend the money on the items to register it yourself (did you look at the price for the BMW M4 Battery @ra88it listed? its about 2k.. yeah 2 thousand dollars). So yeah your not "cruising down to nappa auto" for your typical BMW AGM battery. No idea on the tesla, but I would likely go to tesla for it at least until the car is out of warranty.

I know tesla does not = BMW, but coming from that brand, the thought of an AGM battery does not surprise me, and 2-300 for a battery sounds actually cheap to me...

I'm distantly (in-laws) familiar with BMWs and 12V batteries. That's a, uh, unique thing they have going there. Always issues, always super expensive, always harder to get at than you'd expect (I remember needing trunk access for some reason once). I'm sure you'd glad to be a convert

I have a bit of a bubble to be fair. My dad's a mechanic. Many of my friends and coworkers can be classified as frugal. The thought of getting a 12V battery from the car manufacturer was almost never a consideration for those in my circle.

 

[jjrandorin]

Always issues, always super expensive, always harder to get at than you'd expect (I remember needing trunk access for some reason once). I'm sure you'd glad to be a convert

I have a bit of a bubble to be fair. My dad's a mechanic. Many of my friends and coworkers can be classified as frugal. The thought of getting a 12V battery from the car manufacturer was almost never a consideration for those in my circle.

My wife still has a BMW but yeah I am actually really (really really) happy with my model 3P. Your remembering the trunk because thats where BMW tends to put the actual batteries. They have "jump points" by the engine, but the actual battery (or batteriES depending on which BMW) are usually in the trunk behind a side panel.

 

[Big Ike]

Wait, I had really never thought of this. Getting the battery from Tesla? Is this common in the US, to get batteries from the car manufacturer? Here, I'd just go to Interstate Battery (I assume that's in the US too?) or Walmart or something.

Tesla has replaced two 12V batteries for me at no cost - one in my S and one in my X. I've got to believe they won't do it for my 3.

I was going to do the X myself, but watched a Youtube of a guy spend hours on the project and that drove me to letting the SC do it.

 

[ra88it]

Lots of people get batteries from the car manufacturer. My views might be colored a bit because of my long history with BMWs, but BMW has used AGM batteries for quite a while, AND a battery change also required "re registering" the battery with the car with a specific process that required either a computer with an ODB to ethernet cable and specific BMW software, or later, a wireless ODB adapter and specific iPhone apps.

"Regular" BMW AGM batteries (for lowly 4 series) are like 500-600 installed at the dealer, but the battery itself is like 300 ish even if you go after market, and then spend the money on the items to register it yourself (did you look at the price for the BMW M4 Battery @ra88it listed? its about 2k.. yeah 2 thousand dollars). So yeah your not "cruising down to nappa auto" for your typical BMW AGM battery. No idea on the tesla, but I would likely go to tesla for it at least until the car is out of warranty.

I know tesla does not = BMW, but coming from that brand, the thought of an AGM battery does not surprise me, and 2-300 for a battery sounds actually cheap to me...

call your SC, the model 3 battery is 80$+tax. I laughed hysterically and ordered one without so much as a question.

 

[Kevy Baby]

call your SC, the model 3 battery is 80$+tax.

That's less than I spent for an Interstate I put in the wife's truck last weekend.

 

[dmurphy]

call your SC, the model 3 battery is 80$+tax. I laughed hysterically and ordered one without so much as a question.

Another reason I suspect it’s not an AGM battery. I do believe it’s a sealed lead-acid, but not AGM. I could be wrong but I haven’t seen anyone open the battery, either.

 

[CertLive]

Does this not all depend on how your Tesla handles the charging of the battery? Does it just blanket top up the 12v battery all the time? Or does it do some actual cycle other than top off every time there is a slight drop? An ICE alternator would usually just charge to max while running until full every drive no?

 

[wwu123]

I'm distantly (in-laws) familiar with BMWs and 12V batteries. That's a, uh, unique thing they have going there. Always issues, always super expensive, always harder to get at than you'd expect (I remember needing trunk access for some reason once). I'm sure you'd glad to be a convert

I have a bit of a bubble to be fair. My dad's a mechanic. Many of my friends and coworkers can be classified as frugal. The thought of getting a 12V battery from the car manufacturer was almost never a consideration for those in my circle.

I'm used to getting a 3rd-party batteries as well. However, prior to Tesla had a BMW SUV - after the 12V battery started to show signs of dying, IIRC they don't just use AGM for replacements, but the car keeps track of how old the battery is and adjusts the 12V battery charging based off it. In other words, if you don't have the diag software and cable to reset that value, the car will treat your new 12V battery like it's pretty old, and not use the full capacity. Net is that the new battery may have a shorter life due to not using its full charge.

I did spend about $250 for a 3rd party AGM battery, rather than $80 for a lead acid one. But said screw it, even if lasts only 2 years because the car isn't reset, it's still cheaper to keep replacing than spend $850 at the BMW dealer for a single battery....

 

[Rocky_H]

In my specific case it would be mostly isolated from the cold (and it really doesn't get that cold here most Winters), but is a good point. I understand it has a BMS to manage itself and would maybe limit charging, but that itself seems problematic if Tesla is depending on it to be charged. 99.99% of days it would probably be OK, but I'd hate to have that 0.01% case.

Well, it doesn't have much of a BMS for the 12V battery like the extensive one it has for the main pack. I don't think there are any temperature sensors on the 12V, so it can't look at that. It does monitor the voltage level, though, to determine when it is low to know when to recharge it. And therein lies the problem. Since the programming of the car is counting on it being a regular automotive 12V, I would be almost certain, that it will charge that 12V any time it's low, regardless of how cold it is.

That's less than I spent for an Interstate I put in the wife's truck last weekend.

Yeah, I just bought a battery for our Honda Civic a few weeks ago, and it was a hundred and some. $80 is pretty cheap.

Another reason I suspect it’s not an AGM battery. I do believe it’s a sealed lead-acid, but not AGM. I could be wrong but I haven’t seen anyone open the battery, either.

I do think it is, but they are significantly smaller than regular gas car batteries, which would explain them being cheaper.

Does this not all depend on how your Tesla handles the charging of the battery? Does it just blanket top up the 12v battery all the time? Or does it do some actual cycle other than top off every time there is a slight drop? An ICE alternator would usually just charge to max while running until full every drive no?

I think this is some of both, depending on whether the car is on or off. While the car is on and running, the high voltage pack is connected, so yes, it does use a DC to DC converter circuit and keeps that 12V topped up. But while the car is off, the main pack is disconnected, so it's not constantly keeping the 12V charged. All the minor phantom drain will keep drawing off that 12V, and the car keeps an eye on it, and when that voltage drops low-ish, it will wake up and reconnect the main battery pack to refill the 12V.

At least those are the broad strokes with respect to the S and X. I am not sure if that is a little bit different with the 3.

 

[dmurphy]

I do think it is, but they are significantly smaller than regular gas car batteries, which would explain them being cheaper.

The primary reason I suspect it's *not* an AGM battery is because in Hankook's catalog... the 85B24LS part # starts with "MF" - MF as in "Maintenance Free"; all of their AGM batteries start with "AGMxx-xxx" ....

https://cdn.hankook-atlasbx.com/PRD...(US_version)General_Catalog(2019)_(small).pdf

Just my suspicion - until someone cracks the cover, or works for Hankook, we won't know for sure ...

 

[Kevy Baby]

...the 85B24LS part # starts with "MF" - MF as in "Maintenance Free"...

Are you sure it doesn't stand for "Mother F*****g?"

 

[luke68bird]

I go through a lead battery in about 2 years due to heat. If it can make it 4+ years and not worry about getting stranded again plus lighter weight and better efficiency it's worth it to me.

 

[ElectricLove]

The lithium following is based on belief in their salesmanship period.
It might be good but they have not been in use in volume long enough TO PROVE that.

When I contacted them a couple years ago about my concerns with using a lithium in my very cold climate without full temp control system I got a lot of salesman speak about how it won't shorten life that much to charge at sub-zero fahrenheit..........

For those who claim handling or sound system benefits please explain the the mechanism for that benefit. 20lbs is half a percent on a 4000lbs car and battery isn't rotating weight and the weight is inside the wheelbase and not particularly high so it doesn't have a lot of leverage on suspension.

Were you hoping they would just lie to you and say it will not affect it in the cold? I don’t get it “salesman speak” usually means someone over promises not tells you something like you just said...

 

[smatthew]

Another reason I suspect it’s not an AGM battery. I do believe it’s a sealed lead-acid, but not AGM. I could be wrong but I haven’t seen anyone open the battery, either.

The battery is a VRLA AGM Deep Cycle Battery.

 

[ArizonaP85]

I'm used to getting a 3rd-party batteries as well. However, prior to Tesla had a BMW SUV - after the 12V battery started to show signs of dying, IIRC they don't just use AGM for replacements, but the car keeps track of how old the battery is and adjusts the 12V battery charging based off it. In other words, if you don't have the diag software and cable to reset that value, the car will treat your new 12V battery like it's pretty old, and not use the full capacity. Net is that the new battery may have a shorter life due to not using its full charge.

I did spend about $250 for a 3rd party AGM battery, rather than $80 for a lead acid one. But said screw it, even if lasts only 2 years because the car isn't reset, it's still cheaper to keep replacing than spend $850 at the BMW dealer for a single battery....

I’m not sure about the Model 3 battery, but the S uses a non-standard size and configuration not readily available. I don’t want to be stranded so after several Tesla lead battery failures, I chose Ohmmu’s lithium, as I recently described in another thread: You can’t jump start a Tesla 12V like an ICE car, quickly continue on your way and easily find a new battery at any AutoZone.

Teslas should give a 12V warning, but as we read in many situations recounted on this forum, that does not always happen. Even if you had a warning while on a road trip, you’re still not getting home without either being stranded or relying on finding a service center able to help you with both an appointment time and the correct battery in stock.

Unlike an ICE car, if your Tesla’s 12V dies, you are stuck:can’t get in the car, can’t get in the frunk, etc. If you have the misfortune to suffer a 12V failure overnight during an update, you might be really stuck! Where a new 12V battery doesn’t solve your problem at all. You don’t have to look far on this forum to see those tales of woe. I haven’t seen what Tesla’s out-of-warranty charge might be for rescuing a broken update but I know the tow bill alone will be more than Ohmmu’s price difference. God forbid it hastens an eMMC demise!

Out-of-warranty is another issue, besides reliability, that you’re not considering. As early Tesla adopters and their cars age, we have to pay all the repair and maintenance costs. $250 every 18 to 24 months in Arizona or $420 48 months or more? Again, the money savings for me is just icing on the dependability cake.

I don’t know anything about Canadian Amazon pricing but here in the States, you’re money ahead to buy lithium direct from Ohmmu vs lead from Tesla more often.

 

[camalaio]

I’m not sure about the Model 3 battery, but the S uses a non-standard size and configuration not readily available. I don’t want to be stranded so after several Tesla lead battery failures, I chose Ohmmu’s lithium, as I recently described in another thread: You can’t jump start a Tesla 12V like an ICE car, quickly continue on your way and easily find a new battery at any AutoZone.

Teslas should give a 12V warning, but as we read in many situations recounted on this forum, that does not always happen. Even if you had a warning while on a road trip, you’re still not getting home without either being stranded or relying on finding a service center able to help you with both an appointment time and the correct battery in stock.

Unlike an ICE car, if your Tesla’s 12V dies, you are stuck:can’t get in the car, can’t get in the frunk, etc. If you have the misfortune to suffer a 12V failure overnight during an update, you might be really stuck! Where a new 12V battery doesn’t solve your problem at all. You don’t have to look far on this forum to see those tales of woe. I haven’t seen what Tesla’s out-of-warranty charge might be for rescuing a broken update but I know the tow bill alone will be more than Ohmmu’s price difference. God forbid it hastens an eMMC demise!

Out-of-warranty is another issue, besides reliability, that you’re not considering. As early Tesla adopters and their cars age, we have to pay all the repair and maintenance costs. $250 every 18 to 24 months in Arizona or $420 48 months or more? Again, the money savings for me is just icing on the dependability cake.

I don’t know anything about Canadian Amazon pricing but here in the States, you’re money ahead to buy lithium direct from Ohmmu vs lead from Tesla more often.

You can absolutely "jump start" the 12V battery on a Tesla. You can even trigger the frunk latch externally if it's that dead. Both procedures are in the manual.

If you have batteries dying every 18-24 months, that's also within every battery warranty I know of. The absolute shortest one I've found is 2 years, full replacement. So it should be $0 if it's actually dying as frequently as you say? Or spend just a couple more dollars on a battery with a full replacement warranty if that's the problem?

 

[dmurphy]

You can absolutely "jump start" the 12V battery on a Tesla.

Right. This is why I have a lithium-ion "jump pack" in the undertrunk as well as a trickle charger. It's not that you can "jump start" the car like a traditional ICE engine and let the alternator do the charging; you'd need to float the 12V battery back up to minimum charge... but it's 100% doable in an emergency, if nothing else other than to get you to the nearest service center.

 

[ElectricLove]

You can absolutely "jump start" the 12V battery on a Tesla. You can even trigger the frunk latch externally if it's that dead. Both procedures are in the manual.

If you have batteries dying every 18-24 months, that's also within every battery warranty I know of. The absolute shortest one I've found is 2 years, full replacement. So it should be $0 if it's actually dying as frequently as you say? Or spend just a couple more dollars on a battery with a full replacement warranty if that's the problem?

to be fair P85 said and go to nearest autozone to swap it out... describing an entire procedure that can’t be done not saying it’s impossible to jump start or go to autozone or even find a replacement, if you take each action separately...

 

[Kevy Baby]

Maybe instead of a spare tire, we need to keep a spare battery?

 

[camalaio]

to be fair P85 said and go to nearest autozone to swap it out... describing an entire procedure that can’t be done not saying it’s impossible to jump start or go to autozone or even find a replacement, if you take each action separately...

I don't know about AutoZone specifically, but Interstate will be happy to match an "it'll work" battery. The exact dimensions and capacity are not critical details as long as it can fit, be secured, and connected. I would be flabbergasted if the form factor of a Model S 12V was so unique that a suitable replacement couldn't be dropped in. A quick Google search suggests there are many suitable replacements, even cheaper if you go the route of a mobility scooter battery (those vary in dimensions and such too, so there are ones to pick from for sure).

To me, it's actually nice how similar the 12V process is to an ICE vehicle. It's replaceable, it's not really unique, it's easy to access (heck, it's easier than my Honda Crosstour), cheap replacements can be found, and even the thought of "jump-starting" is actually a thing.