For $85, I am pretty sure it is not an AGM battery. Even if it is smaller than a traditional car battery. The last AGM I paid for a motorcycle was well above $100.
model y long-range 12v battery
- Thread starter sam2020
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For $85, I am pretty sure it is not an AGM battery. Even if it is smaller than a traditional car battery. The last AGM I paid for a motorcycle was well above $100.
Jashev
Supporting Member
It is not an AGM battery. I've had one or two go bad in my previous Model S's. You get a warning message. When I had them replaced, Tesla told me that I would be good for a week or two before it failed. They were correct and changed them both under warranty. The battery was almost identical to the one I have in my lawn mower and my ATV. Nothing magical about it.
Seriously? A little surprised it's NOT an AGM!
(Note to self: Replace Tesla battery with AGM before the traditional lead-acid battery fails.)
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(Note to self: Replace Tesla battery with AGM before the traditional lead-acid battery fails.)
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According to TeslaTap The Model 3 uses a 45 Ah, AGM Battery. One supplier is AtlasBX with the model 85B24LS. One can assume that the Model Y uses a similar 12V AGM battery. The following production Tesla vehicles including Models (S, X, 3 and almost certainly Y) use a 12V absorbed glass mat (AGM) type battery. More here: 12 Volt Battery Compendium – TeslaTap
I'm not trying to troll anyone. I'm only trying to provide the best information.
Looks like a sealed flooded cell.
https://cdn.hankook-atlasbx.com/sta...product/(US-version)General-Catalog(2019).pdf
Note lack of the AGM prefix that their AGM batteries have.
https://cdn.hankook-atlasbx.com/sta...product/(US-version)General-Catalog(2019).pdf
Note lack of the AGM prefix that their AGM batteries have.
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I took photos under the hood of my Model Y this summer July when Tesla Mobile Service paid me a visit. The battery in my Model Y is a Hankook AtlasBX series. The model is 85B24LS, 12V 45Ah battery. This matches the Part No. noted from the following thread: 12V Battery Replacement
This matches also the photo of the Hankook 12V battery Part No. MF85B24LS
The 12 Volt battery in the Model 3, not AGM? - Tesla Owners Online
The specific battery used in the Tesla Model 3 and Model Y appears be a Sealed Maintenance Free battery but not an absorbent glass mat (AGM) type battery. A point of confusion is that Hankook sells different types of AtlasBX series batteries including: Absorbent Glass Mat (AGM), Enhanced Flooded Battery (EFB) and Sealed Maintenance Free (SMF) batteries. The specific model AtlasBX SMF battery (85B24LS) used in the Model 3/Y does not appear in the Hankook catalog, probably because it is specifically made for Tesla.
https://cdn.hankook-atlasbx.com/static/battery/en/171220_AtlasBX_24p_compressed.pdf
This matches also the photo of the Hankook 12V battery Part No. MF85B24LS
The 12 Volt battery in the Model 3, not AGM? - Tesla Owners Online
The specific battery used in the Tesla Model 3 and Model Y appears be a Sealed Maintenance Free battery but not an absorbent glass mat (AGM) type battery. A point of confusion is that Hankook sells different types of AtlasBX series batteries including: Absorbent Glass Mat (AGM), Enhanced Flooded Battery (EFB) and Sealed Maintenance Free (SMF) batteries. The specific model AtlasBX SMF battery (85B24LS) used in the Model 3/Y does not appear in the Hankook catalog, probably because it is specifically made for Tesla.
https://cdn.hankook-atlasbx.com/static/battery/en/171220_AtlasBX_24p_compressed.pdf
The fact that Tesla uses a Sealed Maintenance Free (MF) 12V battery, not an AGM battery, in the Model 3, Y explains why the replacement for this battery only cost $85. An AGM battery would cost considerably more.
I want to thank you for your post. I had incorrect/incomplete information. The Tesla Model 3, Model Y 12V battery is a sealed maintenance free battery (but not an AGM type battery.)
Jashev
Supporting Member
You might want to check with Tesla before you do that. Had a buddy actually put a lithium ion battery there and had some warranty issues.
Jashev
Supporting Member
No problem. If I'm not sure about something I'll hedge by saying something like I'm pretty sure that...... It is confusing and Tesla is not exactly working to get accurate information out there.
You have a good point, although I can't imagine any auto's warranty could be voided by the installation of a different TYPE of battery, as long as its specs are up to the mfr's.
An absorbent glass mat (AGM) type battery would not work, for long, if installed in a Tesla vehicle. The charging requirements of an AGM battery are different than what is required for a conventional flooded lead-acid battery. The charging voltage starts out higher in an AGM battery but then the float voltage (the voltage to maintain the battery once it has been charged) is almost a full volt lower for a 12V AGM battery, typically 13.5V to 13.8V depending on the temperature. The float voltage of a conventional lead-acid battery is ~14.4V.
If you take a voltage reading from the Tesla's 12V accessory port, it is 14.4V. This would result in an overcharge of an AGM battery, shorten the life of the battery. That is one clue to the fact that Tesla does not use an AGM battery in their vehicles. A second clue is that the 12V is installed under the hood of what would be the engine compartment if the Tesla vehicle had an engine. AGM batteries can be installed under the hood as well but they are just as likely to be located inside the passenger compartment, i.e. underneath a rear seat or under the floor of the hatch or trunk.
Automotive designers are free to place an AGM battery in any orientation in almost any location in a vehicle. The same placement flexibility does not exist for a conventional flooded lead-acid battery. If a conventional battery case ruptures due to a collision or a battery fire/explosion then the electrolyte, concentrated sulfuric acid, would be released. If the same was to happen with an AGM battery then at most just a small amount of electrolyte could leak as the electrolyte is held in the fiberglass mat like a damp sponge.
Tesla could have chosen to use an AGM type 12V battery in their vehicles. AGM batteries cost more than a conventional battery.
If you take a voltage reading from the Tesla's 12V accessory port, it is 14.4V. This would result in an overcharge of an AGM battery, shorten the life of the battery. That is one clue to the fact that Tesla does not use an AGM battery in their vehicles. A second clue is that the 12V is installed under the hood of what would be the engine compartment if the Tesla vehicle had an engine. AGM batteries can be installed under the hood as well but they are just as likely to be located inside the passenger compartment, i.e. underneath a rear seat or under the floor of the hatch or trunk.
Automotive designers are free to place an AGM battery in any orientation in almost any location in a vehicle. The same placement flexibility does not exist for a conventional flooded lead-acid battery. If a conventional battery case ruptures due to a collision or a battery fire/explosion then the electrolyte, concentrated sulfuric acid, would be released. If the same was to happen with an AGM battery then at most just a small amount of electrolyte could leak as the electrolyte is held in the fiberglass mat like a damp sponge.
Tesla could have chosen to use an AGM type 12V battery in their vehicles. AGM batteries cost more than a conventional battery.
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jcanoe: Thanks for the clarification. I won't have to think about this again for another couple of years...I hope!
rxlawdude
Active Member
I can relate that when the 12V battery in our M3 died (2.5 years, 57K miles) there was a strong sulfur odor. I thought I might have a gas leak at the water heater a few feet from the car. Turned gas off and smell persisted. Only then did I sniff near the hood of the M3, and put 2 and 2 together (the battery had already died to the point of not opening the door, but probably continued to draw until it finally bit it entirely with a puff of sulfurous discharge).
Jashev
Supporting Member
I believe that the algorithm that Tesla uses to charge the 12V battery depends on a particular type of battery. There were problems way back when I bought my first Model S related to the algorithm allowing the battery to discharge too much before recharging which was causing the batteries to fail prematurely. That was resolved but since then they have been very particular about what 12V batteries get put in the cars.
I'm not sure if it would be an issue but I would certainly check before doing it.
The Hanhook 12V batteries in the Model Y/3 may not be AGM but it appears Tesla is charging them as if they were. I monitor the 12V post voltage with a Bluetooth voltage monitor. Anytime the car is awake the voltage is either 14.4V (actively charging via DC-to-DC converter) or 13.4V (DC-to-DC supplying power to 12V operational loads). Dropping to 13.4V did not happen until a fairly recent firmware update, prior to that it was always 14.4V when not sleeping. I purchased a NOCO Genius G7200 to maintain charge level, with the negative cable not connected, so the battery is not connected to the car while using the charger. The charge mode I use (or should I say the charger automatically selects) is 12V Cold/AGM. According to the NOCO manual the charge voltage in this mode is 14.8V (which is what my BT device measures). Neither Tesla nor the Smart Charger charge at 16V. If I am using the wrong charging mode, what mode should I be using? Note the BT monitor might be off by +/- 0.1V
From Hankook web page:
Charge for 24 hours as following voltage upon battery type.
- 12V MF Battery: 16V
- 12V AGM Battery: 14.4V
See this Hankook webpage for more info.
Battery Maintenance - Hankook AtlasBX Technical Information
That is interesting as I was not aware that Tesla recently changed their 12V charging programming. There was a problem with earlier Tesla vehicles cooking the 12V battery by overcharging so maybe this is how Tesla fixed the 12V battery overcharging issue. 14.8V seems a bit too high for the float voltage of a flooded lead-acid battery but may be ok for the start of a charging cycle. 13.4V may be slightly too low to be the float voltage of an AGM battery. (My 2017 Chevy Volt used an AGM battery and the voltage readings I obtained from the Volt's accessory port would vary with load and temperature from 12.4 up to 15.4V, mostly settled to ~13.0V.)
Perhaps Tesla is moving away from using the current 12V Hankook flooded lead-acid battery. I read that the new Model S and Model X will have a Lithium 12V battery. I am unfamiliar with the charging requirements of the lithium battery such as the Ohmmu 12V lithium battery: Here is a link:
Tesla Model Y Lithium 12V Battery (Ultra Lightweight, 4X Life)
Battery University has a wealth of information on all types of batteries: Basic to Advanced Battery Information from Battery University
So even if the 12V battery is an MF and not AGM, Tesla appears to be charging it at around 14.4V (and not 16V recommended by the MF battery manufacture) which certainly should NOT overcharge or boil out the electrolyte, correct? If it is an MF battery, not charging it to 100% SOC does NOT make sense from a Depth of Discharge cycling lifetime perspective? Please see my post above. Experts??
