Planning for the future: 12V battery dies

[nyc6035]

All,

I've been reading that the M3 has tended to have 12V batteries that die all of a sudden.

In an ICE vehicle you can get an indication that a battery is close to death, particularly in cold weather, by hearing the struggle of the starter.

What warning signs are there in a Tesla of impending 12V battery trouble to look/listen out for?

 

[jcanoe]

None. The Tesla vehicle may detect that the 12V battery is failing, in that case the vehicle will display a message that the 12V battery needs to be serviced. If you see this message then immediately schedule a service appointment, noting that the vehicle has detected a problem with the 12V. If all goes well you will be able to continue to drive the vehicle for a week or two until the 12V can be replaced. Purchase a small lithium battery jump starter pack to keep at home or work. If the 12V fails to boot up the Tesla vehicle you can use the jump starter to open the hood, then use the jump starter a second time by connecting directly to the 12V battery to boot up the vehicle.

 

[Mike_TV]

As @jcanoe points out there aren't any outward warning signs but you may get a message about replacing the battery. I would replace it when you see that message.

If you are really concerned about this and want to be proactive, just replace the 12V battery in three years. That's excessive for some as AGM batteries should last five years or more depending on conditions but if a couple hundred dollars buys piece of mind and your MY is your own car then it may make sense.

The V12 battery, windshield wipers, cabin filter, brake pads, brake fluid, and tires all have a limited lifespan and will need to be replaced at some point. Doing it sooner won't hurt anything except for your wallet.

 

[jcanoe]

As @jcanoe points out there aren't any outward warning signs but you may get a message about replacing the battery. I would replace it when you see that message.

If you are really concerned about this and want to be proactive, just replace the 12V battery in three years. That's excessive for some as AGM batteries should last five years or more depending on conditions but if a couple hundred dollars buys piece of mind and your MY is your own car then it may make sense.

The V12 battery, windshield wipers, cabin filter, brake pads, brake fluid, and tires all have a limited lifespan and will need to be replaced at some point. Doing it sooner won't hurt anything except for your wallet.

The 12V battery currently used in the Tesla Model 3 and Model Y vehicles is not an absorbent glass mat (AGM) 12V battery. The 12V used in the Tesla vehicles is a sealed, maintenance free (MF) deep cycle flooded lead-acid battery. Aside from the part description in the Tesla Parts Catalog, the charging voltage and the float voltage are not setup for an AGM battery. Also, the Tesla replacement 12V battery costs ~$85 USD. If the 12V was an AGM battery it would cost considerably more than $85.

 

[brinox]

This is what I'm planning for when my 12v battery goes:

https://www.ohmmu.com/product-page/12v-lithium-battery-for-tesla-model-y

 

[brkaus]

This is what I'm planning for when my 12v battery goes:

https://www.ohmmu.com/product-page/12v-lithium-battery-for-tesla-model-y

At over 4x the price, is it really worth it? Will it last 8-12 years?

 

[jcanoe]

At over 4x the price, is it really worth it? Will it last 8-12 years?

Lithium 12V batteries have been available for some time; the lower weight appeals to serious auto racers. Not sure how well these batteries hold up in summer heat. In the Tesla the 12V battery is not located inside the passenger compartment. Otherwise cabin overheat protection might help.

 

[brkaus]

Lithium 12V batteries have been available for some time; the lower weight appeals to serious auto racers. Not sure how well these batteries hold up in summer heat. In the Tesla the 12V battery is not located inside the passenger compartment. Otherwise cabin overheat protection might help.

My doctor would suggest I lower my weight as a first step

 

[Mike_TV]

The 12V battery currently used in the Tesla Model 3 and Model Y vehicles is not an absorbent glass mat (AGM) 12V battery. The 12V used in the Tesla vehicles is a sealed, maintenance free (MF) deep cycle flooded lead-acid battery. Aside from the part description in the Tesla Parts Catalog, the charging voltage and the float voltage are not setup for an AGM battery. Also, the Tesla replacement 12V battery costs ~$85 USD. If the 12V was an AGM battery it would cost considerably more than $85.

What's the part number for the 12 volt battery?

 

[brkaus]

What's the part number for the 12 volt battery?

 

[patnshan]

The 12V battery currently used in the Tesla Model 3 and Model Y vehicles is not an absorbent glass mat (AGM) 12V battery. The 12V used in the Tesla vehicles is a sealed, maintenance free (MF) deep cycle flooded lead-acid battery. Aside from the part description in the Tesla Parts Catalog, the charging voltage and the float voltage are not setup for an AGM battery. Also, the Tesla replacement 12V battery costs ~$85 USD. If the 12V was an AGM battery it would cost considerably more than $85.

LOTS more than $85. My BMW AGM costed many times more than that!

 

[CDN-Build]

Anyone know if any 12volt battery work, or does it have to be this this one.?

 

[jcanoe]

Anyone know if any 12volt battery work, or does it have to be this this one.?

Any 12V lead-acid battery (that fits BCI Group 85) would work in an emergency but it needs to be a deep cycle battery or it will quickly fail in the Tesla. Since the Tesla battery is only ~$85, not including installation, you should just use the Tesla replacement battery as it is specifically made for use in Tesla vehicles (12V, 45Ah, deep cycle, sealed maintenance free (MF), flooded lead-acid battery.)

See this thread, especially the later posts:

model y long-range 12v battery

 

[CDN-Build]

Any 12V lead-acid battery would work in an emergency but it needs to be a deep cycle battery or it will quickly fail in the Tesla. Since the Tesla battery is only ~$85, not including installation, you should just use the Tesla replacement battery as it is specifically made for use in Tesla vehicles (12V deep cycle, sealed flooded lead-acid battery.)

See this thread, especially the later posts:

model y long-range 12v battery

That’s what I wanted to know.
Thanks.

 

[silverstoned83]

This is what I'm planning for when my 12v battery goes:

https://www.ohmmu.com/product-page/12v-lithium-battery-for-tesla-model-y

I too am considering the lithium replacement for the 12v battery. Once you understand the advantages, it’s easier to get over the initial cost.

It will, without any doubt, last many more years than any lead acid could dream of. The cycle count by the time it reaches 80% capacity will be several times that of any lead acid. The self discharge rate will be far slower, therefore requiring less energy from the HV battery to float charge.

 

[brkaus]

@silverstoned83 fo you think the self discharge rate on the lead acid battery is significant- relative to the rest of the vampire drain?

 

[silverstoned83]

@silverstoned83 fo you think the self discharge rate on the lead acid battery is significant- relative to the rest of the vampire drain?

I think it makes up a portion of the vampire drain when you take into account how often it must charge the 12v, which has a lot to do with the lead acid chemistry I think. Having said that, it’s hard to say how much of this vampire drain is from the self discharging nature of the lead acid chemistry and how much is due to the parasitic loads within the system.

I would still consider the cycle life to be another important factor as it’s nice to know that I won’t have to worry about having a 12v battery failure every 3-5 years, which is the life expectancy of any lead acid chemistry in the industry. Instead, I would expect 2-3 times that easily with lithium.

After having experienced the consequences of such a failure first hand with my i3, I would like to avoid that experience if at all possible because I expect the result of a 12v battery failure to be similar across all EVs.

 

[jcanoe]

Here is an article on the self-discharge rate of different battery chemistries. For a lead-acid battery the normal self-discharge rate is 5% per month. Elevating Self-discharge - Battery University

Assuming Sentry Mode is turned off, if the Tesla vehicle is locked then the alarm system, BT modem, key card sensors (in the driver's door B pillar and the center console) and the LTE modem will continue to draw power while the Tesla is in sleep mode. My Model Y will power up the 12V electrical system about every 24 to 36 hours. How do I know this? My Amazon Echo Auto device and the Alexa app generates an alert message on my iPhone that the Echo Auto device is active and the Alexa App is ready to drive. This happens every time the 12V system is powered on. Further investigation is needed to determine how long the 12V system remains powered on during these power on cycles.

 

[73Bruin]

... How do I know this? My Amazon Echo Auto device and the Alexa app generates an alert message on my iPhone that the Echo Auto device is active and the Alexa App is ready to drive. This happens every time the 12V system is powered on.

Just curious what do you use you Echo Auto for (e.g. Music, remote control of home devices)?

 

[Berkshire1]

If the 12V goes dead and you can gain access to vehicle using external 12V battery, is the vehicle drivable after disconnecting the external battery?