How do I check the health of the 12V battery?

[OldPro]

I'll have it tested at the Service Center. Tires need to be rotated and cabin filter changed anyway.

 

[BitJam]

I don't see a whole lot of point to "get ahead" and replace the battery before it's bad since the car doesn't leave you stranded anyway, but you do you.

Where I live it's a 4+ hour round trip to the nearest service center. If I'm there for another reason (such as bioweapon defense mode retrofit), I plan to have them replace the 12 volt. OTOH I'm delighted to hear that a dead 12 volt won't leave me stranded.

 

[Blue Express]

How do I check the health of the 12V battery? Replaced early 2019.

You can purchase the battery monitoring meter from Amazon and it connects to your phone via bluetooth for continuous monitoring.

 

[OldPro]

Interesting.thanks

 

[rpiotro]

There’s a procedure where you kill the power to the car by disconnecting the plug under the back seat. This isolates the 12v battery and you can check it directly.

Sounds like a lot of trouble. How about just disconnecting the battery at the negative post? That would isolate it.

 

[txtabby]

Sounds like a lot of trouble. How about just disconnecting the battery at the negative post? That would isolate it.

No, I looked into it, you have to shut off the screen, unplug the HV cable, pull the NEG cable then check voltage. Otherwise you could damage systems. And yes, it’s a big pain! Might as well just change the battery! It’s been almost 2 yrs…

 

[rotarypower101]

No, I looked into it, you have to shut off the screen, unplug the HV cable, pull the NEG cable then check voltage. Otherwise you could damage systems. And yes, it’s a big pain! Might as well just change the battery! It’s been almost 2 yrs…

Possible you can reference the documentation or information that details damage if done improperly?

Not read that among the various ways that have been proposed to cut the LV DC system.

Would that also be true of the first responders loop?

 

[Adam3]

12v lead acid batteries can test fine one day and stop holding a charge the next. If it's more than 3 years old, replace it.

 

[OldPro]

12v lead acid batteries can test fine one day and stop holding a charge the next. If it's more than 3 years old, replace it.

Having the battery checked Tuesday with mobile tire rotation and cabin filter replacement. I'll ask the Tech to check the 12v battery
and have a discussion with the "real owner", my wife. I'm in for replacing at 5 years+ old.

 

[txtabby]

Possible you can reference the documentation or information that details damage if done improperly?

Not read that among the various ways that have been proposed to cut the LV DC system.

Would that also be true of the first responders loop?

I don’t know.. I just don’t want to damage any of the electronics. Besides, changing the battery you have to do all that. I guess it’s not that hard, just a lot of steps. Not like my Prius that’s for sure! Lol

 

[txtabby]

Having the battery checked Tuesday with mobile tire rotation and cabin filter replacement. I'll ask the Tech to check the 12v battery
and have a discussion with the "real owner", my wife. I'm in for replacing at 5 years+ old.

Look into a Litium battery. They hold the charge longer. This is if you have an older model, before they started installing them in all the cars

 

[stopcrazypp]

Look into a Litium battery. They hold the charge longer. This is if you have an older model, before they started installing them in all the cars

A lot of people have had issues when dropping in a lithium battery. Tesla's battery failure detection algorithm does not like them. See the thread for the most popular one.
Ohmmu 12V Battery Feedback

Also, the lead acid from Tesla is only $85. Even doing proactive replacements, you are unlikely to spend more than what a lithium battery costs.

 

[AZAV8R]

Look into a Litium battery. They hold the charge longer. This is if you have an older model, before they started installing them in all the cars

I don't suggest you do this, I just bagged a totally good Ohmmu because Tesla's BMS didn't get along with an aftermarket lithium battery. Initially I was getting intermittent replace 12 Volt battery warnings. What caused me to finally replace the battery is the car would brick for a 4-5 minutes before responding to a reboot (it would increasingly be dead when I got in after it sat for a while) and take a really long time to boot back up. Tesla was telling me that the car was reporting some sort of 12v anomalies. All of that stopped when I went back to a lead acid battery. So much for that experiment!

 

[txtabby]

I don't suggest you do this, I just bagged a totally good Ohmmu because Tesla's BMS didn't get along with an aftermarket lithium battery. Initially I was getting intermittent replace 12 Volt battery warnings. What caused me to finally replace the battery is the car would brick for a 4-5 minutes before responding to a reboot (it would increasingly be dead when I got in after it sat for a while) and take a really long time to boot back up. Tesla was telling me that the car was reporting some sort of 12v anomalies. All of that stopped when I went back to a lead acid battery. So much for that experiment!

Geez! Thanks guys! I almost bought an Ohmmu yesterday but held off. I was weighing the cost benefit too… couldn’t see one, other than not worrying about it for 4-5 yrs. I’m also having streaming issues. New C.Card, had to re-sign up for premium connectivity after it dropped off. Never happened before!! Been 3 days, no streaming. Rebooted several times. Going to put in a service call Monday morning.