[PFRobinson]

My dealer called me and said I can come check it out before PDI, when we walked out to it it had a dead 12V. Two days later PDI was done all accessories installed, no further battery issues.

Did they say why the 12 v battery went dead?

 

[PFRobinson]

These are most likely AGM, which are supposed to have very little vampire drain, unlike lead acid. My Bolt and Mach E both have AGM batteries, and I put a deep cycle AGM on my boat.

If you go to other EV forums, like Mach E or Rivian, the same battery issue seems to occur often on those as well. Not only that, but then because of the PAAK (phone as a key) feature, people also complain that the car apps cause the phone batteries to drain too fast. The phone and the vehicle are always trying to pick up a Bluetooth connection.

When does this 12v battery get charged? Combustion cars have Bluetooth, WiFI, Apps and remote start with both key fob and iPhone. My battery in my corvette lasted 5 years. Not buying it.

 

[PFRobinson]

EVs have much more monitoring systems and the Hummer also has walk up and away light animation. Constantly looking for the fob.

Then the design engineers miscalculated. Ridiculous

 

[PFRobinson]

Also, these vehicles are "connected" (4G/LTE or Wifi) and looking for OTA updates as well. The 12V should be charged when the vehicle is plugged in to an L2 charger and while driving. But when they sit at dealers for a while, they are likely not always plugged in. Also the 12V batteries in EVs are not used to crank the engine, so they are lower power batteries to begin with.

So for those who are EV owners, what is the life expectancy of these accessory batteries?

 

[PFRobinson]

3 or 4 years, but under certain conditions they can go dead, and need to be charged.

Does the owners manual have instructions for independently charging the 12v battery.

 

[PFRobinson]

I know how to charge a battery, not going to waste my time to look it up in the Manual.

So you disconnect the battery terminals.

 

[PFRobinson]

You don't have to... Just get a trickle charger that is designed for AGM batteries and connect it to the terminals.

View attachment 2696

Thank you for providing the owners manual instructions. Great inside for us who have never owned a EV. Appreciate it.

 

[PFRobinson]

There are solar powered trickle chargers available.

Sounds like this issue can be avoided if you just plug in your vehicle every night. Level 2 Charging.