Chevy Bolt EV Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
51 Posts
Discussion Starter #1
During my morning commute the Battery Saver Warning message appeared. On page 135 in the manual, it says that my 12 volt battery voltage has dropped and vehicle features are being disabled. The message may also display when the high voltage battery is low. In my case I still had over 200 miles on the GOM and none of my vehicle features were shutting down. I called ONstar and they said my diagnostics were fine. I have a Monday morning appointment for my Bolt. I have since stopped the car when I arrived at work (my commute is 74 miles). The message reappears when I restart the car. I drove over to the nearest dealer where I work and they said we can't look at it for a week. I am going to drive it back home tonight and cross my fingers. Anyone else had this message appear, preferably without it being an issue of the traction battery being very low. My home dealer has set up a loaner car for me for Monday while they service it.
 

·
Premium Member
Joined
·
787 Posts
It's not the traction battery that's the issue. It's the 12V battery that is having problems. If the car starts, and the regular 12V electronics work (lights, radio, displays, fans), then you should be fine to get home. Sounds like the 12V battery is weak or dying.
 

·
Registered
Joined
·
333 Posts
I've gotten that same alert about half a dozen times. I will be watching this...
 

·
Registered
Joined
·
1,766 Posts
Have you tried charging the 12V battery with a standard 'smart' 12V battery charger? That might fix your problem. But you should check the battery voltage before charging. The Nissan LEAF had huge problems with its "keep the 12V battery properly charged" logic, killing quite a few 12V batteries, regularly. It would be interesting to monitor the voltage on your Bolt's 12V battery yourself. Do you have a voltmeter? (You should be able to easily find a rather inexpensive digital voltmeter.)

Since simply opening the driver door 'wakes up' the computer and other logic in the vehicle, thus increasing current draw on the 12V battery, the recommended testing methodology would be to pop the hood when you get home (so that you don't have to open the driver's door later to lift the hood and 'wake up' the car logic). Maybe even open/prop-up the hood (if the car is inside a private garage).

- pop hood when get home
- let car (battery) sit for an hour or so (making sure all the car logic turns off, and battery is at rest)
- test voltage on 12V battery, add data to your log sheet
- just before leaving in the morning, test battery voltage again, add data to log
- close hood, drive away (propping up the hood upon arrival, and then leaving it up, is a reminder to test voltage)

Sure, it would take an extra 60 seconds or so in the evening and morning to do this, but the results could be rather educational.

A 'fully charged' 12V battery should be about 12.6V. A 12V battery at 12.0V is seriously depleted (not empty, but far, FAR from full). (The best/only real way to test a battery is with a hydrometer, but voltage is 'good enough', unless you are going to write a scholarly dissertation on the subject.) If the Bolt's logic (and hardware) isn't keeping the battery above 12.4V in regular use, your battery will probably not last very long (a properly-sized 12V battery that doesn't have to crank an engine should easily last 8-10 years if kept properly charged). A 12V lead-acid battery that is routinely at or below 12.4V while being used (current draw, even low draw) will sulfate 'quickly' (in a couple of years or less) and needs to get a fully saturated charge every now and then to de-sulfate.

After a friend's 12V battery died in his LEAF (battery 2 years old), I bought a smart 'maintenance' (trickle) charger for my EV, which I use 2-3 times a month on my EV. It charges at less than 1 amp. I just attach it in the evening and leave it til the next morning, which fully, *fully* charges the 12V battery overnight. All that nasty crap sticking to the plates re-dissolves into the solution instead of continuing to build up on the plates and hardening.
 

·
Registered
Joined
·
508 Posts
recharge 12 V battery?

My Bolt is half dead. Main battery is fine, but getting Battery Saver Active and it has shut off most systems. The voltage is reading 9.39 V, obviously low. If I put the EVSC on does that provide a path to charge the 12 V? Propulsion battery shows 174 miles range. I also have an old 12 V charger, is it OK to connect it? I think some of the car systems are operating, but won't shutdown.

Need Advice, thanks.
:nerd:

Have you tried charging the 12V battery with a standard 'smart' 12V battery charger? That might fix your problem. But you should check the battery voltage before charging. The Nissan LEAF had huge problems with its "keep the 12V battery properly charged" logic, killing quite a few 12V batteries, regularly. It would be interesting to monitor the voltage on your Bolt's 12V battery yourself. Do you have a voltmeter? (You should be able to easily find a rather inexpensive digital voltmeter.)

Since simply opening the driver door 'wakes up' the computer and other logic in the vehicle, thus increasing current draw on the 12V battery, the recommended testing methodology would be to pop the hood when you get home (so that you don't have to open the driver's door later to lift the hood and 'wake up' the car logic). Maybe even open/prop-up the hood (if the car is inside a private garage).

- pop hood when get home
- let car (battery) sit for an hour or so (making sure all the car logic turns off, and battery is at rest)
- test voltage on 12V battery, add data to your log sheet
- just before leaving in the morning, test battery voltage again, add data to log
- close hood, drive away (propping up the hood upon arrival, and then leaving it up, is a reminder to test voltage)

Sure, it would take an extra 60 seconds or so in the evening and morning to do this, but the results could be rather educational.

A 'fully charged' 12V battery should be about 12.6V. A 12V battery at 12.0V is seriously depleted (not empty, but far, FAR from full). (The best/only real way to test a battery is with a hydrometer, but voltage is 'good enough', unless you are going to write a scholarly dissertation on the subject.) If the Bolt's logic (and hardware) isn't keeping the battery above 12.4V in regular use, your battery will probably not last very long (a properly-sized 12V battery that doesn't have to crank an engine should easily last 8-10 years if kept properly charged). A 12V lead-acid battery that is routinely at or below 12.4V while being used (current draw, even low draw) will sulfate 'quickly' (in a couple of years or less) and needs to get a fully saturated charge every now and then to de-sulfate.

After a friend's 12V battery died in his LEAF (battery 2 years old), I bought a smart 'maintenance' (trickle) charger for my EV, which I use 2-3 times a month on my EV. It charges at less than 1 amp. I just attach it in the evening and leave it til the next morning, which fully, *fully* charges the 12V battery overnight. All that nasty crap sticking to the plates re-dissolves into the solution instead of continuing to build up on the plates and hardening.
 

·
Registered
Joined
·
1,934 Posts
The Bolt uses a 12v AGM battery... don't use a old charger designed for flooded lead/acid batteries on it, get a charger with a dedicated AGM setting.

You measured 9.39 volts with a VOM at the 12v battery posts?


If your car is in zombie mode with systems that won't shut down... it's okay to disconnect the 12v battery overnight and recharge it on a 12v AGM charger while it's disconnected.
 

·
Registered
Joined
·
508 Posts
The Bolt uses a 12v AGM battery... don't use a old charger designed for flooded lead/acid batteries on it, get a charger with a dedicated AGM setting.

You measured 9.39 volts with a VOM at the 12v battery posts?


If your car is in zombie mode with systems that won't shut down... it's okay to disconnect the 12v battery overnight and recharge it on a 12v AGM charger while it's disconnected.
It was in zombie mode. Chevrolet Roadside assistance charged it. I have to look up what an AGM charge is because my last century battery charger didn't work correctly. What I learned is if the red battery symbol comes up, that is the problem and the other warnings are just consequence of a discharged battery. In what modes the the Bolt charge its 12 V battery?
 

·
Registered
Joined
·
10 Posts
Your car should be charging your 12v battery anytime it's running.

It has a 12v power supply capable of delivering 1.6 kW at any time, well over 100 amps. It should be using this to top up the battery and run the 12v systems.

Either something is wrong with your battery, and it wont take charge, or your car isn't supplying 12v... It kinda sounds like the 12v power supply is dead...
 

·
Registered
Joined
·
1,934 Posts
Under normal circumstances should be nothing the end user could do that would kill the 12v battery as all 12v accessory feeds are shut down when the car is powered down and as soon as you power up the Bolt it charges the 12v battery from the main 60kWh battery.

If your 12v battery is running down... get a full diagnostic done at the dealer.
 

·
Registered
Joined
·
508 Posts
Under normal circumstances should be nothing the end user could do that would kill the 12v battery as all 12v accessory feeds are shut down when the car is powered down and as soon as you power up the Bolt it charges the 12v battery from the main 60kWh battery.

If your 12v battery is running down... get a full diagnostic done at the dealer.
I am guessing the car was not powered down overnight. I assume this would slowly drain the 12 v battery. If that is not true, then I either have a battery problem or a charging problem. Time will tell.
 

·
Registered
Joined
·
1,934 Posts
^ Even leaving the car powered up overnight wouldn't discharge the 12v battery as it's constantly monitored and recharged by the main battery.

IIRC the Bolt even has an auto-off feature that if you don't take it out of Park after so many minutes it shuts the car off?
 

·
Registered
Joined
·
145 Posts
Reviving this thread - has anyone found a reason or fix? I've seen this message almost every day for over a month now with no ill effects. I also don't see any consistency of when it comes up - sometimes early in my commute, sometimes near the end.

I even brought it up with the dealer during my recall/update and they said that they charged the battery and tested it with no issues. Surely someone else is seeing this or has found a fix but I don't see any other posts about it.
 

·
Registered
Joined
·
300 Posts
Sounds like a classic case of bad sensor or bad wiring to the sensor. The dealer needs to apply some brain cells rather than waiting for the computer to tell them what to do. Maybe if you took a picture of the message and showed them that it would help (doubtful). Maybe you would have better luck with a different dealer.

Good luck and thanks for the update.
 
1 - 13 of 13 Posts
Top