Dead Car, Dead 12V Battery

[SparkEVPilot]

I did have a power pack, and I did jump start the car, but it still was undriveable and had to be towed to the dealer.

12 volt AGM batteries have been known to die suddenly. If your car started when the 12 volt power pack was connected and then died when the 12 volt power pack was disconnected, That points to a very bad 12 volt AGM battery. The 12 volt AGM battery used in the Bolt and Spark EV is expensive - about $175.00. But, at this point, it might be worth replacing. It may also be possible if the power pack was left connected, that the 12 volt battery did not allow 12 volts to get to the car's electronics. This is all speculation on my part, but there have been numerous posts on the Spark EV forum relating to 12 volt battery problems. A good volt meter would be useful to measure the voltage across the 12 volt battery as you try to start the car. If the voltage drops below 12 volts, the car probably will not start.

[davemausner]

Agreed with OP that it is confusing when a 60kWh EV does not charge an AGM 12V. But if your Bolt won't start due to "not in proper state to shift" or a 12V battery alarm, there is a trick to try before calling for the tow truck.

Turn the car on, leave the shifter in P. Turn off all accessories. Take a break for 20 to 30 minutes: do nothing to the car. If the 60kWh battery has juice, it is charging the 12V.

After waiting, try shifting into R, D, or L. You may now have enough voltage to run the computers and drive away. This will work provided the 12V is physically (internally) intact.

This worked for me several times. As such, I demanded a warranty 12V battery replacement and received it without question.

[Remodelguy]

I've just had this same issue where we came back to our car and it was "Dead". I found the information from SparkEVPilot (in quotes below) to be helpful in confirming that the big battery was indeed charging the 12v battery when we picked it up from the service dept. We had gotten the phone call that the car had been checked out and was ready, but I was concerned that since I had completely recharged the Bolt's 12v battery, everything would look hunky dory to the tech and he might miss any underlying problems. I checked the battery before starting and it was at 12.5v, then after starting the Bolt it went to 14.75 - so at least I know that there is some significant charging of the 12v battery occuring when the car is turned on.

I'm sure that the OP has already receive a lot of helpful information, but I wanted to offer my experience to let the next person researching this issue that they are not alone.

Some extra details on our experience -

1. Got dropped off after car pooling to dinner with some friends and the door button did not unlock the car, then the remotes got no response - like the battery was dead.

2. Could not get into the car. Called Onstar to see if they could open the car, but they couldn't.

3. Onstar asked if it was possible that we had both pressed our remotes at the same time and that could possibly wipe the remotes and prevent them from being recognised - we said maybe.

4. Went through a routine to try and gain entry to the vehicle, but the ONstar rep did not seem familiar with the process. Ended up figuring out how to get in by accident and then went through the "Reprogram the Key" routine - that may be necessary whenever the battery goes dead (according to ONstar rep). Nothing happened.

5. Then Onstar sent a message to Chevy Roadside to get us towed. Chevy Roadside was supposed to call us back but never did. Spent the time researching the idea of a dead battery in a Bolt online. Called Onstar again and this rep seemed familiar with the idea of a dead 12v battery and told us that if we could get Chevy Roadside or AAA to give us a jump, that the 12v battery would turn the car on and the fully charged big battery would allow us to drive.

6. We gave up on Chevy Roadside and called AAA. AAA had a similar ETA so we waited. Meanwhile, we notice a AAA flatbead truck sitting in the Target parking lot where we were stranded. Finally, the driver came out and agreed to try and help us. At first, he hooked up the cables and the alarm went off and we quickly did the routine to reprogram the key. The alarm stopped and the car was running, but when the driver disconnected his cables, the car died again after a couple of minutes.

7. They guy really wanted to help us and hooked his cables up again for about 15 minutes. That seemed to do the trick and after thanking and tipping the driver, I was able to drive the car home ( as short distance) but the max speed was 30 mph (so don't try to get on the freeway).

8. The warning light stayed on the whole time. When I got home, I hooked it up to a new cheap trickle charger overnight. In the morning, I started to hook the battery up to a heavier duty charger, but it was already fully charged. I started it and pulled it into the garage, but the warning light stayed on.

9. That evening, we took it for a test drive to see if it was still in the "Maximum Speed 30 MPH" mode, but it was not. My wife wanted to take it to work the next day. From driving it that evening, we received a text message that Chevy had run diagnostics on the vehicle and everything checked out. When the wife drove it to work, she reported that the check engine light had gone out. She still made an appt with service and everything seems to have checked out.

10. As I mentioned in the first paragraph, I checked out the 12v battery with a tester and it helped give us more confidence that the big battery was indeed charging the 12v battery once the car started. Problem mostly solved. We still don't know how the 12v battery got discharged. If something is out of whack electronically, it may be a while before we find our Bolt dead again as it probably takes much more time to discharge since the 12v battery does not have to turn a starter motor and only runs a bunch of gauges and led lights. Still, we are aware of the issue and hope to be better prepared next time.

Just having some idea that a typical AAA vehicle or even a good samaritan with jumper cables might be able to get us home was helpful. I recommend that you not follow our lead and end up in a worse situation or get in an accident. You should evaluate your own situation and act accordingly (and probably wait for a flatbed tow truck). Hope this helps someone.



"If the Bolt 12 volt battery charging function is anything like the Spark EV, then this is what I found that might help - I measured the 12 volt battery voltage on my 2014 Spark EV after the car had been powered off for a couple of hours. It read about 12.5 volts. Then I plugged the car into my L1 EVSE set at 8 amps and measured the voltage. It read about 13.3 volts. I removed the charging cord and, after a couple of minutes, remeasured the battery voltage. 12.5 volts. Then I started the car and remeasured the battery voltage. It measured 14.5 volts. I got similar results for my 2016 Spark EV using my L2 EVSE (240 VAC at 16 amps).

Numerous Spark EV electrical problems have been attributed to the 12 volt AGM battery and were corrected by replacing the battery. If the Bolt 12 volt battery charging function is like that in the Spark EV, ( same 12 volt AGM battery ) then the 12 volt battery only gets a small trickle charge when the car is plugged in. The main charging of the 12 volt battery occurs when the car is powered on and continues until the car is powered off.

I would suggest you get a good voltmeter and test the 12 volt battery for yourself; especially with the car powered off and then with the car powered on. If you do not see the voltage jump from 12.5 volts with the car powered off to about 14.5 volts with the car powered on, your battery is not getting charged. Check the 100A fuse at the side of the positive terminal or take the car back to Chevy, explain what you found and have them check the fuse and the charging electronics.

It really sounds like you have a blown fuse, a bad 12 volt AGM battery or a problem with the charging electronics. I would also suggest purchasing a BatteryMinder 2012-AGM battery charger and charging your 12 volt battery at least once per month for 10 hours or more - I charge mine overnight. BatteryMinder has an option that allows you to charge through the OBD2 port inside of the car and it works great. This is what I do for both of my Spark EVs."

[SparkEVPilot]

Below is some information I found regarding the "care and feeding" of a 12 volt AGM car battery. Sulfation of the plates is a "killer"!

The Average AGM Battery Life Expectancy
Posted on June 21, 2018 by JeffreyDrummond
Absorbent glass mat or AGM type of battery is considered to be a better type power cell compared to the different types of batteries available in the market today.

It is a type of power cell that features unique chemical structure that allows it to hold a charge better, offer more efficient performance and makes it a lot safer to use.

As a battery type that features a unique chemical structure, an AGM battery also offers a longer service life compared to other battery types.

Here we are going to take a look at the average AGM battery life expectancy and how many years they usually last. We are also going to check out the different factors that directly affect the battery life of an AGM battery.

This article will also provide you with some tips on how to take care of an absorbent glass mat power to help you extend its life expectancy.

So to begin, let us start taking a look at the average lifespan of an AGM battery!

The Average Life Expectancy of An AGM Battery
Usually a typical sealed absorbent glass mat battery last three to five years. It can be extended up to six to eight years if the battery is properly maintained. There plenty of factors that directly affect the lifespan of an AGM battery.

To properly maintain an AGM battery and to try to extend its life keeping out from these factors is imperative. Just always keep in mind that actual battery life of AGM batteries can be three to five years and it can be extended up to six to eight years if they are properly maintained.

Factors that Affect the Battery Life of AGM Batteries
Having knowledge about the different factors that directly affect the battery life of AGM batteries will allow you to take care of your battery properly. It will give you the chance to avoid doing the things that may significantly shorten its battery life.

Keeping these in mind will also keep your battery healthy, and it will allow it to deliver the optimum performance that you need. Find out about these factors by checking out the list below.

Weather Condition or Climate
Cold weather conditions make it harder for batteries to deliver the performance that they are expected. While Hotter weather conditions discharge batteries quickly. So being exposed to both cold and hot climates can significantly reduce the life expectancy of your AGM batteries.

To help you avoid this situation, you have to make sure that you keep from exposing your battery from hot and cold temperatures.

Suffering from Sulfation
Sulfation is a condition where the plates of the battery are accumulating buildups of sulfate. This condition is considered to be one of the most notorious factors that leads a battery to their death. Sulfation is a condition that limits the battery plates to hold a charge and eventually leads to their death.

Completely Discharging the Battery
When AGM or absorbent glass mat batteries are completely drained or discharged makes it hard for them to recover. So, completely discharging these batteries will significantly reduce the life expectancy of your battery.

To try to extend the battery life of your power cell to up to six or eight years, you may want to keep from deeply discharging your battery until it is completely depleted.

Some Tips to Help You Take Care of Your Battery
To help you take care of your AGM battery and extend its battery life, you have to take care of it properly. And to help you do that in the proper way, here are some tips that you can follow.

Keep it Clean and Well-Maintained
If you want to extend the lifespan of your AGM battery, you may want always to keep it clean and well-maintained. That way the battery will always be healthy, and it will have a better chance of surviving all the tough conditions it may be subjected to.

Avoid Exposing it From Hot and Cold Climate
To try to extend your AGM battery life expectancy, you also have to keep it from being exposed for the hot and cold climate. Hot and cold temperatures can significantly reduce its battery life, so, be sure to store it in a room with an average temperature level.

[trevmar]

Can anyone explain what it is about an EV that makes a traditional SLI (starting, lighting, ignition) lead acid battery unsuitable? These types are built for power (ICE starting) and not so much for energy, so reserve capacity and ability to sustain 'hotel loads' (quiescent current drains) is limited. But they have been used for years and are cheap and generally quite reliable.

You would think it is simply a matter of tweaking the main HV battery to keep the 12 volt battery in its' optimum voltage window, just like an alternator on an ICE. So why the need for AGM?

[theothertom]

Can anyone explain what it is about an EV that makes a traditional SLI (starting, lighting, ignition) lead acid battery unsuitable? These types are built for power (ICE starting) and not so much for energy, so reserve capacity and ability to sustain 'hotel loads' (quiescent current drains) is limited. But they have been used for years and are cheap and generally quite reliable.

You would think it is simply a matter of tweaking the main HV battery to keep the 12 volt battery in its' optimum voltage window, just like an alternator on an ICE. So why the need for AGM?

My guess is manufacturers (all of them, including Tesla) used off the shelf components that operate on 12V as opposed to adding a transformer (?) to reduce the voltage from the main battery to 12V. Components such as A/C, windshield wipers, radio, lights, turn signals, door locks, and yes, the computer(s) are readily available for 12V systems and don't have to be redesigned.

[SparkEVPilot]

Can anyone explain what it is about an EV that makes a traditional SLI (starting, lighting, ignition) lead acid battery unsuitable? These types are built for power (ICE starting) and not so much for energy, so reserve capacity and ability to sustain 'hotel loads' (quiescent current drains) is limited. But they have been used for years and are cheap and generally quite reliable.

You would think it is simply a matter of tweaking the main HV battery to keep the 12 volt battery in its' optimum voltage window, just like an alternator on an ICE. So why the need for AGM?

My guess is manufacturers (all of them, including Tesla) used off the shelf components that operate on 12V as opposed to adding a transformer (?) to reduce the voltage from the main battery to 12V. Components such as A/C, windshield wipers, radio, lights, turn signals, door locks, and yes, the computer(s) are readily available for 12V systems and don't have to be redesigned.

Here is where to find some of the answers to your questions about AGM batteries:
https://batteryuniversity.com/learn/art ... ss_mat_agm

[psyflyjohn]

I've dealt with lead acid batteries for 50 yrs - both on cars and banks of them on RV's. They just get weaker over time, and fail to do their job after a while. It's a slow process characterized by a decreasing ability to hold a charge. The Bolt really doesn't seem to have a good monitoring system to check the lead acid battery functioning. You can get around this by doing two things. One, have a constant monitoring system. My solution is a little plug in device for the "lighter socket" (Amazon). It gives a real time read out of the battery and charging system at work. Typically, upon starting the car, the computer recharges the battery to 14+ volts, then it quickly tapers to a standing 12.6 volts. The battery is then powering the 12v system alone. Periodically, the computer checks the voltage, and if it drops to 12.5 V, it kicks in at 12.6 for a short time. The key is how long the battery can maintain a 12.6v charge. When it begins to fail, I would expect the computer to increase it's charging frequency. If I notice that charging is more frequent, then I begin to question the capacity of the battery to hold a charge. At that point, I would put cheap load meter on the battery (Harbor Freight) and check it's capacity. If capacity is reduced, then replace the battery.

I would love to put a lithium battery in place of the lead acid, but I think the computer charging system may have some difficulty with it since the charging requirements are somewhat different that the computer's lead acid charging program.

[bobo]

Thanks. Good read.
Do you have a link for what you would recommend to buy from Amazon for the lighter socket 12vdc monitor? I want to buy one.

[theothertom]

Thanks. Good read.
Do you have a link for what you would recommend to buy from Amazon for the lighter socket 12vdc monitor? I want to buy one.

I saw this one, maybe in this thread or another similar thread. Anyway, I bought it. Seems to work ok but I think you need to keep tabs on it to know when it's going down.
https://www.amazon.com/Palumma-Charger- ... pons&psc=1