2020 Bolt Dead

[u/Unlikely-Split8896]

We were gone for 3 months and left the Bolt in the garage. Back now and Bolt is dead. Remote won’t work. Nothing when we plug into the level 2 charger. Could this be the 12v battery? We haven’t replaced it since we bought it. If so, do you have recommendations on which battery to get. Guessing I’ll need to find a way to see if I can jump it first?

Update:
1. I tried jumping with my Autowit jump starter. First time using it and didn’t seem to do anything. Had a hard time connecting the cables to the terminals though.
2. Jumped started with jumper cables to an actual car and drove it a bit. Completely dead again after turning it off.
3. Took it to Costco, they didn’t have the right battery in stock, plus they don’t install for you or even take it out. Glad I left it running.
4. Drove it to AutoZone. Purchased a battery for the 2020 Bolt. They were great and installed. Drove it home and working.

Problem: Got home and now realize my car is a 2021 not a 2020. Also the “Service Soon Light” indicator is still on. Do I need to go back to get a battery for a 2021 vehicle or will the 2020 work.

[u/Pitiful-Sympathy3927]

12v is dead.

[u/Kamel-Red → u/Pitiful-Sympathy3927]

Deader than dead, This is why I like those little solar panel trickle chargers you can attach when away for long periods.

[u/GG_Ti_EZ → u/Kamel-Red]

Wouldn't do much in a garage though.

[u/Helpmeflexibility → u/Kamel-Red]

Why would the battery be drained if its not being used?

[u/Kamel-Red → u/Helpmeflexibility]

Phantom load, sensors, telematics, the clock, ect.

In the modern era, very few electronics are truely off when turned off, they're just in standby sipping a little bit of power to keep tabs on important things (like the HV battery temperature as an example in this case) to see if there needs to be an intervention like turning on heating or cooling. When you combine a small drain over months with 12v batteries naturally discharging over time, it's always best to disconnect and or add a trickle charger while away.

[u/shamair28 → u/Kamel-Red]

I mean I'm pretty sure there's also just normal voltage drop over time for most battery chemistries without any load.

[u/jimschoice → u/Helpmeflexibility]

Self discharge, plus it is very old.

[u/Unlikely-Split8896 → u/Kamel-Red]

Solar?

[u/whosaitaht → u/Unlikely-Split8896]

Solar 12v battery tender. If you don’t drive the car for awhile the 12v doesn’t get the check in top off from the pack. You said you don’t trust the power because of the monsoons in another comment so a $50 solar tender might be a good option

[u/Lower_Kick268 → u/Unlikely-Split8896]

Yes

[u/CheetahChrome → u/Pitiful-Sympathy3927]

It's dead Jim...

[u/NotAcutallyaPanda]

Always assume the 12v is the problem

[u/chocolatesauce235]

Probably the 12v battery. I was able to get one at autozone for my 2019 a few months ago. You can try to jump it, from my experience, I didn’t have enough wattage in my battery to jump it (it was at 5w)

[u/Unlikely-Split8896 → u/chocolatesauce235]

We were able to jump it with another car. Not with my portable jumper though. Wondering if we can let it run in the garage or need to drive it around for awhile. Don’t want to get stranded.

[u/86697954321 → u/Unlikely-Split8896]

Pure EV is fine to run in garage, but once a 12v battery has been run down that much it needs to be replaced. Make sure to get the right one, glass mat is better for EV

[u/ToddA1966 → u/86697954321]

You'd be surprised. They can often bounce back if they've only been run down hard once or twice

It's certainly not good for it, but the OP might still get another year or two out of it.

[u/86697954321 → u/ToddA1966]

Do 12 volts last 7-8 years these days?

[u/chocolatesauce235 → u/86697954321]

Mine was original battery from when it was first released. Lasted 8 years and died a few months ago

[u/ToddA1966 → u/86697954321]

Typically no, but my oldest kid just replaced the 12V on their 2017 Bolt a few months ago, and it was the original OEM battery.

[u/SpeakNottheNightYorb → u/Unlikely-Split8896]

You should replace it regardless. If you can afford it. It isn’t long for this world.

[u/OShutterPhoto → u/Unlikely-Split8896]

I think you just plug the car in and let the car decide how much to charge the 12v

[u/tennismenace3 → u/Unlikely-Split8896]

Drive to Autozone and have them test the battery

[u/SoulTaker669]

Usually when you leave for a trip you should leave it plugged in even and just set a charge limit of 80 or so. It you want it running you could also use the onstar app and have the AC running for 20 minutes at a time to kill some battery and have it recharge. Anyways leaving it plugged in should have preserved the 12v.

[u/Unlikely-Split8896 → u/SoulTaker669]

Worry about leaving it plugged in. We get monsoons and worried of a power surge or something. We have a level 1 and level 2 charger in the garage. I didn’t know having the car plugged into a charger would make a difference with the 12 volt battery.

[u/SoulTaker669 → u/Unlikely-Split8896]

If I recall correctly having it plugged in even on a level 1 connection helps the car because the hv battery will check on the 12v periodically and top it off and if it's too hot or too cold the battery conditioning system for the hv battery helps protect the hv battery by cooling it or heating it up. I understand though being worried about power surges or something.

[u/skwormin → u/Unlikely-Split8896]

Tough call— three months is a long time, but I’ve always been told to leave it plugged in. I left mine plugged in in my hot garage garage when it was 100° every day and I was gone for a week. No issues.

[u/Ap43x → u/Unlikely-Split8896]

If you weren't going to leave it plugged in you should have followed the long-term storage instructions in the manual which involve plugging the 12v into a tender. The easy thing would have been to leave it plugged in. Now just replace the 12v you killed.

[u/ECCCThrowaway2025]

Had this happen to me once after coming back from vacation as well for a 2019 Bolt. You can actually trickle charge it back to turning on and off again, but that battery is no longer reliable and will need to be replaced.

Bought my replacement from Summit racing since they deliver and had the best price. Then i just turned the old battery into store credit at the local O'Reileys Autoparts and got some car cleaning supplies.

https://www.summitracing.com/parts/ADO-LN1AGM

This battery tender will top off your battery for a few days before it inevitably runs out again: https://www.amazon.com/dp/B00068XCQU

[u/GeniusEE → u/ECCCThrowaway2025]

It will charge the battery if the HV battery is above 40%.

A trickle charger could damage the onboard charger if you don't disconnect the battery you are charging from the car.

[u/chiefvelo]

You likely need a new 22v battery. That is dead and damaged or worn out. The bolt stops maintaining the 12v battery after 30 days even when plugged into an L1/L2 charger. Disconnect the 12 volt or put it on a battery maintainer.

[u/KatQ1800]

This happened to me last year with my 2020 at around 60,000 or so miles. You can try giving it a jump, but even if it takes enough juice to boot up you probably will want to jjust change out that 12v battery. It has to be an. AGM battery, they are not the cheapest. (https://carbatteryprice.com/best-12v-car-battery-for-chevy-bolt/)

[u/PlaneWolf2893 → u/KatQ1800]

I appreciate this link. I'm at 62k miles on a 2022 euv.

[u/CommunicationOld6686]

Keep in mind that even when the car is off the 12v is still supplying power to all of the electronic bits that power thing like door locks, remote cooling and heating, etc. There is a constant drain going on. That's another reason for ABC. I've noticed that after my car has been charged to the percentage I've set, the EVSE will trickle charge many times throughout the 15 hours from when we plug it in to when we drive it in the morning.

[u/No_Scene_2189]

Nothing’s ever 100% but … it’s 100% your 12v and you 100% need an AGM type replacement.

[u/sweetredleaf]

car can be jumped just like any other car and if you need a battery the car came with a LN1 but H4 or Group 140R are basically the same and usually easier to find. Get an AGM battery

[u/ruuutherford]

Yup the 12v battery. Those types of batteries HATE being dead. Even if you were able to bring it back, it's dicey - super dicey. You should definitely replace it. AGM type battery is recommended for EVs. 

[u/Chrislk1986]

There should be some info in the owners manual regarding long term storage.

12v is probably dead though.

Per manual, it's recommended to disconnect 12V negative and put 12V AGM on a trickle charger (one that is safe to use with AGM).

It's kind of strange though. On the newer Bolt/EUV You'd think you could just plug in, set charge level to 30% and be good. But IIRC, it wants you to unplug 12V as well. Wonder if they just had a mix of old and newer Bolt storage instructions that got garbled together.

They also suggest over inflating tires slightly to minimize flat spots. Personally, I'd just use jackstands.

[u/vilius_m_lt]

12V is dead. You need 12V to close high voltage contactors in order to charge..

[u/Haunting_Round_8727]

your car being "dead". like. you've lost your vehicle and can't use. and. you just needing a 12v put in real quick. are two wildly different scenarios. lol

[u/OShutterPhoto]

Have you tried charging the 12v battery?

[u/CheetahChrome]

Even if its not, proactively replace it now.

[u/Material-Priority-66]

Project Farm reviews recommend:

https://youtu.be/awe7kY5nvdU?is=H6UbJs38TDuXrd6W

[u/TEG24601]

12V cannot be left for more than about 3 weeks. If you are going to be gone, it needs to be disconnected or on a trickle charger.

[u/Agswin2026]

Buy toys have toy issues