Chevy Bolt EV Forum banner

1 - 20 of 29 Posts

·
Registered
Joined
·
61 Posts
Discussion Starter #1
Good afternoon everyone, just a quick question. Bought a 2019 Bolt, plan to store it for 6 months when I leave in January. It will be in garage in Texas. Winters are fairly mild but can occasionally get cold 20 to 30 degrees, in the spring summer it heats up and can be 80-100. I have read that it is best to drop the battery to 2-3 bars, and trickle charge the 12 volt. What I am wondering, would it also be advisable to put the care into long term storage mode. I read this is what dealers do with cars on the lots. A procedure using flashers, holding break pedal and a few other steps to get a message saying storage mode. Assume trickle charging 12 volt is ok in this mode, OR do I just use the 120v evse, plug it in and set the charge to 40-50% only and let it do its thing while gone? This would allow the battery to take care of itself when it’s cold, and or hot. After reading several different opinions, none of them talk about the the battery storage mode so was curious. Thoughts?
 

·
Registered
Joined
·
15 Posts
Hello,

The owner's manual has specific directions for storage of four weeks to 12 months. Page 266 in the 2019 manual.

Short version:
a) Run down high voltage battery to two to three bars.
b) Do not plug in charge cord.
c) Disconnect 12 volt negative and put a trickle charge on the 12 volt battery using a charger compatible with AGM battery.
 

·
Registered
Joined
·
1,818 Posts
Or, if you have a friend you can trust, let them drive it for 6 months. This could push another person to buying an EV. ;)
 

·
Registered
Joined
·
61 Posts
Discussion Starter #5
Yes I read that, but was curious about the storage mode if I should enable it, then was thinking about temperature changes in the garage etc....overthinking it too much.
 

·
Registered
Joined
·
612 Posts
Beware the chapest trickle chargers, claimed to not overcharge because they don't exceed a specific level - 13.5 volts or something. In my experience they will gas the water out of a conventional battery over several months. Step up to a charger that will cycle off.
 

·
Registered
Joined
·
61 Posts
Discussion Starter #7
Does anyone have any battery tender recommendations? Was looking at Chekhov’s but curious what others might be using.
 

·
Registered
Joined
·
462 Posts
a) Run down high voltage battery to two to three bars.
I wonder why GM insists draining the car's propulsion battery down to 2 to 3 bars (10~15% charge, equivalent to 15~20% raw SoC)? The usual Li-Ion battery maintenance strategy calls for keeping roughly 40 to 60% charge for long-term storage (my car was shipped to Korea with 40% charge likely for that reason) and not go below 20% charge during normal use. It would be interesting to hear from a GM engineer on the apparent disparity.
 

·
Registered
Joined
·
317 Posts
To further muddy the waters, there's a contradiction in GMs directions for long term storage, if temps go below 32'F!

"Do not allow the vehicle to remain in temperature extremes for long periods without being driven or plugged in. It is recommended that the vehicle be plugged in when temperatures are below 0°C (32°F) and above 32°C (90°F) to maximize high voltage battery life."

Here's the entire section I copied from GM:

Manual
"Do not allow the vehicle to remain in temperature extremes for long periods without being driven or plugged in. It is recommended that the vehicle be plugged in when temperatures are below 0°C (32°F) and above 32°C (90°F) to maximize high voltage battery life."

*​
Transport Mode On/Off,

  • Start the vehicle (as indicated by the green Ready light),
  • Activate the hazard flashers,
  • Press and hold the brake pedal,
  • Then press and hold the Start/Stop button at least 15 seconds.
  • The “Transport Mode On/Off” message will appear on the DIC.
  • Then turn the hazard flashers off.
  • Allow the vehicle to sleep at least 2 minutes prior to restarting.
*​
Manual
Four Weeks to 12 Months
Discharge the high voltage battery until two or three bars remain on the battery range indicator (Battery symbol) on the instrument cluster.
Do not plug in the charge cord.
Remove the black negative (−) cable from the 12-volt battery and attach a trickle charger to the battery terminals or keep the12-volt battery cables connected and trickle charge from the underhood remote positive (+) and negative (−) terminals.

*​
Manual
When the vehicle cord is not plugged in

The Hybrid/EV Powertrain control module (HPCM2) will check the 12V battery every 4 days (2.5 to 3 days) and if the voltage is below a threshold of 12.0 may activate battery maintenance. If the high voltage battery state of charge is greater than 40% and the propulsion system is not active, Hybrid/EV Powertrain control module (HPCM2) will send the voltage set point to the engine control module (ECM). The engine control module (ECM) will send this to the 14V Power Module. Battery maintenance mode will charge the battery for 45-90 minutes..

Rich
 

·
Registered
Joined
·
1,713 Posts
Does anyone have any battery tender recommendations? Was looking at Chekhov’s but curious what others might be using.
I have a CTEK : CTEK (56-865) US 0.8 12 Volt Fully Automatic 6 Step Battery Charger


Because I have a "full blown" (12A) charger for when my batteries are really low and don't just need a top-off.

It is a super-smart, very low amp (0.8) trickle charger that can be left in for weeks (although I only use it for topping off - getting a full saturation charge - overnight every month or so). It is AGM-safe (maintaining voltage at 14.4 during charging, then dropping to 13.6V during maintenance/float mode, with almost no amperage, and regularly checking that voltage hasn't dropped too much and will re-start charging cycle if necessary). It is a "super-soft" method to fully charge (and maintain) the 12V battery.
 

·
Registered
Joined
·
61 Posts
Discussion Starter #12
To further muddy the waters, there's a contradiction in GMs directions for long term storage, if temps go below 32'F!

"Do not allow the vehicle to remain in temperature extremes for long periods without being driven or plugged in. It is recommended that the vehicle be plugged in when temperatures are below 0°C (32°F) and above 32°C (90°F) to maximize high voltage battery life."

Here's the entire section I copied from GM:

Manual
"Do not allow the vehicle to remain in temperature extremes for long periods without being driven or plugged in. It is recommended that the vehicle be plugged in when temperatures are below 0°C (32°F) and above 32°C (90°F) to maximize high voltage battery life."

*​
Transport Mode On/Off,

  • Start the vehicle (as indicated by the green Ready light),
  • Activate the hazard flashers,
  • Press and hold the brake pedal,
  • Then press and hold the Start/Stop button at least 15 seconds.
  • The “Transport Mode On/Off” message will appear on the DIC.
  • Then turn the hazard flashers off.
  • Allow the vehicle to sleep at least 2 minutes prior to restarting.
*​
Manual
Four Weeks to 12 Months
Discharge the high voltage battery until two or three bars remain on the battery range indicator (Battery symbol) on the instrument cluster.
Do not plug in the charge cord.
Remove the black negative (−) cable from the 12-volt battery and attach a trickle charger to the battery terminals or keep the12-volt battery cables connected and trickle charge from the underhood remote positive (+) and negative (−) terminals.

*​
Manual
When the vehicle cord is not plugged in

The Hybrid/EV Powertrain control module (HPCM2) will check the 12V battery every 4 days (2.5 to 3 days) and if the voltage is below a threshold of 12.0 may activate battery maintenance. If the high voltage battery state of charge is greater than 40% and the propulsion system is not active, Hybrid/EV Powertrain control module (HPCM2) will send the voltage set point to the engine control module (ECM). The engine control module (ECM) will send this to the 14V Power Module. Battery maintenance mode will charge the battery for 45-90 minutes..

Rich
This is what befuddles me, I am leaning towards just plugging the stock EVSE into the 120 volt out let, set the max charge in the car to 40% on the big battery (If I can do this) and just let it sit and take care of itself. Texas doesn't get too cold, but we have had winter temps dip into the 20 degree area (San Antonio) for a few days and of course since we won't be back until end of June, it will definitely be over 90 in the Garage.
 

·
Registered
Joined
·
1,290 Posts
This is what befuddles me, I am leaning towards just plugging the stock EVSE into the 120 volt out let, set the max charge in the car to 40% on the big battery (If I can do this) and just let it sit and take care of itself. Texas doesn't get too cold, but we have had winter temps dip into the 20 degree area (San Antonio) for a few days and of course since we won't be back until end of June, it will definitely be over 90 in the Garage.
That's what I have been thinking as well.
 

·
Registered
Joined
·
317 Posts
OK, I read the manual. What I plan on doing (six months of Cape Cod winter, Nov~May) Bolt under a carport, is, plug in the charger, set the level at 45%, and put a 12V smart-charger on the 12V battery.

I will also perform some secret religious rites, plus a couple of small animal sacrifices, just to be sure. (I'll eat the deceased animals, so as not to waste them...).

Rich
 

·
Registered
Joined
·
2,583 Posts
Does anyone have any battery tender recommendations? Was looking at Chekhov’s but curious what others might be using.
I bought the VMax charger to go with my VMax Tanks 125Ah AGM. Seven stage, and designed specifically for AGMs. Very nice charger/maintainer, but pricey.

BTW, VMax AGMs are among the best, made in the good ol' USA, are a little pricey, but they ship all that weight for free. It's what I put in my lead battery backed-up solar at my old house.
 

·
Registered
Joined
·
3,161 Posts
Do we need to plug in a 12 volt battery tender if the car is plugged in?
There's a been a couple reports from forum members that found the 12V dead after vacationing with their Bolts plugged in.
 

·
Registered
Joined
·
61 Posts
Discussion Starter #18
There's a been a couple reports from forum members that found the 12V dead after vacationing with their Bolts plugged in.
That was an interesting read....So I think I am going to do the following when I get home in December. Please feel free to comment if there is something I should watch or look after.

1. Set BOLT to terminate charge once it reaches 40%. Charge with OEM EVSE at 8 amps only. ( I am probably going to purchase a Juicebox 40 Pro as well) But was thinking of just keeping it simple using the OEM EVSE. The Juicebox does give me other abilities like remote charging on and off I think, along with monitoring it.)
2. Trickle charge the 12v battery as well. The only question I have is should I disconnect the negative lead on the battery or do I need to leave it on since I am also going to keep it plugged in. If the OEM or Juicebox is plugged into the car, I don't want it to have issues with the trickle charger.

I will have family who can check on the car if necessary, and I also have video cameras around the house and in the garage so can monitor. I have thought about buying a Juicebox 40 amp and programming it for the variables as well vice using the OEM charger. Perhaps even activating remote charge vice a schedule. I already have my dual 14-50 plugs installed on a 100 amp dual breaker. I had this done last year knowing I was going to buying an EV at some point.

What do you guys think?
 

·
Registered
Joined
·
3,161 Posts
Trickle charge the 12v battery as well. The only question I have is should I disconnect the negative lead on the battery or do I need to leave it on since I am also going to keep it plugged in.
If you disconnect the negative lead, then it defeats the reason for having it plugged in. The car wouldn't be able to condition the battery as its brain would be offline.
 

·
Registered
Joined
·
61 Posts
Discussion Starter #20
That was my thinking, but what I am not clear on is can I plug in and trickle charge at the same time. Of course not removing the neg. lead. Supposedly pluging the car in services the battery, but after reading the story about the 12 v. Dying, was wondering if you could do both?
 
1 - 20 of 29 Posts
Top