Vacation Storage Plan

[Anonymous]

I am going out of town for a week. What is the best plan for the Bolt to sit in the garage that week? Plugged? Unplugged?

Thanks

 

[LeftieBiker]

If temperatures will be moderate enough that it won't have to cool (or warm) the battery, leave it unplugged at some level of charge above 40% but below 100%. If the car will likely be cooling the battery, leave it plugged in, in Hilltop Reserve mode if possible.

 

[Allelectric]

Same question please to Chevy but for 5 weeks. Vehicle to be kept outside in temps between 15-25 Celsius.
Thx

 

[Allelectric]

Amber/Chevy Customer Care,
I leave for Europe on Tuesday. Any advice you can give before then would be appreciated.
I am sure the original poster would also appreciate any advice on his question.
Thanks
Paul

 

[BoltEV17]

From the Owner's Manual:

Vehicle Storage

Up to Four Weeks
. Plug in the charge cord.

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 the 12-volt battery cables connected and trickle charge from the underhood remote positive (+) and negative (−) terminals.

After the battery cable is reconnected, it is possible that the vehicle may not operate. If this happens, the high voltage battery may need to be charged.

 

[Allelectric]

Thanks BoltEv17 I appreciate you taking the time to post the manual. I had read that but was concerned with the idea that the main battery would fully discharge which is not supposed to be good for it in the long run. Most things I have read suggests unplugged with the battery in the mid to higher mid range so it did not fully discharge.
I am looking for for Chevy/Amber to give some advice on my specific time frame as it is right on the bubble of the two time frames quoted in the manual. 4 weeks to 12 months is a massive time differential to perform the same actions, especially when I'm going for 5 weeks so right at the lowest end of that time frame and the less than 4 week time frame is exactly opposite.
Amber/Chevy can you please advise

 

[SparkE]

I will re-iterate : Chevy/Amber, please advise

 

[Eastocean]

For 5 weeks at up to 25c - 77f, I would simply get car to about no more than 80%, and leave unplugged. I have done a similar thing for 3 wks, which was what also was suggested for the less robust Leaf. The issue seems to be the 12v battery discharging. I have not charged the Bolt for a week several times, with no noticeable effects.
Someone once pointed out that is about manufacture to customer delivery time when a Nissan is made in Japan to arriving on a lot before they were made in TN. ... Bolt batteries are made by LG in Korea.

 

[GetOffYourGas]

I have not charged the Bolt for a week several times, with no noticeable effects.

During that time, was the car sitting unused, or was it occasionally turned on and driven? I ask because it could make a difference to the 12V battery. If the car is on, it will actively manage the 12V battery. If it is off, it may let it go too low.

To the OP, really, you have to consider that you are caring for two batteries here; the "main" HV battery and the "auxiliary" 12V battery.

The main battery pack likes to be low-to-mid level charge. You don't want self discharge to take it too low. For 5 weeks, I'd be comfortable leaving it anywhere above 40%. Lithium just doesn't self-discharge all that fast. I'd want it below 80% though, so you aren't applying high-voltage stress.

The 12V battery is a different beast. It wants to be fully charged all the time. Yet self-discharge is much higher with a Lead battery than a Lithium battery. You could put it on a battery tender if you are worried. The only downside to that is that it will reset your auxiliary systems (clocks, etc) since you have to disconnect it from the car. If you don't want that hassle, just make sure it is fully charged before you go. Ironically, EVs can be much harder on the 12V battery due to all the extra electronics that come with it. It's ironic because there is a huge lithium battery present which could be used for that instead, but never seems to be.

 

[SeanNelson]

To the OP, really, you have to consider that you are caring for two batteries here; the "main" HV battery and the "auxiliary" 12V battery.

...

The 12V battery is a different beast. It wants to be fully charged all the time. Yet self-discharge is much higher with a Lead battery than a Lithium battery. You could put it on a battery tender if you are worried.

My Prius C has the same kind of relatively small AGM battery as the Bolt, and I left it for seven weeks while I was on vacation last year with no special treatment. The Prius C, of course, cannot be "plugged in" and I didn't use any sort of battery tender. When I came back from vacation the car started and operated perfectly normally, no problems whatsoever.

The Bolt may use up a trifle more parasitic power because it has systems such as keyfob and Bluetooth detection that my Prius C doesn't, but as far as the 12V battery is concerned I certainly wouldn't worry about leaving it unattended for just a week.

 

[LeftieBiker]

Yet self-discharge is much higher with a Lead battery than a Lithium battery.

The problem isn't self-discharge here. A charged lead-acid battery will hold most of its charge for months, even a year. The issue is parasitic external loads on the battery. I use a battery tender JR on my Leaf and it works great.

 

[GetOffYourGas]

The Bolt may use up a trifle more parasitic power because it has systems such as keyfob and Bluetooth detection that my Prius C doesn't, but as far as the 12V battery is concerned I certainly wouldn't worry about leaving it unattended for just a week.

I thought we were talking about 5 weeks, not just one? It can make a big difference.

At one point, the Volt would drain the 12V battery via bluetooth. A friend would park his car in the garage, and then leave his phone on the dining room table, just inside the garage door. At least, close enough that the car remained connected (even though it was "off") and killed his 12V battery. I'm hoping they fixed that particular issue, but I would almost be surprised if little gremlins like that weren't in the Bolt.

Yet self-discharge is much higher with a Lead battery than a Lithium battery.

<span> The problem isn't self-discharge here. A charged lead-acid battery will hold most of its charge for months, even a year. The issue is parasitic external loads on the battery. I use a battery tender JR on my <a href="http://www.mynissanleaf.com" class="interlinkr">LEAF<span class="tip">Visit the LEAF Forum</span></a> and it works great.</span>

Fair enough. Especially when talking about 5 weeks (versus 12 months).

 

[devbolt]

The 12V battery will be maintained automagically via the high-voltage battery even when the car is not plugged in, so long as the high-voltage battery is above a certain percentage (probably 30% SOC). Another forum member who is a GM tech posted the details a while ago.

However, if you have followed GM's recommendation and drained the main battery down to 15% because you are going away for more than 4-weeks, and are leaving the car unplugged during that time, the 12V battery won't be maintained. Which is why they recommend you disconnect the 12V battery, or hook it up to a battery tender while you are away.

 

[LeftieBiker]

Why in HELL are they suggesting draining it to 15%???

 

[SeanNelson]

The 12V battery will be maintained automagically via the high-voltage battery even when the car is not plugged in, so long as the high-voltage battery is above a certain percentage (probably 30% SOC). Another forum member who is a GM tech posted the details a while ago.

Do you have a link to that? Most of the cars I've seen with high voltage traction batteries have a contactor that opens when the car is turned off to make sure that the high voltage is disconnected and doesn't pose a safety concern. It would surprise me a bit if the Bolt was different, so I'd be interested in any supporting evidence.

 

[devbolt]

The 12V battery will be maintained automagically via the high-voltage battery even when the car is not plugged in, so long as the high-voltage battery is above a certain percentage (probably 30% SOC). Another forum member who is a GM tech posted the details a while ago.

Do you have a link to that? Most of the cars I've seen with high voltage traction batteries have a contactor that opens when the car is turned off to make sure that the high voltage is disconnected and doesn't pose a safety concern. It would surprise me a bit if the Bolt was different, so I'd be interested in any supporting evidence.

From the chevybolt.org site:
http://www.chevybolt.org/forum/82-charging-batteries/10290-12v-battery-charging-2.html#post119778

When the vehicle cord is plugged in
The Hybrid/EV Powertrain control module (HPCM2) will check the 12V battery every 6 hours if the ignition is off. If the voltage is below a temperature dependent threshold ranging from 12.1 (cold) to 12.4 (warm)V, the 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 2-3 hours. If the Ignition is ON, the APM will cycle on as needed to maintain the 12V SOC.

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..

 

[SparkE]

Or, you run the SoC down to about 40% (or lower), plug the car in to the included 120V EVSE (@ 8 amps) and set "Electric Rate Preference" to "Off-Peak Only". Set your "off-peak" electric rates to be ONLY the time between 2:00 a.m. and 2:15 a.m.

If you do it this way, the battery will charge at a rate of about 1 kW for 15 minutes every day, keeping the battery conditioned (because it is plugged in) and the 12V battery maintained (because it is plugged in) and the main battery SoC around 40% (since 'delayed' charging will charge up to 40% no matter what, and you are only adding about .25 kWh every night).

It's not rocket surgery, folks.

 

[SeanNelson]

The 12V battery will be maintained automagically via the high-voltage battery even when the car is not plugged in, so long as the high-voltage battery is above a certain percentage (probably 30% SOC).

Do you have a link to that?

From the chevybolt.org site:
http://www.chevybolt.org/forum/82-charging-batteries/10290-12v-battery-charging-2.html#post119778

Very cool, thanks a lot for taking the time to find that for me!

 

[SparkE]

It's not rocket surgery, folks.

 

[devbolt]

Do you have a link to that?

From the chevybolt.org site:
http://www.chevybolt.org/forum/82-charging-batteries/10290-12v-battery-charging-2.html#post119778

Very cool, thanks a lot for taking the time to find that for me!

We aims to please!