Need advice fast - does the TMS stop after 2 days?

[mikeg3]

I live in 100+ degree August climate. I'm flying off tomorrow for 10 days and plan on plugging in my Volt and forgetting about it.

I saw a post that said that the TMS does not operate in a plugged in Volt after two days.

Is this true?

Does this negate the periodic TMS cycles on Volts with high SOC and high ambient temps?

I can just put on the car cover and hope for the best, but I thought a plugged-in Volt's main battery was fully protected from heat.

The 12V battery is a separate issue. I can jump-start it if necessary.

[WopOnTour]

I live in 100+ degree August climate. I'm flying off tomorrow for 10 days and plan on plugging in my Volt and forgetting about it.

I saw a post that said that the TMS does not operate in a plugged in Volt after two days.

Is this true?

Does this negate the periodic TMS cycles on Volts with high SOC and high ambient temps?

I can just put on the car cover and hope for the best, but I thought a plugged-in Volt's main battery was fully protected from heat.

The 12V battery is a separate issue. I can jump-start it if necessary.

No, as long as you are plugged in (charging or not) the Volt's BMS will continue to occasionally wake up to assess the pack temps, and take corrective action if necessary.
But the car cover is a good idea as it might provide protection from sun load and perhaps offset some of the TMS actvity.
10 days? You wont need a boost.
But please try to resist temptation to "wake up" the car every 15 minutes (via myvolt or ph.apps) to see how it's doing.
(you'll be losing ALL communication and status updates after 5-7 days anyways as that's how OnStar is set up to prevent 12V drain)
Enjoy your trip!
WOT

[mikeg3]

Thanks, WOT

[DonC]

No, as long as you are plugged in (charging or not) the Volt's BMS will continue to occasionally wake up to assess the pack temps, and take corrective action if necessary.

I'm confused. I remember numerous times when someone from GM said that after a few days the Volt would no longer condition the pack. Is that different than what you're talking about here?

[montgom626]

I'm confused. I remember numerous times when someone from GM said that after a few days the Volt would no longer condition the pack. Is that different than what you're talking about here?

Imagine all the HV batteries in all the Volts sitting on all the dealer lots waiting to be sold going "bad" if this were true.So, it does not make sense that the Volt would stop using the TMS after 2 days. Does it?

[WopOnTour]

I'm confused. I remember numerous times when someone from GM said that after a few days the Volt would no longer condition the pack. Is that different than what you're talking about here?

You'd have to direct me to that piece of misinformation. As per the owners 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.The charging system may run fans and pumps that result in sounds from the vehicle while it is turned off.

Keep in mind the Battery Interface Control Modules (aka VITM, there are 4 of them) operate with supply voltages taken directly off the Li-ion triplets they are connected to . So they don't require any additional energy off the 12V rail to "watch over" the Volt's RESS.

There's additional supporting documentation in the service manual, should you have a copy (or electronic access) and it's also in all of the technician training manuals. If it's incorrect then a whole lot of people are out-to-lunch!

WOT

[dax777]

Thanks for the clarification WOT

[scottf200]

Imagine all the HV batteries in all the Volts sitting on all the dealer lots waiting to be sold going "bad" if this were true.So, it does not make sense that the Volt would stop using the TMS after 2 days. Does it?

The key is it has to be plugged in tho (or if >75[%] SOC). At the dealership I take my car to they have a solar charging system that handles like 6 cars. If they had them plugged in then the TMS would keep the battery conditioned. But for anyone that is not plugged in or any other dealer that does not have all their outdoor parking lot Volts plugged in the battery will get warm. Of course, we know how well insulated it is so if they are driven for any length of time then the batteries will get cooled down and stay that way for a while.

[montgom626]

The key is it has to be plugged in tho (or if >75 SOC). At the dealership I take my car to they have a solar charging system that handles like 6 cars. If they had them plugged in then the TMS would keep the battery conditioned. But for anyone that is not plugged in or any other dealer that does not have all their outdoor parking lot Volts plugged in the battery will get warm. Of course, we know how well insulated it is so if they are driven for any length of time then the batteries will get cooled down and stay that way for a while.

Wow, so if a Volt sits on the lot, unplugged in hot weather, the battery can be harmed. I did not know that.

[Steverino]

If not plugged in, it's my understanding the BMS will still work, it will simply draw power from the battery to run the coolant system. The question is, at what point will it stop working? When the battery SOC is down to a quarter charge? When the battery has been drained completely? Something else?