Will the lack of temperature regulation hurt the battery if it's not being driven?

In the Bay Area? No worries at all, even with the heat wave this week. Active cooling doesn't start until the battery reaches 104F and it has a lot of thermal mass (ie, takes a lot of energy to heat it up and it's not hot 24 hours/day). So if you could ask them to leave it parked inside or in the shade you should not worry at all. And even if it's in the sun the battery won't go over 104 before the temps will start falling again overnight.

Speculation & opinion: I would suspect that they would disconnect the traction battery and the 12 V accessory battery for safety and to protect the batteries. If the batteries are disconnected it should eliminate most of the parasitic drain. A disconnected battery should be able to last several months without any harm. In my opinion if they don't disconnect the batteries and if there is any damage from not being disconnected for service, then they should replace any of the affected batteries without any additional cost to you.

If it's not been charged or drained, it I doubt it would need any thermal regulation for the expected temperatures in your region.

kjl said:

Thanks - that puts my mind at ease. Do you think I need to worry about it getting too cold at night? I mean, just for curiosity - the next week's going to be pretty warm even at night it looks like...

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No need to worry about cold damaging the batteries until it's below zero.

kjl said:

Thanks - that puts my mind at ease. Do you think I need to worry about it getting too cold at night? I mean, just for curiosity - the next week's going to be pretty warm even at night it looks like...

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strider said:

No need to worry about cold damaging the batteries until it's below zero.

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Yes, storage life is better at cooler temps (although output is better when warmer). Check out table three at Battery University.

strider said:

In the Bay Area? No worries at all, even with the heat wave this week. Active cooling doesn't start until the battery reaches 104F and it has a lot of thermal mass (ie, takes a lot of energy to heat it up and it's not hot 24 hours/day). So if you could ask them to leave it parked inside or in the shade you should not worry at all. And even if it's in the sun the battery won't go over 104 before the temps will start falling again overnight.

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Active cooling starts at 104F on the Roadster and 140F on the Model S. There's no chance of hitting that in storage, unless you're leaving the car in a black metal box in the sun! Active cooling can kick in on a track or during Supercharging, but that's about it.

The battery is not damaged by cold storage until long term below -20F.

The battery has more damage ongoing at high temperature while highly charged. IE there is more damage if 90% charged at 100F than 60% charged. Similarly there is more damage ongoing at 100F than 90F while 90% charged. Unfortunately we have no statistics to define how much is occurring or if there are real inflection points like the 104F active cooling might suggest. I suspect the actual storage issue would be higher than the 104F as that is likely set to prevents the temp from hitting 110F or some such.