Phoenix Heat

I hope a Phoenician can respond more knowledgeably, but here is one idea:

Get forum member regoapps's new app for the Model S, "Remote S" - it allows the internal a/c to stay on...which thus would keep the bms in operation, no? - for more than Tesla's allotted 30 minutes. Here's his thread link: Remote S: Tesla app for Apple Watch, iPhone, iPad, and iPod Touch

I have been wondering how this would be managed, from the perspective of protecting the battery pack from temperature damage. IMHO, there should be a setting that can be set by the owner that a) detects that the car is plugged in, and b) activates the heat pump circuit to cool (or heat in cold climates) the pack to stay within acceptable parameters. It wouldn't necessarily heat or cool the cabin, just the batteries... and would be a setting that would keep things going as long as necessary.

As was stated, it makes little sense to maintain a temperature in the cabin 'greenhouse' all day long! But ensuring the long-term survival of the batteries seems like a no-brainer to me.

Death Valley, CA is supposed to be 128 degrees F (53.33 C) on Saturday!! Anybody slated to be there?? :scared:

A setting to continue to use battery power periodically to maintain proper battery conditions would be nice. A setting to "Maintain optimal battery conditions until SoC reaches X", where X is settable to ensure enough battery for home commute (or whatever).

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beeeerock said:

I have been wondering how this would be managed, from the perspective of protecting the battery pack from temperature damage. IMHO, there should be a setting that can be set by the owner that a) detects that the car is plugged in, and b) activates the heat pump circuit to cool (or heat in cold climates) the pack to stay within acceptable parameters. It wouldn't necessarily heat or cool the cabin, just the batteries... and would be a setting that would keep things going as long as necessary.

As was stated, it makes little sense to maintain a temperature in the cabin 'greenhouse' all day long! But ensuring the long-term survival of the batteries seems like a no-brainer to me.

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If the car is plugged in, it already does this, right? I've heard mine run a circulator pump and fan periodically when it was plugged in and not charging, though I can't say that I've heard the compressor come on, but I believe it should if it gets hot enough?

Zarwin said:

If the car is plugged in, it already does this, right? I've heard mine run a circulator pump and fan periodically when it was plugged in and not charging, though I can't say that I've heard the compressor come on, but I believe it should if it gets hot enough?

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I don't know! Based on the schematic diagrams I've seen, I can understand how it works when the car is running and working hard. But when parked? I've had a few hot days lately where the parking lot was very toasty and I've had the car plugged in to see if anything happens. So far nothing. Other than the fan running while SuperCharging, I've seen no evidence of the battery management system actively controlling the temperature of the batteries when left parked and locked - plugged in or not. I will have another look in the manual tonight, (I can't get it to download from the Tesla Motors site today for some reason...) but I don't recall seeing details on this. Admittedly, I was using it as bedtime reading after taking delivery, so might have missed something pertinent...

I could be wrong, but I don't think that Tesla considers 115 degrees F to be a risk for the battery, even an all-day soak at that temperature. The battery warranty cautions against leaving it in conditions exceeding 140F for more than 24 hours. Other than that I think that typical AZ summer temps, as hot as they can be, are within the safe zone for the battery. I do think there's a misconception that the battery TMS likes to maintain the battery at a comfy 70 degrees at all times - it doesn't. It protects against extreme high temps while plugged in and charging, especially at Superchargers, and extreme low temps again while plugged in.

Longevity of Tesla's battery chemistry in hot environments seems to be very good, both experimentally and anecdotally.

Note the second graph:

Development of High Power and Long Life Lithium Secondary Batteries

At 50 degrees C (122 F) the degradation curve is not much different than at 25 degrees C.

The BMS is running all the time, hence, the vampire drain of about 3 miles a day (1 kWh a day, or 40-45 watts). From the Tesla forums, there is a quote from Tesla:

To answer your question, yes the Model S monitors the battery temperatures when asleep and will wake up to cool or heat the battery if the battery reaches very high temperatures that could potentially harm the battery.

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techmaven said:

The BMS is running all the time, hence, the vampire drain of about 3 miles a day (1 kWh a day, or 40-45 watts). From the Tesla forums, there is a quote from Tesla:

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Then that probably answers it... we aren't subjecting the batteries to adequately extreme temperatures, even in a sunny parking lot, to do damage.

It would be nice, however, if there was a way to keep the batteries a *little* cooler when plugged in. If they're up close to the upper limit of 'safe' and you get in and drive, they'll heat up even more and require active cooling (I assume). Given that the interior is also likely to be smoking hot at that time, it would be nice if the HVAC system wasn't hit with heavy loads from both... if the batteries were a little cooler, more cooling power could be given to the interior. And overall, less power pulled from the batteries.

From comments in another current thread, pre-cooling the interior isn't always that effective...

In other words, it would be nice if there was a setting for 'Econo' and 'Normal' when plugged in, that would determine how stingy the car is about pulling power for heating and cooling of both the batteries and the interior.

The battery cooling will kick in when starting to drive after a heat soak. Witnessed it first hand when cabin ac cooling spools down, but you can still hear the compressor running full speed.

I'm confused... the battery HVAC is it's own HVAC, separate from the cabin...
I've come out to my car heating or cooling the pack without any input or anything from me.

You don't have to do any of this, the car handles it all... the only reason to turn the temp to your temp when it's hot or cold out is either comfort, or you're plugged in and want to use shore power for it.

My parking garage sits around 80 degrees and I've come down to pools of water from the battery HVAC running, and lost range in the winter as it's sucking down power to keep the pack warm...

really, after 4 months of ownership... I just drive the thing.

Forget about the battery. Worry about those door handles, and bring pot holders if you plan to park in the sun!

Also, the glue on these cars does not seem to be very well heat-rated. At least in my 2013 vehicle. I was parked in the hot sun last summer and the glue holding the magnet to my charge port door melted right off. They replaced the whole door panel, but I am willing to bet this will happen again. I've also had other glued areas come apart on interior panels.

We have had our car through 2 summers in PHX with no battery issues or range lose. The car seems to manage the heat quite well and after 2 years full charge reads 256. I have heard the cooling system kick on in the garage when plugged in and I could of sworn I have heard it on when parked outside. My opinion is you have nothing to worry about with the heat.

Kenne74 said:

We have had our car through 2 summers in PHX with no battery issues or range lose. The car seems to manage the heat quite well and after 2 years full charge reads 256. I have heard the cooling system kick on in the garage when plugged in and I could of sworn I have heard it on when parked outside. My opinion is you have nothing to worry about with the heat.

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+1

I can't comment on the specifics of what the battery can take, but I'll speculate that 115 is well within operating range of the battery. It wouldn't surprise me if the car reduced power if you started placing significant load on the pack, such as taking it to a track.

I believe the only item I've seen impacted by the heat is the 12V. I ended up stranded at the Snowbowl this year when mine died.

NuclearPowered said:

The battery cooling will kick in when starting to drive after a heat soak. Witnessed it first hand when cabin ac cooling spools down, but you can still hear the compressor running full speed.

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Yep… I've noticed this too when temps are > 110F.

You'll also notice rated miles dropping much quicker than normal -- although only for about 5 min or so until both the cabin and battery are cooled down. Perhaps 5 extra RM lost during those first 5 min. But once the cabin and battery are cool, range loss goes back to normal...

I saw 117 for a few min yesterday ugh...

Which makes one wonder why we can't buy an SC in Tucson, Benson, Deming, El Paso, intermediate points there between or points east. (All of those destinations can experience triple-digit heat for up to triple-digit days in a row)

Sure would be nice to transit the continent (west to east, via SCs) without the need for snow tires and/or chains half the year. Today that's simply not possible.

Sogorman said:

Question for the group... Now that the Phoenix heat is here (115 degrees today) I am wondering if there are any ways I can take care of my S85's battery. Thanks to the scheduling in VisableTesla I typically pre-condition the cabin (and battery) 10-15 minutes before I head to and from work. In addition if I need to run out from the office I will remote start the car before I head. I have tried my hardest to let the car cool itself anytime I drive it when it's over 90 out.

My question revolves around the time from noon - 5:00pm when the car is just baking in extreme heat.

As far as I know, and correct me if I am wrong but the battery's thermal management system does not run unless the car is powered on. Would it be beneficial or hurtful to schedule an event in VisableTesla for 2:00p in where the car's HVAC would be set to 90 degrees (hot but not nearly as hot as it is outside) and let that run for 15 minutes which in theory would let the battery cool down for a while between lunch and the drive home? I'm not concerned about loosing some charge in exchange for helping negate the negative affects of heat on the battery's longterm life.

One other side note I typically charge only to 75% and when I get to work the battery is sitting at 65% during the heat.

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I would:

1) keep SOC < 80%, or even lower. The combination of high temperature and high SOC at the same time is far worse than just one of the two.
2) park in the shade when possible.
3) crack all four windows, and pano roof if you have it. This will keep interior temp down. The batteries are sandwiched between the interior and the hot pavement.
4) use sunshades when parked
5) tint the windows
6) consider A/C for my garage

GSP

PS. I have done steps 2-4 in my old ICE cars all summer long just for passenger comfort, and I don't even live in a warm climate. If I lived in Phoenix, I would do steps 5-6. The Volt does step 1 for me automatically. It will run the A/C when parked in very hot environment until the SOC drops to a battery life friendly level. I don't have to think about it.

GSP said:

I would:

1) keep SOC < 80%, or even lower. The combination of high temperature and high SOC at the same time is far worse than just one of the two.
2) park in the shade when possible.
3) crack all four windows, and pano roof if you have it. This will keep interior temp down. The batteries are sandwiched between the interior and the hot pavement.
4) use sunshades when parked
5) tint the windows
6) consider A/C for my garage

GSP

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I don't think you need to go through all of these gyrations, and suggesting the above will leave someone with the wrong impression of the car.

Your advice might be applicable for a Nissan Leaf, which doesn't actively cool its battery and leaves it at the mercy of the elements. Not so with Model S. Model S has the most advanced battery management system in the world. The batteries and chargers inside the car are liquid cooled. The Model S automatically maintains the battery temperature within Tesla's chosen parameters. If the car sense the battery pack getting into a bad temperature range, it will immediately heat or cool the pack even when parked and unplugged.

Use it like you stole it. Charge to as much as you need and don't worry about the rest. If you ever charge to 100%, try to time your charge so you drive off shortly after the charge completes. Charging to 100% isn't inherently bad, it's letting it sit at 100% for long periods of time (weeks) that could result in slightly more degradation over YEARS and many tens of thousands of miles. Battery degradation also appears to be more strongly related to time than miles driven. So if you baby your car and don't drive it much, your pack is still degrading in much the same way as someone else who drives much more. Tesla's warranty against failure is unlimited miles.

DRIVE THE CAR AND DON'T WORRY!