Suggestion for battery pre-heating and charge-end scheduling sent to Tesla

[Cottonwood]

@Andyw2100, I agree with your points. I was merely trying to remind folks of a work-around for now; a direct function would be much easier and simpler. Also, I have not had regen limits after my method, but then again, I pre-condition in a 45˚ F. garage.

 

[AWDtsla]

It just seems kind of crazy how many hoops we are jumping through to get a partial solution, when Tesla could easily give us a complete solution with no hoop-jumping required.

IMHO it's because no Tesla engineers (i.e. Elon) lives in a cold climate. So they might get a hint with enough complaints, but with Elon not being bothered by it on a daily basis, probably not.

 

[Andyw2100]

@Andyw2100, I agree with your points. I was merely trying to remind folks of a work-around for now; a direct function with be much easier and simpler. Also, I have not had regen limits after my method, but then again, I pre-condition in a 45˚ F. garage.

Thanks!

And I didn't mean to sound in any way like I was denigrating your system, which I, and I know many others use. I was just trying to point out how preposterous it is that we need to do all that, just to get 50-75% of the benefit Tesla could give us with the addition of a fairly simple software feature.

 

[Andyw2100]

I posted about a week ago, in the poll thread, that I have sent another letter to Tesla. That post is here:

Would you use battery heating if it were available? - Page 8


More importantly, there's another thread where all sorts of suggestions for improvements for version 7.1 are being gathered and voted on, and last night one of the posters involved in that thread posted the following:

I *never* quote Tesla employees.

However, I may have been assured that if I prepare the data/links/results to send, that it could get it to the right person. Now, there was absolutely no guarantee this person would do anything about it. But it seemed to me like our best inside chance.

The battery pre-heating suggestion is already the second most popular suggestion in the battery category, but if the information is really likely to make it to someone at Tesla who can make a difference, I think the more people who have demonstrated interest in battery pre-heating, the better. So I'd suggest that if you'd like to see this feature implemented, you take a moment, click on the link below, and cast your vote for it. Thanks!

Battery

This is the thread that explains the voting process:

Vote on software features/bugs to fix in 7.1 and beyond

 

[gpetti]

Out of curiosity, is anyone using the new Maximum power option as a new workaround for this? It seems to heat the battery regardless of any other factors and even if the car is off. It is not clear to me yet how long it attempts to maintain the heated battery but basically when you turn it on it gives you a rough time for how long until the battery is ready. Once ready you could turn it off but the regen limit will be gone. Note that in colder temperatures (about 5F today) it can take more than an hour to warm up. Unfortunately this isnt available from the app so would need to be manually initiated in advance.
(edit: in case anyone hasn't seen this option, it is underneath the sport/insane/ludicrous control.

 

[andrewket]

Out of curiosity, is anyone using the new Maximum power option as a new workaround for this? It seems to heat the battery regardless of any other factors and even if the car is off. It is not clear to me yet how long it attempts to maintain the heated battery but basically when you turn it on it gives you a rough time for how long until the battery is ready. Once ready you could turn it off but the regen limit will be gone. Note that in colder temperatures (about 5F today) it can take more than an hour to warm up. Unfortunately this isnt available from the app so would need to be manually initiated in advance.
(edit: in case anyone hasn't seen this option, it is underneath the sport/insane/ludicrous control.

Funny, I had the same realization last week but haven't had a need to use it yet. I did validate that if you turn it on while still plugged in that it will draw shore power.

 

[Andyw2100]

Out of curiosity, is anyone using the new Maximum power option as a new workaround for this? It seems to heat the battery regardless of any other factors and even if the car is off. It is not clear to me yet how long it attempts to maintain the heated battery but basically when you turn it on it gives you a rough time for how long until the battery is ready. Once ready you could turn it off but the regen limit will be gone. Note that in colder temperatures (about 5F today) it can take more than an hour to warm up. Unfortunately this isnt available from the app so would need to be manually initiated in advance.
(edit: in case anyone hasn't seen this option, it is underneath the sport/insane/ludicrous control.

Brianman and I were discussing this in another thread a couple of weeks ago.

I have a few concerns about using this option to preheat the pack to eliminate the regen limit. One is that Tesla warns about using this often, because of the potential for pack degradation. We're not sure if the way in which this Max Power Option is heating the pack would be the best or even a good way for what we're trying to accomplish, since it was designed to serve another purpose. It almost certainly takes the pack to a higher temperature than we'd need it, so we'd probably want to stop it before it completes, but guessing at that point would probably be difficult.

I find it ironic that Tesla has now provided this ability, which might allow people to shave a couple of tenths of a second off a 0-60 launch time, but still haven't provided the ability to preheat the pack to eliminate the regenerative braking limitation, which would almost certainly have broader appeal, and would without question have more practical application. Since the two are so closely related, and since Tesla has already provided this Max Battery Power, at this point you would think Battery Preheating should be a no-brainer.

 

[jerry33]

I find it ironic that Tesla has now provided this ability, which might allow people to shave a couple of tenths of a second off a 0-60 launch time, but still haven't provided the ability to preheat the pack to eliminate the regenerative braking limitation, which would almost certainly have broader appeal, and would without question have more practical application. Since the two are so closely related, and since Tesla has already provided this Max Battery Power, at this point you would think Battery Preheating should be a no-brainer.

The only times you lose regen are after a range charge and when cold. There's no help for the range charge, but the cold can be mitigated by timing charging to end just before you start to drive and preheating the cabin (when very cold two or three cycles). I've found that procedure will keep regen functional till at least 30 or 35 kW at -5C (parked outside) and will often eliminate the loss of regen entirely at higher temperatures. (Note, that's for pre-v7, I've only had one cold day since installing v7 so that may have changed.) This would be a no-brainer if there was an end-by time rather than just a charge start time.

 

[Andyw2100]

The only times you lose regen are after a range charge and when cold. There's no help for the range charge, but the cold can be mitigated by timing charging to end just before you start to drive and preheating the cabin (when very cold two or three cycles). I've found that procedure will keep regen functional till at least 30 or 35 kW at -5C (parked outside) and will often eliminate the loss of regen entirely at higher temperatures. (Note, that's for pre-v7, I've only had one cold day since installing v7 so that may have changed.) This would be a no-brainer if there was an end-by time rather than just a charge start time.

Sure.

But there are times when you need to drive without being able to charge immediately before. Also you may not want the cabin heated, or heated nearly as much or as long as necessary to have any impact on the regen limit, so that's also potentially very inefficient. (And that's saying nothing about the whole having to remember to turn off range mode for this to work issue.) Finally, when it is very cold, all of the above will typically only get the regen limit down to 30, but won't eliminate it.

Why not just let us preheat the battery directly, instead of having to jump through these hoops? Tesla seems to be "dumbing down" the user interface. How many of the people they are trying to attract by doing that are going to go through the steps we need to go through now to accomplish preheating of the pack? How many would if there was simply a "Preheat Battery" option?

 

[KJD]

I would really like to have the option to schedule the end of charge time. I would advocate for something really simple where I could set the finish time and the amps and the car would calculate the start time.

Nothing fancy and it would be super easy for Tesla to code.

As far as the battery pre heat, I only want to do that when the car is plugged in.

 

[gpetti]

I would really like to have the option to schedule the end of charge time. I would advocate for something really simple where I could set the finish time and the amps and the car would calculate the start time.

Nothing fancy and it would be super easy for Tesla to code.

As far as the battery pre heat, I only want to do that when the car is plugged in.

I don't think the end of charge time is as wonderful as people may think. As I understand it, the main reason is to have a "warm" battery. While this is one way to achieve it, allowing the car to charge at the last possible moment can potentially lead to waking up to a car that is not as charged as one might want. I have occasionally seen the car ramp down the current and if the car has become cold enough, the battery warming demands may slow down the charging progress. I guess if the car kept waking up to see what the temperature was and what the available charge current was, then it might stand a good chance of always accurately starting at the right time but that sounds like a lot of overhead to solve a problem that ultimately is just the need for battery warming. Admittedly if the feature was trying to have the battery fully warmed by a leaving time, the same issue might apply; however, a miscalculation in this case would only lead to a battery that still has some regen limiting - the charging itself can still be allowed to start at a sufficiently early time to safely finish and ideally the battery warming compliments the charging so that it only warms when charging has completed and as required.
While pre-heating when the car is plugged in might be the preference for some owners, I generally have ample battery during my city driving and would happily allow the battery to pre-warm when I'm at an appointment. These days in our neck of the woods, I hardly ever full regen because the car keeps cooling down when I park it. I have started to use the maximum power option but like others who have commented, I'm concerned that this is not an appropriate use of the option.

 

[Lex]

I am not in the "last minute charge" camp. It's too risky, and impedes my ability to get in and drive. I like to have a mostly charged car while at home, most of the time. My lowest time-of-use rate currently starts at 7pm, and sometimes I even start charging earlier.

I am in the "more options please" camp. For this one though I'm actually quite pleased to hear that they're playing with pack heating on P cars because that's exactly Tesla's MO, to develop the tech on the high end, and then bring it to the masses. Perhaps there are more considerations here and they're gathering data.

 

[KJD]

I don't think the end of charge time is as wonderful as people may think. As I understand it, the main reason is to have a "warm" battery.

That would be incorrect. The main reason to have an end time schedule is to have the car charging late at night when the load on the grid is very small.

This helps produce electricity with the least amount of pollution. This will also reduce the need to build new power plants and this will help keep electrical rates low for everyone.

 

[Andyw2100]

I don't think the end of charge time is as wonderful as people may think. As I understand it, the main reason is to have a "warm" battery.

That would be incorrect. The main reason to have an end time schedule is to have the car charging late at night when the load on the grid is very small.

Actually, KJD, I think gpetti --IS-- correct.

There is no need for end-time charge scheduling just to be able to charge at low night rates. If that were the only goal, we can accomplish it now, by scheduling the charge to begin when the low rate starts. If the problem is that the charge might not be finished by the time the rate increases, there are other ways to prevent the car from continuing to charge past a certain time, and the end-charge scheduling we're talking about wouldn't help in this case, because the issue is the charge wouldn't have started in time to end before the rate increased anyway. What you'd be asking for in that case is a cut-off window that charging can't occur in.

The main benefits of end-time scheduling are being able to have a warm battery when you are leaving, and also not having a battery sitting at a higher state of charge for longer than it needs to be.

 

[jerry33]

The main benefits of end-time scheduling are being able to have a warm battery when you are leaving, and also not having a battery sitting at a higher state of charge for longer than it needs to be.

I'd suggest all three are equally important. Warm battery, grid/TOU, and low SOC.

 

[Nigel16494]

I would really like to have the option to schedule the end of charge time. I would advocate for something really simple where I could set the finish time and the amps and the car would calculate the start time.

Nothing fancy and it would be super easy for Tesla to code.

As far as the battery pre heat, I only want to do that when the car is plugged in.

You mean you would like departure time programming so Tesla can almost be as good as my volt. My volt knows all the time of use periods (winter/summer) and can be set to charge within those periods and also using a departure time. The volt stays plugged in (wife uses it) , the battery stays warm/cool depending on what is needed. I find my Tesla as dumb as a stump when it comes to charging. I set it to 2am. Actually if it were clever it could begin charging at 8pm on the the PGE winter E6 schedule. I think this whole area of rate tariffs, battery warm/cool is a lot of low hanging fruit for Tesla.

 

[Mjølner]

Please, could anyone with connections to Tesla, tell them to enable the battery heating function when i pre-heat the cabin!!!!!!!!!!!!!!!
Even when charging, the battery won`t get the right temerature.
This was NO problem earlyer, and occured with the 7.0 software, same as the cabin heater disfunction. It is cold here in Norway, and I`m freezing my ass off at the moment.
I`m using 28% more battery now because of heating the battery when driving.

 

[Andyw2100]

Please, could anyone with connections to Tesla, tell them to enable the battery heating function when i pre-heat the cabin!!!!!!!!!!!!!!!
Even when charging, the battery won`t get the right temerature.
This was NO problem earlyer, and occured with the 7.0 software, same as the cabin heater disfunction. It is cold here in Norway, and I`m freezing my ass off at the moment.
I`m using 28% more battery now because of heating the battery when driving.

Are you suggesting there is a change, and that now the battery heats less when the cabin heats than it did with previous software versions? If so, can you please be specific with respect to the following, both before and after the version change:

--Range mode on or off. (We know that in the past, range mode needed to be off for cabin heating to also impact battery heating.)
--Car plugged in to shore power or not.

Thanks.

 

[Mjølner]

Hello.

I never use Range Mode, so that`s off, and it`s no difference if i`m plugged in or not.

 

[Andyw2100]

Hello.

I never use Range Mode, so that`s off, and it`s no difference if i`m plugged in or not.

Are you suggesting that there is a difference in newer versions of the software?

My experience and others' has been that when it is very cold the preheating of the cabin would not fully eliminate the regen limit. Typically no matter how much we heated the cabin, the battery would heat only enough to reduce the regen limit to about 30 kW or so.

Is your issue that the battery can't heat beyond that, or that the new version of the software has reduced the ability to heat even to that point?