Heat?

[Oldrocky]

Hi all,
I have just one new question today.

1) I see people asking "should I pre-warm my HV before using the vehicle?". Is this really a
thing we should be doing? If the answer is yes, then "how long". I am assuming that in
order to pre-heat a fully charged vehicle you would have to have some 'space' available
to add any power ... and I think that means setting the charging level to 100% I have my
2018 Model X set to stop charging at 90% - is that a good level to use? I will rarely need
more than that level for the trips I take "regularly".
- Jim in Burlington, Wa. 2018 Model X 100D (purchased used)

 

[Rocky_H]

I see people asking "should I pre-warm my HV before using the vehicle?". Is this really a
thing we should be doing?

No. Here's a comment on this I made from another thread:

Preconditioning

Heating of the battery during charging is minimal, i.e, the Tesla battery management system will only warm the battery enough so that the battery can be charged without damage. Charging will not warm the battery sufficiently so that regenerative braking will not be limited when you start to...

teslamotorsclub.com

 

[Oldrocky]

Thanks Rocky - I figured that was bogus but since I am so new to the car I said "better check". *G*

- Jim in Burlington, Wa.

 

[Rocky_H]

While not necessary to take care of the car or its battery, there are a couple of reasons people do it for other things:

When it's cold, the car will limit the regeneration, because you can't charge a battery like that with high power when it's really cold, so that slowing force will be reduced, and that makes some people really upset/uncomfortable. But I just figure that's how winter is, and it will warm up some while I drive, so I'm not going to waste extra energy before leaving just for that.

Or if you are departing on a really long drive and need to squeeze a lot of range in the winter. The early part of the drive will use up some extra battery from really energy usage warming up. So if you want to try to take that in from your house first, then you'll have a bit more driving range because the energy use won't have to be as high at first.

 

[mxnym]

No. Here's a comment on this I made from another thread:

Preconditioning

Heating of the battery during charging is minimal, i.e, the Tesla battery management system will only warm the battery enough so that the battery can be charged without damage. Charging will not warm the battery sufficiently so that regenerative braking will not be limited when you start to...

teslamotorsclub.com

FWIW, with a 72A charger, charging scheduled to start at 5:30 AM, 80% charge limit, 60% battery overnight, and a 7:15-7:30 departure time (not set anywhere, just normal), I leave with full regen every morning all winter long. OTOH, if I don' t use the scheduled charge and instead charge from 60% to 80% at 5:30 PM, my regen is limited in the morning. It may not be of significant benefit/detriment for the pack one way or the other, but I like having full regen in the morning, even if I' m not going to have it when I get back in the vehicle to go to lunch from work.

 

[DCGOO]

Hi all,
I have just one new question today.

1) I see people asking "should I pre-warm my HV before using the vehicle?". Is this really a
thing we should be doing? If the answer is yes, then "how long". I am assuming that in
order to pre-heat a fully charged vehicle you would have to have some 'space' available
to add any power ... and I think that means setting the charging level to 100% I have my
2018 Model X set to stop charging at 90% - is that a good level to use? I will rarely need
more than that level for the trips I take "regularly".
- Jim in Burlington, Wa. 2018 Model X 100D (purchased used)

If it is very cold and you are connected to shore power, you can simply turn on the climate for an hour or so before you depart. There is a symbol in the app, indicating battery heating is occurring. This gives you full regeneration and saves some battery capacity. But it is certainly not required, nor even something "you should do."

 

[Rocky_H]

FWIW, with a 72A charger, charging scheduled to start at 5:30 AM, 80% charge limit, 60% battery overnight, and a 7:15-7:30 departure time (not set anywhere, just normal), I leave with full regen every morning all winter long. OTOH, if I don' t use the scheduled charge and instead charge from 60% to 80% at 5:30 PM, my regen is limited in the morning. It may not be of significant benefit/detriment for the pack one way or the other, but I like having full regen in the morning, even if I' m not going to have it when I get back in the vehicle to go to lunch from work.

Oh yeah, that was the shortcut from long before Tesla ever added any of the scheduled departure or pre warmup features. With a pretty high current charger, you could just do some standard charging for a bit before you go, and that forces the battery to warm itself up, without wasting a ton of energy doing cabin heating.

All this preheating wastes a lot of energy. But charging is something that will be used at some point anyway, so is generally useful.

 

[Big Earl]

If it is very cold and you are connected to shore power, you can simply turn on the climate for an hour or so before you depart. There is a symbol in the app, indicating battery heating is occurring. This gives you full regeneration and saves some battery capacity. But it is certainly not required, nor even something "you should do."

An hour is a waste of electricity. Battery heating stops after about 20 minutes (varies based on actual pack temperature, of course) - beyond that is just wasting energy maintaining cabin temperature.

 

[Oldrocky]

So far (new to car, purchased used) my car stays at about 4 degrees warmer
on the inside compared to the garage temp ... when not charging. When
charging it runs about 10 degrees warmer and stays there for as long as it is
still topping up the battery. This is with the 110v charger. I just got the 220v
charger (wall version, not 220v plug) installed today and so do not yet have
any kind of track record on how much more (if any) temp it will generate. I
expect it to be warmer that when on 110 - just don't know how much. Yet.
- Jim

 

[mxnym]

So far (new to car, purchased used) my car stays at about 4 degrees warmer
on the inside compared to the garage temp ... when not charging. When
charging it runs about 10 degrees warmer and stays there for as long as it is
still topping up the battery. This is with the 110v charger. I just got the 220v
charger (wall version, not 220v plug) installed today and so do not yet have
any kind of track record on how much more (if any) temp it will generate. I
expect it to be warmer that when on 110 - just don't know how much. Yet.
- Jim

In theory, the heat from charging is simply energy lost due to inefficiency. As I understand it, 220v charging is more efficient. Applying basic math to those basic theories (without real-world inputs): if you double the power consumed and cut the efficiency loss in half, you would get the same heat. Perhaps there is a chance you will be pleasantly surprised.

 

[Rocky_H]

I
expect it to be warmer that when on 110 - just don't know how much. Yet.

In theory, the heat from charging is simply energy lost due to inefficiency. As I understand it, 220v charging is more efficient. Applying basic math to those basic theories (without real-world inputs): if you double the power consumed and cut the efficiency loss in half, you would get the same heat. Perhaps there is a chance you will be pleasantly surprised.

Hmm, that is an interesting question with conflicting factors, and I wonder which would outweigh others. Inefficiency is a percentage, so calculated over time, yes, you could say that there would be more overall loss over a very long period of time from the 120V outlet. But the 1.4 kW from a regular wall outlet may have really bad efficiency, but there's just so little energy going through it, that it may not warm the car up much. It gives a tiny bit of heat at a time, while that is being emitted to the outside air. Frequently a 40 or 80A charging rate may be more efficient, but warms up the car pretty quickly.

 

[Oldrocky]

Hi,
So after about 36 hours since I first put the MX on the 220v wall charger I have this to report.
When first on the charger the inside of the car was almost 20 degrees warmer than the garage.
After several hours - and as it neared charging completion - the interior was down to 10 degrees
warmer than the garage. After charging was complete the car remains at "about 4 degrees
more than the temp in the garage". All temps reported are as seen in the Windows Tesla Control
app - so it is what the car itself is reporting for interior and exterior. The exterior reported has
been checked against a thermometer and is within 1 degree of that whenever I have checked it.
So, as expected and no surprise, the 220v charger heats the car more than the 110v. BTW -
I have always had all 4 windows completely down when charging.
I have done two 'significant' charge cycles. The first was from about 100 miles available to
a 90% level. The second was from about 90 miles to the same 90% level. I am finding the
220v wall charger to be both fast and efficient and both times the time it took to charge
has been "easily completed over night". It looks less and less like I'll be using the local
supercharger any time soon - and I have no idea how much quicker a supercharger will
be than my 220v wall charger unit. I -may- be making a trip to Albany, Oregon which is
309 miles and probably too far to reach in a single go - even with 100% charge when I
leave ... so if I make that trip I'll finally be using the charging planning stuff of the apps.
- Jim

 

[Big Earl]

Hi,
So after about 36 hours since I first put the MX on the 220v wall charger I have this to report.
When first on the charger the inside of the car was almost 20 degrees warmer than the garage.
After several hours - and as it neared charging completion - the interior was down to 10 degrees
warmer than the garage. After charging was complete the car remains at "about 4 degrees
more than the temp in the garage". All temps reported are as seen in the Windows Tesla Control
app - so it is what the car itself is reporting for interior and exterior. The exterior reported has
been checked against a thermometer and is within 1 degree of that whenever I have checked it.
So, as expected and no surprise, the 220v charger heats the car more than the 110v. BTW -
I have always had all 4 windows completely down when charging.
I have done two 'significant' charge cycles. The first was from about 100 miles available to
a 90% level. The second was from about 90 miles to the same 90% level. I am finding the
220v wall charger to be both fast and efficient and both times the time it took to charge
has been "easily completed over night". It looks less and less like I'll be using the local
supercharger any time soon - and I have no idea how much quicker a supercharger will
be than my 220v wall charger unit. I -may- be making a trip to Albany, Oregon which is
309 miles and probably too far to reach in a single go - even with 100% charge when I
leave ... so if I make that trip I'll finally be using the charging planning stuff of the apps.
- Jim

A one-way trip to Albany, OR would probably be one stop. Plan on about 200 miles per charge (maybe more if traffic is particularly slow). A round trip, if you don't have destination charging available, would probably add two more Supercharger stops. An ideal charging session is from about 12% to 60%. Running it up to 75 or 80% will add some extra time and going over 80% takes significantly longer - only do that if you're also planning a sit-down meal or some sort of shopping excursion.

Just eyeballing it on Supercharge.info, I'd probably shoot for Burlington to Kelso (194 miles) to Albany (117 miles) to Salem, OR (26 miles) to Tumwater, WA (153 miles) to Burlington (134 miles). I just plugged it into abetterrouteplanner.com and it suggests Kelso, Salem, Vancouver, Tumwater and Seattle - Northgate.

 

[Oldrocky]

Yes, that is pretty much how the car itself did it. There will be about 30 to 50
miles of driving in the Albany area (more?) which isn't covered so I'll probably
have a longer stop in Salem on the return than the planners call out.
This trip will be my longest and my first real test of the car's range and how
it 'fits' with my personal habits/needs. I have always been a long distance
driver - with stops to eat. So I'll be interested in finding superchargers with
food close by (within walking). My last long trip was from San Jose, Ca. to
here in Burlington ... with food and fuel stops but without sleeping - I had
my nephew with me to share the driving. That is over 900 miles without a
sleep over. I don't expect to do that often - it's just the kind of thing I do
from time to time. That one was in a rental truck and was the last of the
move from San Jose to Burlington, Wa.
The trip to Albany is currently "on/open" - but with a cautious watch on the
Covid numbers ... *sigh*.
- Jim