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What should my ideal charge percentage be?

djp

Model 3 Performance
Aug 28, 2011
1,120
59
Toronto, Canada
I guess what I'm saying is that there are all these ways to extend your battery life by small percentages, and then as soon as you battery swap one time that work was all pointless.

One of the conditions of the battery swap is you need to take your own battery back at the end of the trip. If you want to keep the new battery, you pay for it. Tesla hasn't announced the pricing yet but it could be steep depending on how low the capacity is on your old battery.
 

hans

P631
Sep 27, 2012
1,132
13
Menlo Park
I guess what I'm saying is that there are all these ways to extend your battery life by small percentages, and then as soon as you battery swap one time that work was all pointless.

[...]

School me if I'm wrong.

Cheers all

I plan to use the battery swap stations but I will always return and get my original babied pack back on the return trip. I'm even going to put a sticker on it so I'm sure I get my original pack back and not just a similar one.
 

4SUPER9

Active Member
Jun 6, 2013
2,480
1,491
California
If many of us here on this forum baby our batteries to some extent, then we will be motivated to get our original batteries back. Somehow, I doubt that the batteries we would get from a Tesla station would be as good as ours. In fact, given that it is these loaner batteries that, almost by definition, that are most likely to be abused as they are intended for road trips.

Hey, now that I think of it, why would Tesla charge us if we left our battery? Seems like it would be a better deal for them if we ran off with their road trip batteries and left our precious ones with them. :tongue:
 

stopcrazypp

Well-Known Member
Dec 8, 2007
10,025
4,955
Hey, now that I think of it, why would Tesla charge us if we left our battery? Seems like it would be a better deal for them if we ran off with their road trip batteries and left our precious ones with them. :tongue:
Tesla has said they will charge based on the relative condition on the batteries (the one you swapped and the one you left behind). It's not a flat fee. Although unlikely as a policy, it's possible you might even get a refund if your battery is in better condition than the one you swapped for.

For people who don't want to worry about it, just set it at 90% for daily use to approximate the previous Standard mode. That will give you a good portion of the benefit in terms of life (there's diminishing returns) while still giving close to full range. Others who want to baby their pack can set it lower.
 
Last edited:

jerry33

(S85-3/2/13 traded in) X LR: F2611##-3/27/20
Mar 8, 2012
19,631
22,278
Texas
or people who don't want to worry about it, just set it at 90% for daily use to approximate the previous Standard mode. That will give you a good portion of the benefit in terms of life (there's diminishing returns) while still giving close to full range. Others who want to baby their pack can set it lower.

It's probably more important for those that live in a hot area because heat plus high SOC (or heat and very low SOC) are more damaging than either high or low SOC alone.
 
Hmm. My understanding of paying the difference was if you got say an 85 kwh battery an you owned a 60. So I must have missed something.

Seems like it would be quite difficult to keep track of whose battery was whos and ship them back tothe owner and such. To the point that it woul be almost financially and space-wise prohibitive. Seems much easier to just trade them and not keep track then remanufacture the ones that dont hold enough electrons anymore.

But perhaps thats why i am not TMC's CEO. Hahah.

Thanks for setting me straight.


Cheers
 

ElSupreme

Model S 03182
Jan 13, 2012
4,303
89
Atlanta, GA
I am going to put in my two cents here.

When I first got 4.5 (and the slider) I put it at 80% charge. Had no problems at all with it charged there. Felt it was probably a little better for the battery. But I am back to 90% now. Here is why.

Two weeks ago on Saturday, my wife decided at the last moment to drive to Athens (a charging wasteland) 85 miles from where we live. Charging to 80% gives me about 200 miles of rated range. I had already run to the grocery store and Lowes that morning and was sitting on about 180 miles left in the tank. I also had to run to work later that day, to check on an install that finished up very late Friday. And with scattered thunderstorms I was a little concerned about range (knowing the way I drive, and knowing I would have an empty HOT lane begging for 85+ speeds). So I plugged it in, and got another 10 or so miles of range. Before we left.

I took it a little easy on the way there. On the way back it was speed unlimited, and a really good draft for about 2/3rds of the trip. Ended up with ~40 miles left (yeah beat rated miles by a lot on that trip ~260wH/mi). Charged for about an hour then did my 55 mile round trip to work.


Not really a concern. I didn't drive slowly, and barely slower than I would have driven normally. And had plenty of range overall. But I purchased the 85kWh pack for the sole reason of never having to deal with range issues. So I personally don't think it is worth it to me to charge at 80% every day, when on a whim I could drive 200+ miles. If my car started at 90% it would have been concern free.
 
Jan 6, 2012
216
85
I plan to use the battery swap stations but I will always return and get my original babied pack back on the return trip. I'm even going to put a sticker on it so I'm sure I get my original pack back and not just a similar one.

Do you have some way to put the sticker on the pack and check it later? Are you going to put the car on a lift, undo all the bolts, and remove the cover to check for the sticker? Inquiring minds want to know.

- - - Updated - - -

Hmm. My understanding of paying the difference was if you got say an 85 kwh battery an you owned a 60. So I must have missed something.

I thought I read somewhere it would be based on the age of the battery (assuming equivalent original capacity). Elon was saying in an interview about charging based on age difference if you kept a newer battery, but who knows what they will actually decide to do.
 

hans

P631
Sep 27, 2012
1,132
13
Menlo Park
Do you have some way to put the sticker on the pack and check it later? Are you going to put the car on a lift, undo all the bolts, and remove the cover to check for the sticker? Inquiring minds want to know.

I was just going to reach under and slap a unique sticker on the bottom of the pack (being careful not to cover any of the bolt holes). Any place I can reach is a place I can check again.
 

pilotSteve

Active Member
Jul 14, 2012
1,470
1,337
Prescott Az
I was just going to reach under and slap a unique sticker on the bottom of the pack (being careful not to cover any of the bolt holes). Any place I can reach is a place I can check again.

Hmm there is a word for this: software! Each pack has multiple CPUs to track and manage various aspects of battery. I'm sure there is flash memory built in also to track: unique serial number, number of swaps, cycles, temperature extremes and possibly location and temperature at EACH CHARGE in the pack's life time. I think it would be reasonable to assume Tesla will come up with a pricing model based on cycles and capacity consumed.
 

djp

Model 3 Performance
Aug 28, 2011
1,120
59
Toronto, Canada
Hmm there is a word for this: software! Each pack has multiple CPUs to track and manage various aspects of battery. I'm sure there is flash memory built in also to track: unique serial number, number of swaps, cycles, temperature extremes and possibly location and temperature at EACH CHARGE in the pack's life time. I think it would be reasonable to assume Tesla will come up with a pricing model based on cycles and capacity consumed.

The capacity of the pack can also be measured directly. The Calculated Amp hour Capacity (CAC) is reported in Roadster logs and available on the diagnostic port. This is probably what they'll use to price battery upgrades.
 
Jan 6, 2012
216
85
I was just going to reach under and slap a unique sticker on the bottom of the pack (being careful not to cover any of the bolt holes). Any place I can reach is a place I can check again.

So you're saying the bottom cover is part of what gets swapped. I assumed that cover is not part of the pack and stays with the car. I wish we could have seen what happened below the stage in the swap demo. I don't know if I want to be driving around, even temporarily, with a cover that someone else may have scraped up.
 

hans

P631
Sep 27, 2012
1,132
13
Menlo Park
So you're saying the bottom cover is part of what gets swapped. I assumed that cover is not part of the pack and stays with the car. I wish we could have seen what happened below the stage in the swap demo. I don't know if I want to be driving around, even temporarily, with a cover that someone else may have scraped up.

Yes, the bottom "cover" is part of the battery pack. If you look at the bottom of your car, you are looking at the battery pack.

fe_9171226_600.jpg
 

GasDoc

Member
Nov 15, 2012
806
492
SF Bay Area
Here's a picture if my pack from the topside.

The hump is the coolant reservoir and sits at the front of the pack.

I think the black things are protective caps that cover quick disconnects for coolant.

ImageUploadedByTapatalk1373589715.232122.jpg
 

Andrew

Model S #6151, Model 3 #1576
Mar 11, 2013
434
208
Santa Monica, CA
I've been tracking this thread for awhile now, and the only thing that seems to keep coming up is that... we Just. Don't. Know.

And really, it's because Tesla doesn't really know, either. The only thing everyone seems to agree on is that 90% is significantly better than 100%, and as you go lower than 90%, the incremental improvement in battery life has diminishing returns.

My theory about all this 50-100% slider business? I think that Tesla implemented the slider so they could track all of it and look at real-world data across all of our cars. Eventually they'll crunch the numbers and figure out the best recommendations.

And then maybe, someday, if we're really lucky, they might actually include a battery degradation % as part of the warranty coverage.
 
  • Informative
Reactions: Vern Padgett

kendallpb

Model S: P 8061
Oct 29, 2010
1,251
52
MD, USA
My theory about all this 50-100% slider business? I think that Tesla implemented the slider so they could track all of it and look at real-world data across all of our cars. Eventually they'll crunch the numbers and figure out the best recommendations.

That's . . . a pretty good theory. I mean, a bunch of people wanted it, so I suspect that's a big chunk of it, but I could see Tesla going "hey, this would be really useful for us, too...let's add the feature."

I mean, we all know we're guinea pigs regardless, right? ;-) Even without the slider.
 

xray

P85 6313 - X Res 3450
Feb 7, 2013
146
0
Newport Coast, CA
I've been tracking this thread for awhile now, and the only thing that seems to keep coming up is that... we Just. Don't. Know.

And really, it's because Tesla doesn't really know, either. The only thing everyone seems to agree on is that 90% is significantly better than 100%, and as you go lower than 90%, the incremental improvement in battery life has diminishing returns.

My theory about all this 50-100% slider business? I think that Tesla implemented the slider so they could track all of it and look at real-world data across all of our cars. Eventually they'll crunch the numbers and figure out the best recommendations.

And then maybe, someday, if we're really lucky, they might actually include a battery degradation % as part of the warranty coverage.

also agree, very good theory!
 

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