Range Loss Over Time, What Can Be Expected, Efficiency, How to Maintain Battery Health

[TrueTechData]

Oh believe me, I "get" the desire to charge using solar. I also get the "homebrew" aspect of "can I do this? lets figure out how to do this..."

I have a "regular" (professionally installed) PV / Solar system on my roof, and also have tesla powerwalls (whose purpose is not directly for charging the car, but I digress....). There is something very "empowering" about running your home mostly (or all) off solar power, and one doesnt have to be a "save the planet" eco warrior to feel that way.

That is awesome and I totally agree. I've always wanted to do it. Unfortunately I don't own a house yet so a real solar setup isn't practical.

I bought three 300W portable solar panels that are just laying in the back yard of the house I'm renting a room in, and a Bluetti AC200P - which is a 2 kWh, 2000 W output, battery pack. The Bluetti is rated at 3600 full cycles to 80% capacity, so it should last a long time.

If I angle the solar panels correctly, I should be able to charge the Bluetti to about 60-80% twice a day depending on time of year. I charge at 1900W to get the Tesla charging overhead as low as possible.

Total cost for the setup was $2700 ish including extra connectors and cable to run all the way to the garage. If I lived in San Diego forever, it would probably eventually pay for itself. About 3 kWh a day on average, and electricity is 50 cents per kWh here (insane) - so the math comes out to like 5 years to pay for itself. But SD is the only place in the country with $/kWh like this - so again, isn't for the money at all. I just think it is awesome, and I'm planning on going off grid camping some in the future, so I wanted the Bluetti for that (and emergencies) anyway. At least that is how I justify it to myself.....

 

[jjrandorin]

That is awesome and I totally agree. I've always wanted to do it. Unfortunately I don't own a house yet so a real solar setup isn't practical.

I bought three 300W portable solar panels that are just laying in the back yard of the house I'm renting a room in, and a Bluetti AC200P - which is a 2 kWh, 2000 W output, battery pack. The Bluetti is rated at 3600 full cycles to 80% capacity, so it should last a long time.

If I angle the solar panels correctly, I should be able to charge the Bluetti to about 60-80% twice a day depending on time of year. I charge at 1900W to get the Tesla charging overhead as low as possible.

Total cost for the setup was $2700 ish including extra connectors and cable to run all the way to the garage. If I lived in San Diego forever, it would probably eventually pay for itself. About 3 kWh a day on average, and electricity is 50 cents per kWh here (insane) - so the math comes out to like 5 years to pay for itself. But SD is the only place in the country with $/kWh like this - so again, isn't for the money at all. I just think it is awesome, and I'm planning on going off grid camping some in the future, so I wanted the Bluetti for that (and emergencies) anyway. At least that is how I justify it to myself.....

its most of CA, actually.

That 50c a kWh charge is either peak pricing (if on a TOU plan) or the highest tier price for when they are charging you penalty rates. Given the situation you laid out, I am going to guess the electricity usage at your residence is high.

With that being said, its not just San diego in CA thats around that price, SCE is very close, and PGE in NorCal is also right there.

 

[TrueTechData]

its most of CA, actually.

That 50c a kWh charge is either peak pricing (if on a TOU plan) or the highest tier price for when they are charging you penalty rates. Given the situation you laid out, I am going to guess the electricity usage at your residence is high.

With that being said, its not just San diego in CA thats around that price, SCE is very close, and PGE in NorCal is also right there.

What I quoted is the lowest rate on the TOU plan where I live. $0.454/kWh is the lowest, gets up to 0.59/kWh on peak times.

I know other places in California are also extremely expensive, just sort of meant the rest of the country. I've lived in almost a dozen other states and they were all a fraction of this cost and I'll be moving back east soon, which would make my setup not even close to ever being able to repay itself. But I was aware of that when I got everything. Just enjoy charging with the sun.

 

[Apprunner]

What I quoted is the lowest rate on the TOU plan where I live. $0.454/kWh is the lowest, gets up to 0.59/kWh on peak times.

I know other places in California are also extremely expensive, just sort of meant the rest of the country. I've lived in almost a dozen other states and they were all a fraction of this cost and I'll be moving back east soon, which would make my setup not even close to ever being able to repay itself. But I was aware of that when I got everything. Just enjoy charging with the sun.

Aren't you on the EV-TOU plan? The TOU5 plan will get you 11 cents per kwh during peak with a fixed fee of $16 a month. The other EV plan nets you 25 cents per kwh from PG&E. Your plan seems unusually expensive in San Diego.

 

[SillyPosition]

Last night I drove the car down to -2% SOC, it slept overnight and charge this morning. NFP was 80.1 this morning and at work it sad 79.4. This is my all time low, but exactly in line with my calculated about (2.5-) 3% loss so far. I think my NFP will climb back, but I think my BMS is very on track right now.) My car probably would be around 4% when it is two years with the same usage.

Thank you for all the insights. I also found one of your detailed posts regarding calendar aging. I get your point re 55%.
Not sure If Im going to fully follow it, because circumstances for me are something changing throughout the day (leaving quite from from my work place, kids, work, stuff are sometimes unexpected) but I now figure out Its better to let it be at around 50% instead of 80%. My main concern was always to avoid going below 20%.
But from your specific quote above, are you actually suggesting that its better going so critically low charge levels, and then not even charge immediately back, but instead, let it sit for the night just for the sake of proper calibration?
Did you actually see it goes *up* from 79.4kWh to 80.1kWh after a night sitting at almost empty charge levels?

Its the third day now that my car is at 51% charge, since I've been working from home.

 

[AAKEE]

But from your specific quote above, are you actually suggesting that its better going so critically low charge levels, and then not even charge immediately back, but instead, let it sit for the night just for the sake of proper calibration?
Did you actually see it goes *up* from 79.4kWh to 80.1kWh after a night sitting at almost empty charge levels?

Its the third day now that my car is at 51% charge, since I've been working from home.

Calibration: Normally the car should take care of it, and no intervention needed from the owner.
The forums is very much overflooded by calibration tips and I suspect you might ”need” to do them quite often, abd tou gain some km’s on the screen but you probably loose it shortly after. The BMS calibration most often cause people to charge to a higher SOC than otherwise which cause more wear on the battery.
You gain a few km on the screen but the real range is not changed. So I think theres a lot of calib going on that would not be needed.
My driving down to very low SOC(-2%) was because I know my battery has degraded to some extent, but as the range always was full and the BMS nominal full pack showed a value I suspected is to high I did this to try to find the real capacity. I was down to 0.39% SOC this summer and 3% during X-mas so I knew I needed to get much lower.
( In other words, I did this by purpose and knew that if I succeded I would get a lower NFP and shorter range. I think I now know that the real capacity is around 79.4 kWh, which is more or less exactly where my calculations said it would be. It is possible that my NFP stays here but I suspect it will climb again when I use my regular charging schedule).
To be clear, my NFP has been around 80.5-80.9 for very long before i ”forced it down”.

 

[TrueTechData]

Aren't you on the EV-TOU plan? The TOU5 plan will get you 11 cents per kwh during peak with a fixed fee of $16 a month. The other EV plan nets you 25 cents per kwh from PG&E. Your plan seems unusually expensive in San Diego.

I looked at all available plans just the other day, and didn't see anything cheaper than what I had. Don't remember seeing anything related to EVs though, I wonder if that is hidden somewhere else...

I will double check soon, thanks for the info

 

[Apprunner]

I looked at all available plans just the other day, and didn't see anything cheaper than what I had. Don't remember seeing anything related to EVs though, I wonder if that is hidden somewhere else...

I will double check soon, thanks for the info

Electric Vehicle Pricing Plans | San Diego Gas & Electric

www.sdge.com

Hope this helps.

 

[TrueTechData]

Electric Vehicle Pricing Plans | San Diego Gas & Electric

www.sdge.com

Hope this helps.

Wow, yeah that is dramatically different. I assumed the regular TOU plans were all that were available. Great to know, thank you!

 

[Steve446]

In here, it is a quite humble atmosphere ( ) but in some other places there is a very unsoft atmosphere where the members ”know” since 100 years that…. And the knowledge is mostly forum rumors and often not correct.

Really quite agreeable in fact!

There is a sharp step in the calendar aging graph between 55 and 60% SOC, and it is more or less a straight line from 0-55% and relatively flat above 60%.
The easy way for judging calendar aging would be to use the average SOC. If the average is close to 60% one can perhaps count half the time slightly below and half slightly above. This will probably get a approximately correct degradation calculation. It will not be a exact calculation anyway.

Calendar aging lessens with time. The standard way to use the ”square root of time” formula. The calendar aging from the first year will be doubled after a total of four years from start( = another three years after tge first to cause double degradation, with the same conditions).

I created a couple of "seat of the pants" charts for my car to discover my average SoC (M3 LR E5CD in EU Q3 21), first just end of charge SoC (graph 1), then same data but SoC averaged by week since the "dawn of time" (graph 2). The result was rather surprising really, but I don't know if it's meaningful or helpful to plot like that . It did make me want to double down on my storage SoC though... I'm not a heavy user of my car, so 4000 Km on the Odo to date.

I did three Supercharging sessions during the 1000km drive home. First days home I used 80%, due to being new to EV + about -30C most of the first month. After this I reduced the charging successively to 55%.

I did the same for the first ~6 weeks until I read the posts here...

 

[Steve446]

If you dont drive for several days and dont touch the app etc, its not quite 2-3 miles a day, but thats an average number. It doesnt sleep while its charging, so your "7-10 miles a day DIY" homebrew system is likely costing you more miles than its adding, on a tesla.

If you are down to 2 ish miles a day, that means you are not using sentry mode, are not waking the car up, etc. Your home brew system is likely costing you money if you are trying to use it with your car.

A consumption estimate I made a few days ago was, 0.216 kW/h with sentry on, and 0.01 kW/h when sleeping (w/o Sentry).

 

[RonCarX]

2018 model 3 rear wheel drive standard range is now down to max charge of 233 miles.
that's a 10% drop in max range.

Car has 54K miles on it.

Is this normal?

 

[jjrandorin]

2018 model 3 rear wheel drive standard range is now down to max charge of 233 miles.
that's a 10% drop in max range.

Car has 54K miles on it.

Is this normal?

Yes

 

[SillyPosition]

Calibration: Normally the car should take care of it, and no intervention needed from the owner.
The forums is very much overflooded by calibration tips and I suspect you might ”need” to do them quite often, abd tou gain some km’s on the screen but you probably loose it shortly after. The BMS calibration most often cause people to charge to a higher SOC than otherwise which cause more wear on the battery.
You gain a few km on the screen but the real range is not changed. So I think theres a lot of calib going on that would not be needed.
My driving down to very low SOC(-2%) was because I know my battery has degraded to some extent, but as the range always was full and the BMS nominal full pack showed a value I suspected is to high I did this to try to find the real capacity. I was down to 0.39% SOC this summer and 3% during X-mas so I knew I needed to get much lower.
( In other words, I did this by purpose and knew that if I succeded I would get a lower NFP and shorter range. I think I now know that the real capacity is around 79.4 kWh, which is more or less exactly where my calculations said it would be. It is possible that my NFP stays here but I suspect it will climb again when I use my regular charging schedule).
To be clear, my NFP has been around 80.5-80.9 for very long before i ”forced it down”.

Thanks for clarifying.
Re charging habits - would you say that for a 20% needed on daily drive to work (my terrain, driving calm home-work needs about 20%), its best to charge to 60% and arrive back at evening with 40%, or due to the graphing you shared in other posts, its actually better to charge to 50-55%, and discharge to 30-35%?

Aside from charging habits which I hope that I understand better, do you also refrain from specific driving habits?
For example, do you refrain from pushing the car too hard during drive, or only when the car is too cold, or at all?
If you know you will drive 'harder' and consume more from that 20%, would you charge to higher than 55%, or would you simply discharge to a lower state?

 

[Bouba]

While nobody wants battery degradation....it’s more important to enjoy the car...

 

[AAKEE]

Thanks for clarifying.
Re charging habits - would you say that for a 20% needed on daily drive to work (my terrain, driving calm home-work needs about 20%), its best to charge to 60% and arrive back at evening with 40%, or due to the graphing you shared in other posts, its actually better to charge to 50-55%, and discharge to 30-35%?

Aside from charging habits which I hope that I understand better, do you also refrain from specific driving habits?
For example, do you refrain from pushing the car too hard during drive, or only when the car is too cold, or at all?
If you know you will drive 'harder' and consume more from that 20%, would you charge to higher than 55%, or would you simply discharge to a lower state?

First of all, again, following Teslas very advices will be fine. But most probable it is possible to reduce the degradation from that.
Charging habits:
The lower the SOC, the less is the wear.
This is true for both calendar aging and cyclic aging so the best charging level is the lowest SOC that you can use.
The steep step at about 55-60% which means reducing the calendar aging to the half is probably the thing one need to know.
If you have the choise of selecting 55% instead of 60%, the degradation will be clearly less.
My 55% selection is made from that. Even though 50% cause slightly less degradation 55% give me a little bit extra SOC at more or less no cost.
I charge before the drive during weekdays so it stands at work with about 40% and when home again at 20-30% depending on the time of the year.
During weekends 55% gice me a fair range if a unplanned trip is made. I havecthe car set to charge to 55% each night so sone weekends(quite feew) it stands all weekend with 55%. It would be possible to lesve the car with 20-30% over the weekend but then I would need to charge before a pleasure trip etc. Not worth the small gain.

I did get a M3P for the power and I use the power quite often. I dont get full power at 55% but I can live with this, and when I need I charge to a higher SOC, for fun.
For the battery longevity, small/shorts bursts of 10-15s or so will not have a very bad effect on battery life.
Lithium batteries for my hobby is often specified with maximum continous current and also bursts of 10-20s with much higher currents allowed during this period.
You can use the power for these shorter burst without killing thr battery.

If you need more power and charge to a higher SOC charge shortly before the drive, there will be no increased calendar aging as you do not leave it with higher SOC.
The higher SOC cause a cycle with slightly more cyclic aging, but as cyclic aging often is the much smaller part it is so small that it will not be possible to detect the difference.

 

[KenC]

Thanks for clarifying.
Re charging habits - would you say that for a 20% needed on daily drive to work (my terrain, driving calm home-work needs about 20%), its best to charge to 60% and arrive back at evening with 40%, or due to the graphing you shared in other posts, its actually better to charge to 50-55%, and discharge to 30-35%?

Aside from charging habits which I hope that I understand better, do you also refrain from specific driving habits?
For example, do you refrain from pushing the car too hard during drive, or only when the car is too cold, or at all?
If you know you will drive 'harder' and consume more from that 20%, would you charge to higher than 55%, or would you simply discharge to a lower state?

Obviously, the lower SOC you charge to, the lower potential LT degradation. However, the relationship isn't linear; most of the benefit is going from 90% to 80%, etc. I charge to 60%, daily for my 30mile commute, and I've had no estimated deg after 3 ½ yrs, thanks to the top buffer.
All the rest of the stuff you ask about, I don't really think about. Drive as you normally drive. And, I tend to drive in the lower half of the SOC range, only because if I'm on a trip and need to supercharge, it's faster at lower SOCs. If I need to supercharge to 80% on a trip, I do.

 

[Electrifyx123]

Hello,

I have about 1200 miles on my 2022 Model 3 Performance and have noticed that my range shows 316 miles compared to the 315 as advertised in the ongoing weeks. Of course, this is a minor increase, but I was curious why it's higher than it should be, especially with it being extremely cold where I'm located.

 

[UncertainTimes]

Estimation

 

[FlatSix911]

Thanks for clarifying.
Re charging habits - would you say that for a 20% needed on daily drive to work (my terrain, driving calm home-work needs about 20%), its best to charge to 60% and arrive back at evening with 40%, or due to the graphing you shared in other posts, its actually better to charge to 50-55%, and discharge to 30-35%?

Aside from charging habits which I hope that I understand better, do you also refrain from specific driving habits?
For example, do you refrain from pushing the car too hard during drive, or only when the car is too cold, or at all?
If you know you will drive 'harder' and consume more from that 20%, would you charge to higher than 55%, or would you simply discharge to a lower state?

Tesla has recently improved its range calculation algorithm to better account for weather conditions.

Tesla is starting to account for wind, air density, and more when doing range calculation

Tesla is now starting to account for wind, air density, and more when doing range calculations in an attempt to...

electrek.co

"Now Tesla is making new improvements to its energy consumption calculations. The automaker has started pushing a new software update (2022.8.2) that includes a few UI changes, better-charging calculations, and a preconditioning update. That’s according to the release notes, but Tesla hacker Green found a few more changes under the hood. It includes accounting for crosswinds and headwinds, air density, and humidity in the energy consumption calculation when the data is available."