What time will PWs reach 100%- Spreadsheet (downloadable)

[n.one.one]

There are days that you might want to adjust the use of your Powerwalls and it would be helpful to know when they will reach 100%. The spreadsheet linked below will quickly tell you what that time is based on how fully charged they are now and the current or estimated charge rate. I'll put an example in Post #2.

You can download the sheet to use in Google Sheets or Excel. Please let me know if you see any opportunity for improvements and I'll try to make changes that would apply to the majority of users.

Time left to fully charge PWs

Sheet1 Version 3,<a href="https://teslamotorsclub.com/tmc/threads/what-time-will-pws-reach-100-spreadsheet-downloadable.297479/">This sheet is set to read only. To make your own sheet go to the file menu, 'Make a Copy' and open in Google Sheets or in Excel. No share requests please. Link to TMC...

docs.google.com

 

[n.one.one]

There are days that you might want to adjust the use of your Powerwalls and it would be helpful to know when they will reach 100%. The spreadsheet linked below will quickly tell you what that time is, based on how fully charged they are now, and the current or estimated charge rate. I'll put an example in Post #2.

You can download the sheet to use in Google Sheets or Excel. Please let me know if you see any opportunity for improvements and I'll try to make changes that would apply to the majority of users.

Time left to fully charge PWs

Sheet1 Version 3,<a href="https://teslamotorsclub.com/tmc/threads/what-time-will-pws-reach-100-spreadsheet-downloadable.297479/">This sheet is set to read only. To make your own sheet go to the file menu, 'Make a Copy' and open in Google Sheets or in Excel. No share requests please. Link to TMC...

docs.google.com

Here is an example of how I use this sheet. The first screenshot shows my Tesla app and indicates the PWs are 92% full and charging at a 3.8 kW rate. The 2nd shot of the sheet shows that using those two numbers I can expect the PWs to be 100% full at 2:35 PM (about an hour from the current time). Note that after entering your PW capacity the first time you use this you never have to enter anything again. It's just a lookup sheet that adjust itself to your system time.

 

[power.saver]

Here is an example of how I use this sheet. The first screenshot shows my Tesla app and indicates the PWs are 92% full and charging at a 3.8 kW rate. The 2nd shot of the sheet shows that using those two numbers I can expect the PWs to be 100% full at 2:35 PM (about an hour from the current time). Note that after entering your PW capacity the first time you use this you never have to enter anything again. It's just a lookup sheet that adjust itself to your system time.
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You're making a big assumption that the Powerwall charge rate is constant. It's not. The charge rate varies with solar production, increasing and decreasing throughout the day.

 

[n.one.one]

You're making a big assumption that the Powerwall charge rate is constant. It's not. The charge rate varies with solar production, increasing and decreasing throughout the day.

I agree completely but didn't think I'd need to explain that to experienced users. I still find it a useful tool as it gets to mid afternoon and I want an estimate that I can start from. I then adjust that based on clouds rolling in, sun moving away from my most productive panels, heavier home usage based on HVAC heating as temps drop, etc.

Your observation is helpful and I'll add a note on the sheet alerting folks to that.

 

[Big Dunc]

I am sorry, but I am struggling to grasp what use this has.
Firstly, does it matter when the powerwall(s) are fully charged. You might schedule something else, but actually you could do that earlier and the powerwalls would fully charge later.
What I am struggling with, is the need for the accuracy to within a couple of minutes.
I have (for example) a single powerwall say 13.5/14 kW. I am making 3 kW surplus and expect that to remain more or less for the next few hours. (it wont).
Powerwall is currently 50% full so it needs 7 kW (or slightly less to be fully charged). Without even putting a calculator on it, it needs 3 hours and 20 minutes (or slightly less) to fully charge, assuming the surplus PV remains the same, which it won't.
I know most of my panels face South East, so make more in the morning. Everyone will know when they expect to make most surplus PV depending on their set up.
When I wake up, I can look at the weather forecast, the amount of current surplus and the powerwall state of charge and probably accurately tell you to within half an hour when the powerwall will be full. BUT, it doesnt matter if I am wrong. I would not do anything different during the day.
Clearly I am missing something, please do explain.

 

[jjrandorin]

I am sorry, but I am struggling to grasp what use this has.
Firstly, does it matter when the powerwall(s) are fully charged. You might schedule something else, but actually you could do that earlier and the powerwalls would fully charge later.
What I am struggling with, is the need for the accuracy to within a couple of minutes.
I have (for example) a single powerwall say 13.5/14 kW. I am making 3 kW surplus and expect that to remain more or less for the next few hours. (it wont).
Powerwall is currently 50% full so it needs 7 kW (or slightly less to be fully charged). Without even putting a calculator on it, it needs 3 hours and 20 minutes (or slightly less) to fully charge, assuming the surplus PV remains the same, which it won't.
I know most of my panels face South East, so make more in the morning. Everyone will know when they expect to make most surplus PV depending on their set up.
When I wake up, I can look at the weather forecast, the amount of current surplus and the powerwall state of charge and probably accurately tell you to within half an hour when the powerwall will be full. BUT, it doesnt matter if I am wrong. I would not do anything different during the day.
Clearly I am missing something, please do explain.

Some people really like digging into detailed data, and like to model things via spreadsheet. That isnt me, but I dont want to shut anyone down who enjoys that and also is willing to share their work / modeling so others can do it too if they wish.

 

[Big Dunc]

Sorry, maybe I was being over negative. If you are into that sort of thing it is probably great. I am an old guy, not into IT and like to keep things simple. If it is your cup of tea, fill your boots.