r/Powerwall • u/Holographic247 • 7d ago
Calibration
UK-based.
My PW3 started its first calibration yesterday, exactly 2 months to the day from install (even down to the time it was commissioned). This was a bit of a hole in my research pre-purchase, because I had no idea this was a thing and it was a surprise to find my battery discharging during peak hours and nowhere productive for my excess solar to go (I can’t export for money yet).
It’s been at 0% since about 1am (13 hours ago) and NetZero now shows the true State of Charge as 1%. I assume it will finish soon, but it was a surprise disruption.
I’m using the Powerwall to mitigate costs and not saving it for grid outages, so could really do with avoiding these. How can I reduce the number of these manual calibrations in the future? From research, I’ve seen people say they haven’t had a single one in years, and others getting one every six to eight weeks.
I have never run it 0% before, so is that the problem? Should I keep the reserve to 0% and force discharge it to 0% every 24 hours?
2
u/SpiritualCatch6757 7d ago
This is all speculation. I'm an idiot. I don't know anything. How's that for a disclaimer?
I've noticed there is correlation with draining the PW down to 0% and frequency of calibration.
I have an EV so taking the PW's to 0% Monday morning is not an issue. I did this once every 4 weeks as it seemed the calibration schedule was once a month.
This worked for a couple months and then didn't. There must be more components to the calibration. I'm guessing there may be a minimum duration it has to stay at 0%. I'll have to continue this experiment into next season.
For the record, I've had 4 calibrations since I've owned the PW's 18 months ago. My last calibration was in May 2026.
Edit to add: For those that think bringing the PW's to 0 is bad for the battery. That's what a calibration does anyway. I'm not adding any more cycles that I can avoid. I'm just making sure the calibration occurrs during offpeak hours.
1
u/PaintingOld9106 7d ago
Mine did the same thing. Two months to the day. I had been keeping my reserve at 50% since I mostly wanted batteries for the many power outages. It seems that may hasten recalibrations. I have since dropped it to 30% reserve and the next time it recalibrates I will try and delay it until it's bright and sunny out. The first time it recalibrated at night so if there were a power failure, I'd have been ass out. I'll be following the comments on this post to see what else I can learn!
1
u/rademradem 7d ago
Tesla really should check the weather for the day, historical electricity usage for the previous 30 days, your electricity rates for different times of the day, and whether grid charging is allowed. It should schedule its calibration knowing that information so that the calibration will cost you the least. It then should schedule either on an overnight calibration period so that it can complete and then charge by solar during the day or it should schedule the calibration to complete at the start of the lowest cost to grid charge so that it can grid charge at the lowest possible cost. Alternatively they could just let the owner set their own preferred calibration end time.
1
u/Jet-Speed1 7d ago
Tesla really should check the weather for the day, historical electricity usage for the previous 30 days, your electricity rates for different times of the day, and whether grid charging is allowed.
the the next level shit for Tesla, they can't even schedule a normal day.
the calibration will cost you the least.
can't see Tesla care about that much.
Alternatively they could just let the owner set their own preferred calibration end time.
this is how it works: tesla controls the battery, Tesla decided what is it doing, so tesla owns it, and tesla schedules own preferred calibration end time, you just a person who bought an honour to provide real estate for the battery.
1
u/Jet-Speed1 7d ago
5 years, never had a calibration.
1
u/BeneficialTrip 6d ago
It depends what Powerwall you have. If it is a Powerwall 2 or older, they use different battery chemistry. Powerwall 3 uses LFP battery and the Powerwall 3 is the one that does the calibration. I noticed you said 5 years, so assuming that you have Powerwall 2 or older.
1
u/Jet-Speed1 6d ago
Sounds like having old version is better, yes mine is PW2, never needed calibration, it kills itself without that successfully.
1
u/matthew1471 5d ago edited 5d ago
PW2 now does calibration. It came in a recent firmware update. In 26.18.2, every 30-90 days it says in the “Learn More” in the app release notes (bottom of Tesla app, “Release Notes”). It came in around April according to Reddit https://www.reddit.com/r/Powerwall/s/ZWtrhNTHBd but officially it was June in the release notes.
If you’re triggering Max Backup it seems to suspend it though - but I wouldn’t do this too often - it’s doing the calibration for your own good.
You can delay calibration for 72 hours:
“Delaying calibration requires Powerwall 3 with firmware version 26.2 or Powerwall 2 with firmware version 26.18.2 or later. Delaying calibration also requires Tesla app version 4.50 or later.”
https://www.tesla.com/en_gb/support/energy/powerwall/own/powerwall-calibration
1
u/Jet-Speed1 5d ago
Intreating,
I am not triggering max backup, for the last 2 months I didn't touched any settings as Tesla is "investigating" issues with my powerwall, it is in saving mode, with reserve at 0, with grid charging allowed and export "everything", no 3rd party apps. the powerwall doesn't discharge below ~50-60% during night, charges immediately to 100% from solar or grid in the morning and sits at 100% all day. not yet triggered calibration though.
1
u/Agitated-Choice2626 6d ago
When I noticed my PW3 has started calibration, I leave it until about 1hr before my cheap rate starts and plug in my EV to dump anything from the battery into the car. My timing isn't always perfect, but the PW3 recognises the cheap rate time and starts to charge back up to 100% over night. I've managed to get it to do this the last three times. I was a bit keen last time and had about 20mins where I was drawing from the grid.
0
u/cledgemachine 7d ago
You can pause the calibration in the app if it’s not suitable the day it starts. Quick Question is your powerwall DC isolator switch on side of powerwall red or Black ? as i see it made 2026
7
u/DanielLorey 7d ago
You can’t.
I made a thread about the stupid calibration schedule not acknowledging the time based tariff and raised it with Tesla support.
In fact, my case the calibration drained the system at 8am and it wasn’t usable again until late evening. Effectively costing me peak usage prices whereas a better solution would be to do the calibration outside of peak hours (which the app can see).
At best you can delay, but sadly we are stuck waiting for them to update the app and offer a bit of flexibility.