Powerwall 3 set to 45% backup reserve, at 43% now

[LiBeRtAs]

System is new, over the past 12 hours it’s been cloudy and nighttime and instead of staying at 45% the actual charge is now down to 43%, not sure how low it will go, anyone else have one of these and doing the same thing?

I am referring to the actual charge on the “My Home” screen.

 

[LiBeRtAs]

System is new, over the past 12 hours it’s been cloudy and nighttime and instead of staying at 45% the actual charge is now down to 43%, not sure how low it will go, anyone else have one of these and doing the same thing?

I am referring to the actual charge on the “My Home” screen.

Two hours later and now it’s 42%.

 

[dhrivnak]

All numbers vary. On a drive the range and watt/mile will change. When you charge bot the numbers will change. The changes you are reporting are well withing expected variability.

 

[LiBeRtAs]

All numbers vary. On a drive the range and watt/mile will change. When you charge bot the numbers will change. The changes you are reporting are well withing expected variability.

I might be in the wrong forum, sorry, I’m talking about Powerwall solar not a car.

 

[aesculus]

Two hours later and now it’s 42%.

Is the PW discharging or is the SoC just decreasing? If the temperature was colder than it was at the 45% reading it will continue to drop a little bit until the ambient temperatures raise again to the former value.

If it is still discharging below your reserve then you have another issue.

 

[Tazzman]

You said it is a new system, do you have PTO? What mode do you have the system set to?

 

[dhrivnak]

I might be in the wrong forum, sorry, I’m talking about Powerwall solar not a car.

The SAME normal variation applies. Do you weigh the same every morning?

 

[LiBeRtAs]

You said it is a new system, do you have PTO? What mode do you have the system set to?

No, don’t have PTO yet. Self powered.

 

[LiBeRtAs]

Is the PW discharging or is the SoC just decreasing? If the temperature was colder than it was at the 45% reading it will continue to drop a little bit until the ambient temperatures raise again to the former value.

If it is still discharging below your reserve then you have another issue.

SoC decreasing? Not sure what that means. The powerwall was set not to go below 45% on the setting but it dropped to 42% while sitting idle and not being discharged/used at all. It was draining the way a cell phone battery drains when not in use, I assume.

It probably was colder when the battery lost percentage points while not in use by a few degrees.

To be clear I was looking at the app a lot during the time that it lost the percentage points and it was not discharging it was not being used by my house it was just disappearing.

 

[Matt-FL]

From my experience, this is normal. My reserve is set at 20%, and on those times I reach that threshold (sometime in the middle of the night usually), by morning the PWs are down to 18 or 17%.

 

[Vines]

Two hours later and now it’s 42%.

The reserve is the number it will use as a stopping point so that below this number the PW will not intentionally discharge to offset your loads. However it will still consume normal power to keep itself healthy and warm. If you are in a storm and there isnt PV to recharge things it seems reasonable that the powerwalls will drop below the reserve slowly until the sun returns.

If they were to get very low at like 5%, I think they would automatically charge a bit from the grid to keep themselves alive.

 

[IronCoffee_Max]

As others have said, batteries are not so accurate that a few % off is meaningful. It's all relative to what the battery management system thinks each 1% is worth. It's normal for it to be 2-3% off. That and the fact it will use some for it's own operation as someone else said.

 

[Grayson73]

If you don't have it set to charge from the grid, it will only charge from solar, which is why the % dips overnight as it uses battery to maintain battery health.

 

[LiBeRtAs]

If you don't have it set to charge from the grid, it will only charge from solar, which is why the % dips overnight as it uses battery to maintain battery health.

OK, right now I dont have PTO so I dont think it charges from the grid. I wonder how much one would lose over a longer period of time if it was idle, or what is the most anyone has seen. These 3's are so new it wont be known yet I guess. THanks.