Solar Charging Behavior

[edstewbob]

When my PW charges from solar during the day some of the time the power is split between the PW and home when in fact I prefer to completely charge up the PW before sending power to home or grid. Is there any setting to force this behavior to always charge the PW from solar to it’s reserve energy level first? I’m thinking it may be better for battery longevity to more slowly charge the PW and that may be the reason for it operating in this manner? I’m just thinking of days with little solar generation where my preference is to make sure the PW is fully charged as much as possible.

 

[ptdusn]

You can do it manually by going into the Settings tab in the app and setting the standby back up percentage to 100%. But you would have to do this every day manually.

 

[edstewbob]

You can do it manually by going into the Settings tab in the app and setting the standby back up percentage to 100%. But you would have to do this every day manually.

Yes it is set to 100% when this occurs in Self-Powered mode.

 

[yblaser]

Yes it is set to 100% when this occurs in Self-Powered mode.

Yes in self powered mode it seems to limit the charging to 3.3 kW unless your solar production exceeds 3.3 kW + home load. I don't know of any way to avoid that unfortunately.

 

[jboy210]

I believe they limit the PW charging to 3.3 kW per Powerwall. So if you add another Powerwall double the amount goes to the Powerwalls.

 

[ptdusn]

I believe they limit the PW charging to 3.3 kW per Powerwall. So if you add another Powerwall double the amount goes to the Powerwalls.

I've seen my Powerwalls at 4.5kW

 

[edstewbob]

I believe they limit the PW charging to 3.3 kW per Powerwall. So if you add another Powerwall double the amount goes to the Powerwalls.

I have 2 Powerwalls and I do see a limit of 3.3 kW total.

 

[jboy210]

I have 2 Powerwalls and I do see a limit of 3.3 kW.

If you are seeing a limit of 3.3 kW for 2 Powerwalls that is surprising. I saw last summer my 2 Powerwalls charge at close to 6.7 kW. Does the change in percentage for the 2 Powerwalls match with them being charged at a total of 3.3 kW?

 

[edstewbob]

If you are seeing a limit of 3.3 kW for 2 Powerwalls that is surprising. I saw last summer my 2 Powerwalls charge at close to 6.7 kW. Does the change in percentage for the 2 Powerwalls match with them being charged at a total of 3.3 kW?

I was wrong. This is what I’m currently seeing.

 

[jboy210]

I was wrong. This is what I’m currently seeing.

That looks better!

 

[edstewbob]

I was wrong. This is what I’m currently seeing.

But it still limits to 3.3 kW if my home needs exceed the current solar capacity.

 

[jboy210]

But it still limits to 3.3 kW if my home needs exceed the current solar capacity.

I am seeing where your comment about battery longevity came from. My PWs charge rate also reduces when it is cycling near 100%. I think it has to get down to the low 90s before it sends all excess to the PWs.

 

[dailo]

Self powered will always balance between the house usage and charging the battery, with the goal of keeping grid usage at 0 at all times. If you switch to TOU, during off peak times all available solar will be used to charge the PW.

 

[SRO-Sean]

>>> If you switch to TOU, during off peak times all available solar will be used to charge the PW <<<

That may be what Tesla says, but the above is NOT TRUE (at least not for us). We are using TOU and we're seeing the Powerwall switch between charging the battery, powering the house and sending back to the grid seemingly randomly. "Most" goes to the powerwalls, however a decent amount goes to the house and/or grid instead.

The result is on recent (overcast) days, we're not getting to 100% before peak. Yesterday (hot and cloudy) we had to drop our reserve from 50% to 40% to make it though peak due to this unwanted powerwall behavior. Right now (less than 2 hours before peak) our batteries are at 80% and yet we are 3% self powered. We really want that 3% in the batteries, not in the house.

 

[cwied]

>>> If you switch to TOU, during off peak times all available solar will be used to charge the PW <<<

That may be what Tesla says, but the above is NOT TRUE (at least not for us). We are using TOU and we're seeing the Powerwall switch between charging the battery, powering the house and sending back to the grid seemingly randomly. "Most" goes to the powerwalls, however a decent amount goes to the house and/or grid instead.

This does not sound normal. In my experience running on TOU since it's been available, all available off-peak solar has always gone to the Powerwalls.

Are you on a rate plan that has a super-off-peak? If you do, this causes the Powerwalls to treat off-peak as partial peak which means they no longer try to fill up during that period. Instead they will fill up just enough to get through peak without drawing any power. This is often undesirable. If you're in this situation, removing the super-off-peak period would help.

 

[Steve2498]

This does not sound normal. In my experience running on TOU since it's been available, all available off-peak solar has always gone to the Powerwalls.

that’s not quite the behavior I’ve been seeing. in TOU, behavior seems to change sometimes for no obvious reason but generally I’m seeing the house pulling from the grid during off peak, during partial peak solar powers the house with excess going to the battery until full then during peak house is powered by the battery and all solar is exported to the grid.

 

[RKCRLR]

I use TOU with no partial peak. All solar is always used to recharge the powerwalls until they are at 100% during off-peak and my house always runs 100% off my powerwalls during peak. I would prefer my house to be prioritized for solar consumption during off-peak and peak but I haven't found a way to do this and keep TOU settings.

 

[dailo]

I use TOU with no partial peak. All solar is always used to recharge the powerwalls until they are at 100% during off-peak and my house always runs 100% off my powerwalls during peak. I would prefer my house to be prioritized for solar consumption during off-peak and peak but I haven't found a way to do this and keep TOU settings.

With TOU after I lowered the sell price by a few cents, it started to try to balance both. It isn't as great as if I do it manually but it's not too bad. No clue what the algorithm is, but seems like if the PW charge is higher like above 80% and still a few hours left before partial peak it will balance between charging and house load so my grid usage is close to 0. During the months I don't need AC, I can get away with try toggling to self powered during off peak and TOU during peak to get max value.