I recently received PTO for my solar panel system. I am using “Backup” mode. On the first day of activity my 3 PW’s charged to 98%. They are slowly losing charge each day and are now down to 96%. Once they got to 98% all solar energy was directed to the home or the grid. Is this normal behavior? I expected them to charge to 100% and stay there until needed. Will they discharge to a certain level and then charge back up to 98%? Thanks.
PowerWalls not charging to 100%
- Thread starter ahsinfla
- Start date
that is normal behavior. my PW's stop charging at 99% and expend about 1.5% per day in backup mode (aka vampire drain). mine start charging again at 96%.
OP, if you want to see them charge to 100% (just to see it, for example) change to self powered and set the reserve to something like 90%. If the powerwalls are in self powered mode, they will definitely charge to 100%. In backup only mode, they dont, as mentioned by @nyprepper .
charlesj
Active Member
Mine charged to 100% today in self powered mode with 56% set as reserve in that mode.
And, it seems they system responds rather quickly now switching between self powered and backup mode.
And, it seems they system responds rather quickly now switching between self powered and backup mode.
aesculus
Still Trying to Figure This All Out
FWIW I run mine mostly in Advanced - Cost Savings. Rarely did I ever see it charge past 99%. Today it has charged to 100%. On FW 20.40.3
charlesj
Active Member
Even though 100% is not truly 100%, the higher the SOC that you leave it just sitting there, the faster your PWs will degrade.
Is there any evidence to back up this claim as it applies to PW batteries? Or, more specifically, to document how much excess degradation you would see? I have not seen anything that suggests any significant difference, and, with full net metering and no TOU rates, I would see no reason to try and maintain a lower charge when the main result would be less backup power in the event of an outage. And, since Tesla doesn't let you fix the percentage (as in, I always want to be at exactly 80%,) modes that allow you to go to a lower number result in more charging and discharging, which also means more wasted energy.
