What is your reserve percentage set to and why?

[BrettS]

The Tesla app hides 5% of the charge - 0% reading in the app is actually 5% of charge in the PowerWalls. The TEG's web interface shows the actual charge level - 5% in the TEG is 5% actual charge.

Since the Power Reserve % is set in the app, that means you can't set it below 5% of the actual charge level, evidently providing the reserve power needed to keep the PowerWalls and TEG operating.

It’s actually weirder than that. It’s not a straight 5%. At the lower end it’s 5%, so when the app shows 5% the web interface shows 10% (it’s also worth nothing that the powerwalls will turn off at this point. They won’t run themselves all the way down to 0% in the app or the web interface).

Then as you approach a full charge the two numbers converge. At 33% in the app the web interface will say 36%. At 66% in the app the web interface will say 68% and they will both read 99% at the same time.

I’ve also seen it speculated that even the number shown in the web interface is not the actual SOC of the battery and there is some additional reserve built in, but I’m not sure anyone but tesla really knows for sure.

 

[bob_p]

We have 4 PowerWalls - theoretically able to hold 54KW of charge.

The Tesla app appears to hold 5% of the charge in reserve - so 0% in the app means the PWs have 2.7KW of energy - and the Tesla app is measuring only 51.3KW between 0% - 100%. 100% means the PW has 51.3KW plus 2.7KW or the total of 54KW.

As the charge gets close to 100%, the app and website will be the same.

When the Tesla app reads 50% - the charge level will be 51.3/2 + 2.7 = 28.35 KW. The website will read 52.5%.

It is confusing the app and website are providing different readings, which could be explained by just providing a note on the app display indicating the app is holding 5% in reserve...

 

[aesculus]

I have about 5kW of solar. Normally I run my reserve in the summer at 50% and usually don't get near it by Friday end of peak.

But this week with all the smoke I had to set it to 40% yesterday and it got down to 42% EoP last night. Might have to go lower again tonight but the real fear is that fire danger, and potential power shutoffs, are higher today.

 

[jakespeed]

i'm set to 5% b/c i have a generator

 

[Kevrick]

35%

 

[JoelDug]

I was set at 35%. But after reading this whole thread I think I will boost it. I only have a 5.3 kW solar system, so the only way to fully charge my 2 PWs is to set the reserve to 100.

 

[arghx7]

Resurrecting an old thread. I'm new to solar + powerwall, not new to Tesla stuff.

I've got installers here today installing 5kw of solar (probably will produce less due to some tree coverage, have Panasonic panels with micro inverters), and 1 powerwall. Power consumption is on the low side because most my major appliances (dryer, water heater, stove/oven) including heat are natural gas.

Does anyone have any feedback regarding reserve rate and battery degradation? I've had my model 3 LR AWD for almost 3 years now and I've had to keep it to 70% lately because it seems to degrade faster than others, only 20k miles and it's down to 280 out of 310 rated miles. Is there any way to know the battery degradation on the powerwall?

I bought the Powerwall more for continuity of power during grid outages, I'm not concerned as much about saving every last cent on my electric bill.

 

[Redhill_qik]

Resurrecting an old thread. I'm new to solar + powerwall, not new to Tesla stuff.

I've got installers here today installing 5kw of solar (probably will produce less due to some tree coverage, have Panasonic panels with micro inverters), and 1 powerwall. Power consumption is on the low side because most my major appliances (dryer, water heater, stove/oven) including heat are natural gas.

Does anyone have any feedback regarding reserve rate and battery degradation? I've had my model 3 LR AWD for almost 3 years now and I've had to keep it to 70% lately because it seems to degrade faster than others, only 20k miles and it's down to 280 out of 310 rated miles. Is there any way to know the battery degradation on the powerwall?

I bought the Powerwall more for continuity of power during grid outages, I'm not concerned as much about saving every last cent on my electric bill.

The Powerwall is guaranteed to maintain 70% of capacity after 10 years when recharged through solar and discharged to house loads. There are no limitations on leaving it in standby at 100%. You can see the nominal capacity of the Powerwall through an API page after logging into the gateway.

Tesla lets you set the minimum level that it will be discharged to when it is powering your house loads with the grid up (it will go down to 5% if the grid is down), but there is no setting for the maximum level and it will go to 100% during the recharge cycle.

 

[arghx7]

So you can't directly cap the max SOC like you can on a Tesla vehicle? It's all handled internally? Maybe somebody mentioned it somewhere, but is there an upper level buffer? (100% indicated isn't really 100% of what the battery can actually do) ?

It's a little strange to me how there is so much emphasis on protecting battery life on a Model 3/Y by not charging it so much (Daily charging vs road trip charging). Maybe the fact that there is no DC fast charging helps extend the life?

The powerwall is in my basement and of course it has cooling so I'm not too worried about environmental concerns.

 

[nicholb]

Maybe somebody mentioned it somewhere, but is there an upper level buffer? (100% indicated isn't really 100% of what the battery can actually do) ?

According to the specs the total capacity is 14kwh and usable is 13.5kwh, so 100% is not 100% of the battery capacity.

https://tesla-cdn.thron.com/static/RALHZL_Powerwall_2_AC_Datasheet_EN_NA_7LOWBF.pdf?xseo=&response-content-disposition=inline%3Bfilename%3D%22powerwall-2-ac-datasheet-en-na.pdf%22

 

[arghx7]

oh yeah I remember reading that now. So 100% indicated charge should be 96.5% of the nominal max.

I'm pretty sure it's similar for the car batteries, but other EV makers have a big margin (GM for example). It's just weird how relaxed everyone seems about the issue of battery degradation on the power walls. Anecdotally It sounds like there are a lot of people deeply cycling their batteries every day. I don't put that many miles on my Model 3 and don't' fast charge much and I've lost 10% already (yes I know about recalibrating the range estimation).

 

[Redhill_qik]

So you can't directly cap the max SOC like you can on a Tesla vehicle? It's all handled internally? Maybe somebody mentioned it somewhere, but is there an upper level buffer? (100% indicated isn't really 100% of what the battery can actually do) ?

It's a little strange to me how there is so much emphasis on protecting battery life on a Model 3/Y by not charging it so much (Daily charging vs road trip charging). Maybe the fact that there is no DC fast charging helps extend the life?

The powerwall is in my basement and of course it has cooling so I'm not too worried about environmental concerns.

Right, there is no max state-of-charge setting for the Powerwall. It does go all the way to 100% as far as I know as the API will report the nominal_energy_remaining and nominal_full_pack_energy in watt-hours and it will charge until the remaining equals the full value. The app will display a charge percentage number that is not the actual charge percentage and has a sliding gap with it being with 1% as it gets close to 100% and widening to 5-10% as it gets to zero where it displays 0% charge when it gets below 10% (I think) which it needs to be able to restart when the sun comes up.

The charge/discharge behavior for a Powerwall is vastly different than for an automotive pack.

 

[Will792]

Resurrecting an old thread. I'm new to solar + powerwall, not new to Tesla stuff.

I've got installers here today installing 5kw of solar (probably will produce less due to some tree coverage, have Panasonic panels with micro inverters), and 1 powerwall. Power consumption is on the low side because most my major appliances (dryer, water heater, stove/oven) including heat are natural gas.

Does anyone have any feedback regarding reserve rate and battery degradation? I've had my model 3 LR AWD for almost 3 years now and I've had to keep it to 70% lately because it seems to degrade faster than others, only 20k miles and it's down to 280 out of 310 rated miles. Is there any way to know the battery degradation on the powerwall?

I bought the Powerwall more for continuity of power during grid outages, I'm not concerned as much about saving every last cent on my electric bill.

My 2018 Model 3 also had range go down to 279, even though I always used 90% charge limit and used home charger with 40A limit. Mileage was only 11K. Tesla service dismissed this reduction of range. They said that it is acceptable and battery diagnostic did not show any failures.

I keep changing my PWs reserve power between 70 and 50-60, trying to maximize amount of time when charge level is around 70-80%. During a day limit is 70% and in the morning around 50-60. My 22KW PV system produces 20-120 KWh per day so most days 3 PWs are fully charged before lunch hour.

 

[xWren]

I vary it every day (setting it using scripts the run at the start and end of my off-peak supply period) as the only reliable way to control the Powerwall to charge sufficiently from cheap electricity from the grid (in UK so permitted, and load shifting is main use for 6 months of the year). The algorithm of the time based mode is unable to predict my variable solar generation and variable domestic use, whereas I'm pretty good manually. Over the summer, when solar generation well exceeds my use and I'm exporting it will be ~35%

 

[Morts]

I'm using 0% for mine also (and just regular Self-Powered mode). On a typical day it'll discharge to ~45-50% from sundown to sunup, but if I do dishes/laundry or run a portable AC it'll get lower. But I figure why ever draw from the grid unless I have to, and so far the only time I've had to was when I had the reserve set to 20% and the AC pulled it down to there by early morning. I caught it within <1kWh from the grid and immediately changed the reserve to 0% and kicked the Gateway by logging-in to it, so it wasn't a big hit at least.

I also disabled Storm Watch, again to prevent any grid charging to avoid NBCs, etc. My PW is typically fully recharged by 10am-noon, so there's a very limited outage window where I'd be below 20-50% anyway. But I realize my setup is out of the ordinary since my production is high vs. my (current) consumption. Since ideally the PW would never be fully-drained, seems like the Advanced modes are also useless to me, they would only increase the chance that the house would sometimes draw from the grid when it should never need to.

Just had my Powerwall installed recently and installers set it at 20% I dropped it to 15% as I was still drawing from the grid, I have now dropped it to 5% as I can put up with the headache of a blackout more than paying for power from the grid.

 

[GRV0928]

I have 3 pw and 18kw solar sys. I set mine to 10%. Price per kw here is $0.36. Our home average usage is about 55-65 kw a day. Pretty much on a cloudy day im a 100% self power and on sunny day i send about 15-30kw after the battery is full…

 

[Lloyd]

My reserve is set to ZERO as I am operating off grid! Note the 4 power sources available

 

[Zinc_Saucier]

My reserve is set to ZERO as I am operating off grid! Note the 4 power sources availableView attachment 798409View attachment 798409

Does that look like a “check engine” light to anyone else?

 

[MJ_CA_2019]

My reserve is set to ZERO as I am operating off grid! Note the 4 power sources available

Off Grid as in you have no electrical service or put the Powerwall in "off grid" mode?
Or Off Grid as in you have negligible draw from the electrical service?

 

[aesculus]

Note the 4 power sources available

What is that 4th one? Looks like a generator. Did not know that app would monitor that too.

BTW technically these graphs don't show the whole story because you could use the grid or generator to store energy in the Powerwalls first, before extracting them for the home load.