New Powerwall install...appreciate some feedback if all ok

[evanston45]

Hi Everyone,
We recently had 2 PowerWalls and Enphase solar installed at our house. The two power walls only backup one panel. I set the setting to Self Powered with reserve of 10%. I'm a little surprised we couldn't make it through one night without needing to rely on the grid. We didn't have any large usage, just heat pump and home lights (no Dryer, car charger etc). Does the images seem normal to you? Its possible I was duped by the sales agent who claimed the PowerWall's would be enough for 24 hours of backup, but looks like we barely got 11 hours. Are the spikes in usage normal? I appreciate any thoughts or feedback. Thanks!

 

[EVRider-FL]

If 10% reserve isn’t getting you through the night, increase it. I have 3 Powerwalls and keep the reserve at 20%, and that’s enough to get us through the night.

 

[evanston45]

So I should lower to 0% reserve you're saying?

 

[RKCRLR]

Similar to AC, heat pumps can draw a lot of energy. Just like running your AC for 24 hours, it would be hard for two Powerwalls to run a heat pump for 24 hours depending on the temperature.

 

[power.saver]

Two PWs have about 27kWh of energy. You discharged 17.1kWh before midnight and 7.2kWh after midnight, for a total of 24.3kWh. This is 90% of the total energy available (24.3/27.0 = 0.90) and that is correct for a 10% reserve setting.

 

[evanston45]

Thank you for the replies. It must be the heat pumps…it’s pretty cold where I am!

 

[ucmndd]

We didn't have any large usage, just heat pump

Heat pump definitely qualifies as “large usage”. Each one of those 5kw spikes on your graph is the heater running.

 

[jjrandorin]

Its possible I was duped by the sales agent who claimed the PowerWall's would be enough for 24 hours of backup, but looks like we barely got 11 hours

You will probably have more than 24 hours of backup time from March - June.

No one can ever promise any specific amount of hours of backup time, unless you size your system for the max load your home can draw for a 24 hour period (and no one does that). HVAC systems use a lot of power, as you can see from your graphs.

 

[EVRider-FL]

So I should lower to 0% reserve you're saying?

No, I said you should try increasing it to 20%. If 10% isn't getting you through the night, you need to increase the reserve.

 

[power.saver]

No, I said you should try increasing it to 20%. If 10% isn't getting you through the night, you need to increase the reserve.

Increasing the reserve will reduce the amount of energy available. The reserve is how much won't be used except during a grid outage.

 

[EVRider-FL]

Increasing the reserve will reduce the amount of energy available. The reserve is how much won't be used except during a grid outage.

Of course you're right, I don't know what I was thinking. The OP needs to lower the reserve, but of course that means less backup for an actual outage. I had two Powerwalls initially, and once I realized they wouldn't get us through the night without using the grid, we added another Powerwall. Now I don't use any grid power in most cases, and I keep my reserve at 20%.

 

[ptdusn]

Last year when we got PTO in November, our 2 Powerwalls weren't charging to 100% due to the fact that when we started out, they were at 20%. Now that we have started out at 30% coming into non-A/C weather, they are getting to 100% by noon-1 o'clock.

 

[CrazyRabbit]

Obvious statement alert. You need more battery if you want to run your heat pump like that.
If you were running off grid, you should superheat your house during the day and then turn back the thermostat (off) while on battery. You would have to change your usage habits.
I’m griping 8 batteries installed dec 12, and yes that is one more the h2ofun. I still bought two propane heaters in case of another freeze like URI, and a 12kw dual fuel generator with four 100lb propane bottles.
My heat is resistive, but got a hybrid hot water heater. Here in Texas I normally don’t need much heat, and I can tolerate it getting cold inside. I use to keep the heat set at 58-62, now that I have solar I set it a 67-68 in the LivingRoom and 62 in the bedrooms and up stairs.

 

[h2ofun]

Obvious statement alert. You need more battery if you want to run your heat pump like that.
If you were running off grid, you should superheat your house during the day and then turn back the thermostat (off) while on battery. You would have to change your usage habits.
I’m griping 8 batteries installed dec 12, and yes that is one more the h2ofun. I still bought two propane heaters in case of another freeze like URI, and a 12kw dual fuel generator with four 100lb propane bottles.
My heat is resistive, but got a hybrid hot water heater. Here in Texas I normally don’t need much heat, and I can tolerate it getting cold inside. I use to keep the heat set at 58-62, now that I have solar I set it a 67-68 in the LivingRoom and 62 in the bedrooms and up stairs.

You are one up on me. I cannot fit anymore, or afford anymore and stay married, so done.
Yep, folks have NO idea how much electric heating draws!! I use about 100kwh a day now, and solar only producing like 35kwh.
Good point on heaters, I have no backup if mine break, but I have 4 compressors, so maybe okay. I have a 22kw generator connected to my 500 gallon propane tank. I have propane water heater. When it gets cold outside, like now, systems really work overtime to try and get back up to my 72 degree upstairs setting.

 

[aesculus]

Yep, folks have NO idea how much electric heating draws!! I use about 100kwh a day now, and solar only producing like 35kwh.

About the same elevation as you and my 4k sf house is using about 50 kWh/day for heating, water and lighting. My solar is only putting out 20 kWh now. Mostly keep the house around 67F with some setbacks in sleeping rooms at night and I have new variable speed heat pumps and LED lighting so nothing I can do on the efficiency side. With the upcoming storms I will probably generate 5 kWh or solar at best and the heating will be even more dramatic. So yeah, super dependent on PG&E at this point.

 

[CrazyRabbit]

Mr Heater Big Buddy, and refillable 1lb propane tanks for emergency heat.
I produce 45kwh on average for November, good days are 80kwh and worst day 4.4kwh.
But if I was forced off grid, I would change my usage to the day while solar is producing.

 

[h2ofun]

About the same elevation as you and my 4k sf house is using about 50 kWh/day for heating, water and lighting. My solar is only putting out 20 kWh now. Mostly keep the house around 67F with some setbacks in sleeping rooms at night and I have new variable speed heat pumps and LED lighting so nothing I can do on the efficiency side. With the upcoming storms I will probably generate 5 kWh or solar at best and the heating will be even more dramatic. So yeah, super dependent on PG&E at this point.

I have a multistory house with high ceilings and I keep it warmer. Plus lots of large windows.. Either way, when folks have gas heat, ....

 

[zƬesla]

@evanston45 - I'm north of you and have mini-split heatpumps (2 outdoor units + 5 indoor heads). When it's 30s or below they often draw 3.5-4.5kW. I have 3 Powerwalls and in winter have them set ~50% if there is at least alternating sunny days, or 70%+ if there will be a couple of days or more of bad weather. We have oil-based forced hot water (baseboard) heating as our fallback, and I have a script that will shut off the mini-splits if there is an outage longer than 10 minutes as otherwise the PWs will drain quickly.

 

[sunwarriors]

Interesting discussions here on the heating side with limited/low solar. I'm fortunate that we haven't even turned on our heat on once yet. Usually, February or late January is the coldest here. I still wonder if we can even install large propane tanks in our backyard, but it hasn't gotten to that yet (and don't want to put $$ there now). The water heater is probably the first thing we'd replace though with a hybrid.

Solar has been mixed so I've been managing my reserve to fill up the batteries for peak energy rates.

 

[ucmndd]

The number of kilowatt hours in a single 18" piece of almond is pretty impressive. I got a little excited last night and got the living room up to 82 degrees.