New SE setup being installed, Really need help with TOU and SE Batteries concerns.

[Bbad29]

Hi All, I am having a 12kw array with 30 400W Q Cell Panels installed in October with SE 10kw inverter, 2 SE Battery Banks. Also, two SE EV chargers, one stand-alone SE and one coming off the SE inverter. I am currently on the PG & E, EV2-A TOU rate where the peak is from 3pm-12. I want to run entirely off the batteries from 3 pm-12pm.

I have two choices:

Use the SE batteries from 3pm-12, then pull from the grid (after midnight when the rates are the lowest) to charge the 2 EV's and I should have plenty net metering credits from my selling back the excess during the day

Or

Run the batteries every night from 3 pm until they hit 20% (including charging the 2 EV's), then pull from the grid until sun up and repeat. We rarely get power outages where I am at in California, and I just want to use the batteries to beat the TOU rate from the scourge PG&E and be grid-tied but self-sufficient. I'm pretty pissed my peak rate is 0.57kWh That's Tesla Supercharger rates!!

What would you suggest? Also, can I have my installer setup these kinds of profiles for me to use on the SE APP? Or should I ask for administrator access? My yearly consumption (including 2 EV's) is approx 19,200kWh per year. My PVWatts calculation projection with my setup is 18,244kWh per year.

[Mike 134]

You want administrator access after all you own it. I don't have batteries can't help there

[RichardCullip]

It's a bit hard to give a firm analysis of your options without knowing how much energy you use and when you use it. I'd be concerned about charging those batteries, assuming you can't charge from the grid and you have to charge from solar. Your installation plans have a net deficit (use 19,200kWh while producing 18,244kWh). Where's the excess kWh coming from to keep charging the batteries? Back of the envelope says you should use solar to charge the batteries, run off the batteries as long as you can during Peak rate time and charge your EVs overnight.

[OCJ]

So it might be spreadsheet time for you. I'm on SDG&E, so I'm staring at $.69 per kWh, which is insane. So I have a Powerwall, PTO since June. Initially I was trying out self-powered and then TOU, but now I'm on TOU. I initially had a 40% reserve and that would get me through On-Peak, but now with the heat I've got it down to 5%. Once the heat goes down I plan on putting it back to 40%. The main reason is for battery health. It will be much less of an issue with cooler weather, of course.

So your tradeoff really is more offset vs. long term battery health.

Now I have 3 TOU periods, Super Off-Peak from 12am to 6am, Off-Peak from 6am to 4pm, On-Peak from 4pm to 9pm, and Off-Peak from 9pm to 12am. This changes a bit in March and April.

Since you have only 2 TOU periods, you may think about switching plans. The reason is you want to take advantage of the differential between earning and using. With your setup you will earn a bit On-Peak while there is sun left, but the rest of it you earn Off-Peak and use Off-Peak, which is 1:1, not terrible, but not great. In my case most of my earning is Off-Peak ($.458) and some On-Peak ($.69), and then I was charging at Super Off-Peak ($.336). For a while there I was getting 10 kWh of On-Peak, which paid for around 20 kWh of Super Off-Peak charging.

Now I just switched to EV-TOU-5 which has a $16 monthly charge which replaces the $10.65 minimum charge, but for that I get On-Peak credit of $.639, Off-Peak credit of $.391, and get to spend it charging at $.102!

So you might want to think about switching to EV-B which reduces your charge window to 12am to 7am, uses its own meter, and then your main meter you can change to a regular TOU for *possibly* higher generation credits. I say *possibly* because you'll have to spreadsheet it to be sure.

[Ampster]

So it might be spreadsheet time for you. ............

So you might want to think about switching to EV-B which reduces your charge window to 12am to 7am, uses its own meter, and then your main meter you can change to a regular TOU for *possibly* higher generation credits. I say *possibly* because you'll have to spreadsheet it to be sure.

It is definitely a good use of spreadsheet skills.

I looked into the separate meter tariff and the big downside was that I could not aggregate that meter with my solar production. I am in PGE territory and am envious of your $0.102 rate but not the $0.69 rate. Mine are $0.55 and $0.22.
With NBCs and the high off peak rate, I am doing most of my EV charging from solar during the day. It gets tricky when the clouds reduce production and I am considering a Charging Station that will communicate with my Emporia Energy monitor and set the charging rate such that only excess solar is used to charge the EVs.

[OCJ]

It is definitely a good use of spreadsheet skills.

I looked into the separate meter tariff and the big downside was that I could not aggregate that meter with my solar production. I am in PGE territory and am envious of your $0.102 rate but not the $0.69 rate. Mine are $0.55 and $0.22.
With NBCs and the high off peak rate, I am doing most of my EV charging from solar during the day. It gets tricky when the clouds reduce production and I am considering a Charging Station that will communicate with my Emporia Energy monitor and set the charging rate such that only excess solar is used to charge the EVs.

Indeed, that is a big disadvantage. My true-up is in June, so my plan is to build up $1,500 in credits, then switch to charging mid-day under solar. I hear a lot of horror stories about people's inverters going out and not getting them repaired for months, so I want to have a buffer first. But then I want to minimize NBCs by going under solar. I do also plan to get electric space heaters in the winter so that midnight to 6am heating will be cheaper than my usual winter gas bill.

Lots of ways to slice and dice it but the nice thing about annual net metering is you can change your charging behaviors throughout the year.

[bcroe]

I do also plan to get electric space heaters in the winter so that midnight to 6am heating will be cheaper than my usual winter gas bill.

A cold rated heat pump will do the heating with only a fraction of
the KWH energy used by a simple electric space heater. That is
how it works here year around, no electric or gas energy bills, lots
of solar. Bruce Roe

[Ampster]

......... I do also plan to get electric space heaters in the winter so that midnight to 6am heating will be cheaper than my usual winter gas bill.

Lots of ways to slice and dice it but the nice thing about annual net metering is you can change your charging behaviors throughout the year.

As Bruce mentioned earlier a heat pump will be a lot more efficient than space heater. In South California you would not even need a cold rated heat pump minisplit. I am in Northern California and got through the winter with a mini split in the master bedroom and dining/kitchen area. My True Up is in early October so I enter winter without much cushion so I do not want to borrow too many kWhs in winter and have no time to repay them by the end of summer. The days are already getting shorter but the heat is sure not abating.

[toofargone]

I can offer my very novice experience with my SE inverter and energy bank set up (mine's much smaller, one battery, and only one PHEV on a household circuit).

It has been extremely frustrating trying to get my system to do something similar to what I think you're looking for--minimize grid import especially during ToU periods. The documentation and advertising materials indicate this should be possible. It seems like this should be simple, but alas it has not been.

• I don't have CTs due to fitment issues in the service panel. SE says this shouldn't be an issue. The documentation is not very clear on this.
• So, make sure you get CTs installed (correctly) if required for consumption metering or make sure your installer is confident they are not required.
• As Mike 134 said, get administrator access to the battery profile settings. You're going to want to fiddle with the settings.
• Like Ampster, I have an additional consumption meter--it is handy for additional/comparison data. I got the inexpensive and simple Emporia Vue that talks to the PGE meter.
• SolarEdge support is terrible, at least right now. They won't give me the time of day--they say they can only troubleshoot with the installer. My installer is reluctant to call due to 2-hour hold times.
• In my case, the battery is set to maximize self-consumption at 4-9 pm. What happens is that it dumps down to the reserve as fast as the inverter maximum allows and ends up mostly exporting to the grid in 1-2 hours. Then I am back on the grid for the rest of the night, including during ToU hours.
• In the morning when as the sun comes up 100% of the production goes to the battery and I am using grid power until it reaches 100%. After some fiddling, I got the installer to (somehow) start the recharge at 11 am when house loads are low and sun is stronger (to reduce import). On a sunny day, t takes my 5kW system about 1.5 - 2 hours to charge up from 50%. I have to import from the grid during this time for house loads.
• If I charge the PHEV (Level 1, 16 amps) from 12-4, I stay off the grid on a reasonably sunny day but that is only a partial charge.

Hope any of this is helpful for you or readers in the future. Fingers crossed your experience is smooth. I'd love to hear how the SE EV charger works for you.

Edit to add--SE says they are going to give system owners battery profile management in the next 12 months. Also, the battery warranty is valid for unlimited cycles.

[jflorey2]

Use the SE batteries from 3pm-12, then pull from the grid (after midnight when the rates are the lowest) to charge the 2 EV's and I should have plenty net metering credits from my selling back the excess during the day

As someone else said get out the spreadsheet.

I would start by assuming you want to cover 90-100% of your use during peak pricing, done via solar/battery power (and load shedding if possible.)
Recharge with solar as much as possibe rather than the grid.
I would not cycle the batteries beyond that peak pricing period to reduce degradation.
Charge EV's during minimum price time (of course.)

[jflorey2]

[*]I don't have CTs due to fitment issues in the service panel. SE says this shouldn't be an issue. The documentation is not very clear on this.

Those CT's help you zero out if you have other loads between the grid and your inverter. If everything is behind the inverter you don't need it. I had size problems too with my CT's and I ended up having to put them by the street power access point, and then run a long wire back to the monitor.

[toofargone]

Those CT's help you zero out if you have other loads between the grid and your inverter. If everything is behind the inverter you don't need it. I had size problems too with my CT's and I ended up having to put them by the street power access point, and then run a long wire back to the monitor.

Ah, thanks for the intel! The installer didn't try to find alternative solutions. I insisted they try the slim ones but they didn't work either. Since they were here, we slapped them on the sub panel they installed for partial home back up. It didn't help for the battery profiles. If I get them back out for any reason, I'll ask about a different access point before the meter. I can see the wires where they enter the panel.

[albert436]

Great thread, mostly over my head at the moment.

[albert436]

Ah, thanks for the intel! The installer didn't try to find alternative solutions. I insisted they try the slim ones but they didn't work either. Since they were here, we slapped them on the sub panel they installed for partial home back up. It didn't help for the battery profiles. If I get them back out for any reason, I'll ask about a different access point before the meter. I can see the wires where they enter the panel.

Hey toofar, did you ever get the issue resolved ?

[albert436]

Hi All, I am having a 12kw array with 30 400W Q Cell Panels installed in October with SE 10kw inverter, 2 SE Battery Banks. Also, two SE EV chargers, one stand-alone SE and one coming off the SE inverter. I am currently on the PG & E, EV2-A TOU rate where the peak is from 3pm-12. I want to run entirely off the batteries from 3 pm-12pm.

I have two choices:

Use the SE batteries from 3pm-12, then pull from the grid (after midnight when the rates are the lowest) to charge the 2 EV's and I should have plenty net metering credits from my selling back the excess during the day

Or

Run the batteries every night from 3 pm until they hit 20% (including charging the 2 EV's), then pull from the grid until sun up and repeat. We rarely get power outages where I am at in California, and I just want to use the batteries to beat the TOU rate from the scourge PG&E and be grid-tied but self-sufficient. I'm pretty pissed my peak rate is 0.57kWh That's Tesla Supercharger rates!!

What would you suggest? Also, can I have my installer setup these kinds of profiles for me to use on the SE APP? Or should I ask for administrator access? My yearly consumption (including 2 EV's) is approx 19,200kWh per year. My PVWatts calculation projection with my setup is 18,244kWh per year.

Also would like to know if you ever got this solved.

Thanks.