How to set PW's in winter?

[h2ofun]

My inverter is undersized because I added more panels after initial install. Only clips in summer and not all that much. Yesterday I produced ~20 kWh which is about normal for my system on sunny winter days. I had reserve at 75% and panels charged by noon.. Tiday charged by noon as well. If it is going to be sunny, I typically move reserve down to 65% but we were heading into weekend where peak period is shorter

Yep, today, mine is undersized also because the installer did not fully do their job. Oh well, like you, only clips a little in summer. I guess this is why there is the 133% guideline, which mine just meets.

I produced 23kwh yesterday. But so far we have been so lucky with little rain or clouds. When it rained on the 13th I only produced 6 kwh. So the percentage stuff makes sense. But because of how many heat pumps I have to run, would have to watch and adjust reserve as you and many seem to do.

 

[bmah]

Yep, today, mine is undersized also because the installer did not fully do their job. Oh well, like you, only clips a little in summer. I guess this is why there is the 133% guideline, which mine just meets.

I produced 23kwh yesterday. But so far we have been so lucky with little rain or clouds. When it rained on the 13th I only produced 6 kwh. So the percentage stuff makes sense. But because of how many heat pumps I have to run, would have to watch and adjust reserve as you and many seem to do.

The fiddling around with the reserve percentage is something of an optimization. I don't want anybody getting the idea that Powerwalls are these fragile, high-maintenance things that need to be constantly baby-sat and tuned, even though I think some of us here secretly (or not so secretly) enjoy doing this. Put another way, it's perfectly valid to put the Powerwalls in backup-only mode and forget about them, and it might make sense for people in certain situations to do that. Or put them in cost-savings mode with a low reserve and leave them, if taking advantage of TOU pricing is the goal (and one is willing to accept a potentially-shorter runtime on batteries).

Bruce.

PS. I forgot to mention in my earlier post that we use natural gas for our cooktop, hot water heater, and home heating.

 

[Raechris]

I like the advice that it depends as everyone has a different situation. In MA it's 26 cents a kWh 24/7 with full net metering that equals about 21 cents credit. So I don't want to give up the 10% loss from PV to PW to house and keep mine at backup only. Our latitude and azimuth equals 75 kWh and 15 kWh range on 12.9 system. So poor generation in winter plus snow covered panels and going on day five with no solar production equals backup only for me.

 

[aesculus]

I am in cost savings mode and PG&E EVA1 so it can get a bit more complicated. Basically the PWs will want to charge during partial peak until 2PM when peak starts and then ride through until 9PM weekdays using the batteries. My total solar output during the best sunny days in Winter is about 13 kWh, so approximately half my 2 PWs capacity.

I am not too fearful of power outages even though I live in a rural area because we rarely get any accumulating snow and PG&E has cut down about every tree they can find in my area,

I have heat pumps so my PWs get drained real quick. I almost feel like I am better sending the energy to PG&E for credit than trying to use if after the fact through the PWs because of the two way AC-DC-AC conversion hit. So I have mine set to 75% reserve for Winter where in the Summer I run 50%.