Can I get some last minute advice before signing contract?

[sabersix]

1. I don't think they are lying, but once your battery is depleted you will be left with a highly variable power source. The key will be managing your load so as not to fully deplete your battery. Do you have a critical load panel as part of your home electrical system? Here is an interesting article that discusses your system in real use. https://willardm22.medium.com/my-exp...e-3b306348a233

2. The generator will be whatever you purchase. The Backup Interface seems to be the smart piece of the system that manages where and for how long the power is drawn.

[mikedunkel]

1) Your house will be powered from your batteries until they are depleted.../...

2) Why not add a generator instead of the second inverter. The generator can work in with your solar to recharge your batteries and keep the house going.

StorEdge with Generator.PNG

I'm glad you brought these points up.

1. The reason I passed on Tesla is that once I lose the grid their panels completely stop producing electricity and I'm down to whatever my powerwalls have stored. The local company said that even with the grid out, their panels continue to produce power -- I'm not sure of the specifics; whether the panels power the house or they power the batteries which power the house, but the end result was I'd have an indefinite source of power albeit perhaps not enough to run everything at once. Are you telling me my local company is lying about what their system can do in the event of a grid outage?

2. In a system with a generator, are they smart enough to prioritize using excess solar power over the generator? Are the generators variable speed so they aren't going full-bore if I only need a few extra KW to git'er done? The cost of a 5-7kw generac is less than the excess cost of the 2nd inverter and additional panels so this could be a viable option.

[sabersix]

If the power is out, you won't be able to run your A/C as that is a huge load. Your house will be powered from your batteries until they are depleted. Running on battery provides a constant level of power until you are on solar only. Solar power can vary significantly during the day so any dips below your demand is going to put strain on all your running electronics. Solar alone is just not a cost effective backup. You have the battery capacity. Why not add a generator instead of the second inverter. The generator can work in with your solar to recharge your batteries and keep the house going.

StorEdge with Generator.PNG

[mikedunkel]

I think the smaller system. My reasoning is that a long power failure event is usually associated with some sort of weather event or fire that will inhibit your solar production. You will be relying on your batteries which are the same size for both systems. Recharging those batteries can be done by either system with little difference.

The question to me is do you need a 13.1kW system for your normal day to day usage? As you noted, you will only get pennies on the dollar for oversizing.

Its more about the inverters than the system size. The difference in cost between panels in 11.3 and 13.1 isn't that large but the 2nd inverter adds quite a bit of cost. I'm just not convinced that a single 7.6 KW inverter can handle 2 3-ton air conditioners, 2 refrigerators, freezer, well pump, microwave, and all the miscellaneous lights, fans, and outlets my family uses on a day to day basis. Obviously I'll be able to manually manage some of this if push comes to shove.

A weather event can certainly take down power lines, but those lines often stay down longer than the weather event. A thunderstorm or tornado can be over in 30 minutes and the remains of an ice storm can melt the next day (I live near Atlanta) but power has been down for as long as a week (heck, I think parts of TX were down for 2 weeks this past winter). The batteries will get me through the initial event and night time and depending on WX forecast I can prioritize the food storage over creature comforts as required.

[sabersix]

I think the smaller system. My reasoning is that a long power failure event is usually associated with some sort of weather event or fire that will inhibit your solar production. You will be relying on your batteries which are the same size for both systems. Recharging those batteries can be done by either system with little difference.

The question to me is do you need a 13.1kW system for your normal day to day usage? As you noted, you will only get pennies on the dollar for oversizing.

[mikedunkel]

Hello and thanks for looking,

I got quotes from 4 companies (3 local and Tesla) and selected a local company to do my grid-tied system and I'm trying to determine if I need to go with a single or 2-inverter build. My top priority is performance and my 2nd is cost and as everyone knows these two priorities are in direct conflict with each other. I'm willing to spend what it takes to achieve my goals but I don't want a system that has so much excess capacity that I'm constantly selling power back to the utility at pennies on the dollar (my EMC pays like 2 cents a KWH vs charging me 10 cents/KWH).

My desired system performance is to basically run the entire house during a power outage as if there wasn't a power outage, assuming daytime and full system performance. Last year my very highest hourly usage was 10.24 KW, the year prior it was around 12 KW. Most of the time my usage is significantly lower, and in addition to adding solar I'm getting new windows, going from blown to spray-in foam in the attic, and filling-in my 30,000 gallon swimming pool (2 pumps) so there is going to be an unknown but fairly significant decrease in my consumption.

The 2 systems my installer has proposed are a 13.1KW system with 2 StorEdge SE7600 inverters and 2 RESU16H batteries, and an 11.3KW system with a single SE7600 inverter and 2 RESU16H batteries. His initial recommendation was for the smaller system and only a single battery but I told him that having power in the event of an extended grid failure was more important to me than ROI so this company is not trying to gouge me, the extra battery and a quote for a bigger system were at my request and not their prompting.

So, will the single inverter be able to handle my desired output or will I need to spend another extra $9k (pre tax credit) for the additional inverter and 1.8kw of panels?

BTW, I am NOT interested in what brand of panel, inverter, or battery you think is better than what I've selected. I've gotten my quotes and my decision is final regarding the company and products. The only question is how big I need to go .

Thanks for your time.