I currently have 28 panels with an enphase inverter on the house that are paid for. I am about to add 15 panels with a Tesla 13kw battery on a ppa. The current panels are tied to the grid, and I use them to offset power on a one to one buy back program with TXU currently at 13.7 cents per kwh. That's not a real number though because of the AEP delivery charges.

My plan:
The 28 panels will continue to be grid tied and used as they currently are. If there is a blackout, the do nothing. Also, at night, they do not generate power for the house.
The new 15 panels and battery will also be grid tied but during a blackout and at night will continue to produce power for the house and the battery.
My hope is to run the REP (currently TXU) bill to as close to zero as I can get it and even sell back power to the grid for a net negative.
My ppa will be $165 per month. My current yearly average is around $200 per month. So I'll drop my monthly payment amount, have the possibility of gaining credits by selling back to the grid, and have a 13kw back up.
Do I have this figured out correctly?

How much did all this cost you?

The 28 panels were on the house when I bought it. I transferred ownership for $200. They are paid for. With the ppa, I do not pay anything for the new panels and battery. For the next 25 years, they are taken care through warranty and includes labor. I do not pay anything for permits, installation costs, etc. I just agree to buy the electricity they are guaranteed to produce for $165 per month without an escalator. In other words, I pay $165 per month, and it doesn't change.

CCTX knows all things solar. I'll defer to him. Me? Idk what any of that means.

Thanks for the reply. I know a lot more about it than I did. I could go with a generator for a back up and still can. But I may not need to if this system works like I think it will.

How much extra does that cost when you have to re-roof, to take them off and put them back on ??

Not sure living around here. Straight up I think the cost is around $300 per panel. However, the last roof I had put on was paid by insurance because of Harvey. I think just about every roof in Aransas is new. The town of new roofs lol. The roof is six years old. Another option is to pull them off yourself and have someone reinstall them. That may make the cost less.

Hard to believe the first 28 panels isn't enough already. They must be old and not generating much power.

They probably need a check up, but they do a good job. Maybe five years old. We use most of our power from late evening to early morning.

I would've just bought some back up batteries for storage for nighttime use which is the use the Tesla battery is but would end up being a whole lot cheaper in the long run.

I'm not sure it would be much cheaper. I looked at going that route. The Tesla installed is somewhere around 10-14g. plus I still haven't met the house needs without adding additional panels. In addition, my current electric bill averages around $200 per month. If electricity stays the same price in the next 25 years, I will spend $60G. By going with the new install that includes the Tesla, in 25 years I will have spent $49.5 G. Of course, without the new panels and just the battery, I would lower my electric bill but I still have to add the 12G for the Tesla. Also, the life on the Tesla is somewhere around 12 to 15 years or so. With the new install, they will replace the Tesla at no charge. If I buy the Tesla and it fails after 10 years, it's up to me to replace it. Maybe I'm seeing it wrong.

Maybe you should have a professional look at system and your house. Maybe there is an wiring or software issue causing low solar input. Plus is your house fairly energy compliant?

What wattage are the 28 panels?


Maybe reach out to Will Prowse on YouTube for advice.

The greatest savings are found by delivering and installing everything yourself. If you do the shipping and install yourself; you save close to 60% of the cost and break even in five years instead of twenty.

Signature solar in Sulphur Springs has just about everything you could possibly need (except maybe the best deals on server rack lithium batteries)
Be sure to subscribe to Will Prowse’s YouTube channel and website. He’s always reviewing, capacity testing, and breaking down server rack batteries to find the cheapest ones that are the best quality.

I did all mine off grid…wired to a charge controller/battery bank/inverter….then wired two rooms off the inverter with 12/2 Romex running in the walls to separate GFCI plugs.

So, I basically run all the electricity in two rooms off the power of the sun 24/7. Nice way to do it if you don’t want to worry about backfeeding the grid….or getting a visit from the energy provider…..also much less paperwork if you aren’t tying into the grid.

Also have six 305 watt panels dedicated to running a solar powered minisplit in the garage….so the garage is climate controlled by the power of the sun during daylight hours (when it’s sunny)….Also completely off grid…..this is a luxury; but I do a lot of projects in the garage, so I enjoy it….especially in the summer.


I did all of the delivery and install with the help of a buddy and had an electrician check everything and do the grounding.
…..when my wife was out of town

Thanks for the good advice. The house was built in 2019. I don't know the wattage of the panels, but I agree there may be an issue with one or more of the microinverters. I do know that the Envoy is not communicating with Enphase. I've tried to set up a new wi fi connection with their help, but I can't hit the Gateway address from the app. However, I do know the panels are working as the bi directional meter flows both ways. In fact, the panels run the house until I turn on the AC. It's a 3.5 ton unit.

That sounds pretty dang cool CCTX. If I was single and younger, I could see myself doing something like that for sure. Yeah, backfeeding into the grid is an issue and why the panels only work when there is power as the inverter is powered by the grid and shuts down when power is lost. However, the Tesla takes care of that with the new system. There may be a way to tie the old panels to the Tesla as well as the new panels, but I don't know what the trade off will be for that.