diy solar

diy solar

Newbie, with a ton of questions...

rogman16

New Member
Joined
Oct 17, 2020
Messages
2
Greetings Solar DIYers!!! First post, please be gentle...

Retired Air Force family living in Navarre, FL with an all-electric house, pool, spa and about 2.8K sq feet. Tend to run the AC at a very comfortable level. Used to have an electric BMW i3, but that lease ended in Sept, and wife wanted a larger SUV, so no EVs at the present time. Have 500 gallon propane tank for spa heater and/or propane generator if one is purchased down the road.

Currently, have 54 panels (and 54 Enphase IQ7+ micro-inverters) attached to our roof for a 16.2kw solar system. When we purchased in Nov 17, I did NOT do the homework I needed to before purchasing, so shame on me. My main driving factors for the system were to 1) eliminate our power bill to the POCO, and 2) provide power during a grid outage. Well, except for maybe a month or two over the last two years, I've had a power bill. Since I didn't do my homework, which would've been fairly easy/quick, I didn't realize until after the system was installed and working that if I lose grid power, the solar system is not going to be "allowed" to supply power to the house.

Hurricane Sally hit a month ago, and although we didn't get the brunt of the storm, we lost grid power for 3+ days (really not that bad for our area). While not that bad, having to start-up our mini-generator (3kw, gas only), and run extension cords all over the place has me in a learn/plan mode for next step.

End GOAL: Work toward having backup capable of running all current circuits. Don't necessarily need to go off-grid, but be able to live fairly comfortable during an extended outage (5-7 days). Don't need to use range, but would like central air, or at a bare min, a couple of mini-splits or window units (don't currently have).

Here's what I've been looking at:

1) At a minimum, I am going to get a generator inlet box, mechanical interlock, breaker for main box, and a cord for the generator. Don't want to have to run extension cords all over the house again. ;-). Short-term fix, and probably only a couple of hundred bucks.

2) Generator--do I get a larger generator? If so, whole home (22-24kw), or 10-12kw portable (no central AC)? Either choice, need to get one capable of dual fuel (gas/propane).

3) Battery backup--boy, done a lot of reading/researching of the last couple of weeks. Probably more confused than I was before I started researching. Would love to start a DIY project, but seems to be pretty pricy. No idea where to start (12v, 24v, 48v), are my micro-inverters compatible or do they go away, can the generator be used to help charge the batteries at night, etc. Too many questions in my brain can't let me focus on what is "actually" needed.

4) Adding more panels--I have the land to add more panels, but it would need to be a DIY project. Need to do a lot more research before I even think about this, but it is on my list of potential projects.

Guess I would like to start with what I would need to be able to utilize the solar energy if the grid goes down. What would be a smart "size" to start a battery backup system, and where could I get some info about all the different pieces I would need to make this work with minimum changes to current solar array?

I've attached pics of my main power distro panels and a few readouts on our solar production.

Thanks much,

Roger V
 

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1) makes sense.

2) depends on budget and if you can live with the reduced output of a smaller unit. Note that a generator is most efficient around 60-70% total load unless it's an inverter type, and running them at lower power can use notably more fuel per kWh.

3) Off-grid inverter and battery system "AC coupled" to your grid tie inverter. When grid goes down, you flip the switch, and your off-grid inverter provides the "grid" for the grid-tie. If you get surplus solar, an AC coupled off-grid inverter will charge your batteries with the grid-tie solar. IIRC, your total power is limited to the off-grid inverter in this case, so you'd likely just have it powering critical loads.

4) Supplementing an existing grid-tie system might be very painful from a code-compliance, permitting and equipment perspective.
 
I think Enphase has a battery solution that works with IQ7


While mix-n-match of grid-tie and battery inverters may work between vendors, probably easiest to use parts supported by one vendor.
My system is all SMA.

A PV/battery system is going to be nicer than running a generator when you want power. Ideally you can also run a generator for additional power, not sure how it integrates with Enphase systems.
 
Greetings Solar DIYers!!! First post, please be gentle...

Retired Air Force family living in Navarre, FL with an all-electric house, pool, spa and about 2.8K sq feet. Tend to run the AC at a very comfortable level. Used to have an electric BMW i3, but that lease ended in Sept, and wife wanted a larger SUV, so no EVs at the present time. Have 500 gallon propane tank for spa heater and/or propane generator if one is purchased down the road.

Currently, have 54 panels (and 54 Enphase IQ7+ micro-inverters) attached to our roof for a 16.2kw solar system. When we purchased in Nov 17, I did NOT do the homework I needed to before purchasing, so shame on me. My main driving factors for the system were to 1) eliminate our power bill to the POCO, and 2) provide power during a grid outage. Well, except for maybe a month or two over the last two years, I've had a power bill. Since I didn't do my homework, which would've been fairly easy/quick, I didn't realize until after the system was installed and working that if I lose grid power, the solar system is not going to be "allowed" to supply power to the house.

Hurricane Sally hit a month ago, and although we didn't get the brunt of the storm, we lost grid power for 3+ days (really not that bad for our area). While not that bad, having to start-up our mini-generator (3kw, gas only), and run extension cords all over the place has me in a learn/plan mode for next step.

End GOAL: Work toward having backup capable of running all current circuits. Don't necessarily need to go off-grid, but be able to live fairly comfortable during an extended outage (5-7 days). Don't need to use range, but would like central air, or at a bare min, a couple of mini-splits or window units (don't currently have).

Here's what I've been looking at:

1) At a minimum, I am going to get a generator inlet box, mechanical interlock, breaker for main box, and a cord for the generator. Don't want to have to run extension cords all over the house again. ;-). Short-term fix, and probably only a couple of hundred bucks.

2) Generator--do I get a larger generator? If so, whole home (22-24kw), or 10-12kw portable (no central AC)? Either choice, need to get one capable of dual fuel (gas/propane).

3) Battery backup--boy, done a lot of reading/researching of the last couple of weeks. Probably more confused than I was before I started researching. Would love to start a DIY project, but seems to be pretty pricy. No idea where to start (12v, 24v, 48v), are my micro-inverters compatible or do they go away, can the generator be used to help charge the batteries at night, etc. Too many questions in my brain can't let me focus on what is "actually" needed.

4) Adding more panels--I have the land to add more panels, but it would need to be a DIY project. Need to do a lot more research before I even think about this, but it is on my list of potential projects.

Guess I would like to start with what I would need to be able to utilize the solar energy if the grid goes down. What would be a smart "size" to start a battery backup system, and where could I get some info about all the different pieces I would need to make this work with minimum changes to current solar array?

I've attached pics of my main power distro panels and a few readouts on our solar production.

Thanks much,

Roger V
Hi there Roger

You are thinking logically . As i see it there are different approaches to your challenge would start with the easier one which would enable you to keep the system live during power outages .
1. Identify the minimum input required for your Grid Tie inverter and provide the similar power requirement through generator to the inverter to keep it live and the solution would work fine . Not sure about fuel / Gas supply in the event of catastrophes in your area so that may be a challenge.

2. Second option is to size the load that you would require in the event of a power failure . ideally start with the minimum load and then correlate with the budget and go for a DIY of a hybrid solution of that size . ( in order to calculate load size , type of solution, Costing Here you need to evaluate the ROI of the solution check this video
) . Mind you that you can use a segment of the existing panels instead of buying new for the separate solution, sut pair with the new inverter . Hope this resolves your query
 
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