diy solar

diy solar

New from Oregon, can I "fix" my professionally installed system?

xrd

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Dec 25, 2021
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My wife had a solar system installed professionally this summer. A few days ago we lost power and I was surprised that the power went off even though the sun was out. Is this something I could fix by adding a battery to the system? Is this something I as a complete newby should even consider (I'm a software engineer but know nothing about electrical)? Last winter we were without power for a few days during an ice storm and it would be great if we could keep the power with our solar panels but now I'm not sure that's the case if there is no connection back to the grid. The inverter is an Enphase if that matters.
 
Nothing to "fix." Welcome to grid-tie. Many new solar owners aren't told this unless they explicitly ask, so don't blame your wife.

She would have pooed her britches at the increase in cost of a system that could operate independently with battery storage.

That's where you are now. You need to determine how much storage you'll need, and how to interface it with the grid-tie system. Some have battery backup options and others don't. You may need to add a new AC coupled inverter.

As a SWAG, take the cost of your original system and then assume you'll have to spend 1-2X that same amount on getting it usable for off-grid.
 
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Thanks so much for the response.

I don't think I want it to be completely off grid. It would just be nice to have a way to charge devices and run the hot water heater, for example. Or, enough to have lights on for a few hours before bed time. So just enough for a few hours here and there, not fully off grid.

Is that an easier discussion? How do I calculate what I "need?"
 
Thanks so much for the response.

I don't think I want it to be completely off grid. It would just be nice to have a way to charge devices and run the hot water heater, for example. Or, enough to have lights on for a few hours before bed time. So just enough for a few hours here and there, not fully off grid.

Is that an easier discussion? How do I calculate what I "need?"

You've started the calculations of what you "need." List all devices, how much power they use, and how long you want to run them in a grid down situation. Consider that a hot water heater is a massive load. Typical residential units pull 4500W.

Concurrently, identify your system and see if it has a battery backup option or other means of functioning when the grid is down.

When the grid is down, you're off grid. If your existing system has no means of grid-down operation, your only choice is to supply a grid. This requires a high quality off-grid inverter capable of "AC coupling" and frequency shifting and batteries.


 
That's great information. I'll gather more.

We are lucky that we have gas water heater so that solves a big problem for us. I meant to say the hot water heater for coffee, not the house! I suppose I could just boil water on the stove...

I'll review the documentation. I can see from the emails we have Silfab 330 panels x20 for 6.6 kw capacity.
 
If your needs are modest, having a few batteries that you can recharge from the sun may not break the bank. Even a 12v system. Lots of lights, radios, tv, etc
 
That's great information. I'll gather more.

We are lucky that we have gas water heater so that solves a big problem for us. I meant to say the hot water heater for coffee, not the house! I suppose I could just boil water on the stove...

I'll review the documentation. I can see from the emails we have Silfab 330 panels x20 for 6.6 kw capacity.

My system is a standard grid tied solar system as well, but with the flick of a couple switches, I can be completely off-grid in about 5 minutes.

The trick, as Sunshine said above, is a technique called AC Coupling.

My advice:
If you have natural gas, get a natural gas generator.. it is simple, reliable, and cheaper than installing a battery system.

If you don't have natural gas, a gasoline generator is still an option, but then you need to make sure you have gas available and have to keep refilling the generator.

If you want to use your solar system, purchase a couple of SMA Sunny Island inverters and some SIND series Trojan batteries.. From there, you can rewire parts of your breaker panel to a "critical loads panel". The system is simple, reliable, and will work with almost any grid tied inverter.
 
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I’m thinking way under $1,000 all in for a little 12volt 100 amp LiFePo and charger. Good to go.
 
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You're wife did good, Enphase is one of the best systems out there, and has the best warranty. Microinverters also have a lot of advantages over string inverters. As companies go, they're one of the best too, they have online training courses (https://university.enphaseenergy.com/) making it easy for DIYers.

Since you're Enphase, with their new IQ8s you don't really need a battery to get power while the sun is shining.

You could add a few more panels with IQ8s, or swap a few of your existing microinverters. But, you'd also need an Enpower (it's their ATS with autotransformer) and the Envoy in order to not back-feed the grid. The IQ8s should be generally available in February and are priced similarly to microinverters, the Enpower is under $2k.

Or, you could just add the Encharge3 (Enphase's smallest battery for about $3k) and the Enpower. So, that would run you just under $5k. With it, you'll have 3.3 kWh of backup power for nighttime use, solar during the day (which can run the house and charge the batteries), and the ability to charge your batteries or augment power from an inverter generator for cloudy days. I have an Ensemble system, I've blogged my experiences here (mostly good, a few "new system" issues).
 
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