Solar for dummies
maxwell_mcgee
| Posted in General Questions on
Hi All,
Trying to figure out what I want my PV system to look like for my new build. I’m truly drowning in all of the biased marketing docs and/or excessively technical discussion on solar forums.
Can anyone share or recommend a good (“Solar for dummies”) type of website or blog post that helps teach the basics of what you need from a PV system and how to go about choosing good quality panels, inverters, batteries, etc.
Can anyone recommend specific brands of hardware that they think are worth installing?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
Tread very carefully. The industry is chock full of white belt patent leather shoe type salesmen who will gladly steal you blind while making you think your going green.
The only way I would go solar is to buy the system outright, pay cash and make sure the kWh payback makes sense. There are all sorts of websites, youtubes and forums where you can educate yourself. Good luck!
I would avoid trying for "net zero". Net zero is pushed by a lot of the leasing companies, because they make their money selling excess power to the utility. For an average homeowner, a "peak shave" system that is sized to produce enough power to run your home only during the time of day the system is producing is usually a better fit. Peak shave systems are smaller, cheaper to install, and don't need any "net metering" options from the utility. A lot of people seem to think if you can't get net metering in your area you can't install solar, but that is NOT TRUE. For many homes, a 3kw system is fine for peak shave purposes, and smaller might work too depending on your load.
Microinverters or optimizers can help with shading of the solar array. If you have a really clear area (i.e. no trees), and a small system, then you can probably get by without these extra goodies and not loose all that much performance wise. Larger systems and systems where you're more likely to get PARTIAL shading at various times of day will benefit more from these extra goodies.
I don't want to try to recommend any specific brands of equipment here. Do be sure to follow codes though, especially involving the remote shutoffs.
Bill
I'm definitely aiming more for a peak shave type of system. I don't think my roof is big enough / shade-free enough to hit Net Zero anyway.
And I'm not going to finance this thing -- I've heard some of the horror stories.
But even this question of Microinverters vs. string inverters, what type of battery chemistry to pursue, how to integrate a small backup generator to extend the time we can operate the home during a power outage, etc. is a ton of information to try to digest and I'm trying to find good (relatively) un-biased perspectives on this topic is proving difficult.
Don't use batteries -- you don't need them if you're not off grid, and you're much better off with a grid tied system unless you don't have that option available to you.
Integrating a generator is easy: put in a main disconnect after the meter, tie the solar inverter into that (you need a seperate breaker, there are multiple ways to do that part here). Put an ATS between the main disconnect and the main panel for your house. Now when you run on utility power, the solar inverter is paralleled with the system as usual. If you run on generator power, the ATS isolates the solar system from the house, which also isolates it from the generator. You do NOT want to try to use a grid tie inverter with a generator since it won't be able to track the generator properly (generators are not nearly as stable as the utility is in terms of line frequency, which is the important part here). This system lets the generator run your entire home.
You can also use small manual transfer switches such as those made by Reliance Controls. With this type of system, the solar inverter is connected to the main panel in the usual way, and all critical generator loads run off of the little generator panel provided by the Reliance transfer switch device. This system lets the generator run ONLY those loads you connect to the critical generator panel (usually called the "emergency panel"). I prefer the whole-home setup I mentioned earlier though.
Either way works. The important thing is to make sure that the solar inverter is isolated from the system when the generator is providing power. Don't bother with batteries and fancy stuff like trying to have uninterrupted power or anything like that since it just adds cost and complexity. The cheapest and easiest way to go is a simple grid-tied peak-shave system like I just described.
If you're building off-grid, with no ability to get a connection to the grid, then things are different. In this case, you'd need an inverter that can handle batteries. I would use conventional lead acid batteries here for easy of use, cost, and relative availability. I would use front access telecom batteries (C and D technologies has many options, among others) for the battery string. Sizing batteries for off grid systems can be rather involved, depending on how much you want to run, how long you want to be able to run it, and what your average weather is (which affects how long the batteries need to run to ride through stormy periods). Generators in this case are usually run to charge the batteries during prolonged periods of less than ideal solar conditions.
Bill
To gain general knowledge on solar, I would look at Will Prowse's YouTube channel - DIY Solar Power with Will Prowse. He has a good playlist for establishing baseline knowledge around solar and electricity in general - Solar Power Education Videos is the name of the playlist.
To get the federal tax credit your system has to be installed by a licensed contractor. So that takes away a lot of the appeal of a DIY system.
This is false. Here is the Federal Tax form 5695 which mentions nothing about licensed installs. https://www.irs.gov/pub/irs-pdf/i5695.pdf
Don't use batteries. Back up generators are the way to go.
I'm in commercial solar finance, and while I don't install systems and I don't deal with the resi side of the business, I think I can still offer you some good advice.
Go with a company that's a part of the Amicus Solar Cooperative (https://www.amicussolar.com/). All their members make a commitment to fair hiring practices and livable wages for their employees, standing by their warranties, continuing ed to ensure everyone's up to date on current practices...I'm biased because my company's co-founder was the president of solar installer that was a part of the Cooperative, but their members still do great work. Are there good companies elsewhere? Of course! But I can't recommend any particular ones in a particular area, and I /can/ recommend anyone from the Cooperative.