Post
Ok Fedi, I'm starting the process of researching solar panels for my barn. I'm a DIY person, so not looking for install recommendations, more interested in what I need to learn in order to do this wisely. Hardware, unexpected gotchas, other things DIY people need to know.
I can build and I am comfortable with electrical work.
@brianb another thing to be weary of - "remote control" systems for inverters. Most seem to have an rj12 port for rs-485/modbus access, but so far solutions for my inverter have been crap. The WiFi dongle only does "own AP + local app" or "join existing WiFi ssid and use cloud interface" - there's no way to join it to your WiFi SSID AND use the local app.
I bought a "better" official wired dongle which does modbus, but there are no instructions for how to use it locally, so I might have wasted £200 on it :(
If anyone finds a good wired LAN, locally controllable 48v inverter, I would be interested!
I bought a MorningStar one, which is the least bad one so far, but that is still flaky and difficult to set up if you have no idea about Modbus (like me 😥)
@brianb another thing to be weary of - "remote control" systems for inverters. Most seem to have an rj12 port for rs-485/modbus access, but so far solutions for my inverter have been crap. The WiFi dongle only does "own AP + local app" or "join existing WiFi ssid and use cloud interface" - there's no way to join it to your WiFi SSID AND use the local app.
I bought a "better" official wired dongle which does modbus, but there are no instructions for how to use it locally, so I might have wasted £200 on it :(
If anyone finds a good wired LAN, locally controllable 48v inverter, I would be interested!
I bought a MorningStar one, which is the least bad one so far, but that is still flaky and difficult to set up if you have no idea about Modbus (like me 😥)
@brianb budget for connectors, cables, fuses, switches and mounting devices too - it all adds up over time, even though individually they sound cheap :(
Check for shading during different seasons, just to make sure.
If you have different shading areas, split the panels up into different groups if you can, although this will increase the cost.
Do you want an off-grid or grid-connected system?
I went for off-grid, even though I am in a city, because it meant I could do it all myself.
Choose a systems voltage early on (48v / 12v etc), depending on what you want to power, so you spend less on voltage converters, and it determines what battery you will need.
If you have any specific questions - ask away!
@brianb diysolarforum
@donburi @brianb seconded, also there's some forums on here: https://slrpnk.net/
@brianb is it going to generate DC only or also AC?
@wronglang Right now, I'm planning on staying grid-connected, so we'll have inverters to switch everything to AC power.
@brianb so usually the first question is what loads you want to supply and how much power they use
@wronglang We've got some new coolers coming in for the farm, so that's kind of my baseline. It's an east-facing roof in Michigan, so I'm limited to morning sun, but my kWh looks good for summer months when the coolers are running.
I can comfortably fit 6 kWp on my roof with room to expand. Extra production will go back to our utility through a tariff for now.
@brianb back to your original question about diy gotchas:
1. panels need to go on a roof that outlasts them
2. panels add dead load and live load (per code in MA anyway), they modify wind load depending on how they sit, MA code is pretty specific so that might be a nice guide if mi doesn't say. It's not just regs, you want to know you won't lose panels in a windstorm
3. in Michigan with hail... I'd check what sort of impact rating is on the panels you buy...
@brianb it's so nice to have a consistent space... did you check how many hours of sun that means? That lets you translate kW to kWh then those numbers let you size your battery back, battery charge controller and your inverter. Once you size those you get a price range and have to see a) what's locally available; b) if you want to go through the effort of getting something not locally in use; c) where those can live physically (so what environmental conditions they operate in)
@brianb
I believe @ifixcoinops has a lot of DIY experience with this sort of thing that he'd be willing to share lessons learned regarding
@brianb @ShaulaEvans oh: "barn'? I read "brain" and was quite intrigued …
@brianb I don't think you need to learn much, my installation is pretty simple. Make sure that rain water flow is not interrupted, but apart from that...
I'm told that solar panels degrade faster when in partial shade, but mine are in partial shade and ten years old and they're fine so probably not a problem.
@brianb consider the right balance of series vs parallel connection. Just like batteries, series increases voltage and parallel increases current. caveat re: series, a single shaded panel can significantly reduce output in a series run. (1/3)
@brianb Some things are different due to being in a different country, but, if you can bear going to YouTube (via YouTube to avoid the ads and tracking?), then there are several good channels like GaryDoesSolar, that will answer many questions. Broadly, you want to work out what level of electricity you usually use, minus a little bit (since you'll still use the grid as effectively a big backup battery, mainly in winter), and then see if that amount of power and panels is possible/affordable.
You say "barn" but you don't say how far it is from the existing power supply.
Is this going to be off grid?
Two things I've heard are ... how much wind do you get (in regards to fixing them down) and in my experience you always want more than you end up installing.
@brianb One datapoint that you may already have gathered, is the panel angle most appropriate for your latitude.
@brianb This has a good general introduction without too much fuss and it is very pragmatic in my opinion
https://solar.lowtechmagazine.com/2023/12/how-to-build-a-small-solar-power-system/
Start with how big of a system you want, this gives you a scale for all of the components. The gotchas tend to be around selecting too small inverters relative to the total panel output. Enphase iQ microinverters match well to the biggest single panels in a one-to-one format. The outputs parallel together in their “combiner” box. And they have a DIY-friendly gateway for monitoring each microinverter productivity.
And decide on line-side or load-side grid tie.
@brianb Look at batteries first.
Install bonfire.cafe
Get the full app experience
