That's basically what most software Open Sorce projects state in their licenses as well: Use at your own risk. As someone who publishes design files openly you really don't want to be liable if someone uses the hardware in a wrong way.
That being said, the Libre Solar components are also meant to be used as the basis for customization (hence, called building blocks). Some of the devices are used with minor modifications in certified commercial products.
Apart from boats/caravans, DC systems are used a lot for rural electrification in the global south. This is also where the communication features of Zephyr RTOS are very important.
I don't know much about UL but I can say that FCC certification (also technically required) for electronics can range from about $3k to something like $30k depending on what you're doing.
($3k would be for "unintentional radiator" device, i.e., not supposed to be a radio, $30k would be for "intentional radiator" device, i.e., supposed to be a radio)
Because of customs product import rules, that FCC stamp is often not optional. Now if it was a dodgy seller, the stamp will not match the physical devices on rare occasion. =3
In general, almost all insurance companies will demand UL stamped hardware, and most mortgage/lease/commercial property requires insurance.
A hobby BMS is usually a bad idea, as most kits from unknown origins prioritized cost over safety. Depending where you live, prior to roof installation there may be additional zoning and signed engineering drawing requirements.
It is not hard to find UL equipment, but expect to pay about another $600 for the BMS. Yet, it is better than a house burning down, and the insurance provider denying coverage.
Have a look at local certified installer companies, and make sure to get some real references in your town. Just like most HVAC companies... some installers are just over priced scams. Some folks claim https://www.pegasussolar.com/ was inexpensive, and might be worth a call. Best regards =3
It doesn't have to be a certified install company in many places, it just needs to be inspected which most states will do for homeowners. (if your area is different contact your representative)
UL or other certification is a very good idea. They can't automatically deny coverage for lack of certification, but it becomes a much harder fight for you to prove the non-certified equipment wasn't at fault.
This is a very nice development, but it is tackling the easy stuff. I'd love to see an open source inverter that can operate in stand-alone mode or in grid connected mode. All of these grid connected devices with closed source are a massive risk, especially given how small and cheap a WiFi or cell modem is nowadays.
They are pretty clearly targeting DIYers and enthusiasts who like tinkering with off-grid solar.
Grid-connected is an entirely different ball game. You will not see any open source projects there, or at least not any that anyone will want to use.
Let's think about why not. Anything grid-connected, you REALLY want a licensed electrician to plan and install. And competent electricians will NOT go anywhere near a piece of equipment that is not UL certified. A company producing equipment is NOT going to go through the expense of getting UL certified and then just release their design, PCB, and schematics for free.
And I want to be clear that I am a strong proponent of open source hardware, there are just certain situations where the incentives in reality just don't line up. This is one of them.
Bollocks. I've been making grid connected hardware for decades, there is nothing magical about any of that. You just need to be careful, use proper fusing and you need to know how to read the electrical code.
Competent electricians are licensed professionals who (1) stand to make money on selling gear and (2) have customers that hire them simply because they don't want the hassle or the liability. Obviously a licensed professional is not going to install your home brew inverter, but at the same time if you can design a homebrew inverter you probably don't need a licensed professional anyway.
I've rewired lots of homes and have never had an issue with any of this and designed my first inverter when I was 17 to power my room when my betters decided I should go to sleep and cut the power.
This stuff is not magic. If someone designs a modern open source inverter I'm definitely going to build and install it. Fortunately insurance companies here are reasonable: if your homebrew device wasn't the cause of the mishap then you are still insured.
The one thing they are very strict about is gas, because there is no such thing as a 'fuse for gas'. But if you've properly designed and fused your gear then it should be no less safe than any other grid connected device, even if the magic UL or TUV mark isn't there.
The big one is EMI, that can be hard to get right and you need some gear for this, which is why it pays off to pool the money for an open source design to be certified. And once certified of course the design is 'type approved' and frozen, so you can't change any of the hardware without going through recertification. This is expensive, but if you don't do it every other week should still be well within the means of a properly set up open source project.
Why the fearmongering? It's not as if we're 12 here.
A UPS-style grid connected inverter (with phase balancing) would be significantly more complicated by also significantly more useful. More in the critical/specialized part category, rather than near-commodity (like MPPT/BMS)
I opened up all inverters here and disabled all remote access hardware physically. I'd rather not have a warranty than the risk of either seeing my critical hardware hacked or bricked by the manufacturer. And given the size of these (one is a 17KW unit) the risk of real damage to my home circuits and/or the feed is not imaginary, just rapidly turning it off and back on would already be a big problem, especially on a really sunny day. I try everything I can to not trip the breakers on the inverter around solar noon on sunny days because the amount of current is non-trivial, even on a 960V system. It will generate an absolutely spectacular arc.
Glad to hear it - but cost of renewable energy isn't the software or hardware locked behind vendors. Its installers, wholesalers and permitting. Pricing is set to about where homeowners will be willing to pay and installers will make a good profit. If only it was a 5 year payback - we'd see it everywhere in NA.
I got solar installed by the local power company and while it's well done and was a great deal regarding the price, the inverter stats are locked behind a really terrible app. At least there isn't a subscription cost but I wouldn't be surprised if they add one someday.
Would gladly pay more for fully open and serviceable replacement.
I get that - but also solar should be cheap. If we lower the cost of power we knock off a lot of the bad externalities of power production and allow people to be more inventive with their power use.
Agreed - a lot of the inverters do some real BS moves around data management clearly a way to extract more value in a subscription mode. Its mind numbingly frustrating.
This project isn't being marketd to people who call up a company to white-glove the whole-home installation end-to-end. This is for DIYers who have enough knowledge to tinker with self-designed solar projects but not the EE degree required to engineer some of the more specialized equipment themselves.
I'll give a good example: I use solar to power a ham radio station for a weekend in the summer. However, nearly ALL of the equipment you can buy for the production and storage of solar power emits some degree of radio-frequency interference, which is bad when your whole goal is to power a very sensitive radio.
When it comes to charge controllers in particular, there are exactly two companies that claim to make RFI-quiet MPPT controllers. One has mixed reviews (some people say they work great, some say they are not any better than anything else), and one is very good but also very expensive for what you get. So, more open design and community feedback from people like me might get the cost of a reliable RFI-free charge controller down to where it should be.
That's especially nasty when you're doing LF or VLF because the frequencies of the switches in those things are right in the middle of the bands that you are trying to receive.
A meta comment and really don't want to distract from the product but as a Spanish speaker, the word "libre" for open source projects really grids my gears. It's specially bad when used with "libre" before the subject (like LibreOffice or Libre Solar). It sounds a bit like Brad Pitt saying "bonjourno" in Inglourious Basterds.
Libre does mean free as in freedom, but it also means available and released from prison.
It's from French, not from Spanish, and besides, everybody knows what the intentions are here so I don't think you need to feel offended in any way, that's your choice.
> Unless stated otherwise, none of the published devices has passed regulatory certification, so use them at your own risk and responsibility
This somewhat limits the usefulness of the hardware anywhere you need to be insured, e.g. your house, boat or van.
> This somewhat limits the usefulness of the hardware anywhere you need to be insured, e.g. your house, boat or van.
Same goes for all the random Chinese inverters people are buying and installing in their Homes, Boats and Vans. Doesn't seem to stop them.
This is for DIYers and enthusiasts, not someone looking for an off-the-shelf box.
(Also, Amazon is where most people get their solar equipment these days and you would be amazed how much of it is not UL certified either.)
That's basically what most software Open Sorce projects state in their licenses as well: Use at your own risk. As someone who publishes design files openly you really don't want to be liable if someone uses the hardware in a wrong way.
That being said, the Libre Solar components are also meant to be used as the basis for customization (hence, called building blocks). Some of the devices are used with minor modifications in certified commercial products.
Apart from boats/caravans, DC systems are used a lot for rural electrification in the global south. This is also where the communication features of Zephyr RTOS are very important.
How hard is it to get stuff certified by UL? I would assume expensive and time consuming but don't really know.
I don't know much about UL but I can say that FCC certification (also technically required) for electronics can range from about $3k to something like $30k depending on what you're doing.
($3k would be for "unintentional radiator" device, i.e., not supposed to be a radio, $30k would be for "intentional radiator" device, i.e., supposed to be a radio)
Because of customs product import rules, that FCC stamp is often not optional. Now if it was a dodgy seller, the stamp will not match the physical devices on rare occasion. =3
In general, almost all insurance companies will demand UL stamped hardware, and most mortgage/lease/commercial property requires insurance.
A hobby BMS is usually a bad idea, as most kits from unknown origins prioritized cost over safety. Depending where you live, prior to roof installation there may be additional zoning and signed engineering drawing requirements.
It is not hard to find UL equipment, but expect to pay about another $600 for the BMS. Yet, it is better than a house burning down, and the insurance provider denying coverage.
Have a look at local certified installer companies, and make sure to get some real references in your town. Just like most HVAC companies... some installers are just over priced scams. Some folks claim https://www.pegasussolar.com/ was inexpensive, and might be worth a call. Best regards =3
It doesn't have to be a certified install company in many places, it just needs to be inspected which most states will do for homeowners. (if your area is different contact your representative)
UL or other certification is a very good idea. They can't automatically deny coverage for lack of certification, but it becomes a much harder fight for you to prove the non-certified equipment wasn't at fault.
Why ZephyrOS?
ZephyrOS: https://github.com/zephyrproject-rtos/zephyr
Would there be value in modeling this system with TLA+?
Why build another open product?
There are a few GitHub topics for solar electricity:
solar: https://github.com/topics/solar
photovoltaic: https://github.com/topics/photovoltaic
pv: https://github.com/topics/pv
battery-management: https://github.com/topics/battery-management
ups-management: https://github.com/topics/ups-management
inverter: https://github.com/topics/inverter
Photovoltaic system: https://en.wikipedia.org/wiki/Photovoltaic_system
> Why ZephyrOS?
They say right here: https://libre.solar/software/
This is a very nice development, but it is tackling the easy stuff. I'd love to see an open source inverter that can operate in stand-alone mode or in grid connected mode. All of these grid connected devices with closed source are a massive risk, especially given how small and cheap a WiFi or cell modem is nowadays.
They are pretty clearly targeting DIYers and enthusiasts who like tinkering with off-grid solar.
Grid-connected is an entirely different ball game. You will not see any open source projects there, or at least not any that anyone will want to use.
Let's think about why not. Anything grid-connected, you REALLY want a licensed electrician to plan and install. And competent electricians will NOT go anywhere near a piece of equipment that is not UL certified. A company producing equipment is NOT going to go through the expense of getting UL certified and then just release their design, PCB, and schematics for free.
And I want to be clear that I am a strong proponent of open source hardware, there are just certain situations where the incentives in reality just don't line up. This is one of them.
Bollocks. I've been making grid connected hardware for decades, there is nothing magical about any of that. You just need to be careful, use proper fusing and you need to know how to read the electrical code.
Competent electricians are licensed professionals who (1) stand to make money on selling gear and (2) have customers that hire them simply because they don't want the hassle or the liability. Obviously a licensed professional is not going to install your home brew inverter, but at the same time if you can design a homebrew inverter you probably don't need a licensed professional anyway.
I've rewired lots of homes and have never had an issue with any of this and designed my first inverter when I was 17 to power my room when my betters decided I should go to sleep and cut the power.
This stuff is not magic. If someone designs a modern open source inverter I'm definitely going to build and install it. Fortunately insurance companies here are reasonable: if your homebrew device wasn't the cause of the mishap then you are still insured.
The one thing they are very strict about is gas, because there is no such thing as a 'fuse for gas'. But if you've properly designed and fused your gear then it should be no less safe than any other grid connected device, even if the magic UL or TUV mark isn't there.
The big one is EMI, that can be hard to get right and you need some gear for this, which is why it pays off to pool the money for an open source design to be certified. And once certified of course the design is 'type approved' and frozen, so you can't change any of the hardware without going through recertification. This is expensive, but if you don't do it every other week should still be well within the means of a properly set up open source project.
Why the fearmongering? It's not as if we're 12 here.
A UPS-style grid connected inverter (with phase balancing) would be significantly more complicated by also significantly more useful. More in the critical/specialized part category, rather than near-commodity (like MPPT/BMS)
Deye/Solark famously bricked a bunch of inverters remotely not long back
I opened up all inverters here and disabled all remote access hardware physically. I'd rather not have a warranty than the risk of either seeing my critical hardware hacked or bricked by the manufacturer. And given the size of these (one is a 17KW unit) the risk of real damage to my home circuits and/or the feed is not imaginary, just rapidly turning it off and back on would already be a big problem, especially on a really sunny day. I try everything I can to not trip the breakers on the inverter around solar noon on sunny days because the amount of current is non-trivial, even on a 960V system. It will generate an absolutely spectacular arc.
Glad to hear it - but cost of renewable energy isn't the software or hardware locked behind vendors. Its installers, wholesalers and permitting. Pricing is set to about where homeowners will be willing to pay and installers will make a good profit. If only it was a 5 year payback - we'd see it everywhere in NA.
Not sure cost saving is the priority.
I got solar installed by the local power company and while it's well done and was a great deal regarding the price, the inverter stats are locked behind a really terrible app. At least there isn't a subscription cost but I wouldn't be surprised if they add one someday.
Would gladly pay more for fully open and serviceable replacement.
I get that - but also solar should be cheap. If we lower the cost of power we knock off a lot of the bad externalities of power production and allow people to be more inventive with their power use.
Agreed - a lot of the inverters do some real BS moves around data management clearly a way to extract more value in a subscription mode. Its mind numbingly frustrating.
The stats are the least of your problem, the bigger ones are remote updates, planned obsolescence, hacking and bricking.
Yes, and?
This project isn't being marketd to people who call up a company to white-glove the whole-home installation end-to-end. This is for DIYers who have enough knowledge to tinker with self-designed solar projects but not the EE degree required to engineer some of the more specialized equipment themselves.
I'll give a good example: I use solar to power a ham radio station for a weekend in the summer. However, nearly ALL of the equipment you can buy for the production and storage of solar power emits some degree of radio-frequency interference, which is bad when your whole goal is to power a very sensitive radio.
When it comes to charge controllers in particular, there are exactly two companies that claim to make RFI-quiet MPPT controllers. One has mixed reviews (some people say they work great, some say they are not any better than anything else), and one is very good but also very expensive for what you get. So, more open design and community feedback from people like me might get the cost of a reliable RFI-free charge controller down to where it should be.
That's especially nasty when you're doing LF or VLF because the frequencies of the switches in those things are right in the middle of the bands that you are trying to receive.
Open source open hardware microinverter incoming (with certification for EU grid):
https://fosdem.org/2026/schedule/event/7Q9HMF-open-solar-pow...
2025 for archive:
https://archive.fosdem.org/2025/schedule/event/fosdem-2025-6...
Always a bit jarring to see a devboard stacked on an otherwise neat board. Looks promising though.
A meta comment and really don't want to distract from the product but as a Spanish speaker, the word "libre" for open source projects really grids my gears. It's specially bad when used with "libre" before the subject (like LibreOffice or Libre Solar). It sounds a bit like Brad Pitt saying "bonjourno" in Inglourious Basterds.
Libre does mean free as in freedom, but it also means available and released from prison.
It's from French, not from Spanish, and besides, everybody knows what the intentions are here so I don't think you need to feel offended in any way, that's your choice.