[HN Gopher] Libre Solar - Open Hardware for Renewable Energy
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Libre Solar - Open Hardware for Renewable Energy
Author : evolve2k
Score : 185 points
Date : 2026-03-01 09:01 UTC (3 days ago)
(HTM) web link (libre.solar)
(TXT) w3m dump (libre.solar)
| westurner wrote:
| 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
| bityard wrote:
| > Why ZephyrOS?
|
| They say right here: https://libre.solar/software/
| danw1979 wrote:
| > 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.
| fred_is_fred wrote:
| How hard is it to get stuff certified by UL? I would assume
| expensive and time consuming but don't really know.
| aeblyve wrote:
| 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)
| Joel_Mckay wrote:
| 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
| cheema33 wrote:
| FCC ensures a product doesn't cause radio interference,
| while UL ensures the product is safe to use and won't cause
| fires or electric shocks. For DIY, your primary concern is
| UL certification.
| Joel_Mckay wrote:
| 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
| bluGill wrote:
| 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.
| pocksuppet wrote:
| I think expensive and time consuming, but not necessarily
| difficult, if the product is already safe.
| bityard wrote:
| 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.)
| ktm5j wrote:
| DIYers and enthusiasts should still worry about their house
| burning down because one of these boards started a fire. An
| insurance company would investigate and find any excuse they
| can to deny payment.
| Dan_- wrote:
| Should is doing a lot of work there. The reality is most
| don't. These are people who don't understand minimum
| conductor size trying to DIY a solar system.
| mindslight wrote:
| Insurance covers the insured's own gross negligence. This
| is a trope up there with believing the "warranty void if
| removed" stickers.
|
| The real reason this should give you pause is that you
| don't want your house to burn down regardless of an
| insurance payout. _That_ is how your incentives remain
| aligned with the insurance company.
| martinjaeger wrote:
| 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.
| MisterTea wrote:
| > 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.
| throawayonthe wrote:
| those are usually certified?
| Rebelgecko wrote:
| Definitely not UL (if we're talking about the $300
| inverters on Amazon or AliExpress from companies like
| Anenji)
| stephen_g wrote:
| The cheap stuff usually have the certification labels
| printed on them, but a cursory look inside usually shows
| breaches if you know what to look for (like we have had
| stuff from China where the ground wire wasn't connected to
| anything, but even if that's right there are things like
| just not having enough clearance between mains and isolated
| DC in power supplies etc.). So they are definitely not
| actually certified, they just slap the labels on anyway.
|
| Of course, there is a rising group of actually really high-
| quality native brands starting to come out of China - Anker
| were an early one of these, Xiaomi is a massive one, UGreen
| is really popular on Amazon etc. These kind of brands
| actually will be properly certified and are scary good for
| how cheap they are. So it's changing a lot.
| mcbishop wrote:
| Not that this is accepted by insurers or AHJs ("authorities
| having jurisdiction"), but one can use UL-certified components
| in an (open-source) _assembly_ that itself isn't UL certified.
| This at least supports the argument that the overall product is
| safe if thoughtfully designed and assembled. An example is the
| OpenEVSE level-2 car charger (which I had a really good
| experience with).
| stephen_g wrote:
| If you're not selling them then there isn't really any
| certification requirements until you start to get into the
| mains voltages. This all seems to be 12/24V DC stuff on the
| battery side and 60V DC on the solar side which comes under
| 'extra-low voltage' in basically every jurisdiction which is
| usually not really regulated because it's difficult to shock
| someone.
|
| The battery stuff is more risky (bringing lithium cells into
| the picture) but I don't think anyone should be worried by the
| MPPTs.
| jacquesm wrote:
| 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.
| Rebelgecko wrote:
| Deye/Solark famously bricked a bunch of inverters remotely not
| long back
| jacquesm wrote:
| 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.
| organsnyder wrote:
| My SolArk inverter came with a wifi dongle that uses Modbus
| over RS232 to interface with the inverter. I removed the
| dongle and connected a Pi to provide a Modbus-over-TCP
| interface that I can use from Home Assistant. I got more
| control (the officially-supported Modbus interface is read-
| only), and SolArk no longer has any access to my equipment.
| jacquesm wrote:
| That's a nice trick. I should try that.
| f_devd wrote:
| 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)
| bityard wrote:
| 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.
| jacquesm wrote:
| 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.
| hn_acc1 wrote:
| >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.
|
| I would say that rules out about 80-95% of DYI users.
| jacquesm wrote:
| This is 'hackernews', not 'consumersRus'. Though on odd
| days you might think differently.
| relaxing wrote:
| And even days. And twice on Sundays.
| mcbishop wrote:
| > Why the fearmongering?
|
| The main concern is exporting to a downed grid that line-
| workers are trying to restore.
| repparw wrote:
| Could the inverse process work? Design, then (crowdsource?)
| pay for UL certs? Don't know the process for certification,
| but in the software side, I've heard from foss projects
| asking for money for, e.g, security audits
| jacquesm wrote:
| Theoretically, yes. But in practice you need to bake
| certification requirements into the design or it will never
| pass.
| hamdingers wrote:
| > Anything grid-connected, you REALLY want a licensed
| electrician to plan and install.
|
| Have you heard of balcony solar?
|
| It's a solar panel, a microinverter, and a standard wall
| plug. It doesn't need an electrician to install any more than
| anything else, you just plug it in. Outlets work both ways.
|
| LibreSolar doesn't seem to be working on any inverters, but a
| complete open source system like this would be great.
|
| https://en.wikipedia.org/wiki/Balcony_solar_power
| bityard wrote:
| If that wikipedia article is right, then balcony solar is
| not legal where I live (in the US). Here, we require a
| hard-wired, permanently installed automatic transfer switch
| that disconnects the solar generation from the grid when
| the mains power goes out. This is to protect line workers
| when working on downed lines.
| hamdingers wrote:
| It's probably coming soon for you, 30 states have bills
| announced or introduced legalizing plug-in solar and one
| (Utah) has already passed. They should be fairly
| uncontroversial.
|
| Also, there's no need for a transfer switch in any grid-
| tied system, whether plug-in or hard-wired. Grid-tied
| inverters shut off automatically if there's no grid
| frequency to sync to.
| boringg wrote:
| 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.
| progbits wrote:
| 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.
| jacquesm wrote:
| The stats are the least of your problem, the bigger ones are
| remote updates, planned obsolescence, hacking and bricking.
| boringg wrote:
| 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.
| SoftTalker wrote:
| Price isn't determined by the cost of supply but by the
| value provided to the buyer.
| bityard wrote:
| 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.
| jacquesm wrote:
| 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.
| guerby wrote:
| 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...
| f_devd wrote:
| Always a bit jarring to see a devboard stacked on an otherwise
| neat board. Looks promising though.
| viernullvier wrote:
| I've seen commercial products that use socketed devboards
| inside. If anything, it's just an indication that the
| hobbyist and professional spaces are slowly converging.
| lentil_soup wrote:
| 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.
| jacquesm wrote:
| 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.
| lentil_soup wrote:
| chill, I'm not offended, just thought it was worth mentioning
| it sounds bad to native speakers. Wouldn't you mention it if
| someone was misusing a Dutch word?
|
| Also, it comes from French and Spanish
| [https://www.gnu.org/philosophy/free-sw.en.html], it's the
| same word and same grammar, subject before adjective.
| adrianN wrote:
| I'm fine with people using ,,gratis" to differentiate libre
| software from software that doesn't cost anything and I'm
| German.
| jacquesm wrote:
| > Wouldn't you mention it if someone was misusing a Dutch
| word?
|
| Not a chance. Language is a tool, not some kind of holy
| house. If the meaning comes across that's already more than
| you could hope for.
|
| The whole idea that language is something to be condensed
| and frozen is relatively new, it used to be much more fluid
| which made it harder to have a decisive set of words
| (sorry, Scrabblers (tm)) but language could adapt faster to
| circumstances. What we consider the 'final form' of all of
| these languages isn't final at all, it is just what we are
| used to and more of a convention than anything else.
|
| Some countries (including mine, unfortunately) have groups
| that will go out of their way to harass people to use the
| 'correct form' ignoring that what those forms are is
| subject to change and that not everybody grew up with the
| currently agreed upon preferential way to spell things, and
| meaning is so much more complicated than spelling.
|
| I think the easiest way to deal with these kind of
| frustrations is to see them as compliments: at least
| someone was aware enough of your language to name something
| in it, that's more than you could say for many other
| languages, if only because the scripts are different.
| goodpoint wrote:
| > Libre does mean free as in freedom, but it also means
| available and released from prison.
|
| If anything it makes it more apt.
| vanillax wrote:
| Great use case for solar shed/offgrid/cabin... I think people
| underestimate how much you can do with a solar shed , batteries,
| and the sorta reduced risk aspect of a shed catching fire vs a
| house. That being said its really easy to follow safety
| precautions. I cant wait to try this out.
| gosub100 wrote:
| My wishlist:
|
| - dc motor conversions for air conditioners and voltage
| controllers that can adapt to multiple panel types to drive it.
| There's a lot to be gained without going all-in an inverter. What
| if I stayed on grid but heavily offset my heating / cooling bill
| by having a wall mount unit that was free to run during daylight
| hours on a completely separate circuit?
|
| - conversion kit to make the wall mount unit a heater in the
| winter months
|
| - a DC home system for select appliances such as lights,
| computers, or even refrigerators. This requires more precise
| voltage regulators because DC is more finicky when you add /
| remove loads. But you save some losses in efficiency.
|
| - a thermal battery, so my window mount cooler can freeze a solid
| block of ice all day during the sun, and use it to cool me when I
| get home. It would be sealed of course. But condensation would
| still have to be managed. Maybe a hot water tank adapter that
| uses excess electricity and dumps it in the tank, but not so much
| to explode. Again, a form of offset, not a replacement for gas.
| Another thermal battery could be a sewage tank that aborbs heat
| from the AC unit before it goes down the drain. This would reduce
| the load of the fan.
|
| - a wind generator that works best in storms. It could dump
| straight to a heating element and fan indoors. Who wouldn't love
| free heat during violent storms? Maybe it could have a clutch
| (mechanical or electric) to tune the load to the wind gusts.
|
| - a solar cooker, maybe with a molten fluid or superheated steam.
| The latter can go well above 500F so plenty hot enough for
| cooking. But of course very dangerous so would need a
| professional device, if it's even possible. But this would allow
| e.g. restaurants in the summer to offset or replace heating for
| their kitchens. It pains me to think of how much energy is wasted
| in a hot desert city to pay for a gas grill and then pay again to
| pump to he excess heat outside.
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(page generated 2026-03-04 23:00 UTC)