Edit: As suggested in the comments, shaking my fist and yelling at it has, thus far, proven unsuccessful. The cloud appears to be an obstinate one.

cross-posted from: https://piefed.social/c/energy@slrpnk.net/p/2233823/unreasonably-pleased-when-i-can-charge-from-excess-solar

Additional detail for DIYers: I used vuegraf to publish MQTT from my Emporia Vue, which OpenEVSE can natively consume.

I somewhat recently connected Emporia Vue's 'net production/consumption' metric to my OpenEVSE so I can make use of the 'eco divert' feature that only charges from excess solar production. Since my utility charges for transmission of net-metered power, this leads to some savings. When we have cooler summer weather it shows up very nicely on the graph.

EVSE view:

(Hopefully this is OK for this community. Not news, but could be a nice highlight/discussion. If not, glad to find another spot to share it.)

For nearly three hours my house was running off solar. Still more work to do and a ton of add-on batteries to buy, but the system works. Eventually I want to replace the manual transfer switch with an automatic switch that I can run from anywhere. I designed the system and picked the components but hired an electrician to do the permitted installation. Passed inspection yesterday. And today, of course, cloud cover! Come on, man! I want my photons!

We've been running the house on mostly PV since I got the initial install done at the end of June. I ran some smaller loads from it throughout June while I was testing the equipment, but that was kind of ad-hoc.

Just now coming out of a heat wave that started last Monday, and most of the A/C usage has been from solar. Still running from the "temporary" transfer switch hookup, so I'm not yet taking advantage of the "hybrid" aspects of the inverter. That may be a while since I have to do some more prep work before I can start installing the new breaker box and moving circuits over to that.

I've also ordered the fourth rail and 5 more panels, so I should have this upgraded from a 3KW to a 4KW system sometime later in the week. Would have ordered those earlier, but I didn't want to make the UPS guy deal with them when the heat index was 109 degrees lol. That, and I wouldn't want to deal with them in that kind of heat, either.

It's just nice seeing such significant returns this early in the process.

I live in the central US in a south-facing apartment with a TON of sunlight, and I've been wanting to set something up mostly for hobbyist/curiosity reasons. I know actual financial benefits are going to be pretty unlikely, and that's ok.

Balcony solar as I understand it to be an option in Europe is pretty much exactly the sort of thing I want to try, but my understanding is it's not compliant with code in the US. Basically I don't expect to be able to have enough solar capacity to power my whole home, but I'd like to be able to just offset as much as I can when the sun is out. And I think I want a battery in the system so it's not only useful when the sun is out.

I'd love something that works like this:

• Prioritize powering the load from the panels (through an inverter, I assume) when available
• If the panels alone aren't sufficient, backfill from the battery
• If the panels + battery aren't sufficient, backfill from the grid
• When the load does not consume all the power from the panels, use excess to charge the battery
• Grid is only there as a fallback when the panels and battery aren't sufficient to power the load. Grid does not charge the battery or receive excess from the panels.

If it's not realistic to expect to be able to power the load first from the panels (bypassing the battery), skipping that part and just always powering from the battery and backfilling from the grid maybe would simplify things. I just thought it'd be nice to avoid the inefficency of charging and discharging the battery when the sun is out.

My hope is to have a single solar-backed outlet in my living room off my balcony. During the summer, I'd probably use it to partially offset my little window unit AC. Other parts of the year when I don't run the AC, maybe I'd use it to offset my TV.

Does anything like this exist? My preference would be to get a kit (Ecoflow etc) that includes as much of the functionality as possible and then add on if necessary for any missing functionality, but I would be interested in more piecemeal DIY solutions too of they're reasonably approachable for a beginner. I've watched a lot of "solar at various price points" videos on Youtube and sometimes some of the kits sound like they get pretty close to what I want, but I've never seen this exact combination of functionality discussed.

Thanks.

2 20 amp batteries. 2 USB ports outside. 2 USB ports inside. 2 AC outlets. 300 watt inverter that I'll probably have to upgrade.
DeWalt rolling toolbox. Water resistant. Charging posts for when solar isn't the best option.

But it accomplished my goal. It can charge power tool batteries by plugging in the standard tool charger or run A CPAP.

cross-posted from: https://natur.23.nu/post/12050

I wanted to park my bikes - or depending on the Season - my Renault Twizy somewhat protected and easy accessible.

After adjusting the yard fence to form a pocket I put a frame aluminium profiles on top. On top of that is a second frame which is angled at 10 degrees and on that are the solar panels.

10 degrees seem to be a viable compromise between self cleaning, sun capture, construction height and openings to the elements on the side.

It was much more challenging than i thought to find solar modules with a form factor fitting the shed.

4 Standard modules where far to big. So I choose two modern 410 Wp modules and 3 130 Wp “camping” modules.

I got two 600 W dyne (“Bosswerk”) Micro-inverters cheap, because everybody want’s 800 W now and they have a regulatory issue with a missing relay.

The 130 kWp panels are cabled serially but still seem to have issues getting enough voltage to start the inverter in the morning.

I’m happy with the project. Things in the shed are getting much less wet during rain und not baking hot during sunshine.

I might close the gaps between the panels obe day but that is low priority- the thing was never meant to be totally watertight.

I also like it being some kind of Solarpunk landmark in our street.

I'm looking for a small setup that allows the panel to be removed without removing screws from the roof and exposing holes.

I'm doing pre-install system testing before I get started on the real install later this week. Wanted to make sure all the components worked before I went any further. They've basically just been sitting in boxes in the basement since April.

Hooked up six of my 200W panels in a string and temporarily wired the inverter into the breaker panel to make sure that:

• Inverter was getting power from PV
• Inverter was charging the batteries from PV
• Inverter was outputting power
• The output was proper 120/240v split-phase (I tested that with a multimeter before hooking it in)
• The battery-to-battery communication was working
• The communication settings between the batteries and inverter were correct
• All the panels fit on the mounting rails and that my measurements were correct

All systems green!

The only thing that caught me off guard was that I mis-read the input voltage ranges for the inverter. DC input minimum is 120v but the MPPT minimum was 140v, so nothing was happening at first and it was only drawing from battery. I had planned to test with a string of 5 but that was just under the MPPT minimum so I had to lean a 6th one up against the 5 I had on the mounts.

The only untested mode is splitting the power input between utility AC and PV/battery. Due to the temporary way I have this hooked in, I can't really test that. I'm also only able to test the inverter at half load since I only had a 30A breaker on hand to wire it into the main panel.

Hi, I am just wanting some recommendations on a basic microinverter (with safety cutoff protections built in). Essentially, 'balcony solar.'

Just to make sure I am hooking things up properly/safely, lets assume I'm beginner experience level. I have a basic understanding of the general concepts, but not much real world experience. The two panels that I have are 100 watt panels. I've attached a picture for reference:

I have a 300Ah 12V LiFePO4 battery setup with three 100Ah batteries (internal built-in BMS in each battery) in parallel. I have it fused at the parallel junction with a 400A fuse.

I want to put a 125A MRBF fuse on each battery instead. If I do install per-battery fuses, is there a reason to keep the combined big fuse as well? I see wiring guides recommending both but I'm not seeing any explanation for why.

The reason for moving is that the current fuse gets way too hot when pulling 300A sustained. I don't have room in my setup to easily install the really big fuse holders with heat sinks that are made to handle 300+A sustained current. (Yes, I checked the voltage drops across all my connections. They are very low. It really is the fuse getting hot and not a weak crimp etc.)

The inverter is an Eco-Worthy 10KW unit which, like many others you can buy, is just a re-badged SRNE inverter.

It's got two MPPT channels, and the PV input voltage range is 100-500v DC.

I'm planning the layout and wondering if I can have my main string of 12 south-facing panels in series going to MPPT1 at 288 volts and a secondary string of 8 panels going into MPP2 at 192 volts. Trying to make the most of my limited west and south-facing roof real estate.

I can definitely ask the manufacturer support, but figured this was a basic enough question I'd ask here first and possibly get an answer faster.

DALY BMS Python Interface

A Python implementation for monitoring DALY Battery Management Systems (BMS) via Bluetooth Low Energy (BLE) on Linux. This is a command-line replication of the DALY BMS Android app functionality, designed to run on Linux PCs.

I am looking to mount my solar panels on an uninsulated pole barn about 30m from my house.

Does it make more sense to route my 48V dc lines to my climate controlled house or should I build a climate controlled space for just my solar inverter/batteries in my barn?

Are there any off the shelf containers for battery storage? Like a chest freezer designed to keep the interior at 15c?

The system will be hybrid grid tied with about 7kwH of battery capacity. My house is very shaded, but the pole barn is not. That is why mounting panels on the house is not an option.

Conclusion: After reading all your input I think I'm going to build a tiny room in my pole barn with insulation and a ductless mini split in there to maintain a stable temp/humidity over the year. It's a headache, but it's going to be cheaper than giving up 25% of my power to DC resistive losses or killing my battery's life.

Thanks for everyone's input.

I need a small solar charge controller for a 4.2V battery and a 5V solar panel. In my research, I found the SD05CRMA and the SDBK03TA 4V2.

Both use a 472 and a 1201 resistor. They both also use a CN3163 mppt lithium ion battery charge controller.

I see no other differences besides price.

Are there any benefits of one over the other in terms of physical architecture?

How hot are fuses supposed to get / what kind of voltage drop is expected?

I built a system which should allow 300A discharging (1C) / 150A charging (1/2C)

But if I run more than 60A, my main battery fuse gets hot. If I run 300A the fuse get rapidly gets too hot to touch, and the heat spreads through to the attached cables, the battery, and the temperature sensor on the positive battery post. Is this somehow normal?? I’ve tried three different types of fuses with no real improvement.

— Here’s a photo of my installation with voltage drops labeled at 60 amps draw only. I don’t have voltage drops measured for the 300A draw because I don’t want to leave it running that way for long.

The main fuse on the battery is a 400A ANL fuse. I’ve tried with a 300A MRBF fuse and with two 150A MRBF fuses in parallel. All of them get hot to the touch when drawing over 60A.

Help?

The guys at Flow Battery Research Collective have been designing a Redox Flow Battery development kit that you can build yourself using a 3d printer and a few tools. It's a desktop size flow battery that you can use to either do your own research, e.g. on different electrolytes or just to replicate their experimental findings.

Redox Flow Batteries have the potential to become grid scale or home electric energy storage solutions that are way better for the environment than current lithium based batteries. They can often scale power and capacity independently and allow for repairs.

The FBRC project wants to spread the knowledge on RFBs and help kickstart a global community that develops sustainable energy storage technology in an ope source fashion.

Beware that the project is still in its infancy and sourcing the materials can be a bit of a challenge. Be sure to ask around in the forums for help!

Hello. I recently bought an off-grid house with its own solar system. So I'm learning little by little. Right now, I have a Voltronic Axpert VMIII inverter connected to two battery banks. These battery banks have 16 batteries each, totaling 32 batteries (LiFePO4). Each bank has a BMS model JK B2A20S20P. There is no communication between this inverter and the BMS; everything works based on voltages, meaning I have told the inverter what voltage it should have. I am going to upgrade my installation with more panels, a Victron MultiPlus-II 48/10000/140-100 inverter, a Victron Cerbo GX MK2, a VICTRON MPPT 250/100-Tr VE.Can, a VICTRON MPPT 250/70-Tr VE.Can, and some other things that I don't think are important right now. My doubts arise about whether it will be possible to connect the BMS of the battery banks to the Victron system so that it can manage the batteries correctly, or if it is better to buy new BMS that do allow this. What do you think?

If I should buy a new BMS, which one do you recommend for this case?

Thank you very much!

Edit: Added type of batteries Edit2: I'm from Spain

Hi! I’m looking for recommendations for classes/education on off grid solar.

Basically something a little more than watching YouTube videos. I want to learn the basics of how to calculate how much capacity I need for different spaces, and what kinds of systems there are. I know very little about electrical systems so I’m sure I need more there too. I have plenty of time, so I could take some basic electrical classes as well.

Not necessarily planning to DIY my projects, but I want to know enough to know what I need so I can buy my own equipment, and pay someone a fair labor rate to install the skilled portion of the work, while I could do the more basic stuff. From my experience, the best way to get a good price and quality install is to learn as much as you can first. My projects are not really large scale. And I have plenty of room so I don’t need roof install.

Anyone have recommendations on classes on solar?

To see at nighttime ive been getting by with a 5v USB bulb for a while now. Its adequate and power efficient lighting for sure. But honestly I dont want adequate, I want the luxury of nice bright dimmable lighting.

I bought a cheap string light fixture, a male car cigarette outlet connector, and some 12-24v bulbs.

The string fixture had come with home ac outlet plug, so that needed to be cut off and replaced with a DC comparable outlet plug. Theres a few options but for now I choose a car cigarette plug male. I wired it together and plugged it into the 12v system, the bulb works nicely. Its daytime now so excited to test out and see how much of an improvement it made.

It would be nice to wire up a dimmer and intelligent microcontroller or radio frequency controls. I could get a three way socket adapter to put in a couple more bulbs but that may not be necessary.

Im considering installing a small - Maybe 1Kw set of panels into a location but I would like to get an idea of what their actual performance would be like before I do the installation. Its a strange location with some over hanging trees and some shading by neighbours fromntine to time but it could help provide some redundancy. Understanding of it could produce enough or whether a mains powered UPS is required would help before I pick and buy a solution.

Im wondering what is a cheap way to test out what Im actually going to be able to capture?

I was thinking of putting a small panel in place for a year and seeing how it performs. But I realised I might need a controller amd logger as well as and something to dunp the energy captured.

What would be the simplest / cheapest way to do this?

I've added an inverter sizing calculator to my website WattBuild. The goal is to establish what devices will be used, and to calculate continuous and surge power requirements using typical loads from our device research.

Open to any feedback!

I'm in the process of converting my garage to my home office and want to set up solar to run my laptop, a couple monitors, lights, phone charging and I'm sure a few other small things.

I'm looking at this power station EcoFlow DELTA Portable Power Station 1300 and getting 4 of these panels Topsolar Flexible Solar Panel 100W 24V/12V to run parallel.

It seems like this setup would work, but I'm just curious what people who know more think about this setup and if there's a better way.

I do like the portable power station so if the power goes out I can bring it in the main house as well as being able to plug it into an outlet for those cloudy days and I like the flexible lightweight panels as I'll be installing these myself.