Hitechluddite
New Member
But did you have a Merlin modem?LOL... lucky you... I had to use a soldering iron to build my first computer. Not just for connecting bits together, but soldering all the components to the PCB... Yes, I am that old
Deciding to DIY my solar battery was one of my worst mistakes ever
- Thread starter kolek
- Start date
wheisenburg
Independent Solar Consultant
Where do I start?
I bought a professionally installed grid tied system with Enphase IQ8+ micro inverters. I had the idea at the time that I would eventually add a battery backup system to it as a DIY project. The Enphase system, as a grid tied system has really met every expectation. It is reliable (not a single panel of inverter has failed). I actually oversized the micro inverters over what was recommended. I figured at the time they were designed to handle larger panels so smaller panels would not push the micros as hard and there should be less heat build up and longer life.
On paper these micros can deliver 10.3 KW. Because some of my panels are east facing and the others are west facing, at most I get around 9 KW at the peak of the season. So to AC couple I wanted inverters that could do at least 180 amps of charging and 9 KW of output. I looked at Sol Ark and thought they were good, but too expense. I also saw some videos about them not handling surge current very well. I heard the Schneider Low Frequency inverters had great surge capability. One would now provide enough charging or inverting power, so I got the "Two Inverter AC Coupled combo".
Now individually, both the micro system and the hybrid system have many great features. The problem is getting them to actually work together has proved more challenging then I anticipated. First, for 1.5 years I couldn't get the micro inverters to turn on and produce power at all. Then Enphase released an update to the firmware that fixed this issue. Thank you Enphase. Then I could get on string to come up and run fine. When I added a second string in ALL the PV would shut down. Presumably, this is due to some incorrectly configured setting that I have yet to figure out.
So, I built a PV shedding controller to manage the PV strings myself and turned off the "AC Coupling" function in the Hybrid inverter. On testing this worked perfectly. My system always would have worked fine as a battery backup system. I could have used a generator during those rare actual blacks outs we experience, if needed. The thing is I really wanted to be able to recharge my batteries with my solar when needed. I have that working now proving that the hardware is not the issue. More than likely it is a configuration problem. I am going to try and experiment more with the setting to see if I can figure out why the PV shuts down and won't come back on without rebooting the PV inverters.
So I think my biggest mistake was just not asking on this forum "Has anyone gotten this combination of hardware to work together, when connected in this manner"?
At least I hooked everything up the way it was designed to work. Maybe I would have decided to try and do this anyway. At least I would have gone into this with totally different expectations. I see many new forum members here thinking that AC coupling is going to be easy. You just buy a bunch of different stuff from different manufactures. Then you plug it all together in a novel way that it was never intended to be used, and everything will just work. Sorry but with AC coupling it is just not that easy.
I also see people thinking they can just add a generator, AC coupled PV, and their Hybrid Inverter. Then start them up all at the same time and some magical electron controller will make electrons go where they are supposed to. In reality these devices are connected to an AC bus just like the one in your main electric panel. Now some devices such as the Enphase "System Controller" do have CTs on each input / output and they do actually have proprietary communication channels to control the attached devices. They actually can balance PV production, battery charging, grid power and generator power. Most Hybrid inverter companies can't do this. Grid tied inverters are not designed to work with generators. They will attempt to back feed power into them. Sometimes the companies will give you this information, but it is not always prominent. Like Sol Ark on it's "AC coupled to Load" line diagram has a little "Do Not Use" blurb on the Gen Input. They don't explain why. It seems like AC coupled requires a whole different level of understanding to get it all working correctly.
So can AC coupling be made to work as a backup system when the grid is down? Yes, but don't expect that is will be easy or that any products will actually work together, unless you know of people that have gotten it to work.
diysolarforum.com
I bought a professionally installed grid tied system with Enphase IQ8+ micro inverters. I had the idea at the time that I would eventually add a battery backup system to it as a DIY project. The Enphase system, as a grid tied system has really met every expectation. It is reliable (not a single panel of inverter has failed). I actually oversized the micro inverters over what was recommended. I figured at the time they were designed to handle larger panels so smaller panels would not push the micros as hard and there should be less heat build up and longer life.
On paper these micros can deliver 10.3 KW. Because some of my panels are east facing and the others are west facing, at most I get around 9 KW at the peak of the season. So to AC couple I wanted inverters that could do at least 180 amps of charging and 9 KW of output. I looked at Sol Ark and thought they were good, but too expense. I also saw some videos about them not handling surge current very well. I heard the Schneider Low Frequency inverters had great surge capability. One would now provide enough charging or inverting power, so I got the "Two Inverter AC Coupled combo".
Now individually, both the micro system and the hybrid system have many great features. The problem is getting them to actually work together has proved more challenging then I anticipated. First, for 1.5 years I couldn't get the micro inverters to turn on and produce power at all. Then Enphase released an update to the firmware that fixed this issue. Thank you Enphase. Then I could get on string to come up and run fine. When I added a second string in ALL the PV would shut down. Presumably, this is due to some incorrectly configured setting that I have yet to figure out.
So, I built a PV shedding controller to manage the PV strings myself and turned off the "AC Coupling" function in the Hybrid inverter. On testing this worked perfectly. My system always would have worked fine as a battery backup system. I could have used a generator during those rare actual blacks outs we experience, if needed. The thing is I really wanted to be able to recharge my batteries with my solar when needed. I have that working now proving that the hardware is not the issue. More than likely it is a configuration problem. I am going to try and experiment more with the setting to see if I can figure out why the PV shuts down and won't come back on without rebooting the PV inverters.
So I think my biggest mistake was just not asking on this forum "Has anyone gotten this combination of hardware to work together, when connected in this manner"?
At least I hooked everything up the way it was designed to work. Maybe I would have decided to try and do this anyway. At least I would have gone into this with totally different expectations. I see many new forum members here thinking that AC coupling is going to be easy. You just buy a bunch of different stuff from different manufactures. Then you plug it all together in a novel way that it was never intended to be used, and everything will just work. Sorry but with AC coupling it is just not that easy.
I also see people thinking they can just add a generator, AC coupled PV, and their Hybrid Inverter. Then start them up all at the same time and some magical electron controller will make electrons go where they are supposed to. In reality these devices are connected to an AC bus just like the one in your main electric panel. Now some devices such as the Enphase "System Controller" do have CTs on each input / output and they do actually have proprietary communication channels to control the attached devices. They actually can balance PV production, battery charging, grid power and generator power. Most Hybrid inverter companies can't do this. Grid tied inverters are not designed to work with generators. They will attempt to back feed power into them. Sometimes the companies will give you this information, but it is not always prominent. Like Sol Ark on it's "AC coupled to Load" line diagram has a little "Do Not Use" blurb on the Gen Input. They don't explain why. It seems like AC coupled requires a whole different level of understanding to get it all working correctly.
So can AC coupling be made to work as a backup system when the grid is down? Yes, but don't expect that is will be easy or that any products will actually work together, unless you know of people that have gotten it to work.
Building a PV Shedding Controller for AC Coupled Solar
Back Ground I have an Enphase system with 35*350 watt panels. It uses the IQ8+ micro inverters at 295 watts each. So the total possible output is 10,325 watts. The actual maximum output is about 9000 watts. I have 7 panels that face east and 28 that face west. The slope of my roof is about...
diysolarforum.com
Last edited:
I trust that is a sarcastic "thank-you"... 1.5 years with no power !
OMG
wheisenburg
Independent Solar Consultant
Just to clarify, this has to do ONLY with their off grid operation. When these inverters were grid tied they produced power as they should. They operated with basically perfect reliability. It was only when "cutting my cord" to the grid that I had problems.I trust that is a sarcastic "thank-you"... 1.5 years with no power !
Lily Aldridge
New Member
There are things that we think we can manage to do. I've done some DIY myself, and it surely wasted my time.
squowse
Solar Enthusiast
- Joined
- Jan 4, 2021
- Messages
- 586
Possibly you’ve over complicated it? Can be as simple as lining the cells up, crimping rings on the balance leads, placing the busbars and screwing them all down.
Daddy Tanuki
Solar Wizard
No I get that, building a computer is easy, I didn't mean to compare the complexities, but the broad strokes of it all. But with the amount of time you've spent, I bet you've learned some stuff along the way, so maybe not a complete waste of time
Shiiii--it! 20 years ago building a computer was easy... these days i just buy them as too many ocnfsing choices to track and research. So while I find the battery builds easy and fun, you find the computer builds easy and fun. To each his own, but like above you are learning something even if you decided to never do it again.
Daddy Tanuki
Solar Wizard
i have mine compressed to raise cycle count, to keep the pack neat, and to bring my aluminum plates in firm contact to transfer heat in the winter from the heating pads. I used spring loaded rods to put a variable load that starts out at 10PSI at 30% charge and climbs up to 16 at full charge.
Daddy Tanuki
Solar Wizard
Brucey
Solar Wizard
Are those the 180Ah from batteryhookup?I recently completed my first battery build using nylon case CALB cells. I used a MRBF terminal fuse and corrugated plastic separators.
Do I qualify for "CHAD" status? Please note it is only a 12 volt system.
Daddy Tanuki
Solar Wizard
Windows 3.11 for workgroups... that would have been around 1993 or so...
Brucey
Solar Wizard
My wife's first husband, big into computer overclocking. Ended up drilling into freezer section of their fridge to eek out more performance.....so compared to that my solar shenanigans are of very low concern to her lol.
Daddy Tanuki
Solar Wizard
the lives we live huh?
Brucey
Solar Wizard
Yes so consider me out of the running for any experiments like, "can a Victron SCC that's placed in a freezer outperform one at ambient 75F thats approaching the temp of the sun due to less derating?"the lives we live huh?
Daddy Tanuki
Solar Wizard
Dunno, might be worth the doghouse for a night or two to figure that one out.Yes so consider me out of the running for any experiments like, "can a Victron SCC that's placed in a freezer outperform one at ambient 75F thats approaching the temp of the sun due to less derating?"
Brucey
Solar Wizard
I do have a chest freezer I can empty, what happens in the power shed stays in the power shed ...Dunno, might be worth the doghouse for a night or two to figure that one out.
Why not wire oversized in that case so that if a battery or two gets pulled, you aren’t self limiting your power
timselectric
If I can do it, you can do it.
- Joined
- Feb 5, 2022
- Messages
- 18,609
Or both. lolYou could do that.
Or buy more battery
Yeah, I upgraded TONS of systems to WFW, huge speed improvement over 3.1 disk cashing for the win!
