Smasher3545
New Member
not sure, he gave 3 options, the HMS-2000 wasn't among them. maybe it wasn't in stock?
microinverter recommendation
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Hedges
I See Electromagnetic Fields!
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A string inverter like Sunny Boy costs less per watt, can handle multiple parallel strings of different orientation for more hours production & flatter curve (even lower cost per Wh), is more efficient, has higher reliability, is easer to swap out for service.
Downsides include PV panels biased to higher voltage, which may cause PID. RSD, if required, negates much of the cost savings. Higher power string is greater arc-fault risk (Large single panels may be getting into the wattage range where arc-fault will be required in microinverters.)
Hedges
I See Electromagnetic Fields!
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A moderate number of guerilla grid-tie users won't destabilize the grid. What the utility doesn't know won't hurt them.
If someone is sub-metered with an old mechanical meter that spins both ways, any export will supply neighbors, won't spin the community's master meter backwards.
Good ol' net metering.
I think instead of requiring grid support for installations after a certain date, should have required grid-support for inverters manufactured after that date. No reason to invalidate old stock or relegate removed inverters to the scrap heap. They work find, move them around and install them elsewhere, don't require new feature units instead.
zanydroid
Solar Wizard
Those are true in general, but the system in question is at the extreme small end.
Sure, with strings you can easily start with 50% the cost per watt with standard 1.2x overpaneling. And if you do the orientation-based overpaneling you can easily chop it down to 25% (which probably does a good job at canceling out the RSD overhead). This ability to do orientation diversity is intractable for microinverters to overcome.
What is the wattage range that requires arc fault in a microinverter?
Hmm. This AP-Systems RSD has a 8-80V operating voltage for $25 apiece. This should be able to do 2s of 60 cell in mild climates and 2s of 54 cell in almost all climates. RSD-S-PLC. For some reason though the power limit is 700W, maybe I'm missing something.
EDIT: IE, what is the mechanism by which power is relevant when both maximum voltage and maximum current are maintained, when there is no power conversion
Same applies for the equivalent from TIGO.
I was thinking of suggesting to ship them to other countries... but a lot of countries that would want them also have crap grids. And grid-tie inverters are not what customers want to mitigate that. Maybe they can use it for hodge-podge utility-side installations.
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Hedges
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Yup. Which is why, if new grid-support features aren't needed, I suggest an old SWR 2500U or similar. Just hook it to the 5s panels and it works.
Well, may clip at a current limit with larger panels, 13A max. If so, either let that happen or consider higher wattage inverter.
RSD 2014 was 30V, 250VA
The newer RSD is 80V, what VA? May no longer have a limit.
Arc fault, I see mention of 80V, not seeing VA for required (but detection limits quote watts.)
https://pv-magazine-usa.com/2023/03...ments-and-recent-developments-for-pv-systems/
So the microinverters may be exempt. For now, until some 500W or 1kW PV panel starts a fire.
Old Sunny Boys are great with Sunny Islands for off-grid.
My micros list:
NEC 2020 Section 690.11 DC Arc-Fault Circuit Protection
NEC 2020 Section 690.12 Rapid Shutdown of PV Systems on Buildings
NEC 2020 Section 705.12 Point of Connection (AC Arc-Fault Protection)
Product Safety Compliance
UL 1741-SA, UL 1741-SB, CSA C22.2, NO 107.1, IEC/EN 62109-1, IEC/EN 62109-2
Grid Code Compliance (Refer to the label for detailed information)
IEEE 1547, VDE-AR-N 4105*, VDE V 0126-1-1/A1, G83/2, CEI 21, AS 4777.2, AS 4777.3, EN50438, ABNT NBR 16149/16150
Smasher3545
New Member
I'm progressing slowly on my build. I got the microinverters and finished building the frame on which I'll install the racking. Friday I got the main unit of the Anker Solix F3500 battery. I got in on the 35% off kickstarter. Waiting on the extra battery and 10 circuit manual transfer switch.
My plan is to wire the PV's directly to the battery so I don't connect to the main breaker panel and then use the transfer switch to switch over those circuits to power from the battery. If needed I just switch back to grid, but otherwise stay on battery to reduce my grid power usage.
Speaking of which, when it comes to grounding/bonding, would it be proper to bond all the PV parts together and then wire that to a ground wire that I connect to the ground in the main breaker panel? I'm thinking I'd have a junction box under the panels where the microinverter trunk cable connects to, then run a cable from the junction box under the porch roof to a breaker box at the porch to be used as a manual shutoff switch, then from there run the wires under the house and over to the point where wires go up into the breaker panel, but only have the ground wire connect there and run the other 2 wires out the wall and have the XT60 adapter on the end of those to connect to the Anker battery.
Also, would RSD be necessary in this sort of setup?
[p.s. turns out the panels do have MC4 connectors]
My plan is to wire the PV's directly to the battery so I don't connect to the main breaker panel and then use the transfer switch to switch over those circuits to power from the battery. If needed I just switch back to grid, but otherwise stay on battery to reduce my grid power usage.
Speaking of which, when it comes to grounding/bonding, would it be proper to bond all the PV parts together and then wire that to a ground wire that I connect to the ground in the main breaker panel? I'm thinking I'd have a junction box under the panels where the microinverter trunk cable connects to, then run a cable from the junction box under the porch roof to a breaker box at the porch to be used as a manual shutoff switch, then from there run the wires under the house and over to the point where wires go up into the breaker panel, but only have the ground wire connect there and run the other 2 wires out the wall and have the XT60 adapter on the end of those to connect to the Anker battery.
Also, would RSD be necessary in this sort of setup?
[p.s. turns out the panels do have MC4 connectors]
Smasher3545
New Member
not exactly, I had a porch roof extension built and the PV's are going on that, but I also built a frame to get a better angle going, so it's kind of like a ground mount, but on a roof... ?
the joys of owning a mobile home.
If your plan is for micro inverters, you don’t need separate RSD.not exactly, I had a porch roof extension built and the PV's are going on that, but I also built a frame to get a better angle going, so it's kind of like a ground mount, but on a roof... ?
the joys of owning a mobile home.
Smasher3545
New Member
ah thank you! good to know
Can you guys comment on the difference between these Hoymiles micros?
HM-1200NT $280
HM-1500NT $339
HMS-1600-4T-NA $354
HMS-2000-4T-NA $381
The first two are older versions, second two are current ones at NC Solar. I have a bunch of REC N-Peak 3 400 panels and from what I can see, the HM-1200NT would probably work fine, with maybe a little clipping? I say maybe, because these panels would be a mix of NW and SE facing at 10 degree angle, so not optimal. I call this my "supplemental" solar project, where I know it's not optimal, but I also got the panels closeout at about $.30/watt, so nice panels that aren't breaking the bank.
REC spec sheet shows nominal output at 302W. Seems like combined with non-optimal orientation and tilt, plus shading from early and late day... I probably won't get 400W, except at the peak of the day anyway.
Edit: I am looking at five of these microinverters, so the savings would be around $500 between the 1200 and 2000. Decent savings, which is why I ask if anyone has feedback. Thanks!
HM-1200NT $280
HM-1500NT $339
HMS-1600-4T-NA $354
HMS-2000-4T-NA $381
The first two are older versions, second two are current ones at NC Solar. I have a bunch of REC N-Peak 3 400 panels and from what I can see, the HM-1200NT would probably work fine, with maybe a little clipping? I say maybe, because these panels would be a mix of NW and SE facing at 10 degree angle, so not optimal. I call this my "supplemental" solar project, where I know it's not optimal, but I also got the panels closeout at about $.30/watt, so nice panels that aren't breaking the bank.
REC spec sheet shows nominal output at 302W. Seems like combined with non-optimal orientation and tilt, plus shading from early and late day... I probably won't get 400W, except at the peak of the day anyway.
Edit: I am looking at five of these microinverters, so the savings would be around $500 between the 1200 and 2000. Decent savings, which is why I ask if anyone has feedback. Thanks!
zanydroid
Solar Wizard
I know these well, and one of the distributors (ncsolarelectric (oh heh you linked him already)) is also on the forum / has been helpful for me for product support over e-mail.
I have a lot of HM-1500NT installed and I cross shopped them with HMS series.
With Hoymiles the cost difference between different grades of the same series will be pretty small. I surmise (as a solar DIY scrub, not a systems designer, but I'm also an engineer in other discipline) that the main reason to go with smaller is to stay under POCO export limit policy and to avoid overloading branch circuit. You can fit more 1200's than 1500s on a 30A branch (the biggest branch circuit allowed for Hoymiles).
The difference between HMS and HM 4 port is that (1) most HMS are going to be 4 Tracker (that's what 4T means) (2) 900MHz comms vs 2.4 GHz comms. So you don't want to mix HM and HMS in the same system, unless you are OK with having two separate management boxes, one for each frequency
HM-1500NT is 2 tracker. So two of the inputs are paralleled together, which will result in less optimal tracking and theoretically prevent bypass diodes from being activated as optimally. FWIW I don't think I ever saw my bypass diodes activating on my half-cut panels, but YMMV.
Another opportunity with HMS (although I never discussed it with ncsolarelectric, and nobody I suggested it to came back and said they tried this) is that it has a much higher ISC per port than the HM series. So in theory you can parallel two older generation panels together into one port! And save money that way. For this the idea is to basically overpanel a HMS-2000. I don't think HMS-1600 would be a good fit.
Smasher3545
New Member
so I've completed my install and have been up and running for a little over a week. I've been working on creating the one line diagram so I can get the permit [any suggestions on the easiest DIY way of doing this? currently using draw.io and trying to figure it out].
So... I'm currently operating guerilla and hoping. I'm curious about this, does any excess electricity I produce count as usage by the utility company and I get charged since I don't yet have a permit and they don't know about the PV system yet?
Hedges
I See Electromagnetic Fields!
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I installed the free OpenOffice Draw.
But permit offices may be asking for more detailed and properly formatted drawings now, site map, certain views of house etc. all in one .pdf; I haven't figured out how to do it all.
If you backfeed the utility is likely to tell you to stop under threat of being disconnected. Some meters might count as consumption, haven't seen that myself.
But permit offices may be asking for more detailed and properly formatted drawings now, site map, certain views of house etc. all in one .pdf; I haven't figured out how to do it all.
If you backfeed the utility is likely to tell you to stop under threat of being disconnected. Some meters might count as consumption, haven't seen that myself.
zanydroid
Solar Wizard
The way you're operating is super easy to detect if you have any kind of smart meter.
Smasher3545
New Member
ah ok. I've watched a few videos on youtube about doing the one line diagram, there's some pay for apps and services, one guy used Google Draw. 
funny enough the utility company installed smart meters the same day I went live....
so I should probably get the permitting done ASAP me thinks
funny enough the utility company installed smart meters the same day I went live....
so I should probably get the permitting done ASAP me thinks
Smasher3545
New Member
I wasn't aware of zero-export controllers. did a web search, I like the idea. I have Hoymiles micro-inverters so I'll have to check for something that works with them
