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So, is aluminum and stainless okay to use together or not? One intersection shows green, one shows red. Mike C.

I don't think it is, actually. It is a manipulation of the code to increase sales of microinverters and MLPE. Studies showed firefighters are not seriously at risk from a PV array. This covers the issue reasonably well: Years ago, no RSD was required. Then it was when pushed by companies...

A simpler solution is the 9 VAC signal through a 4.7 megaohm resistor to the gate. You don't need to divide it down, rectify it, or anything. No, the 9 VAC voltage won't harm the gate because it has protection diodes and the current you push through such a high value resistor is minimal. If...

Yes, 8 x 8 x 48 trough. The EG4 indoor battery terminals exceed 8 inches from the wall and thus won't fit into the 8 x 8 trough. I got fooled because the dimensions on the EG4 website say it should fit but they didn't include the rear bracketry. I've elected to not use the EG4 conduit box or...

Is that Voc at the lowest temperature your panel will experience? You can't just use the Voc for 25 C. All the parts rated at 100 volts have some engineering margin in them, and the circuit designed may have added their own margins to everything, but how much is uncertain. Going over less...

The issue here is how the control system operates for each mode. In on grid mode with net zero export, the system is pumping energy into the local load and monitoring the CTs to prevent export. The CTs are slow devices, you basically have to measure a half or even full cycle to know the...

That is what I was planning to do for my three strings but I am concerned they do not conduct heavily enough. The current versus applied voltage curve for MS DC SPD devices: The MNSPD600 doesn't really start to conduct until 1000 volts, and it takes 1200+ volts to get solid clamping of a...

Indiana, too! Yeah! This might mean no RSD requirements for me. Mike C.

if you don't use the LOAD connection, then the 18KPV does basically the same thing as the two inverters in your diagram. The key advantage is that you can reconfigure the 18KPV to due backup (add batteries, and it will work with the grid). When (not if) your utility stops net metering, then...

They provided further details privately. The conclusion was the pricing of the Hoymiles HSRD-2C devices was not materially different than the commonly available and seemingly equivalent Tigo TS4-A-2F devices. I dislike the RSD requirements, so anything I can do to reduce the cost impact of...

Correct. An illegal way to do this is to: 1. Turn off main panel main breaker. this disconnects you from the utlity. 2. Turn off every breaker in the main panel you do not want to power. 3. Turn off the main panel inverter breaker. 4. Turn on the backup panel grid breaker. 5. Defeat the...

$140K for 962 panels is $145 per panel, which seems high. An Ironridge roof setup would run about $60-70 per panel and there are plenty of cheaper ways to mount panels. The power warranty is among the worst I've seen, 80% in 25 years, despite the datasheet saying "industry leading 25-year...

The documents provide authorization to mark, but is the device ACTUALLY marked as such on the label? Inspections have failed for that reason. A document saying they CAN mark doesn't mean they do. Mike C.

Did you consider microinverters? If you are exclusively grid tie, that would seem to be the simplest system to build. It eliminates the PV isolators, the two string inverters, the AC combiner box, and the array AC output can go directly to the RGM. The microinverters, like Enphase, will give...

Does the install manual specify mounting on a non combustible material and does the 2x4 qualify as that? Wood makes an easy mounting material, but I thought I couldn't use it. Mike C.

Sorry, I see no explanation of why neutral loops are dangerous or violate code. Can you be a bit more explicit about this? Mike C.

Useful to know. 3 months puts that about end of July, maybe beginning of August. My experience with NRTLs is that it can often take longer than they predict. Maybe SGS is better than most (can't be worse than UL!). The UL9540 would only apply with your inverter? Nobody else? What inverter...

I think you mean "adjuster". The agent is just a sales person. I am not as jaded as you are about the lack of basis in settlements. I sure hope it is not the mood of the insurance person that determines your results. Insurance knows if they get a reputation for petty denial, their sales will...

The code book. It says 480 VAC in plastic conduit is okay, but 480 VDC in plastic isn't (just picking some voltage). Both are lethal if contacted while energized. Why the difference? What makes plastic conduit acceptable for a 480 VAC circuit but not for 480 VDC? The code requirement for...

It will help. How much it helps depends a great deal on the specifics of your situation and setup. Mike C.

For my size building, the utility only does 3 phase. To rewire the building to split phase would be exceedingly costly in any case. We have maybe 2 things that are truly 3 phase (like a large temperature chamber). I'm not to the point of buying stuff yet. Mike C.

Thinking about this more, this solution is overly complex. You don't need an inductor. PV panels feed input cap. MOSFET (or IGBT) connects input cap to water heater. PWM the MOSFET to get the desired voltage on the cap. That's all you have to do. The inductor is there to provide steady...

This is evident when you look at the inverter efficiency numbers. Using EG4 18KPV: PV to AC: 97.5% Battery to AC: 94.0% The higher voltage of the PV array yields higher efficiency in the inverter. Mike C.

What is the regulatory basis for this? Mike C.

Or Amensolar N3H-X10-US available now for $2200. There are other grid interactive, 10 KW class, sub $3K, string inverters out there. Add panels and battery to complete the system. If you want fast backup (like a big UPS), then you have to find units with fast switchover times. If the...

That's kind of limiting since those settings are material to controlling the device. The remote config ability is kind of important since I will be remote monitoring this install. Mike C.

I find it really upsetting when such limitations are not CLEARLY defined in the manual. It leaves you wondering what other gotchas are lurking in the system. What this means is that if your batteries are down due to fault, maintenance, replacement, whatever, you've lost you solar system...

But it doesn't actually do that. Pulling the inverter grid disconnect leaves the critical panel running off the inverter batteries, leaves the batteries energized, leaves the PV array attached an operating. As far as the inverter is concerned, it looks like a grid failure, nothing more, so it...

They are using a CM (contract manufacturer). He indicated he wants to keep them from having other customers by saying this: "We need to keep that confidential as others would want to use the them." That's not saying others would use MNS IP, it is saying MNS wants to block the CM from new...

What prevents you from turning on both breaker sets and crossing grid to load? Why not use one of these: https://www.amazon.com/gp/product/B07RQVDJ71 Assures no crossing, can be switch manually, and it can switch automatically if inverter load fails. This isn't a breaker, however, so a...

Good thought, but the spikes have occurred when I was on battery comms and when I was off it. It does seem to be less occurrence when off it, though. I had 3 events in 2 days on battery comms. I had 2 events in 7 days off comms. Maybe that's a clue, maybe not. The battery comm event is in...

That is very interesting. The Amensolar inverter clearly has Megarevo design heritage, so that is the one I chose. That would be useful. I don't think this means anything for my power drops, but still worth investigating. Mike C.

There is a proposal to update Indiana to NEC 2023. There are committees working on that now and I expect this will happen perhaps by early 2025. There are some nice things about NEC 2008, though. It lacks the RSD requirement for solar strings, for example. Mike C.

Quick Hook is extruded aluminum and depends on ears slid into channels: All Tile Hook is stainless steel which is a much stronger material naturally, roughly 2.5 times as strong per unit size. In the test reports for the Quick Hook, the failure mode was "broken hook". For the failures in...

Yes, it will work. The battery near the charger end will charge faster and discharge slower than the battery at the load end. If you want to balance them, have the charger feed the top negative and bottom positive, have the load tap the bottom negative and the top positive. Now all batteries...

I have so much excess HVAC capacity (despite being less than half the office building guidelines) that it would be reasonable to install a control system to peak shift thermostat demands. Basically, avoid a random event where too many are on at once. The top end idea is to monitor my total...

How will that prevent simultaneous starting of two HVACs units? How will that allow all three to operate but not at the same time? How will it know what units to enable based on thermostat requests? Genuine questions, hoping it does do the above. Mike C.

No. It worries me, too. I want to put the button under a cover to make it less obvious and to avoid a nuisance switch if someone leans on it. Note that anybody could cut your meter security tag and pull your meter to shut off your power, but that's a lot more commitment than flipping a...

https://www.amensolar.com/n3h-x10-us-10kw-48v-split-phase-hybrid-inverter-amensolar-product/ The Amensolar N3H-X10-US is what Watts247 is selling. He calls is the NHX-10kW, but the certifications have the Amensolar model numbers...

I heard back from Emporia. After they kept trying to tell me how to download CSV files (which I knew), they finally understood my question was how to get 3 hours of 1 second data. it is already lame that 3 hours is all you can get, but at least I wanted that. Their answer: Mike, The app...

As an electronics engineer, there are a number of issues I have with this cable strategy. First, he taps the A/B lines of the RS-485 signals on the RJ45 but has no ground pin. He leaves that floating. This is bad. RS485 has a limited common mode voltage range (max +/- 7 volts difference...

Since you already have that, it is the natural choice for your system. There are two concerns, of course, natural gas leaks and explosions risk, and the fact that in a major earthquake, the natural gas lines will likely be inoperable. Outside of those concerns, you already have it, so you...

With the better picture from his video, I found a possible candidate: https://www.aliexpress.com/i/3256805461901492.html I don't have the inverter, so someone would need to take measurements to see if this looks close, and if so, order some and try them out. I'm reaching about 90%...

Not very efficient, that size panel is usually in the 450 watt class. Mike C.

I'd suggest absorption be 52.5 volts, which is 3.5 volts/cell. Equalization volts can be the same, probably doesn't matter with 0 times. Float at 51.0 volts is 3.4 volts/cell which is okay. It doesn't seem to actual provide a float voltage since your voltage has drooped below the setting...

Batteryless backup is very unstable. A passing cloud and your power goes down. A system with a battery, even a small one, is vastly better than a system without one simply due to buffering variations in the PV output. The cost spent to buy lots of panels to deal with variations is better...

Agnostic dyslexic insomniacs lie awake at night wondering if there really is a dog. Mike C.

The battery datasheet: https://www.sicetelecom.it/wp-content/uploads/2021/07/Intelligent-Lithium-Battery-ESM-48100B1-Datasheet-Draft-A%EF%BC%8801074746-010%EF%BC%89-....pdf It feels like this is a 15S battery, 15 cells in series which has a nominal voltage of 48 volts. Most "48 volt" LFP...

In the interest of trying to debug this, it feels like there is an unintended coupling of something between inverters that is a subtle fault that has escaped detection. The big clue here is that isolating the battery changes the behavior. I would check any sort of connection between the...