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Assuming you have standard 24 VAC discrete thermostat controls (not RS-485 communicating ones), then: Divide your units into #1, #2, and #3 priority. You need a relay that closes when #1 turns on, another relay that closes when #2 turns on. Then run #3 turn on signal in parallel through the...

This is tin foil hat talk. The utility grid frequency is VERY tightly controlled. The utility is not going to shift it for some solar inverters. That would screw up people's clocks and the phasing of all the utilities power sources, including the interconnection of other grids across a wide...

That usually means they didn't pass FCC conducted emissions (electrical noise on the wires) with the filtering internal to the unit. The classic treatment for that is placing ferrite/toroid on the lines that exit the unit. Units which don't have that didn't need it to pass. This is why you...

I'm going to postulate that there are cases where the potential output of the 18KPV exceeds what the utility agreement is and the utility wants a hard, non user settable limit that they can positively assure won't be exceeded. For example, Florida Tier 1 agreements limit output to 10 KW AC and...

PV arrays are commonly strung to 400-500 volts instead of the common per panel voltage of 50 volts. This is because PV wires are long and the cost for heavy gauge wire would be excessive. This is the same issue with batteries, we just accept it due to short cables. But it sure would be nice...

There are free or nearly free CAD programs out there. Example: https://www.onshape.com/en/ https://librecad.org/ https://www.freecad.org/ and more... I have not used any of them, but you might be able to get this done at or near zero cost. Did they specify the file format? Or even CAD...

One nice thing about QO breakers is that you can get them with various features and accessories. It has a lot of versatile features. Available in GFCI, AFCI, and combination of both? They got that. Want two circuits per slot? They got tandems (panel has to be compatible): Want key...

You should have a bypass option so you can run the critical loads panel from grid directly while isolating the inverter. A relatively simple way to do this is an interlock breaker in the critical panel. The grid feeds the main breaker which is usually off, the inverter feeds the inverter load...

FPL will net meter on a yearly basis, meaning you only pay the for the difference between what you import and what you export in KWH. If you export more in a month, you roll over that credit to next month and it accumulates. If, after a year, you have a net export balance, they then pay you...

Short answer: it is highly likely to be okay for small magnets. A large static magnetic field can lead to saturation of inductors and transformers. When this happens, they lose their ability to store energy in the variable magnetic field. So putting a big magnet on an inductor can disrupt the...

Sometimes the utility also forces requirements. In Florida, if above 10 KW AC capability, they require an external AC disconnect. Below 10 KW AC, they don't. They measure AC power by taking 85% of the panel nameplate capacity, which is a bogus way of doing it since it penalizes those who have...

The 3 phase SMA inverters I found had no battery capability. Given my net metering rules and demand charges, that's a non starter. I can find single phase units which I can triple up, usually using 48 VDC battery systems, say 3 X 18KPV, but the extra wiring is not for nothing and you are...

The motor only cares about the magnetic field. If it takes 32 turns at 100 A or 2 turns at 1600 A, it is the same current density in the overall winding and thus the same magnetic field. A single turn motor is technically possible. When leaving the motor, however, the 1600 A current is a huge...

When things are weird, you have to get very detailed about what the numbers mean. I presume the above are AC current measurements taken with an AC clamp meter, properly zeroed prior to measurement, on the L1 and L2 outputs of the LOAD1 connection on the inverter. I further presume there is NO...

Interesting idea. You have your hybrid inverter with its own battery bank. That charges from solar when the sun shines but the house runs from the battery otherwise. I have an Ioniq 5 with V2L rated at 1800 watts. Let's say this can put in 1.2 KW into the battery by the time we leave some...

Funny you should say that... Today we were running the system grid down on battery to do a burn in test. About 3 hours into the test, the inverter shutdown and the backup panel went dark. Battery was at 88%. The inverter reported a battery comm error. In lithium mode, if the battery comms...

No better place to find wisdom and experience. Mike C.

I'm deep into getting a house setup with solar, inverter, batteries, and net metering with FPL in Sarasota, FL. The system is 11.7 KW of Canadian Solar CS6R-390MS-HL panels on a concrete tile roof, Amensolar N3H-10K-US inverter (still very new and has some teething issues), two EG4 14.3 KWH...

That is not how it works when PV is available. The MPPTs make the panel voltages into the desired voltage for the AC inverter (usually about 350 volts DC which is optimum for making 240 VAC and why making strings that produce about 360 volts DC is best for MPPT efficiency). There is no going...

If I had done that with my HVAC system, it would have turned out to be a mess. We definitely did it differently than the pros would have following their cookbooks. We designed it and hired an HVAC company to install it per our plans. We would design the solar system and we would hire an...

Then you should challenge your AHJ to justify their position of illegally ceding authority to the utility. It works that way on your county only because no has done that yet. It is often not very hard to challenge this. Sometimes a simple letter to the AHJ asking them to justify their...

If Victron's gear blows up under any circumstance at 0.68% over rating, it is extremely poorly designed with no safety factor provided. Ordinary component tolerances greatly exceed that figure. I'd be very surprised if the components aren't chosen to be at least 20% over the input rating. You...

There is no such thing as too much surge protection. Every bit you add moves the threshold higher for what the system can survive. In some places, surge is not an issue since they have few electrical storms. Other places are under constant lighting threat. Mike C.

All 9 of my HVAC units are in one mechanical mezzanine centrally located in the building, so easy to get to and wire however I want. I chose to make long supply and return ducts to do this, but it shortens everything else such as loop piping, electric power, drains, and control wiring. Net...

10 times the voltage rating means 100 times less current losses for any given resistance. So the 280 to 750 mOhm Rds is actually LESS power loss than the 10 mOhm part when you up the voltage 10 times and reduce the current 10 times. You also happened to pick a poor MOSFET. Consider...

That would mean the meter is basically a huge VFD capable of the entire service power. It would be grid AC to DC to VFD AC again. Nope, not happening. The cost and losses would be intolerable. Mike C.

Update on connector: The connectors I found do work and seem to be exactly the right physical fit. The pin out listed on Solar Assitant website is corerect: Pin 1: +5 VDC Pin 2: RS485 A Pin 3: RS485 B Pin 4: GND The picture shown on the Solar Assistant website is WRONG, however. The index...

Not clear I do. Indiana is using NEC 2008 presently which doesn't have RSD. Later NEC (2023?) allowed for UL 3741 which doesn't need per panel RSD, either. So I need per panel RSD only if I get sandwiched in a brief period of time on code compliance. In any case, Tigo TS4-A-2F is a lot...

Basically. The EV would be a relatively low power generator. A dedicated charger takes car's V2L output and charges the battery bank. The V2L power doesn't have to be what the house could momentarily draw, only be as high as the average over a long time, hours, maybe a day. Thus the inverter...

This is a very confusing thing, and I'm not sure I have it entirely figured out, but here is what I think: 1. External RSD button/switch NEC 690.12 rapid shutdown requirement. A button on the exterior of the building, near the utility meter, shuts down the PV array, the inverter, and any...