If connecting generator to grid input, how does one assure no back-feed to the generator (besides disconnecting) if there is sometimes a small amount regardless of the zero export settings?
Is 18k pv the cheapest battery to grid inverter?
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I don't blame ya. We have this thing here called traffic there can make a person go crazy
zanydroid
Solar Wizard
Just to get it out of the way -- spurious export is not going to hurt the POCO.
The rules could say the PTO is for specific equipment (it is with PG&E).
The POCO could care where the kWh come from with ESS export (PG&E adds 50 pages of regulations for ESS on top of the non-ESS regulations).
If you are confident with your parsing of the interconnection agreement & other regulations (whatever your equivalent of Rule21 is), feel free to proceed I guess.
I hear you. Thankfully it's way more relaxed out here
zanydroid
Solar Wizard
You aren't allowed to connect a generator to grid without an interconnection agreement.
A power plant will synchronize phase and voltage as needed to take in & push out the appropriate power to the grid. A standard power plant (IE not a bootstrapping black start power plant) definitely does need some power to get the juices flowing and (possibly) some reactive power to keep going.
EastTexCowboy
Solar Wizard
Spent plenty of time driving in Houston and still do occasionally. Many years ago I had an office on Hillcroft just off 59S and drove in every day. I don't terribly mind it but given the option I'll stick to the rural traffic. I get mad every time I have to wait for more than two cars before I can pull out of the driveway.
It’s a nice day when the biggest inconvenience is the combine or tractor being too wide to get around
timselectric
If I can do it, you can do it.
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One of the biggest benefits (to me) , of owning my own business. Is scheduling my driving around rush hour. lol
Grid input of inverter. Gen input with be solar AC coupled. No utility connected.
zanydroid
Solar Wizard
Not sure what you are asking.
I’m not sure it’s safe in the general case for a hybrid inverter to turn on both generator and AC couple input at the same time, assuming both are AC coupled together. How would the hybrid inverter know the safe level of unintended backfeed into the generator, it probably varies by generator. Moreover frequency shift modulation would not be possible. I expect the hybrid inverter to have no choice but to pick the generator as the frequency to lock to. (Show me a home generator that can follow the frequency of another AC source…….)
If one or the other is DC coupled first then having both on simultaneously is viable. It would be easier to DC couple the generator by sending it through a chargeverter. This both eliminates the backfeed concern as well as restores the possibility of frequency shift.
Ya, I’d only run the generator at night if I needed to charge the batteries. So I guess a simple disconnect would probably work when I’m not using the generator..
timselectric
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I think that the better option would be to connect the generator to the generator input. And the AC coupled to the loads panel. The only thing that you have to do is set the hybrid to ramp down the AC coupled system before the battery reaches full. (Maybe 90%?)
Solar Guppy
Red Cobra Guppy
Just about any storage inverter will do this and there are plenty lower cost than the 18K pv or the Solark 15K
Of the top of my head and far from complete:
Solis 5G HVES ( 6kw backup )
Solis S6 ( just coming to market, 11.2kw backup top model )
Goodwe GW7600A-ES ( upto 11kw backup top model )
Growatt XH series ( upto 10kw Backup top model )
Generac ( do not recommend )
Solax X1
Tigo TSI ( looks like a relabed Growatt )
All of the above are less than half the cost, UL9540 certified. Note this are high voltage, not 48V and the UL9540 listings are for a small set of listed batteries, not DYI or flavor of the month rack batteries.
zanydroid
Solar Wizard
Is this safe? There is no disconnecting relay for the AC coupled inverter, only on the generator (presumably). If something out of spec happens the hybrid inverter can only instantly disconnect the relays it knows about. For the AC coupled panels it can only hope that anti islanding kicks in quickly enough.
Is it safe to presume that a nicer inverter like a solark or the 18kpv will be somewhat idiot proof with the most obvious ways to install? Feels like someone should read the manual and line diagrams multiple times (and even then I'm not sure how precisely specified the generator +AC coupling behavior will be)
timselectric
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Safe, yes.
At least Sol-Ark said it was.
The reduced battery setting was their recommendation.
zanydroid
Solar Wizard
How does the total system cost including battery come out to with those HVDC batteries?
I did not list those few posts up because I assume most people on this forum would be interested in the 48V systems
zanydroid
Solar Wizard
Hmm. I don’t think it can ramp down the AC coupled inverter if the generator is on. Feels like this is intended to turn on the generator after dark. With some conservative algorithm to guess how much PV output is available before turning on the generator (maybe taking into account local time)
Well, IF one is connected to utility grid, isn’t the generator on a transfer switch connected to GRID input when PV AC coupled?
timselectric
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No, it can't shift frequency while generator is running.
It shuts down the generator first. If batteries are full (or close to it), you wouldn't need the generator.
timselectric
If I can do it, you can do it.
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I suppose that could work. If the hybrid is in control of the transfer switch. Or at least the generator.
