Enphase IQ8 vs IQ7

Hi, I’m thinking of holding out till IQ8 is released to the market in going from my present single phase 6 KW grid tied basic system to a hybrid, off grid capable system. I am a sparky.
I’m on 3 phase which presents some issue’s. I don’t have any 3 phase appliances.

Currently I have a back up permanently mounted 11KVA single phase diesel geny, so when I lose power, I can manually turn the changeover switch which shorts out all three phases on the load side and start the geny.

My question regarding IQ8 is and feel free to pull it apart and maybe no one knows the answer yet, I’d like to put more panels in across all three phases in the future, maybe 9KW in total, and change over from my Solax single phase 5KW grid tied inverter to Enphase micro inverters IQ8.
It appears the microinverters can detect the frequency/phase and sync as needed but what if in a hybrid system where I’d like to run it all as single phase when the grid is down, can the microinverters sense that it is all on one phase now when a change over switch shorts out all three phases and adjust accordingly to the new reference frequency? ie: the battery bank is generating single phase only, charged up by the single phase geny when needed.

Single phase is simpler/cheaper for components and ensuring the most is made from power generated as well as the Cat/Gough Geny is single phase.

Any thoughts

Cheers
Martin

Hi @Den_Thomson

Have you got any thoughts on hanging out for the Enphase IQ8 range for these reasons? It’s an interesting one.

Cheers
Marty

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Hi, at this stage I will hang out for the IQ8. The grid tied inverter I installed this year is only a cheap way to get up and running until I figure out the next stage. I do like IQ8s concept and would like to AC couple all components in the future. Steep learning curve for me but very enjoyable. Playing around with batteries at present as I can get used banks from substations. Cheers Martin

Hi Guys,
Sorry, it’s taken me so long to respond I’ve been flat out, which is weird considering it’s been raining cats and dogs over here lately. I wanted to run this by a few guys that are more solar savvy than me before I responded, I’m a Fitter Machinist by trade, that in itself should tell you I’ve worked on some pretty huge voltage gear. But I’m no sparky. Anyway, it sounds to me like (Vandevere) Martin is waiting for IQ8 in as far as it’s going to be grid agnostic and should do the trick. IQ7 is smart enough to detect and adjust to frequency changes. I spoke to Enphase today (regarding another Envoy R comms issue, seems to be the only issue with any of Enphase systems we have installed and only the old Envoy R’s) I mentioned this topic with the guy, and he said cabling may be an issue as the 3phase cabling works by sending down phase1 then phase2 then phase3. In his explanation of it, he thought that throwing the change over switch may limit the inverters into giving you 1/3 productivity. I will keep hunting the answer this as it is a little out of the square😉, I quite often chat with off-grid electrical engineer guys, and I think the answer lies there.

Questions.

  1. No 3phase appliances, but what do you have running on each phase?

  2. Is installing single-phase Enphase IQ8 an option as you seem to have a
    single-phase solar inverter now?

  3. Would a conversion back to single phase break the bank?

Bad News,
It turns out that IQ8 will be launched 1st quarter USA only, Australia middle of the year (if all goes well), this pisses me off no end because the good panels are getting out of range size-wise.

Kind regards
Den

Hi Den
Thanks for your reply and for asking around.
It’s not unusual for me to come up with out of square questions :slight_smile:
I’m on a lifestyle block so appliances used include a 2HP single phase pump which is used for irrigation as well, two electric water heaters (large house) on nightrate, Logburner heats the house but have a Air Con as back up and cooling in summer.
At present I have all load on one phase to maximise solar as buy back rate is around 8c in NZ. I would like to use all 3PH so I can put more panels in, 5KW limit per phase in NZ.
Sort of like having the best of both worlds is what I’m after, spread load over 3PH as the voltage does dip a bit much on one phase, install up to 15KW but then when the grid is down I can use the simpler single phase set up from a battery bank and back up diesel geny when the changeover switch is used to short the 3PH.
Thanks for checking with the off grid experts.
Looking forward to getting a plan together but ultimately will have to wait anyway for the IQ8 to arrive.
Cheers
Martin