Inverter with off grid capabilities WITHOUT battery

[Rho]

Off grid inverters
No export capabilities
But can share the loads with the grid
SUB mode (solar, utility, battery)

Careful with relay changing modes dc ac. Can click click,boom then several weeks later smoking wires. It seems the change from ac to dc hangs up. Eventually if restart the system it will go to line mode. Then it does not want to use pv power or batteries first if at all. Even if pv is at 270v and battery is 54.2. Still uses 90 % of amps from grid.
This happens for several days . Then loss of grid and click click boom smoking wires. Turn off remove from grid entirely wait couple days. Start up solar only seems fine. Grid is over rated.

 

[Ampster]

I might also wonder if the inverter would last longer using a small battery bank, because the main board would be able to supply itself with a steady power source instead of a fluctuating power source where it may not have a steady voltage bus to operate. While they work batteryless, it seems like it would be less optimal. So a battery would give a stable voltage bus for the main board to operate with and could allow it to last longer.

Another comment I saw on another forum also suggested that a battery gives and inverter some surge capacity not just from motor loads but from the 60 cycle change in voltage. That poster suggested without enough battery capacity the inverter would run hotter. I don't know enough to know if that is only certain types of inverters.

 

[timselectric]

Careful with relay changing. Can click click,boom then change several weeks later smoking.

Relay changing?

 

[Ampster]

Careful with relay changing. Can click click,boom then change several weeks later smoking.

If that is in response to the earlier load sharing comment it is not a problem with my inverter because it uses CTs and voltage to allocate and/or share the load with the grid. That functionality is programmable on some well designed hybrids that are designed to be grid interactive. It can be time based, kW based or both. As @timselectric , mentions below, the relays are static and only acitvated when the grid drops to prevent injury to linemen from backfeed to the grid,

 

[timselectric]

I'm not sure what they are talking about.
In SUB mode the transfer relays are static.
They remain in grid connected position.
They don't switch back and forth. (If that's the concern) it's probably the mode that would cause the least wear on the system.

 

[Rho]

Relay changing?

Guess I said this wrong. When it goes from grid to solar or battery. It makes the noises. The real bummer is solar will have plenty of volts avaliable as will the battery have plenty avaliable. It will use grid then use solar and never battery. Suks it wants use more amps from grid than solar. SBU not better. Sol for me is the best mode. I can actually use my pv power and battery without it switching to grid and using 60 % of amps or more from grid.

 

[timselectric]

Guess I said this wrong. When it goes from grid to solar or battery. It makes the noises. The real bummer is solar will have plenty of volts avaliable as will the battery have plenty avaliable. It will use grid then use solar and never battery. Suks it wants use more amps from grid than solar. SBU not better. Sol for me is the best mode. I can actually use my pv power and battery without it switching to grid and using 60 % of amps or more from grid.

SOL is too annoying for me. In the evening it keeps switching back and forth.
SUB runs smoothly. Solar provides all that it can, and grid makes up the difference if needed. Any excess Solar goes into the batteries, if they aren't already full.
Batteries are only used if Solar and grid aren't available.
It works like a charm.

 

[Ampster]

I can actually use my pv power and battery without it switching to grid and using 60 % of amps or more from grid.

Since the volts vary from those sources I use Watts to decide which is more efficient. Actually, I don't even think about it and let my inverter decide based on time of day. Solar is the least expensive source of energy for me.

 

[Fardenco]

Thanks to all of you for your interesting posts, I'm learning many things.
Just to update, after some research, I'm attracted by the Enphase IQ8 series.
It seems suitable to what I'm looking for, with the ability to provide emergency power without the need of any battery when used in conjunction with the IQ system controller.
I've found really useful informations here :

Overview of Enphase Energy Systems

Learn how Enphase Energy Systems can be customized to meet your solar + backup power needs.

www.gogreensolar.com

Enphase IQ8+ Review: Is It Worth It?

Our Enphase IQ8 review explores the new Sunlight Backup feature, which promises "backup without batteries." Let's find out if the IQ8 live up to the hype.

blog.gogreensolar.com

The only real downside to this solution in my opinion is that from what I understand, if I later decide to add a battery, I'll have to go with an enphase battery. But I can live with that.
What do you think ?

I also have a question about something I don't quite understand regarding the power of those inverters (same thing with IQ7 serie).
I can read everywhere things like "The IQ8+ micro inverter from Enphase are designed to handle 235 to 440 watt solar panels."
But when I look at the technical data here https://enphase.com/store/microinverters/iq8-series/iq8plus-microinverter
It says "input power : 235 - 440+ W, Maximum continuous output power : 290 VA"
But if the max output power is 290VA, that means that I'll never be able to fully exploit a 400Wp during a sunny day, right ?
Then for a 400Wp panel I'd have to go with something like the IQ8H, which have a max continuous output power of 380VA, which is the closest of all the series, right ?
Is that misleading or am I missing something ?

Anyway, I'm attracted by this solution because to me it seems to be the best one in term of function vs cost.
The upfront cost is quite high, but since the inverters come with a warranty of 25 years, compared to a string inverter that have a lifespan of 10 to 15 years (from what I understand), it's basically like cutting the cost in half in the long term. I've read that the efficiency might be a little bit lower but I can live with that.
What do you think ?
Thank you for your help

 

[Ampster]

The only real downside to this solution in my opinion is that from what I understand, if I later decide to add a battery, I'll have to go with an enphase battery. But I can live with that.
What do you think ?
s

I have AC coupled IQ7s to my hybrid inverter so you have plenty of options. The IQ8s are capable of the same thing.

I also have a question about something I don't quite understand regarding the power of those inverters (same thing with IQ7 serie).
I can read everywhere things like "The IQ8+ micro inverter from Enphase are designed to handle 235 to 440 watt solar panels."
But when I look at the technical data here https://enphase.com/store/microinverters/iq8-series/iq8plus-microinverter
It says "input power : 235 - 440+ W, Maximum continuous output power : 290 VA"
But if the max output power is 290VA, that means that I'll never be able to fully exploit a 400Wp during a sunny day, right ?
Then for a 400Wp panel I'd have to go with something like the IQ8H, which have a max continuous output power of 380VA, which is the closest of all the series, right ?
Is that misleading or am I missing something ?

It is very common to have a higher DC capacity than AC capacity. My IQ7s are also limited to 290 Watts and I have 345 Watt panels . Today they are clipping but on cloudy days or in winter i am getting less. Panels rarely put out their rated capacity so DC to AC ratios of 1.25 to 1 are very common especially with string inverters. . Of course I could have spent more on inverter capacity but the extra power would not be worth the expense.

 

[Fardenco]

Ok I understand, thank you for your explanation.
I'll just have to wait then, since the IQ8 series is not available in France yet.

Edit : Enphase has a great document about the consequences of having panels more powerful than the max output of the inverter, really interesting

https://enphase.com/download/iq8-pv-module-rating-larger-inverter-rating

 

[Hedges]

It says "input power : 235 - 440+ W, Maximum continuous output power : 290 VA"
But if the max output power is 290VA, that means that I'll never be able to fully exploit a 400Wp during a sunny day, right ?
Then for a 400Wp panel I'd have to go with something like the IQ8H, which have a max continuous output power of 380VA, which is the closest of all the series, right ?
Is that misleading or am I missing something ?

Marketed based on how big a panel you can connect without damaging inverter, rather than on the power it can output for you to use.

Anyway, I'm attracted by this solution because to me it seems to be the best one in term of function vs cost.
The upfront cost is quite high, but since the inverters come with a warranty of 25 years, compared to a string inverter that have a lifespan of 10 to 15 years (from what I understand), it's basically like cutting the cost in half in the long term. I've read that the efficiency might be a little bit lower but I can live with that.
What do you think ?
Thank you for your help

25 year warranty, but what is actual track record?

10 year warranty standard, 20 year available for Sunny Island.
(Warranty terms also put a limit on kWh, in line I think with nominal PV array size not one that delivers extended hours of full power.)

Back when warranty was 5 years on an earlier model, I installed several. Couple of failures. Total worked out to 35 years MTBF when I removed at 17 years. Perhaps if I ran a few more years they would have started dropping like flies and reduced MTBF to 20 years? Or maybe would have pushed out beyond 35 years MTBF?

String inverters are also more efficient and more economical than microinverters.
Unless Rapid Shutdown is required; that extra box per panel wipes out the savings.

https://files.sma.de/downloads/SBxx-US-DS-en-41.pdf

 

[dennis301]

Delta H6 hybrid inverter will supply 6kw as a grid tie inverter and will also supply 6kw to offgrid love ads without using a battery. I have one I’d be willing to get rid off. I used it for one month before I realized my electric company wasn’t 100% honest about their solar program.

What did your electric company do?

 

[Cheap 4-life]

What did your electric company do?

They verbally informed me that they give credit for backfeed but what they say they actually meant was that I get credit for the power my inverter produces to use as it’s produced.. meaning that I don’t get credit for anything I don’t instantly use.. the. If I don’t use it they get it for free to sell to my neighbors.. I stopped that chit quick