Off grid and grid tied inverters vs single hybrid inverter

[KauaiMolokai]

This is a great thread, thanks to all.

Could some of you please provide recommendations for what you have found to be the best off grid (grid completely disconnected or not available at all) inverters, preferably AIO, for a high electric demand property using 120V AC (240V possibly later but not necessary). 20-50kWh of battery available. Thanx

 

[Ampster]

This is a great thread, thanks to all.

One way to keep this thread great would be to start a new thread specifically about Off Grid inverters. You will probably also get more relevant results.

 

[Johneb]

This is a great thread, thanks to all.

Could some of you please provide recommendations for what you have found to be the best off grid (grid completely disconnected or not available at all) inverters, preferably AIO, for a high electric demand property using 120V AC (240V possibly later but not necessary). 20-50kWh of battery

Not an AIO but a solid inverter off vrid or grid tie. Outback Radian 8048. Yes you will need a few accesories but when your done you won't have to worry about it. This is my plan for our place.

 

[KauaiMolokai]

Not an AIO but a solid inverter off vrid or grid tie. Outback Radian 8048. Yes you will need a few accesories but when your done you won't have to worry about it. This is my plan for our place.

Thanks.

 

[zanydroid]

Normally you don't want to be draining the battery when running on utility. Usually when connected to utility. You would want to be charging the battery

What about:
- local consumption and time of use arbitrage for smaller loads, but not large loads (basically what this thread is asking about)
- generator assist when grid is down

For California TOU peak (4-9pm) there is a substantial period of time when the sun is down but you want to local consume or time shift grid power

 

[50ShadesOfDirt]

If grid is down (not very often?) and large loads can't be powered by current solar, you could:
- oversize solar for the largest loads (gets expensive), or
- add an on-demand generator (your fuel choice, diy options) to handle occasional outage, or
- reduce loads (water tank buffer to feed from during small outage)

Hope this helps ...

 

[zanydroid]

our showers and cooking

Hot water tank is a form of storage that is cheaper than battery. If you have an 80 gallon HPWH you can let it recover during the day on solar power and bank the energy until the evening.

I’ll note that resistive water heater is a popular , time honored way to bank excess solar production in the summer to avoid selling back or leaving solar power to burn off unused in the panel.

I mostly bring up cooking because it has a counterintuitive high power but low-ish total energy profile.

Incremental battery capacity for cooking might be cheaper than burning propane. I haven’t crunched the numbers though. If you run the math for incremental cost of extra water storage for HPWH vs battery storage or propane and the 300% vs 70% efficiency and it’ll probably look good. I guess you might want to compare to 95% efficiency of using tankless propane too.

California… then off grid all the way makes sense

For NEM2 going off grid completely is illlogical because of 1:1 net metering, and battery is mainly valuable for time shifting

For post-NEM2, net metering value is slashed by several times so the battery can easily minimum double solar ROI across the whole day. And I mean double relative to the slashing of ROI due to the reduced net metering payback.

Going completely off grid implies you need to scale solar to supply power in 99.99% of cases. Not doable with our lot sizes in urban parts of california for winter heating load, and not doable for an extended period of reduced production during winter storms even when on gas heat.

 

[timselectric]

Please let us know when you are fully off grid how it's going, and how much it cost.

It will all be in my Build thread.

 

[timselectric]

What about:
- local consumption and time of use arbitrage for smaller loads, but not large loads

None of that applies to off grid.

(basically what this thread is asking about)
- generator assist when grid is down

That's not how this thread started. It was asking about either or..
But it has leaned heavily in that direction, now.
I'm an all in or nothing kind of guy. I can't do halfway. But it works well for some.
I wouldn't be of any help in that regard.
Cheers

 

[1201]

None of that applies to off grid.

That's not how this thread started. It was asking about either or..
But it has leaned heavily in that direction, now.
I'm an all in or nothing kind of guy. I can't do halfway. But it works well for some.
I wouldn't be of any help in that regard.
Cheers

Why are you so against using the grid?

 

[timselectric]

Why are you so against using the grid?

The grid is fine for backup. I just don't have a use for grid-tied. NEM agreements are going downhill fast. And I wouldn't recommend anyone to spend money primarily in that direction.
The grid suppliers have no use for residential production. It's more of a hassle to them. It's available at the wrong place and time to help. If the governments didn't force them, they wouldn't even let it be an option.
In my opinion grid-tied is just throwing money away.
It's a temporary solution, and I prefer to solve things permanently.

 

[1201]

The grid is fine for backup. I just don't have a use for grid-tied. NEM agreements are going downhill fast. And I wouldn't recommend anyone to spend money primarily in that direction.
The grid suppliers have no use for residential production. It's more of a hassle to them. It's available at the wrong place and time to help. If the governments didn't force them, they wouldn't even let it be an option.
In my opinion grid-tied is just throwing money away.
It's a temporary solution, and I prefer to solve things permanently.

A grid tied zero export solution - is - 100 % using the grid as backup. You don't send anything to the grid but rely on the grid to power heavy loads and step in if solar is not enough

 

[Ampster]

The grid is fine for backup. I just don't have a use for grid-tied. NEM agreements are going downhill fast. And I wouldn't recommend anyone to spend money primarily in that direction.

I tend to agree with your strategy based on recent events in California. I saw the erosion of NEM benefits several years ago and became more committed to using a hybrid inverter with batteries to allow me to optimize my system and squeeze as much value out of my existing NEM agreement as I can.
Last calendar year, I generated 12 mWhs of energy and used 13 mWhs so I was a Net consumer, However I had a small dollar credit so that mWh of consumption did not cost me anything, other than the amortized cost of my system and the minimum charges from PG&E. Despite efforts to conserve energy, I have two EVs and have converted my gas furnace to a minisplit which provides heat in the winter and cooling in summer. My winter loads are more than summer but my summer production is greater so I need to use the grid as a giant battery to store energy during the different seasons. My True Up is the end of September and as we ended March my Net Consumption was 2.8 mWhs so I have six months to whittle that down to my sweet spot at True Up. I feel fortunate that I may still have 18 years on my NEM agreement but rates will continue to shift and I will have to adjust my montly tactics through out the years.
I have already added 2 kW of solar production beyond the amount allowed in my NEM agreement and will probably add more but will have to develope more tactics to prevent that potential peak production from causing my power provider from cancelling my current NEM agreement.

 

[Ampster]

A grid tied zero export solution - is - 100 % using the grid as backup

I wish it were that simple. Every market has its differences and the solution for me in California is going to be a different mix of components than one might have in Texas. I have to export to the grid to earn enough credits to offset my seasonal differences. I am not saying your philosophy is wrong, I am just saying that mine has to be tweaked to fit my use case and my rate environment. Over the years I have begun to move in the direction of zero export by consuming more of my solar energy when it is produced. I am now using excess solar to charge my EV batteries and will be converting my gas water heater to a heat pump water heater that can store solar energy.

 

[1201]

I wish it were that simple. Every market has its differences and the solution for me in California is going to be a different mix of components than one might have in Texas. I have to export to the grid to earn enough credits to offset my seasonal differences. I am not saying your philosophy is wrong, I am just saying that mine has to be tweaked to fit my use case and my rate environment.

True. But with net metering there is no need for zero export. In my case I need zero export because I don't want to sell to the utility for .04 per kWh AND pay $15 a month for a solar plan. It's cheaper to waste the energy and save the $15.

 

[Ampster]

In my case I need zero export because I don't want to sell to the utility for .04 per kWh AND pay $15 a month for a solar plan.

And that is why our strategies will be based on where each of us are standing. Did I hear correctly that in some places in Texas that at certain times energy is free?

 

[1201]

And that is why our strategies will be based on where each of us are standing. Did I hear correctly that in some places in Texas that at certain times energy is free?

There are some companies they offer free nights and weekends. Unfortunately where I live I only have one provider and that is not an option they provide.

I would be all over that if I had the option ?

 

[timselectric]

A grid tied zero export solution - is - 100 % using the grid as backup. You don't send anything to the grid but rely on the grid to power heavy loads and step in if solar is not enough

If that's the way you want to go, that's fine.
No need to convince me what you think would work best for you.
Freedom is a wonderful thing.

 

[1201]

If that's the way you want to go, that's fine.
No need to convince me what you think would work best for you.
Freedom is a wonderful thing.

Well you told me why you preferred an off grid setup and was just letting you know that gtze does the exact same thing.

 

[Cheap 4-life]

SUB mode is solar + utility.
SBU mode is solar +battery.
No mode for battery and utility together.
The same board used for inverter is bidirectional for utility charging. So, it's one or the other.

So you can’t use battery and grid power for the same loads at the same time? i thought AC/grid charging was simply disabled when utility was pasdingbthru to the offgrid panel to assist the inverters solar and battery output