Why "critical load panel only" when grid is down?

[ButchDeal]

Sunking Are you saying I have to have a generator for the Radian to work? Hmmmm, Outback hasn't mentioned that...

NO
You don't need a generator for the Radian or any other outback inverter to work. What he is saying is that to live off grid indeffinitly you would need a generator. In your case the grid will sufice. They are refering to living off grid mostly because of your want to run everything in the house during an outage.

[gmanInPA]

ButchDeal
I understand there is no way I can run all my loads but I'd rather choose what I want to run at any particular time after the grid goes down rather than before I build out my critical load panel. So for example I envision marking all my non critical loads at the breakers in the main panel and when the grid goes down flip them all off. After they are off I close the switch at "2" so the main panel is now live (but "1" is open so no power is going back to the grid to zap workers). I can then selectively turn breakers on if I need power at a certain place for some amount of time. [ATTACH]n306809[/ATTACH]

kingofbanff I would humbly ask... why do solar if you're not sure beforehand what your critical loads are? That might be the cart before the horse. Admittedly, I know much less than most people here... however, in my opinion and experience, one of the best favors you can do yourself before you ever by any solar components, is to move your critical loads to their own panel. Next, add some form of measuring/monitoring to that panel to find out 1) you continuous consumption 2) your peak consumption. Second, go get a proper generator that supports what you actually need for those critical loads - using the data you now have vs guessing. You might get a generator that is bigger if you want to use it for the whole house. You may find after all that monitoring and small investment that you don't have need of a 13kW system. You'll also be able to properly size your generator. You can send me a check for saving you a few grand when you do

An electrician or experienced DIYer can fairly easily setup your generator's output with a DPDT (you MUST have switched neutral) to direct your generator output either to an inverter's generator AC input, or your main panel (you'd need a generator interlock if your locale allows such or something the GUARANTEES that backfeeding grid power is not possible).

This would allow you to run anything you wanted in a power outage (assuming a large-enough generator) - not just your critical loads. This assume yours inverter is on a branch circuit off of your main panel - not before it. No matter how the above DPDT switch is in use, the inverter will receive power, thus your critical loads remain powered.

[Sunking]

NO
You don't need a generator for the Radian or any other outback inverter to work. What he is saying is that to live off grid indeffinitly you would need a generator. In your case the grid will sufice. They are referring to living off grid mostly because of your want to run everything in the house during an outage.

Strongly disagree. If the goal is to only cover a short outage, OK to keep a few lights on and TV. But for any extended outage and user wants want some loads like heater fans, refrigerator, freezer, coffee pot, and a microwave so they can heat food is going to need a generator. Works like a hybrid car. The batteries are sized to only last a few short hours. When discharged, the generator is needed to recharge the battery and run the loads at the same time. When batteries are charged, generator shuts down and cycle repeats itself until power is restored.

[ButchDeal]

Strongly disagree. If the goal is to only cover a short outage, OK to keep a few lights on and TV. But for any extended outage and user wants want some loads like heater fans, refrigerator, freezer, coffee pot, and a microwave so they can heat food is going to need a generator. Works like a hybrid car. The batteries are sized to only last a few short hours. When discharged, the generator is needed to recharge the battery and run the loads at the same time. When batteries are charged, generator shuts down and cycle repeats itself until power is restored.

Sunking He was under the impression (from comments) that the inverter would not work at all without the generator.
It will, flat out, no debate.

your argument is, will it handle a long outage, totally different than "will it work"

[kingofbanff]

Sunking He was under the impression (from comments) that the inverter would not work at all without the generator.
It will, flat out, no debate.

your argument is, will it handle a long outage, totally different than "will it work"

Thanks ButchDeal This is the answer I was looking for. If a generator was mandatory for the inverter to work and Outback wasn't telling me that it would speak to the honesty of the company and I wouldn't deal with them. I was skeptical that was the case because the reviews would be so bad the company wouldn't be in existence for long.

[Sunking]

Sunking He was under the impression (from comments) that the inverter would not work at all without the generator.
It will, flat out, no debate.

your argument is, will it handle a long outage, totally different than "will it work"

So who would want a system that only provides lights and a few outlets for a few hours?

[SunEagle]

So who would want a system that only provides lights and a few outlets for a few hours?

If it is free it's for me.

[Sunking]

If it is free it's for me.

So who bought your batteries for you?

[ButchDeal]

So who would want a system that only provides lights and a few outlets for a few hours?

define a few hours! mine keeps lights on for days. allows us to flush in the bathroom, wash dishes, brush teeth, etc. We have no water without power.
We can work form home when power is out (both my and my wife's offices have been without power but we were able to continue working).
keeps our fridge and freezer working. come home during random short power outage and garage door still works.

We have maintained power for over 5 days during the longest outage so far with battery and solar. Yes solar was required and if the modules were under snow I would have had to clear them, the were not this time. It is also possible that we could have an outage for several days where the weather remains bad the entire time (pretty rare in this area), in in such we would have to limit our use but would still get some power even in cloudy days from solar.
The funny thing is that I have lived for 12 years in the same house with the same outages and suffered through the outages using by travel trailer battery and inverter with candels and no water before.

My bymodal system gives me a better tool to handle that and the rest of the time the batteries sit there gathering dust but the inverter and modules generate electricity, reducing my bill and creating SRECs, to pay for itself.....

Yes a generator and a grid tie inverter could do the same thing but then I would have to maintain the generator, buy fuel for it, etc. and in my case it would have cost the same (self install).

[gmanInPA]

I too could go a pretty decent amount of time for the investment. And to the point that batteries sit there not getting used.. we intentionally shut our power down at the main ~ 1/month. We could (and may start to) do weekly. Some would scoff at such, but it is good for our industrial battery to do so, and saves us approximately 15% of our electric cost for that week. Further, we are able to get a realistic test of the equipment, et al. Without much conservation, my battery would go ~24h with no additional charging. That is to a 50% DoD. I could certainly go lower - and the battery manufacturer recommends such at least a handful of times per year.

To me the redundancy and just good old-fashioned options are worth the investment.

[kingofbanff]

I might have found my solution. This guy has three panels. Main, critical and "switchable". See photo. When the grid is Up this panel is fed from the grid. When the grid goes down he has the option to manually switch it over so it is now fed by the inverter. The gate on it prevents both the inverter and the grid being able to feed at the same time. Thoughts?

[gmanInPA]

If your inverter is on a branch circuit, any of the loads on the inverter are grid supported with grid power and supported by pv/generator/battery when grid down. It sounds like you're viewing your loads as either/or. If you're planning on a hybrid inverter, that's just not the case.

Where this could be helpful is where I mentioned it earlier - to switch where the output of your generator goes. That device is an interlock.

When th grid is down, it can't feed a panel. When it's up and powering an inverter, it powers the inverter and the inverter determines how to use / combine the grid, pv, generator, battery to support the loads. You don't need to manually work that out if you're considering a hybrid setup.

[gmanInPA]

If you're inverter is not on a branch circuit off your main panel, then I could understand this approach. I'm not sure why that would be either necessary or desired for a hybrid setup tho. Just bear in mind you can't load an inverter more than its AC output breaker size.

[ButchDeal]

I might have found my solution. This guy has three panels. Main, critical and "switchable". See photo. When the grid is Up this panel is fed from the grid. When the grid goes down he has the option to manually switch it over so it is now fed by the inverter. The gate on it prevents both the inverter and the grid being able to feed at the same time. Thoughts?

This makes no since if you are using the outback inverters just put this panel on the critical load side, and done.

[gmanInPA]

kingofbanff - I am providing this to demonstrate how you can have your cake and eat it too - albeit expensive cake. All of the negatives about cost and maintenance aside (as Sunking has often mentioned), if you are dead-set on a battery-backup system, and want to be able to run anything, here is one way to do it. It's important though that you understand a few important details:

Okay, firstly... please pardon the very poor symbology in this diagram - the tools I had at the time had very little to offer and I was trying to convey to an electrician what I needed setting up. Secondly, I have a lot of extras in this setup that many would not incur the cost of doing and aren't required, but I wanted them: A DPDT that allows me to bypass the entire inverter system and runs everything directly off the main; a generator selector that allows me to optionally run my interlock from either my backup (diesel) or portable (tri-fuel) generator. It is a belt and suspenders approach. I'm sure Sunking will have a hay day with me for this setup

1. Without a very expensive system, you likely won't be able to run your whole house on battery backup. That is why the critical loads are isolated.
2. You can however run your entire home on a generator.
3. Because generator is usually feeding only the inverter (via the inverter's AC2 input), this would normally rule out using that generator for the whole house.
4. The diagram above shows what I did to work around this. My backup generator can alternatively feed either the inverter or the main panel which blocks it from feeding the inverter's AC2 input and routes it ultimately to the AC1 input. You need an interlock for the generator feed into the main panel (what is in the photo you attached). You also need some sort of switching to manually direct the generator to the main panel vs the inverter. I accomplished this with an interlock between two breakers in my power distribution panel (see photo 2 for mine).
5. If for some reason I want to run a circuit on the main panel in a grid-down situation, I must flip the two switches above
   1. One to direct power away from my inverter
   2. The interlock in my main panel to prevent the generator from back-feeding into the grid.
6. Supposing I have my generator directed toward my main panel instead of the inverter, the inverter would still receive power (via the AC1 input) because it is a branch circuit off the main panel. Important: If enabled, I also have to turn off "Sell Mode" (where the inverter "sells" power back to the grid) because you DO NOT want to try to send surplus power back into a generator-based utility. I'm not entirely sure how the inverter would handle that situation, but I'd rather not find out.
7. I'm sure some would argue that I'm relying on a setting in my inverter to prevent flow. The same could be said of trusting the islanding features of all hybrid inverters.
8. Because I have the main panel interlock. There is no way for the above system to backfeed the grid. It passed all local electrical inspections with flying colors.
9. This does require that you have some means of determining when grid power is restored so you can reverse the above steps at that time.

*The above is ONLY for the case where I want/need something from the non-critical loads to be powered during a grid-down event.