Off-Grid Generator Use

ColoradoSolar · February 2017

For you off gridders I have a question about generator runtime.

I am about to replace the undersized system that came with the house I purchased with a larger system and I am looking at generators. I was wondering what is the average monthly/yearly runtime for those of you who full time off gridders in a sunny climate. I am in the high mountains in Colorado so I get pretty good sun year round.

Estragon · February 2017

I rarely use mine in summer. With shorter days and more cloud into fall, maybe 10-20 hours runtime in 3 months. Not there much in winter, but if I was there full time, generator would need to run about 10-12hrs/wk. Nov/Dec/Jan. After that it could be 10hrs/wk or nearly zero. Overall, maybe 200hrs/yr. I'm at 49.5°N ~1000' ASL.

I use a 35 year old onan 4kw diesel to bulk. If solar couldn't finish absorb after 5 days or so I would use my Honda eu2000 to get to fully charged. That wouldn't happen often.

Mangas · February 2017

Excluding monthly 15 minute exercise runs, with new HVAC high efficiency units and appliances with everything running properly and normal weather patterns, 30 to 50 hours a year.

ColoradoSolar · February 2017

Mangas said:

Excluding monthly 15 minute exercise runs, with new HVAC high efficiency units and appliances with everything running properly and normal weather patterns, 30 to 50 hours a year.

Is the generator usage mainly because of cloudy days or for EQ?

Also I notice that you have Schneider equipment. How do you like it? Do you have the ComBox?

Mangas · February 2017

Winter inclement or cloudy weather exceeding 2 1/2 days extended period, chances are the AGS low voltage trigger will run the genset to full charge the battery banks (takes about 4 1/2 running hours from the start trigger). Our off grid system usually gets 2 to 3 days of reserve battery capacity which is in line with Bill's rule of thumb.

Lot of variable factors are involved but that's our windage.

Planning wise it also depends where you live i.e. Sunbelt vs NE etc. When asked, I always steer people to build their system capacity around 125% to 135% estimated usage after judicious conservation.

But, that's just me.

westbranch · February 2017

well if you plan the system with 3 days autonomy you will have significantly less run time vs 2 days autonomy... and that doesn't include the option of (over) paneling by designing for Dec 22 sunlight vs the yearly average amount of sunshine per day.
hth

mike95490 · February 2017

Wintertime generator usage only here. average winter daily consumption about 6.5KWh.
5kw of panels got me 1.5Kwh of harvest today. Cloudy days, I use about 2 hours runtime with 2.5Kw AC charging load off a 6hp diesel

Image: https://us.v-cdn.net/6024911/uploads/editor/wa/nyqu0k95i594.png

ColoradoSolar · February 2017

westbranch said:

well if you plan the system with 3 days autonomy you will have significantly less run time vs 2 days autonomy... and that doesn't include the option of (over) paneling by designing for Dec 22 sunlight vs the yearly average amount of sunshine per day.
hth

I do have the planned system with 3 days of autonomy and I am over paneled.
My winter usage (no A/C so winter is higher) was calculated out to be 16KWh/day so I have designed the battery capacity and PV around that number. I think my actual usage will be lower. I was initially designing the system while I was living in my on-grid house in Alabama and now that I have been living in my off-grid house in Colorado for the last 6 months with an undersized system I think I will be able to shave a few more KWh off the daily usage, I just don't want to undersize the system. And by having a larger usage in the calculations then if I actually use less then I will not cycle the batteries as deep, but on those cloudy days when we have family over the system will still be able to handle the load.

Estragon · February 2017

16kwh/day is pretty high for off-grid. Roughly 2000ah@48v bank, 12kw panels to charge?

ColoradoSolar · February 2017

Estragon said:

16kwh/day is pretty high for off-grid. Roughly 2000ah@48v bank, 12kw panels to charge?

I agree 16KWh is on the high end but we didn't want to give up too much of the convenience of on grid and both the wife and I work from home.

SolarOne HUP batteries 1270ah@48v warrantied for 80%dod (48.77KWh usable so more like 2.5 days of autonomy)
11.3kw of panels

Estragon · February 2017

Certainly better (within reason) to overestimate and not need the extra capacity than to underestimate.

ColoradoSolar · February 2017

Estragon said:

Certainly better (within reason) to overestimate and not need the extra capacity than to underestimate.

That was my thinking.

I had read so many times that most people underestimate their usage and have chronically undercharged batteries. I wanted to make sure that I am not going to do that.

Mangas · February 2017

Expect the retrofitted Schneider equipment to perform as well and reliably as my 11 year old Trace Xantrex equipment it replaced. The Xantrex equip was simply bullet proof, easy to figure out and maintain for someone like me.

The Schneider technology is state of the art. I really like its design quality, full scope integrated components and firmware architecture. Very flexible system wise. Performance wise no complaints so far.

Setting it all up was a little challenging. In my opinion, the installation manuals were a somewhat biased towards grid tie than off grid applications but during the installation Schneider did a great job getting it all sorted out. Accessible and good support from their Tech Support and Engineering.

Dave knows these applications well too. He answered a couple questions I had about the technology. Thanks again Dave.

Don't have the Combox. I'd like to install two of them but don't want to go through more installation ups and downs.

Also, can't get a networked internet or Cel feed into the solar mechanical building.

Dave Angelini · February 2017

I think for Offgrid the key to "ups and downs" is to always remember that when connecting/doing firmware to a working system is to always disconnect the Inverter/charger device from xanbus. This will give you the safety of power on if you can't have a 45 second power interrupt or can't risk an error that is caused by the Human. I have never lost power since 1992 other than me shutting down during nasty lightning. We had some last night that was as loud as I have ever heard. It was like sitting at the end of a carrier flight deck with FA-18's doing business.

The 300 foot distance for a reliable network connection is about 300 feet.

There are repeaters for longer networks available.
I would look into it as having a system without a combox really makes learning difficult for a person who has basic computer
skills. Not talking about someone like you Mangas. Why in heaven do you need 2 comboxes?

The combox also separates the load data from the power it takes to recharge nicely. It is one of the ways people can learn to save energy in poor winter weather in a place that has a decent solar (very large array) resource. One of my Female clients just could not go 3 days without running the washing machine until I had her buy more clothes... It is funny what I hear sometimes.

99% of the winter days a large system should be able to run the loads during the day off the solar for 2 people. It is so rare in the southwest to have more than 3 days in a row of nothing. I never have and it is how I do without a genset. It is easier for me as I started out cruising a sailboat for a decade and almost nothing is much of a challenge or as rewarding after that.

Mangas · February 2017

We're set up with two separate systems i.e. two inverters, SPC and CC power 1/2 of the house and two inverters, SPC and CC for the other. We designed it this way for redundancy. Costs more but always "on line" so to speak.

Assumed I would need a Combox for each side?

Good point about the network signal. I need to test our wi-fi to see if the signal reaches the solar mechanical building about 100 feet or so from the house. I would like to monitor harvest and performance data plus be able to update firmware as we go along so may do this.

The off grid system is large enough where we don't worry too much about conservation during inclement weather. Genset runs so infrequently that propane fuel costs are pretty much a non issue. That said, I need to cowboy up and test real time our conservation profile.

So far, over 12 years we have never lost power either. But, our grid neighbors frequently do!

Sailing lifestyle builds independence and self reliance!

Dave Angelini · February 2017

In my testing now of the Bridge I have both systems on the same combox. There is a finite number of devices, 15 comes to mind and then you have to master/slave comboxes to do a really large XW based system with over 15 devices.

2 battery systems each associated with their own XW on a combox. I do have to be careful when changing firmware but this would not be an issue for the average user.

The Combox needs a network connection to your router at this time. It will have a wifi option in the future I am told. Once it is in your network you can use other devices like the Tablet Ap with your wifi to control the system or Insight anywhere there is internet. There are other ways also but if you can run an Ethernet cable 100 feet, you will be in the cat bird seat.

The one light I see out the window at night is how I can tell if the Utility is up. I really like being remote as long as my AR is loaded

Mangas · February 2017

Good deal Dave!

One networked Combox waiting on Wi Fi.

10-4!

Dave Angelini · February 2017

Please drop me an email to my address below my sig when you have some time.
We are at 70" of rain out here, sounds like the tropics huh?

Off-Grid Generator Use

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