Sizing Off-Grid Systems And Using Gen Support

[SunEagle]

Chris,

Are your renewable energy projects located where you shoot
the YouTube videos about your farming and amateur radio set-ups
in Barron, WI, a couple of miles from downtown.

You mentioned in your 2/15/15 YouTube that you spend a lot of
time over the winter in your little radio station.
I assumes that is also where the marvelous weather station dat
you and Kristian operate is located.

Adding the GPS feature was nice so people can zoom in on you
and 'mentally' be a little part of the action.
It's wonderfuls.

Bill Blake

Bill

I believe Chris lives much farther North in Bayfield County close to the Lake.

He has not posted on this forum for a while so is probably very busy with other projects.

[Sundetective]

No. We heat 100% with wood in a central forced air Daka furnace (made in Pine City, MN) that has a catalytic recombustor on it to burn the particulates in the wood smoke. We have a virtually endless wood supply here that will last us for over 1,500 years just doing select cutting of mature hardwoods on our own property. There is no way we can keep up cutting the mature trees for firewood to open up sunlight area for the new undergrowth before they die. I have probably 3 years worth of harvested logs that I haven't processed, but got out of the woods because if I don't they will start to rot and go bad. I sell processed firewood and chips to about 30 customers in the area and still can't keep up with the rate that hardwoods reach maturity and are ready for harvest on our land.

It is not worth it to mess with CHP when we have a fuel source like that.

We do not burn any propane at all, nor will my wife allow a propane line into the house. Years ago we had an explosion in a rented house we lived in that blew one wall and all the windows out and lifted the house off its foundation and shifted it about 2 feet. It was due to a valve on the water heater that malfunctioned and we lost most of our personal belongings from it. We had a propane genset for a couple years and my wife made me hide the tank for that behind a rock wall and bunch of pine trees where she couldn't see it. But it bothered her to no end that it was there. And the propane genset didn't work worth a crap anyway in cold weather so we got rid of it.

IMO, propane is one of the worst choices for off-grid fuel. You couldn't even buy the stuff around here this winter because all the suppliers ran out. And the last they had when they were rationing to people for fillups, they were selling for over $7/gallon. Plus there is no way in hell a LP truck can get in here. Our 500 gallon tank for the genset used to be mounted on a wagon running gear and I towed it 25 miles to where the truck could come and fill it up, then towed it home. The only upside to propane is its shelf-life. But it has so many downsides that it's not even worth considering unless you live in a tropical climate like Missouri. I can haul a 500 gallon tank of diesel fuel in here and it's got one hell of a lot more energy in that 500 gallons of diesel fuel than 500 gallons of propane has, for less than half the cost per BTU.

The only thing we use the waste heat from the gensets for is to heat the powerhouse in the winter. The powerhouse has thermostatically controlled ventilation that keeps it at 75F in there in the winter for the air-cooled engines so they don't run too cold. Never did get into using liquid-cooled genset because it takes too damn much time to warm them up properly before they can accept full rated load.

Chris,

Are your renewable energy projects located where you shoot
the YouTube videos about your farming and amateur radio set-ups
in Barron, WI, a couple of miles from downtown.

You mentioned in your 2/15/15 YouTube that you spend a lot of
time over the winter in your little radio station.
I assumes that is also where the marvelous weather station dat
you and Kristian operate is located.

Adding the GPS feature was nice so people can zoom in on you
and 'mentally' be a little part of the action.
It's wonderfuls.

Bill Blake

[Bala]

A generator assisted system is more than likely going to be my only option. Since my power requirements are way too high. Cutting to the chase as I put it. What equipment would you need to create this type of system? I need to run at least one 48 volt DC mini split 12000 btu air conditioner http://www.hotspotenergy.com/DC-air-conditioner/ along with the rest of my power requirements for a total of 837 kWh. I know it is a pipe dream financially to create a solar system and battery bank to handle this entire load. I would like it to handle around half. Or at least be able to run the air conditioner on solar during the day and let the generator carry the load at night and let it charge the battery bank if the panels cannot during the day for whatever reason. Without air conditioner my power figure is around 254 kWh. The air conditioner would only be used during the summer months.

Before anyone brings up why not just run on grid power. That will never happen since the closests power is over 7 miles away and the COOP out here charges $ 42000 a mile. $294000 for grid power leaves some room for solar system instead. LOL So it is either create a system to handle some of the load via solar or run on generators 24 hours a day in summer. Which I would like to avoid. My ranch is located in west Texas and I believe my sun figure is 5 hours a day. I have been at this 600 acre location for over 12 years now. Have already went to the expense of building cabins and drilling a $35000 1000 ft deep water well. Which runs on a larger generator already to fill a 2000 gal concrete cistern tank.

Any and all the help of proper equipment and sizing would be greatly appreciated. I have been reading for posts, websites and articles for two weeks and my head is going to EXPLODE or my wife is going to shoot me. Whichever comes first. Good information and proper equipment is worth trading for hunting on my place. LOL Not a pay ranch for hunting but you can see what i have on my personal website. www.singlestackranch.com I promise not selling anything. If this post is in the wrong place in forums please excuse a newbie mess up. Thank you.

It may help you if you take this and start a new thread in the off grid section, and repost your comments from your intro thread that you know it is costly but that you are prepared for that

what is your expected daily need in KWH.

Try to ask specific questions, but you need to supply the right info to get the right answers.

It is not a simple task to get the best result for what you need.

[Pooba]

Sake of being way over my head on this subject

A generator assisted system is more than likely going to be my only option. Since my power requirements are way too high. Cutting to the chase as I put it. What equipment would you need to create this type of system? I need to run at least one 48 volt DC mini split 12000 btu air conditioner http://www.hotspotenergy.com/DC-air-conditioner/ along with the rest of my power requirements for a total of 837 kWh. I know it is a pipe dream financially to create a solar system and battery bank to handle this entire load. I would like it to handle around half. Or at least be able to run the air conditioner on solar during the day and let the generator carry the load at night and let it charge the battery bank if the panels cannot during the day for whatever reason. Without air conditioner my power figure is around 254 kWh. The air conditioner would only be used during the summer months.

Before anyone brings up why not just run on grid power. That will never happen since the closests power is over 7 miles away and the COOP out here charges $ 42000 a mile. $294000 for grid power leaves some room for solar system instead. LOL So it is either create a system to handle some of the load via solar or run on generators 24 hours a day in summer. Which I would like to avoid. My ranch is located in west Texas and I believe my sun figure is 5 hours a day. I have been at this 600 acre location for over 12 years now. Have already went to the expense of building cabins and drilling a $35000 1000 ft deep water well. Which runs on a larger generator already to fill a 2000 gal concrete cistern tank.

Any and all the help of proper equipment and sizing would be greatly appreciated. I have been reading for posts, websites and articles for two weeks and my head is going to EXPLODE or my wife is going to shoot me. Whichever comes first. Good information and proper equipment is worth trading for hunting on my place. LOL Not a pay ranch for hunting but you can see what i have on my personal website. www.singlestackranch.com I promise not selling anything. If this post is in the wrong place in forums please excuse a newbie mess up. Thank you.

[inetdog]

The is no legal way to convert an standard off grid inverter to work as a grid tie. There are Hybrid systems the allow you to connect to the grid as well as charge a battery system but that equipment is manufactured and UL listed. Making your own equipment to connect to the grid would never be accepted by the POCO or your local code team.

Not only is there no legal way, there is no practical way. The inverter circuitry is not designed to be controlled in voltage and phase by an external input, does not have any way to prevent it from running in island mode in the case of a grid failure and if it matters to you it does not have MPPT to allow it to run directly from a panel array.

[SunEagle]

great post.. then may I ask you how to convert off grid inverter to grid tie inverter? how about the system block of the controller?

The is no legal way to convert an standard off grid inverter to work as a grid tie. There are Hybrid systems the allow you to connect to the grid as well as charge a battery system but that equipment is manufactured and UL listed. Making your own equipment to connect to the grid would never be accepted by the POCO or your local code team.

[Pande Sutawan]

great post.. then may I ask you how to convert off grid inverter to grid tie inverter? how about the system block of the controller?

[inetdog]

When you put panels in series you double the voltage but keep the same current. So twice the panels, places in series, give you twice the voltage at the same current, but an MPPT controller will convert that to twice the current at the same battery voltage in either case.

[Alpaca-Meadow]

Same panels

If you can't get the same 205 watts panel, buy one that is a little more like 225watts or so. make sure the VMP and IMP are close enough like with in 5% different.

Thanks for getting back to me, I must admit as soon as I connected the panels up the light on the controller turned from red to green in about 25 minutes and the batteries came up to 25.7 volts with in about 3 hours with overcast sky!

I will have a look out for a panel with a similar specification. Then if I do and tack this onto the end and wire in the same way, will that then give me about (I think the volts on the picture I showed was 26v not the 33 doh!) output about 80 volts? 24 amps?

with all the above working correctly could I then start running some more heater lamps as follows

1 @ 75watts
1 @ 150 watts

could the system run this 24 / 7 without any need to use a generator to top up even in the winter here in southern England?

again really enjoying the education

best wishes Derek

[paulcheung]

If you can't get the same 205 watts panel, buy one that is a little more like 225watts or so. make sure the VMP and IMP are close enough like with in 5% different.

[Alpaca-Meadow]

Solar panel wiring

Hi All I finally got around to wiring the panels in as suggested, now that the rain has stopped.
Although a very overcast day as soon as I tested the result I was rewarded with 45.5volts

I notice on the back of the panel that they could achieve 33v solar-panel.jpg
so when the sun is shinning I should get 66v ? is this correct? and if that is the case the mppt controller is rated at 40amps / 100 volts so just checking all is ok please

also one more question, If I was to add another panel to the one I have left over, and wire it in in the same way, does it also have to be 205watts as these are hard to come by now

thanks for all your imput Derek

[SunEagle]

Yes, ours are all the same. But I have run totally mismatched parallel strings as well in the winter when I take our RV batteries out and put them on our off-grid bank and work the snot out of them all winter instead of leaving them set around on a battery maintainer. Those camper batteries are not even CLOSE to the big RE batteries, but yet they still do their part and end up at the same SOC as the big ones on either discharge or charging. And there is no cross-currents in the bank with those camper batteries on there. I put a TriMetric on those as well. When I watch during charging and the net amps to the batteries falls to zero, the amps to the camper battery fall to zero at exactly the same time. Then watch closer and the system starts to take amps from the battery bank. The camper batteries go to discharge exactly with the rest, and put out the amps they are capable of at the particular system voltage at the time.

So Big Deal if the parallel strings are mis-matched. It still works just fine. I have done this with our camper batteries for almost 10 years and have yet to destroy any batteries, or see a problem, because of it.

Chris I believe with your years of experience of using and maintaining a battery system you have developed a skill that most others may never get. Through trial and error you have found the (excuse the pun) "battery" limits of your system as well as how to not only take care of them but bring them back from what I would call an early death.

For the rest of us Newbees when it comes to really understanding how to charge, maintain, monitor and return a complex battery system to good health we are just babes in the woods.

[ChrisOlson]

My guess is that you get all your batteries on the same time at the same vendor and they are all the same identical batteries. Mine are from different vendor, different time and different size batteries even though they are close enough. Mine strings are about 1 to 10 amps different on each string depend on the load and the charge rate.

Yes, ours are all the same. But I have run totally mismatched parallel strings as well in the winter when I take our RV batteries out and put them on our off-grid bank and work the snot out of them all winter instead of leaving them set around on a battery maintainer. Those camper batteries are not even CLOSE to the big RE batteries, but yet they still do their part and end up at the same SOC as the big ones on either discharge or charging. And there is no cross-currents in the bank with those camper batteries on there. I put a TriMetric on those as well. When I watch during charging and the net amps to the batteries falls to zero, the amps to the camper battery fall to zero at exactly the same time. Then watch closer and the system starts to take amps from the battery bank. The camper batteries go to discharge exactly with the rest, and put out the amps they are capable of at the particular system voltage at the time.

So Big Deal if the parallel strings are mis-matched. It still works just fine. I have done this with our camper batteries for almost 10 years and have yet to destroy any batteries, or see a problem, because of it.

[paulcheung]

My guess is that you get all your batteries on the same time at the same vendor and they are all the same identical batteries. Mine are from different vendor, different time and different size batteries even though they are close enough. Mine strings are about 1 to 10 amps different on each string depend on the load and the charge rate.

[ChrisOlson]

I have two bank of batteries in parallel, it give me hell to balance the charge and discharge rate of each bank. can't get them equally.

I don't totally understand how people have so many problems with parallel batteries. It's not uncommon to see semi trucks, off-road equipment, and large generators with six or eight 4D or 8D batteries in parallel. We have three parallel strings on our off-grid system with battery monitors on each string and I have yet to ever see them get out of balance. Amps on each string is within 0 - 0.3A on both discharge and charging. Used to run six parallel strings with the same batteries when we had our stacked 24V inverters, and never had any problem then either.