Running AC off grid ??

[warewolff]

So again .. please remember this is all in beta stage. Forgive my sloppy wiring and sketchy mounting.

The bus from the outside. The outdoor mini split unit is mounted on the rear bumper. 12 solar panels on the roof.



The mini split. I'm going to add a wind shield and two "L" brackets on the top + additional side supports, as well as give it it's own bumper to protect from collisions.



The right side of my garage. Four 6v 430aH Crown batteries, two TS-MPPT-60 charge controllers, one Magnum MM1512AE inverter/charger dedicated to the a/c, one Xantrex ProWatt 2000 SW inverter dedicated to my 120v wall outlets, two 150v/50amp breakers and breaker box between solar and charge controllers, two 60amp breakers between charge controllers and batteries. The yellow wire plugged into the GFCI outlet is a 12 gauge extension cord spliced into a fused disconnect for my mini split, in the next photo ... Am I missing anything?



Closeup of my solar breaker box:



and the breakers between the charge controller/batteries:



Meter hub and DC panel for all my 12v appliances:



Charge controllers:



Inverters:



Wires running along the roof to the right side of my garage. 120v is inside the conduit, solar is coming through the roof on either side through two junction boxes, 12v wiring to right side and the yellow mini split cord.



Right side of my garage, the 30 amp fused disconnect. My mini split is connected to line side and the extension cord is connected to load.



Right side of garage. Refrigerant lines / communication wires between the outdoor and indoor units. I left the long length of lineset in case I wanted to move the position of the indoor unit. I'll probably shorten it.



Indoor unit. 65 degrees inside, 81 outside. Forgive the messy wall. Still under construction.



The remote meter. I unplugged the fridge to show the mini split is pulling ~500w in direct afternoon sun. The temperature sensor is wonky -- ignore that. Voltage at 12.1 is 50%. The voltage reading is slightly off -- I'm 12.3v at the batteries.. If I were to remove all load the battery would bounce back up above 13.



Hope that answers your questions.

[Defjr333]

I too originally intended to run AC via inverter when off grid. But after research and calculations determined it to be FAR more financially efficient to just use an inverter style generator (for low noise) with the auto start switch wired to a relay to auto start when AC unit is turned on. The difference in cost was over a grand. Thats a lot of fuel. Especially when my Champion 3000watt inveter generator will run all night on under 3 gallons of gas:
3 gallon tank x $2.08= $6.24
$1800 (cost for xtra solar/ batteries) divided by 6.24= 288 days and change
Since dont run AC every day Spring/Fall/ Winter I figure will be over a year, possibly more to cover that cost.
Now if price is no object, and u got the room (not a short bus) go for it!!! There are some people that have done it, but not very many that I have seen. The only thing preventing me from doing this is, cost of panels/ batteries, and space. Already going with 00awg wiring and 3000/ 6000 pure sine inverter. Dont forget the loss on DC side while doing calculations!!

Doug

[warewolff]

I agree with your points but that's not truly off grid. Unless you're hauling around a big tank of gas to fill the generator. It'd work in a cabin where you can have a permanent and giant reserve tank, but you can only haul so much. Even still you'll run out. The whole point of going off grid, for me at least, is to spend multiple weeks at remote locations. All I need to carry is water and food. No gas. Not for most people but then most people are happy hooking up to the grid and bringing a generator for a few nights of boondocking. Both are viable options depending on needs.

[Tootalltechie]

To be totally off grid you will need wind, solar, water, steam power generation.

Sent from my SM-G530W using Tapatalk

[warewolff]

Originally Posted by Tootalltechie

To be totally off grid you will need wind, solar, water, steam power generation.

Sent from my SM-G530W using Tapatalk

Would love a steam powered engine. Don't forget a good rifle for hunting game.

[Tropf]

Thanks for sharing the images!

[Brewerbob]

Originally Posted by warewolff

Hope that answers your questions.

Who; me? No it doesn't but that's because I don't know enough about solar to ask the right questions. I'm fine with electrical and even most electronics vut for whatever reason solar is a mystery to me. Seems overly complicated with all the different components.

I do have one question for you tho. You have 12 panels you said. You also said you are slightly under sized? That a shitload of panels!! How do you have that many panels and 4 batteries (?). Other systems I've seen talked about have 10 or even 12 batteries.

1.2KW for 12 panels means 100W panels. I know they come in as high as 325~350 each. That's only 4 panels.

Originally Posted by Defjr333

Especially when my Champion 3000watt inveter generator will run all night on under 3 gallons of gas:

I have a 5500W genny that I bought yrs ago for the house. I might use that short term but if I go the genny route long term, it'll be diesel. I like the idea of having a genny in case I need it but I'd rather be mostly solar.

Originally Posted by warewolff

The whole point of going off grid, for me at least, is to spend multiple weeks at remote locations. All I need to carry is water and food. No gas.

Your bus is electric??? This is why I want a diesel genny. My bus has a 60 gallon tank from B.B. That just won't do even as engine fuel only. I'm thinking of adding instead of replacing. I have a huge about of space between the frame rails both in front of and behind the existing tank. 30" of space in front of and 90" behind (without moving anything). More than enough room to install a 100 gallon.

Originally Posted by warewolff

Don't forget a good rifle for hunting game.

So, you're bringing mining equipment too? Where's the lead, brass, and gun powder coming from?

Off grid = a knife. Gotta catch a rabbit. Rabbit gut bow. Maybe a deer next. Now you might have bone big enough to make real arrow heads. Get a moose and you're good.

[warewolff]

Originally Posted by Brewerbob

Who; me? No it doesn't but that's because I don't know enough about solar to ask the right questions. I'm fine with electrical and even most electronics vut for whatever reason solar is a mystery to me. Seems overly complicated with all the different components.

I do have one question for you tho. You have 12 panels you said. You also said you are slightly under sized? That a shitload of panels!! How do you have that many panels and 4 batteries (?). Other systems I've seen talked about have 10 or even 12 batteries.

1.2KW for 12 panels means 100W panels. I know they come in as high as 325~350 each. That's only 4 panels.

I have a 5500W genny that I bought yrs ago for the house. I might use that short term but if I go the genny route long term, it'll be diesel. I like the idea of having a genny in case I need it but I'd rather be mostly solar.

Your bus is electric??? This is why I want a diesel genny. My bus has a 60 gallon tank from B.B. That just won't do even as engine fuel only. I'm thinking of adding instead of replacing. I have a huge about of space between the frame rails both in front of and behind the existing tank. 30" of space in front of and 90" behind (without moving anything). More than enough room to install a 100 gallon.

So, you're bringing mining equipment too? Where's the lead, brass, and gun powder coming from?

Off grid = a knife. Gotta catch a rabbit. Rabbit gut bow. Maybe a deer next. Now you might have bone big enough to make real arrow heads. Get a moose and you're good.

My batteries are big. I'll probably add two more so I can run the air 24/7, but they are 430aH a piece. The battery banks you 're referring to are probably 100-200aH each.

[Brewerbob]

Originally Posted by warewolff

My batteries are big. I'll probably add two more so I can run the air 24/7, but they are 430aH a piece. The battery banks you 're referring to are probably 100-200aH each.

Electric cart batteries for some of them (12+ batteries) so those would be 6v as well. They definitely were 400+.

[warewolff]

I'd like to see the systems you're referring to. That'd be over 28kWh ... it's a lot of power and honestly I've never seen that much on a bus. Not doubting you but I'm curious.

Also, I disagree that off grid = knife. Off grid is the idea of not relying on utilities. Bullets aren't utilities. Water supply, sewer, natural gas, electric. These are utilities. Water is everywhere. Park near a stream. As for diesel, presumably with a solar setup you don't have to use any once you're parked. Or gas. Kind of derailing a bit but as far as I see the people nit picking over the term are the ones hooked up at RV parks and running to the gas station to refill that genny.

[Brewerbob]

Originally Posted by warewolff

I'd like to see the systems you're referring to. That'd be over 28kWh ... it's a lot of power and honestly I've never seen that much on a bus. Not doubting you but I'm curious.

Me? Doubt away!! I think I saw one with twelve 6v. I've no idea what a golf cart is in amp or hrs but that's 6 pairs in parallel to get a 12v system so you're only multiplying the current by 6.

Also, I disagree that off grid = knife. Off grid is the idea of not relying on utilities. Bullets aren't utilities. Water supply, sewer, natural gas, electric. These are utilities. Water is everywhere. Park near a stream. As for diesel, presumably with a solar setup you don't have to use any once you're parked. Or gas. Kind of derailing a bit but as far as I see the people nit picking over the term are the ones hooked up at RV parks and running to the gas station to refill that genny.

Lol. Just depends on how extreme you're taking it. I'll never be that off grid. IMHO, the point of a bus build is to have wheels. Wheels makes moving easier but generally requires a fuel source of some sort. If all I wanted was off-grid, helo some shipping containers into AK. Pack a saw so you can make tree stump stools.

Without going that extreme, get a shed on some dirt without utilities from Lowes. Would be cheaper and easier than building a bus.

[warewolff]

Originally Posted by Brewerbob

Me? Doubt away!! I think I saw one with twelve 6v. I've no idea what a golf cart is in amp or hrs but that's 6 pairs in parallel to get a 12v system so you're only multiplying the current by 6.

6v at 400aH * 12 batteries = 4800aH at 6v = 2400aH at 12v

12v * 2400aH = 28,800Wh = 28.8kWh

HUGE. I would love to have a system like that. And yeah, I'm just busting your chops. No disrespect intended.

[Brewerbob]

The cart batteries are only 200aH aren't they?

My memory is total crap so doubting especially on a topic I don't know is erring on the wise side.

[warewolff]

I was going off this statement:

Electric cart batteries for some of them (12+ batteries) so those would be 6v as well. They definitely were 400+.

Mine are 6v batteries at 430aH. They are technically golf cart batteries. You can find them anywhere from 100aH to 400aH and higher. What I was saying before was that the giant banks you're talking about are probably the 100 or 200aH varieties. Not because I don't believe there are mobile systems out there with twelve 400aH+ 6v batteries, just that it's more power than I'd know what to do with in a mobile home (unless you're growing weed) and I've never seen it. It's easily possible. Eight batteries of that size would take a lot of space in my bus garage. Twelve would probably fill it. You saw how big that battery box was in my photos. Each of those golf cart batteries is 135lb. Wasn't doubting you -- I'd actually like to see a system that big in a mobile application. I just can't think of any practical scenario for it unless you're talking about the 100 or 200aH varieties, in which case that makes sense, because while they are lower in aH, they also take up significantly less space. Each of my batteries is 12.38 × 7.19 × 15.29 inches. That's 12 inches deep and 15 high. Big.

[willvalenton]

Thanks a lot for all the contributions. After googling and youtubing, I'm now thinking that Lithium Ion battery is an option to get higher Amp-hours. Will it be compatible with Samlex, Powermax, AIMS, Xantrex inverters? How about charge controllers?

[warewolff]

Lithium ion won't give you more amp hours but you can run them down all the way so you get more usable amp hours. I don't know too much about them but, no, not all inverters will work with them. Most won't, as they include a factory low voltage setting of 10.9v or something similar. This means they turn off below that voltage. The fancier inverters have custom settings you can manually input. I know someone on the forum has done it.

[Defjr333]

Since I have yet to find the right vehicle, I have been testing my components to see what they are capable of. I have 4 255W(1KWatt) LG Poly solar panels with a Midnight Classic MPPT charge controler hooked to 8 Duracell GC2s (860ah). They are running a 3000/6000W inverter/ charger. When I test an LG 5500btu window unit on it, it does run it without over taxing the system, but the draw on the batteries force me to shut it down within a few hours(aprox 2. before batteries are at 50%. The space, weight, and cost of adding more panels and batteries seem to far outweigh carrying a can or 2 of gas or diesel to me. Im not saying somebody cant do it, check out this guy:

2013 CarMate 100% Solar Heated and Cooled Over The Top Cargo Trailer

But also realize the time and $$$ he has in it. Great guy, he is a regular on tnttt, but he even admits, its mostly for bragging rights.

[Brewerbob]

Originally Posted by warewolff

I was going off this statement:



Mine are 6v batteries at 430aH. They are technically golf cart batteries. You can find them anywhere from 100aH to 400aH and higher. What I was saying before was that the giant banks you're talking about are probably the 100 or 200aH varieties. Not because I don't believe there are mobile systems out there with twelve 400aH+ 6v batteries, just that it's more power than I'd know what to do with in a mobile home (unless you're growing weed) and I've never seen it. It's easily possible. Eight batteries of that size would take a lot of space in my bus garage. Twelve would probably fill it. You saw how big that battery box was in my photos. Each of those golf cart batteries is 135lb. Wasn't doubting you -- I'd actually like to see a system that big in a mobile application. I just can't think of any practical scenario for it unless you're talking about the 100 or 200aH varieties, in which case that makes sense, because while they are lower in aH, they also take up significantly less space. Each of my batteries is 12.38 × 7.19 × 15.29 inches. That's 12 inches deep and 15 high. Big.

If I typed 400 then I goofed. I was thinking 200. I've no idea what they actually were but I do know they were "6v size". The little half car battery footprint. They definitely weren't 8D size. 8D in 12v is what my bus has; 2 of them.

[aaronsb]

If it helps (for a slightly different take on the same goal: solar powered aircon)

I'm building a 48 volt lithium battery pack, with a nominal voltage between 44 and 59 volts.

I expect to be able to do a deep discharge/recharge cycle, and incomplete charges without much drama. Lithium will require a battery management system install. Once complete, I expect 22kWh of usable power from the pack.

For solar, I've got 8x 24 nominal volt panels (45 volts open circuit), producing 320 watts each. They will be arranged in a 2x4 array, so each array is pmax 1280 watts per array, and max voc (voltage open circuit) is 91 volts, minimum 86voc.

This allows me to use a single 60 amp mppt solar charge controller. Higher voltages is less resistive and smaller wiring. (8 gauge will be perfectly adequate at ~90v nominal)

If I'm running air conditioning all day, I don't know if I'll be able to refill the battery fully, but since it's a lithium pack and the aircon isn't running at full duty cycle, there should be a net gain on charge.

Lithium chemistry (and it's related charge profile) is a huge benefactor to this type of usage profile.

Originally Posted by warewolff

6v at 400aH * 12 batteries = 4800aH at 6v = 2400aH at 12v

12v * 2400aH = 28,800Wh = 28.8kWh

HUGE. I would love to have a system like that. And yeah, I'm just busting your chops. No disrespect intended.

[warewolff]

Make sure your figures are right on that single 60 amp controller. I suspect they're not. My 60 amp MPPT maxes out at 60 amps OR 150v or OR 700w. There is no clever design to avoid total wattage. It's a Morningstar TS-MPPT-60. I needed two of them for my 1.2kW system. I called Morningstar to confirm and they agreed.

If I'm correct you'd need 3 or 4 of my controllers.

Excluding the cost of 2 or 3 good MPPT controllers (which youll need running a high voltage array, an extra 1-1.5k in cost), did you get a quote on this system? I imagine it's a lot. Would like to know so I can educate myself a little more.