Hoping to get some design ideas for off grid cabin

[k2kunu]

I have a cabin in upstate NY that is off grid. We use wood and propane heat and have a propane fridge. We currently power the cabin with a 6000 watt propane generator ran as 240 volts. The well pump is on one leg and the rest of the cabin being lights and tv is on another. The cabin gets no use from mid December until March because of snow, simply can't get back to it. We use it primarily on weekends, get there Friday afternoon and leave Sunday afternoon with an occasional extended stay until a Monday or Tuesday. Here is what I would like the solar system to handle:

5 lights at 13 watts for 5 hours per day
1 TV at 40 watts for 5 hours per day
1 Cpap machine 16 watts at 8 hours
1 1/2 HP deep well pump (120v) for 30 minutes per day
There is a fan on our propane heater I'm guessing 5 watts max for 10 hours per day.

I've talked to several companies about a design and of course they all have different opinions. Just trying to see what others might do. I've never worked with solar before and am a total newbie to this. I believe I need to o thus as 24v because I need the inverter to be capable of 240 volts as I want the generator hooked to it using both legs and being capable of charging my batteries. I want sealed batteries as I don't trust people will check them. I was considering using VMAX batteries either 155AH or 200 Ah (6 or 4 depending on which I choose). Any feedback on specific equipment would be much appreciated. Thanks in advance for any help!

[Mike90250]

4, sealed 6V AGM (not gel) golf cart batteries. Cheapest way to do this.
Several companies make 24V / Inverter/Chargers

[bcroe]

I have a cabin in upstate NY that is off grid. We use wood and propane heat and have a propane fridge. We currently power the cabin with a 6000 watt propane generator ran as 240 volts. The well pump is on one leg and the rest of the cabin being lights and tv is on another. The cabin gets no use from mid December until March because of snow, simply can't get back to it. We use it primarily on weekends, get there Friday afternoon and leave Sunday afternoon with an occasional extended stay until a Monday or Tuesday. Here is what I would like the solar system to handle:

5 lights at 13 watts for 5 hours per day
1 TV at 40 watts for 5 hours per day
1 Cpap machine 16 watts at 8 hours
1 1/2 HP deep well pump (120v) for 30 minutes per day
There is a fan on our propane heater I'm guessing 5 watts max for 10 hours per day.

I've talked to several companies about a design and of course they all have different opinions. Just trying to see what others might do. I've never worked with solar before and am a total newbie to this. I believe I need to o thus as 24v because I need the inverter to be capable of 240 volts as I want the generator hooked to it using both legs and being capable of charging my batteries. I want sealed batteries as I don't trust people will check them. I was considering using VMAX batteries either 155AH or 200 Ah (6 or 4 depending on which I choose). Any feedback on specific equipment would be much appreciated. Thanks in advance for any help!

If you put in a pretty large water tank, and conceded to running the generator to pump
it up, the rest of the equipment would be hugely reduced. There would be a charger on the
generator for the batteries, to help out when pumping, or under extended overcast. Bruce Roe

[k2kunu]

Thanks for the input on this. I realize cutting the pump out of the equation drastically cuts down on the system requirements and I guess that is something I have to weigh out. I currently a tank that can gravity feed my toilet but there are times it would be nice such as hand washing and so forth that wouldn't require the generator being fired up. I get it's probably doubling the size of the system I actually need. Do you guys have any feedback on AIMS inverters? I have a feeling they are not good but had a company spec that out in one of the builds. I was leaning towards a Schneider.

[ButchDeal]

Thanks for the input on this. I realize cutting the pump out of the equation drastically cuts down on the system requirements and I guess that is something I have to weigh out. I currently a tank that can gravity feed my toilet but there are times it would be nice such as hand washing and so forth that wouldn't require the generator being fired up. I get it's probably doubling the size of the system I actually need. Do you guys have any feedback on AIMS inverters? I have a feeling they are not good but had a company spec that out in one of the builds. I was leaning towards a Schneider.

you could use a much smaller 12V RV pump and pressure tank for fixtures from the storage tank.

Also with an auto-transformer you could drop the need for 240V split phase for charging, could save a bit more on the inverter that way.
I would look at the OutBack Flexpower 1 system (all in one pre-configured) with the FXR3648 inverter/charger and add the PSX-240 transformer.

Or if you really want the split phase go up to the radian 4048

[Matrix]

I run my whole 24v system - including a 1/2 Hp well pump on 240v - from a Schneider Conext SW 4024 inverter. BUT my pump only draws 3.7 amps on each leg and the most I can see at start up using a Max Hold Amp meter is 14 amps total (about 7 amps per leg) for just a "split" second. And even with the max hold amp meter, I still tend to believe that my start up might not be being "seen" by the meter, and so it might be as hi as 30amps total (give or take). I was running the pump only one 1 leg for the first 2 months, but I felt it might be a bit too much on that one leg at start up, But the 14 amps ... or even if it is 30 amps ... is within the spec at 240v for the SW 4024.

So I am having pretty decent success with the SW 4024, 4 Trojan L16 435ah batteries in series, a Midnite solar charge controller, and a 2.5 kW array. Still tweaking the bugs after 3 months, but I believe the system is large enough for about 15 hrs of continuous use with no sun. (my daily Watt hours for a 24 hr day is 3000 or so). You might need more battery storage in a truly off-grid situation. And if i could do it again, I would probably go with a 48v Schneider, and 8 229-360ah batteries. So it really depends on how much you want to spend. Did you mention a Budget?

[k2kunu]

I run my whole 24v system - including a 1/2 Hp well pump on 240v - from a Schneider Conext SW 4024 inverter. BUT my pump only draws 3.7 amps on each leg and the most I can see at start up using a Max Hold Amp meter is 14 amps total (about 7 amps per leg) for just a "split" second. And even with the max hold amp meter, I still tend to believe that my start up might not be being "seen" by the meter, and so it might be as hi as 30amps total (give or take). But this is within the spec of the SW 4024.

So I am having pretty decent success with the SW 4024, 4 Trojan L16 435ah batteries in series, a Midnite solar charge controller, and a 2.5 kW array. Still tweaking the bugs after 3 months, but I believe the system is large enough for about 15 hrs of continuous use with no sun. (my daily Watt hours for a 24 hr day is 3000 or so). You might need more battery storage in a truly off-grid situation. And if i could do it again, I would probably go with a 48v Schneider, and 8 229-360ah batteries.

That's the one I was looking at.. It appears they can be bought for around $1500 or so. My question is can you get away with just the inverter or do you need other add on components to control the inverter such as type of batteries you are using? I plan on AGM batteries because I know people won't check the batteries and toast them.

[Matrix]

You will need a Charge controller. I have the Midnite Solar Classic 150. Here is my system pretty much as it stands right now. I'm sure others more knowledgeable can point out my short comings and limitations as it pertains to your specific needs, but this might be a good starting point for you. But again ... it all comes down to costs.

[Matrix]

With the SW 4024 (or the 2524 or the 4048) ... You will also need:
- A solar array large enough to charge your battery selecion
- batteries with enough amp hours to supply your loads when you have no sun
- An MPPT charge controller sized for the array and batteries
- And at 24v the SW calls for 3/0 battery cables. (48v would be smaller)

And possibly a good idea to have ...
- The SW System Control Panel (SCP) to fine tune the inverter (mostly necessary)
- The SW Combox for LAN access to that inverter (not necessary but nice to monitor and send commands to the inverter from you kitchen table if you have a LAN. A wifi LAN would be easy to set up even with out an internet connection)
- A combiner box (breaker box) for the solar array
- A "Solar Sub-panel" for all the electrical connections and breakers associated with the install. (Schneider has one but I chose the midnite solar box designed just for the SW inverters. Worked better with my space limits for set up.

The reason I chose the MIdnite solar over the SW Charge controller was I liked the LAN app better. BUT the Midnite Classic 150 and the SW products to not relate as well together than if you went all SW components (ie. SW Charge controller and SW Inverter, with the SCP, Combox and even battery monitor)

[k2kunu]

With the SW 4024 (or the 2524 or the 4048) ... You will also need:
- A solar array large enough to charge your battery selecion
- batteries with enough amp hours to supply your loads when you have no sun
- An MPPT charge controller sized for the array and batteries
- And at 24v the SW calls for 3/0 battery cables. (48v would be smaller)

And possibly a good idea to have ...
- The SW System Control Panel (SCP) to fine tune the inverter
- The SW Combox for LAN access to that inverter

The reason I chose the MIdnite solar over the SW Charge controller was I liked the LAN app better. BUT the Midnite Classic 150 and the SW products to not relate as well together than if you went all SW components (ie. SW Charge controller and SW Inverter, with the SCP, Combox and even battery monitor)

That's what I meant the SCP and SW Combox...Is it actually needed. I don't have internet connection where this will be located. It's a cabin a mile in the woods. I want it simple and affordable and reliable..LOL I know I'm not asking for much. I have the battery requirement and the solar requirement I guess I'm looking at the best bang for the buck with the inverter. The AIMS inverter is $900 for 24v 4000w 120/240....The Schneider is around $1500 but it may appear I need the other add ons such as SCP or Combox to make it functional. Thanks again for the help I truly appreciate!

[Matrix]

If you check around, reviews and such seem to point away from AIMS. I went with Schneider because they are UL 1741 approved for install in homes and it was 240v split.

You do NOT need the combox. But a local area network is easy and cheap and does not need an internet connection only a Wifi router. But you DO need (IMO) the SCP. Can you operate the SW with out it? Well yes ... you can turn it on and it will run off it's presets, but IMO, the presets are inappropriate for my needs and I have found are not successful in fully charging my battery from the SW charger on AC / Generator current. The good thing about the SW is it is also a charger that can operate off your Gen if there is not sun. So you could charge your batteries in 3-5 hrs (+/-) and then turn the generator back off.

[Matrix]

Follow the link above in post #8 and you can see my whole set up.

[Matrix]

To the OP, one other thought I just had ... if you go with the SW inverter family, you might want to get the Distribution panel for AC / DC. Easier than making one up yourself. BUT ... I went with the Midnite Solar MNE250SW combo AC/DC rather than Schneider's individual AC panel and DC panel. Cost difference is almost half, and the layout of the system footprint worked better for me with Midnite Solars product.