Bought an off grid cabin - system is next

[KMac]

It's true, if you go to a 24v system you will be much happier in the long run , I think. In my one room weekend cabin I'm very happy. I've seen the arguments made time and time again here why people think 12v is what they want, and with a few exceptions (where they are certain they never want more than their really light loads and already blew money on 12v) the 24v or even 48v argument wins out. It's much easier to expand in the future, uses thinner (cheaper) wiring that you can hook up without special termination tools, I'm told it is less of a fire hazard (which makes sense), etc. There is sort of a sweet spot at 24v for what size loads you describe when you try to puzzle all the pieces together economically and safely. At least that's what I found. Consider it carefully because you sort of commit to 12v, and then to switch later it's difficult. And can you explain any perceived advantages of 12v over 24v?

Also, your loads are 180 out of one 12v 230Ah battery? Get two of them and the panels to match or I am afraid that battery won't last. Actually, you can do the math better than my comment but it's a ballpark that says you need bigger battery if you want it to survive with those loads. Shoot for less than 50 percent discharge (many will say 20 percent but mine are used 2 days a week and will die of old age before dying of cycling). Also, I'd suggest not AGM if you are trying to save unnessary expense. Flooded are cheaper, and have advantages worth considering - for example being easier to test when you are trying to figure out what is going on. A hydrometer gives the best insight, and you can't get into an AGM to test them so you're left guessing. You just want something to store the energy then release it when you want, and flooded do that very well and much cheaper. Now, if you have to put them inside and can't vent, then that's too bad. But if you can go outside with them or vent them okay then get flooded in my opinion.

Good luck. With my cheap 1000 watts of 24v 250watt panels, I run a 315 Ah 24v battery setup, with a 1500 pure sine inverter. Not top quality but it all works together well at my cabin. Charge controller is my gem, a 60amp mppt Morningstar and to me that's the heart of it - wifi view into the controller webpage to see the logs. With it I run lights, CPAP, music, laptop, charge phones, run TV (rarely, but it's fine), microwave (Not top setting is all), and in summer a 5000 BTU window AC in the day and even overnight on low.. This weekend adding a transformer to run our 1/2 HP 230v Grundfos well pump (on a timer to run in the day) to fill a cistern. I'll put a float switch on it in the spring when I really get it going). It's far easier for me to do all that than a 12v RV style system would be. Also, panels are cheaper, wire is cheaper, and I've suggested cheaper batteries. So reconsider your options.

[PNPmacnab]

"1 - 7.2AH philips respironics 8 hours a day: 57.6 AH"

That is 7.2A. I use plenty of humidity at home, but don't seem to need it at the camp. At least don't use the heated hose. You can get away with only 10AH with 120V inverter at 12V without humidity. If using the 120V pack, get a small 400W inverter solely for use with the CPAP, smaller ones will kick off. This power level in a cheap MSW is about the most efficient and cut the wires to the fans to save extra current as it will run cool. The best money you will ever spend is buying the official 12 to 24V converter for that unit and it will use half that current. Shop around it is pretty cheap. There is communication between the main unit to the power pack so you are screwed out of building your own. I made mine turn off automatically after the sun comes up, well later than mu normal wake up time, so I wouldn't leave it switched on all day wasting power.

Everyone wants to go cheap on panels. I'd double that. I get refrigeration and hot water along with everything else on that much power. Go on ebay and search for power meter 130A. These are great little devices for $10 that will give you AH, A, W, WH, V min and max amps of DC. The kill o watt of camps. I have several.

[Moonie]

Hey guys, just wanted to update you on what's been going on at the cabin. I've learned a LOT over the last couple months reading, watching youtube videos and just experimenting. I ended up buying 4x100 watt cells, tracer BN 40a charge controller, Samlex 600watt PSW inverter, 4x105ah AGM batteries, and a 55amp 12v battery charger for when the generator is running. I installed a new panel below the old one and moved all 120v circuits to it. The inverter powers that exclusively, and so far has done a fantastic job. The old generator fed panel has the central A/C(not working), 1x120v for the battery charger, a feed from the backup generator, and the well pump.

I ended up starting with 12v just because I wanted a basic system and that(at the time) seemed like a logical start. I didn't want to spend the extra money on a 1500-2000w 24v inverter. I've been to the cabin 4-5 times in the last 6 weeks and everytime I get there the batteries are happily at 13.7 volts. I'm able to run ceiling fans, lights, tv and dvd for the night and still have 12.6v remaining in the morning before the sun comes up.

I'm now ready to step the system up a little, and wanted to get some input on my plan. I want to add 4x100w cells to double the input at 800watts. My charge controller is already a 12/24v unit so to handle that much solar I'll need to rewire the batteries to 24v. I won't be able to use the 55amp charger because it's 12v only, so here lies the questions for you guys. Should I get a Samlex 2000w inverter, and a pro marine battery charger that has 4 leads(12v x 4) or should I just spend the money and get a Schneider 2524 inverter/charger. I'm going to double the battery bank also so I'll have 420ah @ 24v.

The advantages I see with the Schneider is the charger feature, also it's 240v so I can feed my panel the correct way without going in hot on a 240v breaker with a loop to energize both sides of the panel.

Last thing I installed a Panda washer and it works great! 1.jpg
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Since this picture I've doubled the battery bank to 4x105ah batteries and installed the Samlex 600w.
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You can see in the below picture I need to cut down some tree's.
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[J.P.M.]

Looks kinda' small to hold a panda, but if it's made in China, I guess they'd know best.

Question: Do you need a permit to keep and arm bears or does that come under the 2d amendment to the U.S. Constitution ?

[ButchDeal]

I would:

• get the batteries in a box and vent to outside.
• go with 48V inverter
• go with schneider or Outback inverter/charger
• get grid tie PV modules and not continue with expensive 12V modules
• sell existing 12V inverter and PV modules.

Why 48V? it has much more room for expansion and simpler cabling of batteries.
Why grid tie modules? They are cheaper, a lot cheaper.

If you want to keep the existing PV modules then mount them on the west face with their own CC to extend your charging.

[Moonie]

Looks kinda' small to hold a panda, but if it's made in China, I guess they'd know best.

Question: Do you need a permit to keep and arm bears or does that come under the 2d amendment to the U.S. Constitution ?

Funny you mention bears. I had one in camp the other day that tore apart my "chemical" box outside lol.. Sept 15th bear season opens so he better watch his back.

Webp.net-resizeimage.jpg

[Moonie]

I would:

• get the batteries in a box and vent to outside.
• go with 48V inverter
• go with schneider or Outback inverter/charger
• get grid tie PV modules and not continue with expensive 12V modules
• sell existing 12V inverter and PV modules.

Why 48V? it has much more room for expansion and simpler cabling of batteries.
Why grid tie modules? They are cheaper, a lot cheaper.

If you want to keep the existing PV modules then mount them on the west face with their own CC to extend your charging.

Ya, not interested in selling everything I've done and starting over. I realize 48v is the holy grail, but I'm going to stick with upgrading what I already have. The biggest draw I've seen is 378 watts, that was with 4 fans on, TV running playing a DVD and several lights on. I don't need a massive system, just enough for a weekend hunt.

Moonie

[J.P.M.]

Funny you mention bears. I had one in camp the other day that tore apart my "chemical" box outside lol.. Sept 15th bear season opens so he better watch his back.

Looks like a prepper to me. I can tell by the demeanor and the facial hair.

[Moonie]

Looks like a prepper to me. I can tell by the demeanor and the facial hair.

Actually that's my 70 year old dad. From Kansas. But that doesn't mean you're not in the ballpark lol.

[J.P.M.]

Actually that's my 70 year old dad. From Kansas. But that doesn't mean you're not in the ballpark lol.

Is he the one who took out the commode ? Hormel chili and a couple of 6 packs will do a number on those things most every time - the commode that is - but maybe bears to come to think of it.

[KMac]

If it is just a weekend cabin, I'd go with a 120v inverter (compare price and spec of Samlex to Cotek, I think they are the same manufacturer). Limit the total wattage of the inverter you buy to your battery and its max rate of discharge for AGM. There is a great sticky post on that. I exceed the recommendations but carefully and only briefly.

Then get a 24v charger knowing you may never need it at a weekend place with the loads you mentioned. I've never had to charge mine that way. I have plenty of power for a weekend even a cloudy winter one. Batteries will likely die of old age before anything else as long as you don't go too low and they can charge up in a day or two when the sun shines and you aren't there using any power four days a week.

Finally, compare the price of new larger grid tie panels of the same total wattage you want to have to the price of the four 100w ones you are considering. lt might be the same price or lower! That would leave you you old ones to play with or sell. It's worth shopping.

Good luck!

[Moonie]

If it is just a weekend cabin, I'd go with a 120v inverter (compare price and spec of Samlex to Cotek, I think they are the same manufacturer). Limit the total wattage of the inverter you buy to your battery and its max rate of discharge for AGM. There is a great sticky post on that. I exceed the recommendations but carefully and only briefly.

Then get a 24v charger knowing you may never need it at a weekend place with the loads you mentioned. I've never had to charge mine that way. I have plenty of power for a weekend even a cloudy winter one. Batteries will likely die of old age before anything else as long as you don't go too low and they can charge up in a day or two when the sun shines and you aren't there using any power four days a week.

Finally, compare the price of new larger grid tie panels of the same total wattage you want to have to the price of the four 100w ones you are considering. lt might be the same price or lower! That would leave you you old ones to play with or sell. It's worth shopping.

Good luck!

Ya I'm leaning towards the samlex 2000w over the 1500 because it has direct wire. Can you recommend a good 24v charger? I like the ProMariner one because it charges individual batteries and should keep the battery Bank equalized right? I'm looking at the four Bank 36 amp one.

ProMariner Tournament 36 Amp 12/24/36/48V Elite Battery Charger https://www.amazon.com/dp/B00TUNYO1O..._MGSLzbZNJKR80

Also for $400 I can add 4x100 watt panels that match my existing panels for 800w total. Or I can spend $700 and get 3x335w panels for 1005 Watts like you mentioned. That's 20% more power and by the time I sell the existing panels it should be close to a wash.

[Sunking]

Hey guys, just wanted to update you on what's been going on at the cabin. I've learned a LOT over the last couple months reading, watching youtube videos and just experimenting.

Are you sure you learned something?

Looks like you did everything we warned you not to do.

You used parallel batteries which will cost you big bucks and teach you a lesson when you replace them in a year.
You esed very expensive battery panels rather than GT panels.

Me thinks you used Screw Tube Videos. rather than professionals. If you would listen, we can save you a lot of money.

[ButchDeal]

Are you sure you learned something?

Looks like you did everything we warned you not to do.

You used parallel batteries which will cost you big bucks and teach you a lesson when you replace them in a year.
You esed very expensive battery panels rather than GT panels.

Me thinks you used Screw Tube Videos. rather than professionals. If you would listen, we can save you a lot of money.

and still doesn't want to listen, planning to continue down the same path.

[KMac]

Looks like you are going to get out of the 12v world and going 24v. That's important progress, and advice you were given early, so put on your sack cloth and ashes, rend your robe, and wail appropriately. You are losing your charger and spent more on wiring, etc. But moving on . . .

In my view, the 12v battery charger isn't a big loss. Do you really need one? If so, earlier advice from a pro was to be careful in your choice as you are using AGM. I don't use one and can't help on a recommendation. I just switch to generator if need be (very seldom), and the panels will charge batteries fast enough for me in a day or two (for a weekend place).

I understand you don't want to lose your charge controller at this point that can do 24v at 40 amp. I agree 48v would be better, but I understand not wanting to go there now.

But you are willing to ditch 100w panels as it is a wash to buy bigger grid tied and sell the small ones. So far, so good. I might add that if you shop hard for the panels you might get them cheaper still.

Advice about venting your AGMs or moving them outside? He is the pro, so you probably want to follow up on that. I have my flooded ones in a half buried box in the shade outside. Gives a nice stable battery temperature.

Again good luck.