Off-grid solar power

Will they have cold weather charge and discharge issues like KSJoe mentioned with the other ones?
I do know they struggle more in cold. Would need to heat them. Forgot about that. All batteries do worse in the cold though.

And, on fuse, I guess it depends on maximum amp rating for inverter, so would need to just be 10 or so amps below that. I run a 4000/8000 inverter with large amp rating, so I have a large amp breaker there. Don’t remember but like 150amp maybe.

You can see my water pump on the right. It will spike the amp/watts when it turns on. Again, ask me how I know!
 
What's the advantage of breakers over fuses?

You can just flip back on if it trips, so its easy.

But the cheaper DC breakers can be polarity sensitive, meaning you cannot run the current through them in the "wrong" direction. Even if its not over current, just having the current flow the wrong way through a polarized DC breaker is enough for it to burst into flames if you try to turn it off. Here's a video showing one catch on fire due to nothing more than reverse polarity on a DC breaker when its turned off.

So if your'e using DC breakers, make sure they are wired in the correct polarity, or make sure they are not polarity sensitive. If a cheap imported DC breaker claims to not be polarized, I wouldn't necessarily trust their word on it.

If you want to keep it very simple and safe, go with fuses and accept that you'll have to replace them rather than have the convenience of resetting a breaker.

Also on the solar panels, if there are no more than 2 parallel strings of them, there is no need for over current protection on the panels. The panels are fine with their short circuit current, so if they're all in series, there is no over current protection needed. If its two strings in parallel,the two strings do not need protection because the most current they could see is 1x the short circuit current. If there's 3 or more strings in parallel, over current protection is required, because shorts in a single string could see 2x the short circuit current of the panels. What's worse - (depending on where the short is) that current can be in the reverse direction. Which means if you have 3 or more parallel strings of panels, there is no safe way to use a polarized DC breaker to protect to panels. Although a polarized DC breaker may be fine and protect you in most circumstances, if the short is in the wrong place, the breaker itself can cause a fire.

So on the panels (when 3 or more parallel strings) I'd suggest fuses for protection, and breakers for convenience elsewhere.

My charge controller is rated 500v on the PV input. One string of 12 panels in series would slightly exceed that, so I have two parallel strings of 6. My max voltage will be 250v, and I have no fuses or breakers on the solar panels because no panel can see more than 1x its rated short circuit current, and the wire is fine at the full current. Which is a long way of saying, in my configuration, the panels are not capable of producing enough current trip a properly sized fuse/breaker. So I just have a big DC rated switch.

BTW, diysolarforum.com is a great resource for figuring this stuff out.
 
Your cooking was gas there KS Joe. The inverter controllers can put out some heat when the batteries are fully charged and the sun still is cranking. Give them some air gap on the back. Maybe avoid mounting on wood, or gap it good if you do.

I would of made a roof for that solar rack. So you have a place to relax outside while it's raining. Get something to wash the panel up twice a year or so.

Overkill is better than underkill. Your system makes the one I have at camp a toy. Just (1) group 24v battery, 12x12 panel, and a few DC lights when you don't want to run the generator.

What are you doing for refrigeration? With that amount of solar cells, you could put A/C in a small room easily.
 
How do you deal with the heat in buildings
 
What are you doing for refrigeration?
I forgot to mention that. We're looking at a small dorm refrigerator. Either a large 1 door (with the tiny freezer area), or small 2 door. We'll also get a small microwave. For frozen food we'll probably just have a few hot pockets or something like that. But I'm thinking I might want more freezer space to store some ziplock bags of water. That way I can have ice blocks on site for hunting.

How do you deal with the heat in buildings
Nothing yet. I'd welcome suggestions though. I've thought about putting a roof vent, maybe with a fan. The building isn't insulated, so I don't think there's any point in getting a split unit.
 
What are you doing for refrigeration? With that amount of solar cells, you could put A/C in a small room easily.
I have an 18 cubic foot propane fridge and freezer. They get a mint for them new, but they are nice to have if off-grid. Mine uses 8 gallons propane/month and I run it from April - November.

A guy could maybe look for a used one out of a camper. I knew a guy that was going to throw away a 10' fridge/freezer because he couldn't find anyone to buy it. I bet the used value of that unit was over $1200.
 
I have friend that has a insulated building with vents and he says when it's 100 degrees outside it's 100 inside unless doors are open
 
I got it connected today. I made it semi-portable. The aluminum rack is not secured to anything and the PV input and AC output are both twist lock plugs. So I can disconnect it and set in the truck as a portable power supply if needed.

I was a little concerned because the batteries were in sleep mode when they arrived, as if they had been shorted and the BMS shut them down. Maybe they put them in that mode to ship them? It delayed me a bit because I didn't have a 50vdc +/- power supply, so I had to wait on one to arrive. Once the batteries saw an appropriate charge voltage, the BMSes woke up and said they had around 50% charge (which is what the vendor says they're shipped with).

Once I powered it up (around noon), it charged at 2650 - 2700 watts and had the battieries fully charged by 2 pm. I wasn't sure how much to expect out the solar panels. They're labeled for 3660 watts (305 * 12), but they should be angled more, especially for the winter sun angle. I hoped to see more than that, but that should be plenty of power.


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For the smaller systems who would you recommend getting charge controllers from?
 
For the smaller systems who would you recommend getting charge controllers from?

What do you consider to be small?
How much solar? How much battery? Biggest load?
I have one of these for my solar powered irrigation. Its been great. I'd buy another. The bluetooth app is handy.

There are a lot of very cheap PWM (pulse width modulation) charge controllers. MPPT (maximum power point tracking) style charge controllers cost noticeably more. MPPTs are quite a bit more effiicent. I only get MPPT. I figure extra cost for MPPT is better than extra solar, mounting hardware, etc to compensate for the power lost to a PWM. Be suspicious of the cheaper controllers on amazon claiming to be MPPT. Many are not.

The EG4 pictured above has been mostly ok. The fans our loud - we won't be using EG4 when building a cabin. It has a quirk I wasn't expecting. It gets really cranky about triacs. Triacs clip out part of the sine wave only allowing power to pass through for part of the cycle. My variable speed Milwaukee drill uses a triac to make it variable speed. If I use the drill at low speed, after a few seconds the inverter trips a fault that the manual indicates L1/L2 load imbalance. That inverter has only one line out (120v). So the error message was stating something impossible. It took some back and forth with support but I eventually figured out what's happening and after I explained it, their support agreed with my explanation. I think If I had a big load on it, the funkiness introduced by a triac wouldn't cause a problem. With low steady state power use, a triac makes it mad.
 
For the smaller systems who would you recommend getting charge controllers from?

Call Backwoods Solar. Every person that answers the phone understands the entire product lineup and they can pick for you. There is too much on their site to be able to understand. I got my last one from them and they got me exactly what I needed and nothing more.



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I gave them a call and we may have figured it out my issue.I have a 4ft led light that is motion.Well for motion detector to work the controller and inverter have to be working when working using power and in turn the fan has to run on inverter so using even more power.I think I will change my wiring so that I turn on the the inverter when I turn on light. This way the only time the inverter is working is when I am there.
 
I gave them a call and we may have figured it out my issue.I have a 4ft led light that is motion.Well for motion detector to work the controller and inverter have to be working when working using power and in turn the fan has to run on inverter so using even more power.I think I will change my wiring so that I turn on the the inverter when I turn on light. This way the only time the inverter is working is when I am there.
Have you looked into getting a 12 volt light to bypass the inverter completely? The RV and marine world have a little bit of everything that can make a solar powered system not need an inverter. I still have inverters in my building, but they are small, and at the item being used. Otherwise, my lights, fans, and outlets are all 12 volt output. I just run tiny automobile inverters on my TV/DVD/Antenna setup. I also keep a spare to run my tool batteries charger.
 
Yeah, on small sysstems I wouldn't do an inverter.
On my deer blind I now have 800w of panels, 200ah of LiFeP04 12v self heating batteries and no inverter. I get DC to DC buck/boost converters to get the DC voltages I need to power the camera NVR, wifi access point, network switch, raspberry pi, computer monitor, etc.
 
What kind of blind do you have that you can use 800W of panels?
 
For me, the grid is the answer......and I don't need no stinking converters and array of solar equipment to weld or refrigerate my beer. Carry on. (grin) (I do appreciate solar folks for their persistence. Fun to READ about your escapades in power.....but for me the grid is king.)

EDIT: I do find it "odd" that nobody offers an "all in one" package of solar, inverters, and storage power that you can simply install at your site and plug stuff in.
 
What kind of blind do you have that you can use 800W of panels?

Yeah, that’s twice the size of what runs my whole cabin.


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For me, the grid is the answer......and I don't need no stinking converters and array of solar equipment to weld or refrigerate my beer. Carry on. (grin) (I do appreciate solar folks for their persistence. Fun to READ about your escapades in power.....but for me the grid is king.)

EDIT: I do find it "odd" that nobody offers an "all in one" package of solar, inverters, and storage power that you can simply install at your site and plug stuff in.

Probably way too much variability. You can plow tens of thousands into systems if you’re not careful.


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What kind of blind do you have that you can use 800W of panels?

Here's the thread for building the blind. Here's the thread for 4k security cameras that use AI to identify animals and buzz my phone when a deer walks by. The NVR (network video recorder) records 4k video on 5 cameras. With the current hard drive in the NVR I have around 3 weeks of 24/7 video on all cameras, with motion & animal events flagged for easy finding.

I started with 400w of panels and a single 100AH 12v LiFePO4 battery. That's more than enough power for almost all the time. But in the short days of winter, if its cloudy and overcast for a few days, my cameras would shut off when the battery ran down. I got tired of having to reboot stuff after a few dark days, and the next easy bump up was to just double the solar and the battery. So I did.

I had additional motivations for gettign extra power on the blind. I'm working making 60 feet of extensions for the hydraulic post hole digger I made for the front loader of my tractor. I'm hoping to be able to drill my own wells. The water table is very high on my property. If I can drill my own wells, I'll do several on the 70 acre property. I'm thinking a well by the blind to create an irrigated food plot would make a great draw for the deer in dry Kansas. If that works out, I'll be running a water pump for hours.
 
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For me, the grid is the answer.....
If grid is available, I agree grid power is by far the best option.
For me, I think it would be 50k or more to get grid power to the edge of my property. + 1500 feet to the blind. Another 800-1000 feet to where we're wanting to build a cabin.
 
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