Looking to build new solar system

OffGridJoe

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Jul 27, 2020
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Looking for a bit of insider knowledge here. I've had a small 400W 12v solar system with (6) 125AH vmax batteries for about 6 years.

I have recently purchased (18) 310w 48V solar panels at an incredible price. I had never intended to go 48V but the deal was excellent so it seemed like that was the way to go for me.

Having said this I'm relatively green on solar. no pun intended. My home is completely off-grid with no grid tie in. My only real source of power comes from a propane generator.

I'm on a tighter budget, but I understand there's a line between getting what you pay for and over priced.
Ideas on system items I can purchase to get my panels into use without buying everything at once would be ideal.

Thanks Guys,
Joe
 

DThames

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What is the Voc on the back of the panel?

If you use an MPPT type charger, you can use the large panels with 12v, 24v, 48v battery systems. You just need a proper charger. The EPEver Tracer 40a AN charger (for example) can take 100v input. The BN model can take 150v input. MPPT chargers will step down the voltage to properly charge the battery.
 

MichaelK

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Can you post the specifications of the panels you refer to? I'm guessing that it's the Voc that's around 48V. That does NOT mean they can only be used to charge a 48V system, and it also does NOT mean they can be used to charge a 48V system. So, more details are needed.

That being said, for a whole-house system, I think 48V is a good choice. That's what I'm running at my place. Your panels amount to 5580W, which is about what I have online myself right now.

Buying stuff piecemeal though is not very realistic. The first thing you should do is determine the kinds of things you want to power. At 48V you can have a standard AC refrigerator, freezers, power tools, and everything else you would expect to have with a 21st century lifestyle. An All in One (AiO) system might be appropriate if you do not have big motor driven loads like pumps. Component systems usually are low-frequency transformer based and have the larger surge capacities needed to run well-pumps, big saws, ect.

With an AiO you will need the AiO, batteries, and panels.
With a component system you'll need a charge controller, batteries, and inverter, and panels.

Both kinds typically can be paralleled to increase overall power, though I'm guessing that since you've been off-grid for 6 years now, your power demands are not that high?
 

OffGridJoe

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Our energy consumption is pretty low as you could expect. My largest electrical item is my well pump. its just shy of 300 feet deep. I have a Smaller sized refrigerator, washer, gas dryer, and a dishwasher. lights all over the place. I do have chest freezers but theyre outside in garage and we live in cold country so come the minimum day light season theyre kept frozen by nature.

Thanks
 

DThames

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Your panels say 45.5 Voc. Not under any load they have a voltage of 45.5v under normal temp. On a clear, sunny, cold day that voltage will be a little higher. In a warm climate, two of those in series would give you 91Voc and would be somewhat safely under 100v max input or 3 in series would be a little under 150v max input. Because you are in a cold climate, you want to stay maybe a bit further away from that max of your solar charger or inverter/charger. So when shopping for an inverter/charger look at the max PV input voltage. Some of the new "All in one" units have a higher max PV in, so maybe look hard at those for a solution. Being able to have a higher PV input allows for more panels in series and allows the wire to be a smaller size. So for example if you could connect 6 panels in series, you could have 3 strings of 6 with fairly small wire gauge. But if you had only 2 panels in series, and did that 9 times, you would have much larger wire or many runs of wire to carry the large current/amps.
 

MichaelK

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Will you want to run your well pump on this system? It's doable, with the right inverter. Can you document its specifications? Right now I'm running a 1hp Grunfos 240VAC pump off my solar system, with a XW+6848 inverter. It draws ~9.5A while running, and 38A at startup. What I find is that solar is producing cleaner AC than my generator did. With the generator, the pump drew 10.1A and pumped 275gph from -380 feet. On solar, I'm pumping 305gph but only drawing 9.5A. The inverter is making cleaner AC then the generator, so the pump is running more smoothly and pumps more water.

I have my panels on rotating pole mounts, and I can run my pump at 8:00am if I rotate my panels East. I keep it running till 4:00pm by rotating the panels West. If you wire your panels 3S6P, you'll be making a system comparable to mine.
 

OffGridJoe

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Will you want to run your well pump on this system? It's doable, with the right inverter. Can you document its specifications? Right now I'm running a 1hp Grunfos 240VAC pump off my solar system, with a XW+6848 inverter. It draws ~9.5A while running, and 38A at startup. What I find is that solar is producing cleaner AC than my generator did. With the generator, the pump drew 10.1A and pumped 275gph from -380 feet. On solar, I'm pumping 305gph but only drawing 9.5A. The inverter is making cleaner AC then the generator, so the pump is running more smoothly and pumps more water.

I have my panels on rotating pole mounts, and I can run my pump at 8:00am if I rotate my panels East. I keep it running till 4:00pm by rotating the panels West. If you wire your panels 3S6P, you'll be making a system comparable to mine.
Yes the goal is to shift primarily to solar, and reduce the use of my generator. Essentially we use the generator for anything we need power for. It runs several hours a day to keep up with laundry dishes and showers. I dont know my well pump specifications, or how to find it. I know our well is in the 290ft deep range but i dont know its electrical need other than its 240v
 

DThames

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Yes the goal is to shift primarily to solar, and reduce the use of my generator. Essentially we use the generator for anything we need power for. It runs several hours a day to keep up with laundry dishes and showers. I dont know my well pump specifications, or how to find it. I know our well is in the 290ft deep range but i dont know its electrical need other than its 240v
A lot of the "all in one" type inverters can be stacked. So you could get a 3000w, add 3000w if the first one is not large enough to run the pump. For 240v you will need 2, 120v inverters connected to create 240v split phase. Or you will need a 240v inverter and an autotransformer with a center tap so you can get a neutral for 120v. If you go the two 120v inverters for split phase route and they are not large enough, you would need to buy two more. If you go the 240v route (with autotransformer) and the inverter is not large enough, you would need one more inverter. You would not need a second transformer. You can get a 5000w 48v input that will output 240v for about $900-$1000 and a transformer for $300-$400. The 3000w 120v inverters that I have are about $700 each. David Poz video on 5000w with autotransformer. Another video. For insurance reasons you might need to get UL listed equipment.

What is the rating on the generator that you run the pump off of now?
 

OffGridJoe

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I run a 6300 watt running and 8300 watt start up propane generator. I believe its only a 30 Amp plug that the whole house runs off of.
 

Wellbuilt

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I run a 3600watt out back system with 16 sams club GC battery’s .
I will be using a Grunfos SQF solar pump ’ It runs on 1500watts or solar or really anything .
I have a deep slow filling well @ 730 feet .
I pump into 2 holding tanks 475 g one inside for winter , the other is out side and I drain it at thanks giving .
I use a A/C RV pump to pressurize the system .
You could down size your inverter by just pumping water with your genarator into a tank
My tank inside is 250 gallons and out side I’m using a square tote ,I bought 3 for 50 bucks.
last year my solar panels where covered with snow for 10 weeks I just charged with a 2800watt generator
I use 5 gallons of fuel a week +- with no solar at all .
 

OffGridJoe

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I run a 3600watt out back system with 16 sams club GC battery’s .
I will be using a Grunfos SQF solar pump ’ It runs on 1500watts or solar or really anything .
I have a deep slow filling well @ 730 feet .
I pump into 2 holding tanks 475 g one inside for winter , the other is out side and I drain it at thanks giving .
I use a A/C RV pump to pressurize the system .
You could down size your inverter by just pumping water with your genarator into a tank
My tank inside is 250 gallons and out side I’m using a square tote ,I bought 3 for 50 bucks.
last year my solar panels where covered with snow for 10 weeks I just charged with a 2800watt generator
I use 5 gallons of fuel a week +- with no solar at all .
That sounds like a decent idea too. so you do not use a pressure tank at all? just a pump from the holding tanks?
 

MichaelK

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I dont know my well pump specifications, or how to find it. I know our well is in the 290ft deep range but i dont know its electrical need other than its 240v
That's easy to measure with the right meter. I'm using a Uni-T216C (Ebay, 77$) right now that reads AC current, DC current, and AC inrush. You just need to open up your breaker panel, remove the protective panel that covers the wiring, and place the clamp around either the black or the red wire (not both) that powers your pump. Set meter to "inrush" mode, and flip the breaker, to start the pump. The inrush reading will be in AC amps. I'll guestimate that your inrush is likely to be in the 30-40A range. Once the pump is running, you can switch to real-time amps and measure the current draw while running (likely is 8-10A).

Alternatively, you can pull the cover off the pump control box, and find the same black or red wire leading down the hole to the pump and measure the amps there.
 

Wellbuilt

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That sounds like a decent idea too. so you do not use a pressure tank at all? just a pump from the holding tanks?
I think the pump is continuous pressure but I have a presser tank, I can get a shower with out the pump turning on .
Michaelk has a lot of good pump ideas , mike allso has a wealth of information , they have been coaching me on my well problem for 5 years but Im no Electrision 🤣.
I ended up just buying a very expensive solar well pump.
I had a hard time finding sch120pvc well drop tube and 10g well cable for reasonable money.
I ran a 4” pipe from the side of the house in to the utility room .
Last week I found out that my line was crushed and after days of fooling around I had to jack hammer the floor out and fix the pipe . 🤬
If the weather holds out I’m going to try to drop the pump down 700’ in 2 weeks .
341B9D3D-8026-417C-BDEB-4818E4011D52.jpeg3043167C-EA7E-409D-BFCD-F24BB4A305F9.jpeg47317552-4EE6-4FEE-939F-057A94DD46BD.jpeg
 

OffGridJoe

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Jul 27, 2020
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I think the pump is continuous pressure but I have a presser tank, I can get a shower with out the pump turning on .
Michaelk has a lot of good pump ideas , mike allso has a wealth of information , they have been coaching me on my well problem for 5 years but Im no Electrision 🤣.
I ended up just buying a very expensive solar well pump.
I had a hard time finding sch120pvc well drop tube and 10g well cable for reasonable money.
I ran a 4” pipe from the side of the house in to the utility room .
Last week I found out that my line was crushed and after days of fooling around I had to jack hammer the floor out and fix the pipe . 🤬
If the weather holds out I’m going to try to drop the pump down 700’ in 2 weeks .
View attachment 69589View attachment 69590View attachment 69602
that would be very frustrating to deal with. 700' is also an incredible distance to fight.
 

Wellbuilt

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791
UPDATE
I dropped the pump down the hole today .
It went easy for a change .
I’m getting 5 / 51/2 gallons a min .
My inverter started reading a 800 watt draw .
I pumped for a hour and at the end I was getting just short of 5gm but the power use went up to 1000watts .
I figure the water level started to drop after a hour of pumping so the pump needed more power to push it up .
The pump was a lot of money but it really made every thing easy .
700 ‘ sch120 4 check valves 700’ of jacked well pump cable .
One pump.
The well puller just lowered the pipe ,‘wire , pump down the hole .
It slid in the pitiless adapter and I wired it up and plugged it into a wall outlet and out came water .
My inverter dident even grunt a bit .
 
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