Justkeepitsimple
New Member
Hi my name is Eric. My wife and I life far off and away in very off grid AZ. About 6000’ elevation so milder summers (about a week or two it pushes over the 100 Fahrenheit mark, and we see an average of about 8 to 12 inches of cumulative snow throughout the winter. about 3 to 4 months of the year the nighttime temperature dips into the 30’s-40’s °F at night). All things considered pretty mild for Arizona.
I’ve been researching and learning about solar for about a year now. Some one gave me a turnkey system to tinker with experiment/ learn on. (3) 100 watt harbor fright (freight) panels, a cheap Amazon PWM charge controller (that little blue 20$ infinitely rebranded one with simple digital readout), (2) medium- large Walmart flooded lead acid deep cycles (nominal 100 Ah each) and a modified sine wave 2000 watt harbor fr[e]ight inverter.
I went into this knowing almost nothing about basic electronics or solar.
What I’ve learned:
With that said we’re some learned up and getting ready to build a new system from the ground up. I like things to be reliable, durable, simple, modular, and good cost-benefit ratio.
Our loads are pretty minimal we generally power down the inverter overnight.
I’d like to build and design a system that’s easy to troubleshoot, somewhat redundant, and preferably compatible with the little Honda 2000 inverter generator to top of batteries on cloudy days.
I’ve had the circumstance come my way to acquire some used 40 W panels. I know I know…old stuff…be a lot of work to string together… a lot of new better options ($$$) but hey! they still work and they free!
Brought a bunch home. 11 out of 14 tested still good. 440w nominal. There is no manufacturer or voltage rating listed anywhere on them so I’m guessing but by their size they appear to be 40 W nominal panels. I cleaned them all off and put them in perpendicular to the sun at high noon and tested the open circuit voltages.
Maximum measured 23.4 V
Minimum reading was 18.6 V
Average over the 11 good ones was 21.95V
I am planning to also add the (3) 100W harbor freight specials to the parallel string feeding the charge controller for a total of 740W nominal solar going in to charge control/ battery bank.
Then I did a thing and bought (4) 12V nominal (4D group size) 290 Ah nominal flooded lead acid deep cycle batteries (DEKA). I know I know… I’m kind of doing this ass backwards but bear with me.
I pretty well have my heart set on building A 12 V system. I know… I know the wiring is gonna be expensive! But for the following reasons mostly to do with redundancy and ease of troubleshooting/repair:
1) I will string panels together to use solar panel input in parallel to provide voltage/ current to the charge controller (i’ll get to my selection criteria for the controller/ inverter toward the end of this post).
Because I:
A) Don’t know if these panels can handle being run together in series
B) Don’t want any funny undrevoltage going to my charge controller if one of them happens to bite the dust (ie in a 24 or 48 V configuration).
C) If one does go out it’s a pretty small percentage of my system and I can eliminate and/or replace with another 40W panel (I have access to about a dozen more free ones where these came from).
-If a 12 V battery kicks the bucket I can just take it out of the parallel bank and replace when I get to it instead of limping along on two batteries (if 24V system) or being so out of luck (ie situation in a 48V system with 3 out of 4 Twelve Volt batteries).
Our sunlight hour loads are pretty minimal and our overnight loads are even smaller for the proposed new 12 V system.
200w for deep freezer (off at night)
75w for Starlink router (18hr on 6hr idle)
200w for laptop/ phone chargers (all powered down 2-4 hours after sunset)
100w for box fan (run 24/7 in the summer)
150w for nighttime lighting (2-4 hours post sunset, could be even less if I switched over bulbs to LED).
Water all gravity fed. No water pumps. No well to run. Don’t do TV. Our luxuries are our 3 ft.³ chest freezer and star link for the smart phone email, wifi calling/ YouTube. Burn wood for heat.
Apx 3800 w/ h on the high side consumed during average 12hr period of darkness.
Out of our 13920 w/h battery bank equals//
About 27% DOD on battery bank.
My design target depth of depletion on these batteries bank is 15 to 30% for longevity.
Which leads now to the back asswards figuring of the inverter and the charge controller.
I am a big fan of overbuilt reliability and durability. As far as I’m concerned cost is no object when durability and reliability is concerned.
I’m thinking of going with:
Morningstar TS-MPPT-60 > TriStar 60 Amp 12/24/48 Volt MPPT Charge Controller
My thinking for this is that at some point when we want to expand at that point yeah I’ll probably go to $$$LithiumFe 48 V system and fancy new 300 W panels… Bam I’ve already got a charge controller that can handle that.
Also thinking of going with the largest 12 V rated morning star pure sine wave inverter they have available (looks like the biggest one they have for 12 V is 700W continuous with some surge capability up to 1300 W under 100°F).
Morningstar SureSine 700 Watt 12VDC 120VAC Pure Sine Wave Inverter with North America Type B Outlet .
if I decide I want to install a mini split I’ll either get one that can run straight DC no inverter needed day time only running straight off a string of dedicated panels, or get another 700W inverter dedicated for a small sized mini split and up the panel count and battery bank some. I know some people say 700 W inverter isn’t all that much but we pretty simple people and I know it’s sorta fiddly and convoluted but if I have to we can always throw the 2000watt modified sine wave harbor freight special on the battery bank and use that to run our lights and chest freezer anyway. I don’t know. I’m just impressed by MorningStar reliability record and the biggest 12Volt inverter looks like they make is their 700 W model.
I know 12 V isn’t considered very optimum by most people these days but for the reasons that I listed mainly to do with reliability and ease of troubleshooting that’s what I’m inclined to go with for my current circumstance.
My question for the community TLDR is have I picked an appropriately sized charge controller for this load? I know at 12 V DC theres a lot of current (amperage) potentially going into the charge controller and I’m not sure if that Morningstar 60 amp charge controller I’m looking at can handle it or not?
Quick stats (11) 40 watt panels 21.95 V avg.
(3) 100 watt panels not sure about the open circuit voltage on these panels. I need to put the multimeter on them I guess. They the harbor freight hundred watt specials. But assuming on the average side they’re about 20 V output each.
So that’s Approximately 740 watts of panels nominal. @20 V avg.
That’s about 37 Amps. Well that answers that question lol sometimes you just gotta write things out, think about it, and look at it twice and you can answer your own questions! Thanks forums for listening to me think out loud.
Going to keep batteries, charge controller and inverter in their own earth sheltered concrete ventilated storage box, earth sheltered in ground installation and shaded by static solar panel ground array. Big diameter cables shortest runs possible from panel parallel sequence to inverter input. May not keep batteries at perfect operating temperature but will keep them warmer in the winter and cooler in the summer. Some battery sacrifice performance maybe during the more mild months but really it seems the extreme high or low temperature that murder them. At least the inverter and the charge controller will stay happy and cool.
Any thoughts criticisms or suggestions? I’m open to hearing all but pretty well made up my mind I am going caveman simple 12Volt system at least for this stage in our life.
Got the panels already… Already ass-backwards bought the (4) 12 V flooded deep cycle lead acids, they seem like a good value for the money as long as you’re diligent to check the water levels at least every month more often in hot weather, and keep depth of depletion to a maximum of 30%. I don’t know. Change my own oil. Cut my own firewood. What’s checking the battery water level once a month?
Oh another thing I side forgot to mention I would really like a charge controller that can handle being hooked up to a generator to charge batteries on cloudy days. I’m assuming the 60A morning Starr MPPT should be able to handle that I’ve read the documentation up and down on it but don’t see it specifically stated there how one goes about wiring that up? I’m not looking for anything fancy like an auto Gen set kick in. Just want to get the alert on the charge controller Bluetooth app: “battery voltage below 50%” stroll out to the shed pull start the honda 2000 genny, drag the ole 10gauge extension cord out and plug it in to the charge controller. It’s probably right in front of me. But my brain is so fried from crash course in solar design and amps ohms watts I probably missed it somewhere.
No possibility of grid tie now or in the future. Nearest powerlines are 20 miles away and it just ain’t gonna happen for electricity to get brought out here. so that simplifies things at least from a design choice standpoint.
Thanks for those 2 bearing with this long ramble. Good community I’ve learned a lot from searching through the forums here.
I’ve been researching and learning about solar for about a year now. Some one gave me a turnkey system to tinker with experiment/ learn on. (3) 100 watt harbor fright (freight) panels, a cheap Amazon PWM charge controller (that little blue 20$ infinitely rebranded one with simple digital readout), (2) medium- large Walmart flooded lead acid deep cycles (nominal 100 Ah each) and a modified sine wave 2000 watt harbor fr[e]ight inverter.
I went into this knowing almost nothing about basic electronics or solar.
What I’ve learned:
- panel efficiency degrades greatly when it gets hot out.
- Cheap PWM charge controllers kinda suck
- Don’t run flooded lead acids lower than 12.5 V (after many cycles down to 11.5 V… well 2 years and they’re about toast now).
- Check/Top off flooded lead acids with distilled water at least every month.
- Modified sine wave kind of sucks.
- Amps/ watts/ volts formula.
With that said we’re some learned up and getting ready to build a new system from the ground up. I like things to be reliable, durable, simple, modular, and good cost-benefit ratio.
Our loads are pretty minimal we generally power down the inverter overnight.
I’d like to build and design a system that’s easy to troubleshoot, somewhat redundant, and preferably compatible with the little Honda 2000 inverter generator to top of batteries on cloudy days.
I’ve had the circumstance come my way to acquire some used 40 W panels. I know I know…old stuff…be a lot of work to string together… a lot of new better options ($$$) but hey! they still work and they free!
Brought a bunch home. 11 out of 14 tested still good. 440w nominal. There is no manufacturer or voltage rating listed anywhere on them so I’m guessing but by their size they appear to be 40 W nominal panels. I cleaned them all off and put them in perpendicular to the sun at high noon and tested the open circuit voltages.
Maximum measured 23.4 V
Minimum reading was 18.6 V
Average over the 11 good ones was 21.95V
I am planning to also add the (3) 100W harbor freight specials to the parallel string feeding the charge controller for a total of 740W nominal solar going in to charge control/ battery bank.
Then I did a thing and bought (4) 12V nominal (4D group size) 290 Ah nominal flooded lead acid deep cycle batteries (DEKA). I know I know… I’m kind of doing this ass backwards but bear with me.
I pretty well have my heart set on building A 12 V system. I know… I know the wiring is gonna be expensive! But for the following reasons mostly to do with redundancy and ease of troubleshooting/repair:
1) I will string panels together to use solar panel input in parallel to provide voltage/ current to the charge controller (i’ll get to my selection criteria for the controller/ inverter toward the end of this post).
Because I:
A) Don’t know if these panels can handle being run together in series
B) Don’t want any funny undrevoltage going to my charge controller if one of them happens to bite the dust (ie in a 24 or 48 V configuration).
C) If one does go out it’s a pretty small percentage of my system and I can eliminate and/or replace with another 40W panel (I have access to about a dozen more free ones where these came from).
-If a 12 V battery kicks the bucket I can just take it out of the parallel bank and replace when I get to it instead of limping along on two batteries (if 24V system) or being so out of luck (ie situation in a 48V system with 3 out of 4 Twelve Volt batteries).
Our sunlight hour loads are pretty minimal and our overnight loads are even smaller for the proposed new 12 V system.
200w for deep freezer (off at night)
75w for Starlink router (18hr on 6hr idle)
200w for laptop/ phone chargers (all powered down 2-4 hours after sunset)
100w for box fan (run 24/7 in the summer)
150w for nighttime lighting (2-4 hours post sunset, could be even less if I switched over bulbs to LED).
Water all gravity fed. No water pumps. No well to run. Don’t do TV. Our luxuries are our 3 ft.³ chest freezer and star link for the smart phone email, wifi calling/ YouTube. Burn wood for heat.
Apx 3800 w/ h on the high side consumed during average 12hr period of darkness.
Out of our 13920 w/h battery bank equals//
About 27% DOD on battery bank.
My design target depth of depletion on these batteries bank is 15 to 30% for longevity.
Which leads now to the back asswards figuring of the inverter and the charge controller.
I am a big fan of overbuilt reliability and durability. As far as I’m concerned cost is no object when durability and reliability is concerned.
I’m thinking of going with:
Morningstar TS-MPPT-60 > TriStar 60 Amp 12/24/48 Volt MPPT Charge Controller
My thinking for this is that at some point when we want to expand at that point yeah I’ll probably go to $$$LithiumFe 48 V system and fancy new 300 W panels… Bam I’ve already got a charge controller that can handle that.
Also thinking of going with the largest 12 V rated morning star pure sine wave inverter they have available (looks like the biggest one they have for 12 V is 700W continuous with some surge capability up to 1300 W under 100°F).
Morningstar SureSine 700 Watt 12VDC 120VAC Pure Sine Wave Inverter with North America Type B Outlet .
if I decide I want to install a mini split I’ll either get one that can run straight DC no inverter needed day time only running straight off a string of dedicated panels, or get another 700W inverter dedicated for a small sized mini split and up the panel count and battery bank some. I know some people say 700 W inverter isn’t all that much but we pretty simple people and I know it’s sorta fiddly and convoluted but if I have to we can always throw the 2000watt modified sine wave harbor freight special on the battery bank and use that to run our lights and chest freezer anyway. I don’t know. I’m just impressed by MorningStar reliability record and the biggest 12Volt inverter looks like they make is their 700 W model.
I know 12 V isn’t considered very optimum by most people these days but for the reasons that I listed mainly to do with reliability and ease of troubleshooting that’s what I’m inclined to go with for my current circumstance.
My question for the community TLDR is have I picked an appropriately sized charge controller for this load? I know at 12 V DC theres a lot of current (amperage) potentially going into the charge controller and I’m not sure if that Morningstar 60 amp charge controller I’m looking at can handle it or not?
Quick stats (11) 40 watt panels 21.95 V avg.
(3) 100 watt panels not sure about the open circuit voltage on these panels. I need to put the multimeter on them I guess. They the harbor freight hundred watt specials. But assuming on the average side they’re about 20 V output each.
So that’s Approximately 740 watts of panels nominal. @20 V avg.
That’s about 37 Amps. Well that answers that question lol sometimes you just gotta write things out, think about it, and look at it twice and you can answer your own questions! Thanks forums for listening to me think out loud.
Going to keep batteries, charge controller and inverter in their own earth sheltered concrete ventilated storage box, earth sheltered in ground installation and shaded by static solar panel ground array. Big diameter cables shortest runs possible from panel parallel sequence to inverter input. May not keep batteries at perfect operating temperature but will keep them warmer in the winter and cooler in the summer. Some battery sacrifice performance maybe during the more mild months but really it seems the extreme high or low temperature that murder them. At least the inverter and the charge controller will stay happy and cool.
Any thoughts criticisms or suggestions? I’m open to hearing all but pretty well made up my mind I am going caveman simple 12Volt system at least for this stage in our life.
Got the panels already… Already ass-backwards bought the (4) 12 V flooded deep cycle lead acids, they seem like a good value for the money as long as you’re diligent to check the water levels at least every month more often in hot weather, and keep depth of depletion to a maximum of 30%. I don’t know. Change my own oil. Cut my own firewood. What’s checking the battery water level once a month?
Oh another thing I side forgot to mention I would really like a charge controller that can handle being hooked up to a generator to charge batteries on cloudy days. I’m assuming the 60A morning Starr MPPT should be able to handle that I’ve read the documentation up and down on it but don’t see it specifically stated there how one goes about wiring that up? I’m not looking for anything fancy like an auto Gen set kick in. Just want to get the alert on the charge controller Bluetooth app: “battery voltage below 50%” stroll out to the shed pull start the honda 2000 genny, drag the ole 10gauge extension cord out and plug it in to the charge controller. It’s probably right in front of me. But my brain is so fried from crash course in solar design and amps ohms watts I probably missed it somewhere.
No possibility of grid tie now or in the future. Nearest powerlines are 20 miles away and it just ain’t gonna happen for electricity to get brought out here. so that simplifies things at least from a design choice standpoint.
Thanks for those 2 bearing with this long ramble. Good community I’ve learned a lot from searching through the forums here.
