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  • pbennison
    replied


    Well, it is getting warmer up here in NY and I plan to start purchasing some equipment. Below is my first stab at a list of equipment I am going to purchase, (thank you MichaelK!). I will build the prototype at my house for proof of concept then disassemble and bring to cabin.


    - (6) 250W grid-tie panels - Santan Solar
    - (8) 6V batteries - I have a friend in the battery business
    - Epever 50A MPPT controller 12/24/36/48V - Amazon
    - Schneider 4048 48V Sine Wave 120/240VAC split-phase inverter - Amazon
    - Transfer Switch, Lugs, heat shrink, cables, etc.

    My next step is to figure out the last item on the list, (Transfer Switch, Lugs, heat shrink, cables, etc.). Is there a site/can someone help me decide all the miscellaneous items that will be required.

    Leave a comment:


  • chrisski
    replied
    I did build my own cables to lock the portable panels, and I’m glad I did. Most nights I’ve used the RV the wind has picked up and the cables have kept the panels from blowing away. So, for securing the potable panels the cable has been awesome. Of course, the panels have flipped over, so now I put them inside at night. I have stayed at the edge II a mountain near a flat area these times. The wind is calm, but when the sun sets it picks up. There’s not a weather station nearby, and the weaather reports I can read don’t get predict this wind.

    I have four 100 watt panels and these have outperformed the 600 watt panels on my roof. I usually get about 30% more power off the portable panels.

    The roof panels are tiltable, but because the winds have been as much as 25 gusting to 35, I do not tilt the panels. Also, the flat panels on the roof are set to be set up parking so they face south. Sometimes the spot or few won’t let us do that, so obstructions like the vent pipes and AC cause shading.

    I face The portable panels towards the sun two or three times a day. Because true portable panels are tilted and faced at the sun, I also get useful sunshine two hours earlier in the day.

    One other thing about the portable panels is they are not maintenance free like the roof panels. I’ve done some repairs from wind damage. Not to the glass and cells, but I’ve had to rivet a hinge back in and make some repairs to my Anderson power poles I used as connectors.

    If I’ve used 165 AH out of my 220 ah useable in my 440 AH bank and its a sunny day, by 1 pm the panels are charged. When it’s been cloudy, we’ve used around 110 ah, and the panels have still managed to charge the batteries with help from the generator for an hour or two that provides 15 AH. Sunny days, that’s mostly from the portable panels, and cloudy days, mostly from the flat panels, followed by the portable panels, followed by the generator.

    Leave a comment:


  • pbennison
    replied
    Originally posted by chrisski View Post
    For the solar getting stolen, not sure how valid a concern that is. I was worried about my portable panels, but they’ve been fine. For a cabin build, a lot of that stuff is bolted down. If you worry about that stuff disappearing, you may need to just forget the idea of living out there. Could be a valid concern if police reports make that likely. My father in law got decades of enjoyment out of his cabin. There was one incident of teenagers breaking in to have a party during the week when it was not occupied. That didn't ruin all the fun had out there.



    Plz keep in mind there’s a bit left out of this like wiring, mounting, and battery holders. My RV build was 10% to 20% of the cost building a collection of tools. My guess is if you’re not tooled up and have a lot of extra hardware for mounting lying around, could cost close to the estimate.
    I also have an RV and thinking of building a smaller portable version, 24V, two 12V batteries and a couple 250W panels. Is that something along the lines you did for the RV? Any advice and/or suggestions, plans, pics, etc. for the RV build would be much appreciated.

    Leave a comment:


  • pbennison
    replied
    Originally posted by chrisski View Post
    For the solar getting stolen, not sure how valid a concern that is. I was worried about my portable panels, but they’ve been fine. For a cabin build, a lot of that stuff is bolted down. If you worry about that stuff disappearing, you may need to just forget the idea of living out there. Could be a valid concern if police reports make that likely. My father in law got decades of enjoyment out of his cabin. There was one incident of teenagers breaking in to have a party during the week when it was not occupied. That didn't ruin all the fun had out there.



    Plz keep in mind there’s a bit left out of this like wiring, mounting, and battery holders. My RV build was 10% to 20% of the cost building a collection of tools. My guess is if you’re not tooled up and have a lot of extra hardware for mounting lying around, could cost close to the estimate.
    Agree.....Funny, I actually thought to my self after totaling up, that this will be more than just the "big" stuff. I have some stuff around and figure I have 20-25 % additional costs.....As for stuff disappearing, well, that sucks...........hopefully, that doesn't happen...

    Thanks everyone.....these forums are really awesome...getting experience from people that have actually done this is worth sooooo much.....

    Leave a comment:


  • chrisski
    replied
    For the solar getting stolen, not sure how valid a concern that is. I was worried about my portable panels, but they’ve been fine. For a cabin build, a lot of that stuff is bolted down. If you worry about that stuff disappearing, you may need to just forget the idea of living out there. Could be a valid concern if police reports make that likely. My father in law got decades of enjoyment out of his cabin. There was one incident of teenagers breaking in to have a party during the week when it was not occupied. That didn't ruin all the fun had out there.

    Originally posted by MichaelK! View Post

    Very doable. You can get eight 6V batteries at Costco right now for 99$ each. Throw in tax, and core charges, and you might be ~1100$ out the door.

    To keep that charged...210Ah X 0.125C charging rate X 52V charging X 1.25lossfactor = 1706W. If you get six 250W grid-tie panels like I did that would be 55$ X 6 = 330$

    Epever makes a 50A controller that can do 12/24/36/48V for 210$ plus tax.

    A really nice 48V Sine Wave 120/240VAC split-phase inverter is the Schneider 4048. 1540$

    This would be a system that produces at least 5kWh of power in winter on the sunny days. On batteries, with no more than 50% depletion, you'd have the same.
    Plz keep in mind there’s a bit left out of this like wiring, mounting, and battery holders. My RV build was 10% to 20% of the cost building a collection of tools. My guess is if you’re not tooled up and have a lot of extra hardware for mounting lying around, could cost close to the estimate.

    Leave a comment:


  • pbennison
    replied
    Originally posted by MichaelK! View Post

    Very doable. You can get eight 6V batteries at Costco right now for 99$ each. Throw in tax, and core charges, and you might be ~1100$ out the door.

    To keep that charged...210Ah X 0.125C charging rate X 52V charging X 1.25lossfactor = 1706W. If you get six 250W grid-tie panels like I did that would be 55$ X 6 = 330$

    Epever makes a 50A controller that can do 12/24/36/48V for 210$ plus tax.

    A really nice 48V Sine Wave 120/240VAC split-phase inverter is the Schneider 4048. 1540$

    This would be a system that produces at least 5kWh of power in winter on the sunny days. On batteries, with no more than 50% depletion, you'd have the same.
    Thank you. I appreciate the advice and guidance. This will make our cabin much more comfortable to spend and enjoy our time there.

    Leave a comment:


  • MichaelK!
    replied
    Originally posted by pbennison View Post

    Hmmmm. I have two portable generators, a 3500W generator (very loud) and a 2000W generator (very quiet). My concern about this was the time it takes to charge batteries, but I guess if I have enough and don't deplete too much I could keep them charged. Maybe something along the lines of a 48V golf cart battery system?
    Very doable. You can get eight 6V batteries at Costco right now for 99$ each. Throw in tax, and core charges, and you might be ~1100$ out the door.

    To keep that charged...210Ah X 0.125C charging rate X 52V charging X 1.25lossfactor = 1706W. If you get six 250W grid-tie panels like I did that would be 55$ X 6 = 330$

    Epever makes a 50A controller that can do 12/24/36/48V for 210$ plus tax.

    A really nice 48V Sine Wave 120/240VAC split-phase inverter is the Schneider 4048. 1540$

    This would be a system that produces at least 5kWh of power in winter on the sunny days. On batteries, with no more than 50% depletion, you'd have the same.

    Leave a comment:


  • pbennison
    replied
    Originally posted by foo1bar View Post
    I don't know if I'd do solar - I probably would just do generator + batteries (so the generator isn't running all the time and/or can get by with a smaller generator.)
    I would be concerned about the solar getting stolen since there's no one around for significant parts of the year..

    BTW - you said electric would be 3x the cost of the cabin.
    Are there other properties that would benefit and would be interested in getting electricity service as well? (And willing to pay for it?)

    How much does the property increase in value if it has electrical service?
    Hmmmm. I have two portable generators, a 3500W generator (very loud) and a 2000W generator (very quiet). My concern about this was the time it takes to charge batteries, but I guess if I have enough and don't deplete too much I could keep them charged. Maybe something along the lines of a 48V golf cart battery system?

    The cabin was listed for sale with one benefit being, "no neighbors". I have seen some land nearby that is being advertised with more than one lot. I guess sometime in the future tht is a possibility, but for right now I am on my own.

    It would definitely increase. However, the first estimate I got from National Grid was 3500 feet @45 per foot ($157,000). The cabin cost $55,000.

    Leave a comment:


  • foo1bar
    replied
    I don't know if I'd do solar - I probably would just do generator + batteries (so the generator isn't running all the time and/or can get by with a smaller generator.)
    I would be concerned about the solar getting stolen since there's no one around for significant parts of the year..

    BTW - you said electric would be 3x the cost of the cabin.
    Are there other properties that would benefit and would be interested in getting electricity service as well? (And willing to pay for it?)

    How much does the property increase in value if it has electrical service?

    Leave a comment:


  • foo1bar
    replied
    Originally posted by pbennison View Post

    Ok, this may sound foolish, but here goes. How do I get a 6V battery (Trojan L-16) to produce 48V? Do I get 8 of these?
    Yes. 8 of 6V in series will give you 48V.

    You can also buy 2V batteries - and 48V would be 24 of those.
    if you need more amp-hours, you'll wind up getting 4V or 2V batteries. More amp-hours == larger plates. Larger plates == heavier/bigger. But since a 6V battery is 3 of 2V cells, they can be separated out. And it's a lot easier to move three of 200lb 1600Ah 2V battery than if it were a 600lb 1600Ah 6V battery

    Leave a comment:


  • pbennison
    replied
    Originally posted by MichaelK! View Post
    Let your loads dictate the size and scale of your system. A good general rule of thumb is if your loads are never more than 1000W then 12V if OK. If less than 2000W, then 24V, and more than 2000W, then 48V. I've built all three. Currently I'm operating a 24V system with 2000W of solar for my workshop, and a 48V system with 4500W of solar for my main cabin. 24V would have been good enough for most household items, but I designed my cabin to run my 240V well pump, which it does very well.

    I would recommend you start out with lead-acid. Don't worry about the 50% depletion issue. It is so much easier to scale lead-acid that you can double the capacity and still pay far less than Li. When working with lead, you can literally scale a single string from 100Ah to 2500Ah, depending on what what batteries you buy.

    When scaling for your loads, look at the max discharge the batteries will take. Let's say you want to run a 2000W load on your 48V system. You don't want to drain the batteries at more than 1/10 of their capacity. The math would work out to be...
    (2000W/48V system voltage) / 0.1C discharge rate =416Ah. So, a battery of about 400-420Ah would work fine. A 6V Trojan L-16 fits nicely. Rolls also makes 6-8 batteries in this size range.
    You can multiple that number by the days of autonomy you want, to account for rainy days when there's no solar.

    Now, determine how big an array you need to keep this battery charged. Let's say you went with the 400Ah battery. The math would be....
    400Ah X 0.125C charge rate X 52V charging X 1.25X losscorrectionfactor = 3250W of solar panels.

    As a general rule of thumb, I use the 2X rule for most of things I need. If I need to run that 2000W load, I'd buy 4000W of panels. If I need to run 2000W on the inverter, then buy at least a 4000W inverter. If I need about 2600W to charge the batteries, then buy 5.2kW generator. I'd get an inverter(s) that can produce standard NA split-phase 120/240VAC. Look at brands like Magnum, Outback, Schneider, and Sunny Island. I would NOT advise you to buy any of the cheap Chinese high-frequency inverters. They typically can not handle stuff with high startup surges, typically things with big motors. IE: the refrigerator, air conditioners, pumps, ect.

    BTW, I designed most of my solar arrays as single-pole ground mounts, which lets me point the panels at the morning and afternoon sun. I built them primarily out of HomeDepot unistruts that I welded together. They were designed to hold 4-6 250W grid-tie panels. So, 2-3 of these arrays would completely supply all of your power, even in the depth of winter, when you have sunny days.


    Keep in mind that the numbers I presented are for what works for me. Find your own numbers, and plug them into the forumulas if you like. The numbers may change, but the math stays the same.
    Ok, this may sound foolish, but here goes. How do I get a 6V battery (Trojan L-16) to produce 48V? Do I get 8 of these?


    Leave a comment:


  • organic farmer
    replied
    The solar-power lifestyle is a different lifestyle that may take a while for your family to adjust to.

    In the mornings my wife wants to percolate a pot of coffee for herself. So long as it is clear and sunny she can do that with no problems, as we have sufficient power. On cloudy days she must make her coffee on the woodstove.

    When she was working, my wife insisted that when she got home from work, she wanted to eat a meal, relax and watch TV for an hour, and then to take a hot shower. But by then the sun will have gone down, so everything is done from battery power. I tried for years to convince her that when she got home, the first thing she needed to do was to take her shower, while the sun was still up. She would kill our battery charge every night with her shower.

    If you can work out a lifestyle where you only consume power during daylight, then solar power can be beautiful. But once it is dark, you need to stop consuming power.

    Leave a comment:


  • MichaelK!
    replied
    Let your loads dictate the size and scale of your system. A good general rule of thumb is if your loads are never more than 1000W then 12V if OK. If less than 2000W, then 24V, and more than 2000W, then 48V. I've built all three. Currently I'm operating a 24V system with 2000W of solar for my workshop, and a 48V system with 4500W of solar for my main cabin. 24V would have been good enough for most household items, but I designed my cabin to run my 240V well pump, which it does very well.

    I would recommend you start out with lead-acid. Don't worry about the 50% depletion issue. It is so much easier to scale lead-acid that you can double the capacity and still pay far less than Li. When working with lead, you can literally scale a single string from 100Ah to 2500Ah, depending on what what batteries you buy.

    When scaling for your loads, look at the max discharge the batteries will take. Let's say you want to run a 2000W load on your 48V system. You don't want to drain the batteries at more than 1/10 of their capacity. The math would work out to be...
    (2000W/48V system voltage) / 0.1C discharge rate =416Ah. So, a battery of about 400-420Ah would work fine. A 6V Trojan L-16 fits nicely. Rolls also makes 6-8 batteries in this size range.
    You can multiple that number by the days of autonomy you want, to account for rainy days when there's no solar.

    Now, determine how big an array you need to keep this battery charged. Let's say you went with the 400Ah battery. The math would be....
    400Ah X 0.125C charge rate X 52V charging X 1.25X losscorrectionfactor = 3250W of solar panels.

    As a general rule of thumb, I use the 2X rule for most of things I need. If I need to run that 2000W load, I'd buy 4000W of panels. If I need to run 2000W on the inverter, then buy at least a 4000W inverter. If I need about 2600W to charge the batteries, then buy 5.2kW generator. I'd get an inverter(s) that can produce standard NA split-phase 120/240VAC. Look at brands like Magnum, Outback, Schneider, and Sunny Island. I would NOT advise you to buy any of the cheap Chinese high-frequency inverters. They typically can not handle stuff with high startup surges, typically things with big motors. IE: the refrigerator, air conditioners, pumps, ect.

    BTW, I designed most of my solar arrays as single-pole ground mounts, which lets me point the panels at the morning and afternoon sun. I built them primarily out of HomeDepot unistruts that I welded together. They were designed to hold 4-6 250W grid-tie panels. So, 2-3 of these arrays would completely supply all of your power, even in the depth of winter, when you have sunny days.


    Keep in mind that the numbers I presented are for what works for me. Find your own numbers, and plug them into the forumulas if you like. The numbers may change, but the math stays the same.

    Leave a comment:


  • organic farmer
    replied
    Originally posted by pbennison View Post
    ... I was thinking 4 12V. My next decision will be AGM or Li. I really want to go Li while understanding how expensive they are. From everything I have researched, if you can afford them they are the way to go.
    Since your cabin will be vacant all winter long and un-heated, I would suggest that you plan to remove the batteries each fall. So they are not subjected to the temps the cabin will experience.


    Leave a comment:


  • pbennison
    replied
    Originally posted by chrisski View Post
    I recommend looking at a site like PV Watts

    https://www.google.com/url?sa=t&rct=...UzjiUrPd4XuBSC

    to see how many watts a day your panel can produce and then see if your area can produce 5000 WH of power for two days backup you ask for. I have only had my system operational during the shortest days of the year. I also have 1000 watts of panels and I feel I’d be hard pressed to make 5000 WH of power in one day. I have used up to 1800 wh of power and I have been fully charged by 1pm. Those 10 hour long days where my panels only produce power for 8 hours, but only make 30 to 40 amps for about 8 of those, really make 5 kw of energy production in a day tough,

    If you use lead acid batteries, you could get the storage you’re asking for out of 8 golf cart batteries with a 50% reserve. The batteries I mention will have over 10kwh of storage, so can’t be depleted below 50% which really cuts into storage.

    I have a 12 volt system. If I had a 3000 watt inverter that was used to its potential, I’d really want a 48 volt system. If the 3000 watt inverter was not used to its potential, like to power a microwave that pulls 1800 watts, and I fused the inverter for around 2000 watts, then I’d go with 24 volts, but then I really ought to just put a 2000 watt inverter in.
    Thank you. I will check this out.

    Leave a comment:

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