Help with alternatives

elesaver
elesaver Solar Expert Posts: 185 ✭✭
in Solar Beginners Corner #1
This question is looking far into the future but it's good to have fodder to chew during the winter. :-) I'm not up and running yet but will have a 24V system with a 480Ah battery bank, 6 panels at 300W and 8.18 amps each. I will be using the solar for small ac loads...lights, TV, computer, etc...nothing gigantic.

Knowing that a single phase inverter will not power a well pump and/or heat source, I would like to research ways to satisfy these needs without burdening myself with extra "stuff", ie, split-phase inverter, heavier wiring, possibly more panels, etc. There must be ways, especially for running a well pump, that are available. The heating would not be quite as necessary although it would be convenient, but just not a priority.


Would someone help direct me into alternatives to run a well pump and maybe even some heating on a system without 240V? Thanks for always being willing to help.
1st system:  24Vsystem with 8 X 300W panels, Midnite Solar combiner box, Midnite Solar mini-dc disconnect, Midnite Solar Classic 150, Outback VFX 3524 with mate, 2 X 12V  fforklift batteries in series 938 aH,  (Outback PSX transformer, Honda EU3000is...not currently hooked up but available if/when needed)

2nd system:  24V system with 4 X 310W panels, Midnite Solar combiner box, Midnite Solar mini-dc disconnect, Midnite Solar Classic 200, Cotek 1500W pure sine inverter, Trojan 125 batteries (8 available but "currently" using 4)

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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Help with alternatives

    Actually a 120VAC inverter will power a well pump or heat source. You just stick a transformer in to put the Voltage up to 240 VAC.

    The issues mainly arise as a function of the amount of power required, both in terms of "at the moment" and "over time". I have a 240 VAC septic pump run through an autotransformer from my 120 VAC VFX3524. It pulls 8-9 Amps @ 120 VAC running, and only needs to run for 30 seconds a day. I also have a water pump that runs from 120 VAC and pulls about the same current and runs for 6 minutes. No problem if you time it with the solar output.

    Otherwise it's fire up the generator. Again it can be a 120 VAC gen providing you have the transformer and it has sufficient output to handle the load.

    I'd strongly recommend against trying to use any sort of electric heat because the load is unpredictable: it will turn on/off according to the thermostat's demand and that may not coincide with when the power is available. For example any off-grid system has the most power available when the sun has charged the batteries but the panels are still producing. But usually heat is needed at night when things cool down, which is when the least amount of power is available.
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  • elesaver
    elesaver Solar Expert Posts: 185 ✭✭
    #3
    Re: Help with alternatives

    Cariboocoot, I knew you'd have an answer! May I impose upon you to direct me to a site that will help me understand how to do this? It seems as though it would not be difficult for a well pump? The heating issue I understand the power demands that has so again, it is not a priority. I can just put on more layers! Anyway, thanks for the tip on this and hopefully a way to learn more about this so that I can implement it.
    1st system:  24Vsystem with 8 X 300W panels, Midnite Solar combiner box, Midnite Solar mini-dc disconnect, Midnite Solar Classic 150, Outback VFX 3524 with mate, 2 X 12V  fforklift batteries in series 938 aH,  (Outback PSX transformer, Honda EU3000is...not currently hooked up but available if/when needed)

    2nd system:  24V system with 4 X 310W panels, Midnite Solar combiner box, Midnite Solar mini-dc disconnect, Midnite Solar Classic 200, Cotek 1500W pure sine inverter, Trojan 125 batteries (8 available but "currently" using 4)

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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #4
    Re: Help with alternatives

    This is an example of an autotransformer: http://www.solar-electric.com/x-240.html
    There are others available if you search around.

    You still have to know how much power the pump demands so that you can get one capable of handling that much. A smaller one should cost less. You'll also need to know how long the pump runs for so you can determine if the system can handle it. I use a very large pressure tank and fill it up during the day so it's no problem: minimal water needs can be met for 24 hours afterwards. If more is needed I start the generator.

    Wiring the transformer is fairly simple: 120 VAC goes in one side, and a mirror image is created on the other side. This is 'stacked' to the input creating 240 VAC. With the Outback it's simple: black wire is L1, red wire is L2, and the two whites are neutrals. The whites are tied together, 120 VAC connected to L1 and the neutral, 240 VAC comes from L1 and L2. Outback has numerous wiring diagrams on their web site for using the transformers in various ways.
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #5
    Re: Help with alternatives
    elesaver wrote: »
    Knowing that a single phase inverter will not power a well pump and/or heat source
    <snip>
    Would someone help direct me into alternatives to run a well pump and maybe even some heating on a system without 240V?

    Depending on your climate and needs, you may find a heat pump type of heater to be feasible.

    As for the pump, Cariboocoot points out that you can run a conventional 240 volt pump with a transformer. Depending on your well depth, well distance from house, and your needs (gpm), you may find that you can run a conventional 120 volt well pump.

    Conventional pumps are readily available and cheap, but are not the most efficient pumps. There are more efficient pumps available but they are expensive. They may be worth the extra cost if you were planning to supersize your entire power system for no other reason than to run the pump.

    The most efficient option is to use a solar direct (no batteries) well pump, and then when the sun shines, pump the water to a storage tank or cistern. Then use a 24 volt demand pump to pressurize the house from the storage tank.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • Rybren
    Rybren Solar Expert Posts: 351 ✭✭
    #6
    Re: Help with alternatives

    I use a 120V Shurflo pump to draw water from the lake and distribute it through the cabin. It only draws ~1A on the AC side. I'm happy with its performance so far.
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #7
    Re: Help with alternatives
    Rybren wrote: »
    I use a 120V Shurflo pump to draw water from the lake and distribute it through the cabin. It only draws ~1A on the AC side. I'm happy with its performance so far.

    I was briefly happy with my 120 volt Shurflo: http://forum.solar-electric.com/showthread.php?22792

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • elesaver
    elesaver Solar Expert Posts: 185 ✭✭
    #8
    Re: Help with alternatives

    Thank you all for this info. Back to the drawing board! :-)
    1st system:  24Vsystem with 8 X 300W panels, Midnite Solar combiner box, Midnite Solar mini-dc disconnect, Midnite Solar Classic 150, Outback VFX 3524 with mate, 2 X 12V  fforklift batteries in series 938 aH,  (Outback PSX transformer, Honda EU3000is...not currently hooked up but available if/when needed)

    2nd system:  24V system with 4 X 310W panels, Midnite Solar combiner box, Midnite Solar mini-dc disconnect, Midnite Solar Classic 200, Cotek 1500W pure sine inverter, Trojan 125 batteries (8 available but "currently" using 4)

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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #9
    Re: Help with alternatives

    A wood stove was my heating solution, you might also look into direct vent propane heaters. There are propane heaters that will vent through the wall, pretty easy to understand and install. I purchased one for my cabin, but never installed it. I was using a little "buddy' open propane heater, but even with a window cracked 1/2 inch, required with open heat sources, I would feel light headed sometimes in winter.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • Alaska Man
    Alaska Man Solar Expert Posts: 252 ✭✭
    #10
    Re: Help with alternatives

    I have used the Ventless Propane heaters up here. I did it for one winter, but after awhile I would wake up hacking and coughing in the morning. If your need is intermittent it would work well.
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  • Alaska Man
    Alaska Man Solar Expert Posts: 252 ✭✭
    #11
    Re: Help with alternatives
    Cariboocoot wrote: »
    This is an example of an autotransformer: http://www.solar-electric.com/x-240.html
    There are others available if you search around.

    You still have to know how much power the pump demands so that you can get one capable of handling that much. A smaller one should cost less. You'll also need to know how long the pump runs for so you can determine if the system can handle it. I use a very large pressure tank and fill it up during the day so it's no problem: minimal water needs can be met for 24 hours afterwards. If more is needed I start the generator.

    Wiring the transformer is fairly simple: 120 VAC goes in one side, and a mirror image is created on the other side. This is 'stacked' to the input creating 240 VAC. With the Outback it's simple: black wire is L1, red wire is L2, and the two whites are neutrals. The whites are tied together, 120 VAC connected to L1 and the neutral, 240 VAC comes from L1 and L2. Outback has numerous wiring diagrams on their web site for using the transformers in various ways.

    Can I put the transformer infront of my charger? When charging I'm only hot on one side of my panel because the genny only has 120V outlet. So the red lead in the Xentrex is not connected. I understood that side only passes power through to the distribution panel when charging. As a result when I do charge half the breakers are not powered.

    Sorry not meaning to thread jack, just a quick question.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #12
    Re: Help with alternatives
    Alaska Man wrote: »
    Can I put the transformer infront of my charger? When charging I'm only hot on one side of my panel because the genny only has 120V outlet. So the red lead in the Xentrex is not connected. I understood that side only passes power through to the distribution panel when charging. As a result when I do charge half the breakers are not powered.

    Sorry not meaning to thread jack, just a quick question.

    Yes you can do this, but keep in mind the power limitations apply. You'll have 240 VAC, but at 1/2 the current the generator can supply. If the gen can't put out enough power for charging & loads it will fault.
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  • Alaska Man
    Alaska Man Solar Expert Posts: 252 ✭✭
    #13
    Re: Help with alternatives
    Cariboocoot wrote: »
    Yes you can do this, but keep in mind the power limitations apply. You'll have 240 VAC, but at 1/2 the current the generator can supply. If the gen can't put out enough power for charging & loads it will fault.

    Would I be better off just jumpering the power from the Black line over to the red? The inverter switches off when it senses incoming AC and since I don't have any 220A needs it occurred to me that may be an alternative?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #14
    Re: Help with alternatives
    Alaska Man wrote: »
    Would I be better off just jumpering the power from the Black line over to the red? The inverter switches off when it senses incoming AC and since I don't have any 220A needs it occurred to me that may be an alternative?

    Better off in that it removes the transformer expense (and slight loss).
    Power restrictions are the same, code will be violated, and you could make a mistake in wiring that would give unpleasant results. I'm a bit unclear as to why you have this odd mix of 120/240.
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #15
    Re: Help with alternatives
    Alaska Man wrote: »
    Would I be better off just jumpering the power from the Black line over to the red? The inverter switches off when it senses incoming AC and since I don't have any 220A needs it occurred to me that may be an alternative?
    That would work just fine and be code compliant as long as there is a label indicating that the input power is 120V only and that no shared neutrals (Multiwire Branch Circuits or MWBCs) should be used.

    An electrician wiring up a home with 120/240 service will sometimes use one red and one black wire and one white wire to run essentially two 120V circuits with the neutral (white) wire shared between the two. With full current in both red and black, there will be zero current in the white. Just fine.
    Do that same circuit with the same 120V supplying both sides of the panel and you will be putting double the line current through the unprotected neutral. Not good, and a code violation!

    Although it is not common to use different colors (black, red, blue, often used for three phase, for example) for wiring up the same phase, it is not a code violation as long as there is a description somewhere that states that.
    SMA SB 3000, old BP panels.
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  • Alaska Man
    Alaska Man Solar Expert Posts: 252 ✭✭
    #16
    Re: Help with alternatives
    Cariboocoot wrote: »
    Better off in that it removes the transformer expense (and slight loss).
    Power restrictions are the same, code will be violated, and you could make a mistake in wiring that would give unpleasant results. I'm a bit unclear as to why you have this odd mix of 120/240.

    I don't really think it's a 240 mix.

    The Xentrex has Red/Black/White/Green lugs. The Genny I had before had a 220V outlet so using 4 wire 8 AWG I could fire up all sides. I think I was only pushing 120V on each side (red and black) Now with the new genny and only 120V I only had three wires Black/White and Green to connect to the Inverter/Charger.

    I was told the Red side just passes power through to the distribution panel when the unit senses AC power coming in. The Charger apparently only uses 120V on the black side to charge the bank.

    Once I'm done charging the inverter is back on and powers both sides of the panel. I assume pushing 120V on each leg into the 30Amp breaker I use for a Main Disconnect at the top of the distribution panel.
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  • Alaska Man
    Alaska Man Solar Expert Posts: 252 ✭✭
    #17
    Re: Help with alternatives
    inetdog wrote: »
    That would work just fine and be code compliant as long as there is a label indicating that the input power is 120V only and that no shared neutrals (Multiwire Branch Circuits or MWBCs) should be used.

    An electrician wiring up a home with 120/240 service will sometimes use one red and one black wire and one white wire to run essentially two 120V circuits with the neutral (white) wire shared between the two. With full current in both red and black, there will be zero current in the white. Just fine.
    Do that same circuit with the same 120V supplying both sides of the panel and you will be putting double the line current through the unprotected neutral. Not good, and a code violation!

    Although it is not common to use different colors (black, red, blue, often used for three phase, for example) for wiring up the same phase, it is not a code violation as long as there is a description somewhere that states that.

    Isn't the threeway light I have wired in the kitchen sharing a neutral?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #18
    Re: Help with alternatives
    Alaska Man wrote: »
    Isn't the threeway light I have wired in the kitchen sharing a neutral?

    Nope. It's a 120 VAC circuit. 3-way (switches in two locations to work one light) uses three wires between the switches: two 'travelers' and one 'hot'.

    Shared neutral is as inetdog described: an outlet with one half taking its hot from L1 and the other half taking from L2 so that the neutral carries only the current difference. That's what gets you in trouble with the re-wire feeding both hots from one source: you get two pieces of 14 AWG carrying potentially 30 Amps to the outlet and only one piece of 14 AWG (the neutral) for the return. Usually the inverter is low-powered enough that it will fault before the line is overloaded, but it is something that must be watched out for.

    Some jurisdictions will not allow it even with labels. But then some won't allow the shared neutral situation either!
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  • Alaska Man
    Alaska Man Solar Expert Posts: 252 ✭✭
    #19
    Re: Help with alternatives

    Ah, right on. Thanks
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