NEWB looking to the experts for help

[Ampster]

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It seems that for the solar power I would need to power my existing pump, I could probably design a system to cover my entire house AND build a gravity/storage water solution.

Gravity water storage may be less expensive than the extra batteries need to keep your pressure system going. More storage can also compensate for lower flowing wells in summer.

[MichaelK!]

I have a gravity fed system a lot like Mike's above is describing. The numbers in his chart closely follow my own observations. My solar-only system has been working well for several years now, so I can give you a couple of guidelines based on what works for me. In the design of your system, plan on installing 2X the number of watts of whatever your single largest load is. Assuming your well pump is your largest load, multiply 6amps X 240V to get 1440 watts. Twice your watts would be 2800-3000 watts of panels.

For my own system, my 1hp pump consumes about 2200watts, so I installed 4500 watts of panels. It works. For your battery, I don't want to draw more than 1/10 of capacity, so divide your load wattage by your battery voltage and multiply that by 10X. With a 12V battery, you'd need a (1440W/12V) X 10 = 1200AH battery. At 24V you only need a (1440/24)X10= 600AH battery. At 48V you need (1440/48)X10=300AH battery. As the numbers show, you need much less capacity if you simply increase your voltage. Trojan L-16s can be used to make a bank in the 300-400AH range.

You need an inverter that puts out both 120 and 240VAC, and there are several choices. Magnum makes the MS4048A, 5000 watts max; Outback makes the GS4048, at 6000W max. Then there are the Schneider XW series, with the XW+ 5548NA and XW+ 6848NA, at 9800 and 12,000W max. You might get Schneider's Conext SW 4048 to work?

So, you need 3000+ watts of panels, a 300AH+ 48V battery bank, and a good (read expensive) 120/240V inverter. From experience, I can tell you it WILL work. With a fixed mount facing south, expect to pump water between 10am and 2pm into a vertical tank. If you have rotating mounts that can turn east or west, expect it to work from ~8am to 4pm. Then, by gravity, you'll have 24/7 water as it flows back downhill.

[AspiringHermit]

I have a gravity fed system a lot like Mike's above is describing. The numbers in his chart closely follow my own observations. My solar-only system has been working well for several years now, so I can give you a couple of guidelines based on what works for me. In the design of your system, plan on installing 2X the number of watts of whatever your single largest load is. Assuming your well pump is your largest load, multiply 6amps X 240V to get 1440 watts. Twice your watts would be 2800-3000 watts of panels.

For my own system, my 1hp pump consumes about 2200watts, so I installed 4500 watts of panels. It works. For your battery, I don't want to draw more than 1/10 of capacity, so divide your load wattage by your battery voltage and multiply that by 10X. With a 12V battery, you'd need a (1440W/12V) X 10 = 1200AH battery. At 24V you only need a (1440/24)X10= 600AH battery. At 48V you need (1440/48)X10=300AH battery. As the numbers show, you need much less capacity if you simply increase your voltage. Trojan L-16s can be used to make a bank in the 300-400AH range.

You need an inverter that puts out both 120 and 240VAC, and there are several choices. Magnum makes the MS4048A, 5000 watts max; Outback makes the GS4048, at 6000W max. Then there are the Schneider XW series, with the XW+ 5548NA and XW+ 6848NA, at 9800 and 12,000W max. You might get Schneider's Conext SW 4048 to work?

So, you need 3000+ watts of panels, a 300AH+ 48V battery bank, and a good (read expensive) 120/240V inverter. From experience, I can tell you it WILL work. With a fixed mount facing south, expect to pump water between 10am and 2pm into a vertical tank. If you have rotating mounts that can turn east or west, expect it to work from ~8am to 4pm. Then, by gravity, you'll have 24/7 water as it flows back downhill.

Excellent info! Thank you very much!

On a side note... I was considering running power to an external genny hookup that leads to a sub-panel with a disconnect for utility/generator power. It is a 240 hookup that leads to a 2 leg panel in the house that supplies some bare essentials that are both 120 and 240v. What's your thoughts on being able to run a 240v inverter to that hookup somehow to provide both 120 and 240 to my off-grid sub panel. I haven't done a ton of research on split phase inverters or anything yet, so not sure if I am just grasping at straws here.

[MichaelK!]

What's your thoughts on being able to run a 240v inverter to that hookup somehow to provide both 120 and 240 to my off-grid sub panel. I haven't done a ton of research on split phase inverters or anything yet, so not sure if I am just grasping at straws here.

All of the inverters I listed above handle split-phase 120/240V AC that can be wired into a standard American main panel. My inverter is Schneider's XW+6848NA, which has powered every thing I've thrown at it. I've run my well pump, power tools, and a cement mixer simultaneously in the summer. The XW (NA version) has standard American split-phase AC output. That means the AC output has three connections (plus ground). They're L1, L2, and N. The wiring is run to the main house panel where L1 gets wired to one breaker bank, and L2 to the second. N then is connected to the Neutral busbar. Neutral is also bonded to ground in the XW's power center. L1 to neutral is 120V. L2 to neutral is also 120V. But, L1 to L2 is 240V. For the 240V well pump, it's connected to a single double-pole breaker that's wired to both L1 and L2. The XW is also designed to receive input from a generator to alternatively charge batteries, or to also connect to the grid.

[Mike90250]

A caution about split phase inverters, is their Load Imbalance spec. Schneider is pretty tolerant of odd load balance. Many others are not so tolerant. Check the balance spec before you commit.

[MichaelK!]

A caution about split phase inverters, is their Load Imbalance spec. Schneider is pretty tolerant of odd load balance. Many others are not so tolerant. Check the balance spec before you commit.

Hello Mike, I know exactly what you are talking about. I've seen that problem myself. However, I've never seen a "Load Imbalance specification" for any inverter I shopped for. I looked through my XW owner's manual and didn't find it either? How many manufacturers actually publish these numbers? Could they be calling it something else?

[Mike90250]

Page 126 of the conext manual, and in the 2 page spec sheet

AC Input Frequency Range
(Bypass/Charger Mode)
52–68 Hz (default)
44–70 Hz (allowable)
AC Output Current (maximum 75% imbalance between L1-N, L2-N) in Inverter Mode
L-N: 48 A
L-L: 28 A
L-N: 46 A
L-L: 23 A
AC Output Breaker 60 A double-pole
AC Output Frequency 60.0 ±0.1 Hz