Cheap 48V inverter for pump

[boondox]

Hi All,

A buddy of mine needs to be able to run a water pump to occasionally water some new fruit trees. He is off the grid and the power system is currently too far from the water tank to be able to use it. He has a 48V golf cart used as a utility vehicle. The idea is to hook an inverter up to the cart bank to power a pump.

I have no experience with the newer, cheap inverter market out there. Any recommendations for a 1.5 - 2kW inverter?

Thanks!

 

[snoobler]

Even a 1/2hp pump is going to have a notable surge. Is a smaller DC pump and a few solar panels an option?

 

[boondox]

Maybe. The thing is that it will just be needed every couple of weeks for about 6 moths of the year. So we are just trying to keep it as simple as possible. The pump will be low pressure and flow, I guess one thing we need to do is identify that and then we can figure the exact power draw.

 

[Q-Dog]

Put a water tank on the golf cart?

 

[boondox]

The thing is that there is a 2500 gallon water tank close to where the trees will be. So moving the water is the way to go. It is only about 15 vertical feet to the orchard site. I can't seem to find any 1/4 hp non-submersible pumps. 1/2 hp is more power than would be needed.

 

[snoobler]

YaeMarine 24V DC Stainless Solar Submersible Pump Solar Deep Well Submersible Well Water Pump 330'/100m Lift 3.2GPM - - Amazon.com

YaeMarine 24V DC Stainless Solar Submersible Pump Solar Deep Well Submersible Well Water Pump 330'/100m Lift 3.2GPM - - Amazon.com

www.amazon.com

Not an endorsement, but 24V/5A (120W), 3.2gpm with a 330' lift. I would expect this could deliver most of the 3.2gpm with a 15' head and "close" linear run. Could empty the 2500 gallon tank in 13-14 hours.

A single 200W+ 72 cell panel and a 10A 24V wide input DC-DC converter as your "charge controller" would run that nicely for probably 3-4 hours/day.

 

[Hedges]

Surflow 12V DC pump:

https://www.northerntool.com/shop/tools/product_527_527

 

[A.Justice]

YaeMarine 24V DC Stainless Solar Submersible Pump Solar Deep Well Submersible Well Water Pump 330'/100m Lift 3.2GPM - - Amazon.com

YaeMarine 24V DC Stainless Solar Submersible Pump Solar Deep Well Submersible Well Water Pump 330'/100m Lift 3.2GPM - - Amazon.com

www.amazon.com

Not an endorsement, but 24V/5A (120W), 3.2gpm with a 330' lift. I would expect this could deliver most of the 3.2gpm with a 15' head and "close" linear run. Could empty the 2500 gallon tank in 13-14 hours.

Even better, it claims 3.2 gph at 100m of lift, up to 190 gph, at what I assume to be 0 or negative head. Those are actually pretty Impressive specs for that price. I work on $2000+ pumps that won't safely push 100m of lift.

Neat. I want it.

 

[boondox]

Really would rather not a submersible pump. The tank is for potable water and regularly opening and tossing a pump in is a sure way to introduce debris. However, maybe a DC pump with a panel is the way to go. As well do I have a few orphan panels laying around and so does he. One thing is many pumps don't like being run directly off a panel, the brushes can burn out as the motor "browns out" in the am and pm. I have burned up Rule bilge pumps that way in my off grid hot tub.

@Hedges, any idea if the sureflo can handle "brown outs"?

@snoobler, would using the Dc to DC prevent the "brown out" situation?
Thanks for the posts and ideas!

 

[A.Justice]

The pump Hedges recommend could probably run on a panel alone, but should for sure have a battery (even a small one) as a buffer against clouds and indirect sunlight. "Brownouts" shouldn't happen with a battery system and a ~100 watt load. Panels can produce a very wide voltage range, especially in colder months, and I wouldn't want to attach any components directly to the panel.

I would get a cheap PWM charge controller, put it on the golf cart batteries, charge with solar, and use the 12 volt pump straight off the golf cart batteries.

Or, that pump only uses about 100 watts, so for intermittent use you could probably just get away with the golf cart battery alone, just make sure you go out there with a full charge.

 

[Hedges]

I think it is just brush type, so as sun came up would sit there conducting current getting warm.
I have some fans that run PV direct, but those are brushless so the electronic BLDC controller has the potential to kill itself. I sorted through surplus hardware using a variable bench supply, passed over the ones that struggle and give up with slow voltage rise.

As A.Justice says, small battery on charge controller (with sufficiently high low voltage disconnect) could smooth it out. Maybe PV direct is fine, but for a water pump there is a good chance either it wouldn't run fast enough to be effective or it would see excessive voltage. Fans I selected for PV VoC and they ran slower with less sun. What you want is for water flow rate to vary with sunshine.

There used to be products called "linear current booster" sold in the Real Goods catalog. When PV made moderately high voltage but not enough current for pump, that would convert to lower voltage higher current, providing better variable flow.

Here ya go. New parent of Real Goods has them:

Linear Current Boosters for Solar Water Pumps | altE

Find and compare linear current boosters (LCB). LCBs are used in solar direct pumping applications to optimize solar water pump output throughout the day.

www.altestore.com

 

[Supervstech]

https://www.northerntool.com/shop/tools/product_200646314_200646314?cm_mmc=Google-pla&utm_source=Google_PLA&utm_medium=Lawn%20%2B%20Garden%20%3E%20Sprayers&utm_campaign=NorthStar&utm_content=282780&gclid=Cj0KCQiA4feBBhC9ARIsABp_nbVQDXli94YT5K_2bEXUjwgjuXmRpB1gumThReT-9BtbEsb5Wp33FncaAi18EALw_wcB&gclsrc=aw.ds

 

[Rider]

There used to be products called "linear current booster" sold in the Real Goods catalog. When PV made moderately high voltage but not enough current for pump, that would convert to lower voltage higher current, providing better variable flow.

Here ya go. New parent of Real Goods has them:

Linear Current Boosters for Solar Water Pumps | altE

Find and compare linear current boosters (LCB). LCBs are used in solar direct pumping applications to optimize solar water pump output throughout the day.

www.altestore.com

Isn't that what an SCC basically does? Use an SCC that has a LOAD port with a small battery to satisfy the SCC logic, and you run off solar while the sun is out.

 

[boondox]

@Rider, you remind me that I have a Morningstar small SCC that has a load output. Only 10 amps but that might be enough with the right pump.

@Supervstech , thanks for that link! While it may not be the right solution for my buddy (tank too small, we need to be able to do a couple hundred gallons) that looks perfect for my spraying needs for my orchard. I have 20 or so fruit trees that need spraying a couple times a year.

This place is a brain trust. Thanks for the help!

 

[Hedges]

Isn't that what an SCC basically does? Use an SCC that has a LOAD port with a small battery to satisfy the SCC logic, and you run off solar while the sun is out.

Yes but, only basically.

With Linear Current Booster, you don't need a battery, and it is designed to deliver lower voltage than battery at higher current to run the pump at variable speed.
Think of that as MPPT for the motor. Don't know how optimum their implementation, but the idea is to put maximum power into the pump given a PV panel.

Much better than PV --> SCC --> battery --> pump.

(which would periodically run the pump at nominal speed, cycling on and off depending on SoC and PV production.)

 

[Rider]

Much better than PV --> SCC --> battery --> pump.

I was thinking more PV >SCC>Pump
-----------------------------^
--------------------------Battery
Battery wasn't to drive the pump, just satisfy the SCC logic and buffer the voltage. But I get how the Current Booster would be a better fit.

 

[Supervstech]

@Rider, you remind me that I have a Morningstar small SCC that has a load output. Only 10 amps but that might be enough with the right pump.

@Supervstech , thanks for that link! While it may not be the right solution for my buddy (tank too small, we need to be able to do a couple hundred gallons) that looks perfect for my spraying needs for my orchard. I have 20 or so fruit trees that need spraying a couple times a year.

This place is a brain trust. Thanks for the help!

They have larger tank options there, but I was mostly showing the pump... I figured you already had a tank...
the pump is on the shelf there at the store.