Solar Set-up for Well Pump

[hicktown21]

Trying to be as cost conscious as I can and I have been speaking to off-grid solar companies and it seems all of them want me to build a huge production plant. I am a complete novice at all the lingo but getting better by watching videos, reading and viewing comments here in this forum.
Based on the info below and the pump tech information can anyone point me in the right direction. I am ready to purchase and install once I have all the components. I will be going with a lithium battery set-up for possible emergencies.
The well pump is my biggest energy (start-up from reading here) pull and I will only use it during the long AZ sun days. I don't see running the well pump at night unless an emergency or I messed up the scheduling. The water is being pumped up to very large holding tanks and the pump is only rated at 7gpm (see pump tech worksheet)

Listed the items below and usage expected.

** 2HP well pump (7gpm) - see attachment for specifications (the pump will only be used during daylight hours, run 2x a month and runs usually for 5 hours) no other appliances will be ran during this time.
** Clothes washer (runs a few times a month when in use)
** String lights to be used only during the night will LED.
** One ceiling fan (not on all the time)
** ½ hp RV pump to run water to 3 shower locations (runs a few times a month when in use)
** A few cell phone charging stations/plug ins
Thank you all..!!

 

[DThames]

How deep is the well (what is the head?) that you need 2HP to get 7GPM? That sounds like head of greater than 300 feet! If that is a normal pump, don't buy it if you want to run it off of solar. You will need a more solar type solution and likely a large surface holding tank.

 

[hicktown21]

How deep is the well (what is the head?) that you need 2HP to get 7GPM? That sounds like head of greater than 300 feet! If that is a normal pump, don't buy it if you want to run it off of solar. You will need a more solar type solution and likely a large surface holding tank.

Based on the paperwork the well is set at 673 feet. This was all on the property before we purchased. The pump is used to move water up to larger holding tanks. I use a generator now but the modifications I am making on the property I want to use solar.

 

[DThames]

Based on the paperwork the well is set at 673 feet. This was all on the property before we purchased. The pump is used to move water up to larger holding tanks. I use a generator now but the modifications I am making on the property I want to use solar.

So if you have a pump already, why is there a pump in the quote? Normal pumps are hard to start, take huge power just to start, which drives up inverter and battery sizing. For solar, you need a tiny solar type pump that will pump a low GPH for hours with a few hundred watts of DC.

 

[42OhmsPA]

** 2HP well pump (7gpm) - see attachment for specifications (the pump will only be used during daylight hours, run 2x a month and runs usually for 5 hours) no other appliances will be ran during this time.

Do you have a clamp meter to measure inrush current of the pump?
My 1hp around 300' pulls 37a on startup. I'd imagine yours will be significantly more.
I'd look at the Schneider 6048 for your pump size, that will likely run everything you throw at it.

 

[hicktown21]

So if you have a pump already, why is there a pump in the quote? Normal pumps are hard to start, take huge power just to start, which drives up inverter and battery sizing. For solar, you need a tiny solar type pump that will pump a low GPH for hours with a few hundred watts of DC.

this was just the paperwork I have been able to get that has various information. I am learning about all the property stuff as i go... I have been told many things about what I should do. From to expensive for a solar pump, to replace the pump to newer to just use the generator. I need to go solar for all the items that will be happening on this side of the property. If there is a simple solution as to just get a small solar pump then great.

 

[hicktown21]

Do you have a clamp meter to measure inrush current of the pump?
My 1hp around 300' pulls 37a on startup. I'd imagine yours will be significantly more.
I'd look at the Schneider 6048 for your pump size, that will likely run everything you throw at it.

i don't yet have one but I plan to purchase to measure. I will look at the Schneider, thanks

 

[OzSolar]

So if you have a pump already, why is there a pump in the quote? Normal pumps are hard to start, take huge power just to start, which drives up inverter and battery sizing. For solar, you need a tiny solar type pump that will pump a low GPH for hours with a few hundred watts of DC.

That would be my first thought but I think it's a pretty narrow selection of solar pumps when you get down that deep and the power will be above 1.4kW to move ~5 GPM but still it's far more manageable than than a 2HP 240v pump.

The static level will greatly affect this of course.

 

[Risky Rob]

A conventional 2HP might need 50 amps @ 240V which is 12,000 watts.

 

[hicktown21]

A conventional 2HP might need 50 amps @ 240V which is 12,000 watts.

I was sent a chart and I will be at 230v @ 57amps to start it... This is getting up there now....

 

[hicktown21]

That would be my first thought but I think it's a pretty narrow selection of solar pumps when you get down that deep and the power will be above 1.4kW to move ~5 GPM but still it's far more manageable than than than 2HP.

The static level will greatly affect this of course.

View attachment 111347

View attachment 111348

I was told by the previous owner that a solar pump is not doable because of the depth. I will have a good battery bank plus with the AZ sun I would think this wouldn't be a huge issue, guess I am wrong...

 

[MichaelK]

If others haven't seen the other thread, I cut and pasted my response from it.

I took a look at the attachment, and I'd say no way can the numbers they wrote down be accurate. They listed 10.2A on L1 and 11.67A on L2? Immediately, that makes me very suspicious that they were NOT using a meter that can read inrush. Again, referring to the chart posted above, I find the numbers in this chart to be an accurate representation of what you will actually see.
Looking at the chart, I see 13.2A running, with 57A starting. At 230V that 57A means 13,100W for maybe 500 or so milliseconds. That is a really massive starting surge and I don't think there is a single inverter that will power that alone. But, either two XWPro 6848s or two Radian 8048s wired in parallel should be able to handle that surge. You are talking though about 7600-8800$ just for two inverters, depending on which you chose.

Maybe a single Sol-Ark SA-15 might handle it.

If you go that route, I'd suggest using the 2X rule for solar panels, that is have double the watts of panels for your biggest single load. That is.....
13.2A X 230V X 2X = 6072W of panels. Call it 24-27 250W grid-tie panels.
Yes, it's doable, but the cost is going to be very high. I don't think one other load you might have is going to approach what that pump needs. Since you only plan to run the pump a few times/month, one alternative is the design a system around everything else you need to power, and use just a generator biweekly to power the pump.

The amp level coming out of the battery suggests you'll need a 48V battery in the 500-600Ah range to meet that need.

So, nothing about this is going to be cheap!!!

 

[OzSolar]

I was told by the previous owner that a solar pump is not doable because of the depth. I will have a good battery bank plus with the AZ sun I would think this wouldn't be a huge issue, guess I am wrong...

I'm not tracking. What are you wrong about? Grundfos makes a pump that can do 5 GPM at your site with ~1500 watts of PV.

 

[Risky Rob]

The pump control box must have a starting capacitor that contributes to the LRA surge?

 

[Sebanavila]

If you are on a budget and want to get one of the best options, get in touch with signature solar, their EG4 line of batteries and their new 6000 EX-48 HV plus some of their solar panel packages, will do the job right and you don't have to build a power plant.

At least for the purpose of what you are looking for.

 

[ChrisG]

@hicktown21 what size generator currently starts and runs your well pump?

 

[DThames]

After thinking about this (sleeping) I would say, if you have a working pump at 600 feet, let it be. Pulling a pump is hard work or expensive work, maybe both. If it will run on your generator, get an amp meter that will record the max starting amps when it starts. Use the generator's rated watts and what you recorded on startup to determine what inverter "might" work.

There are some fairly low cost All In One (AIO) units that are stackable, meaning you can set them up to work together. If you buy two 6000watt units and they don't work, you can add a third, then a fourth until you can start your pump. High frequency inverters (the most common in today's market) are not known for starting motors very well as they can't handle amps over their rating for more than a fraction of a second.....for the most part. Low frequency inverters will handle starting currents for a few seconds. Low frequency (LF) are often more costly.

To start, the battery voltage at the inverter terminals will need to stay at full voltage, meaning don't skimp on battery cable size. Adding super capacitors to the inverter battery input might help as well, making sure there is plenty of energy close to avoid a voltage drop.

Someone mentioned the Sol-Ark. One thing the Sol-Ark will do (other good hybrid inverters do this too) is pass more grid power through the inverter than they can actually output from the inverter power output section. Where that might be an advantage to you is suppose you start the generator and allow the Sol-Ark to pass through the "grid" power to start the pump. Once the pump is running, the pump demand would be just normal work (start surge had passed). So after starting, you could kill the generator and just pump with solar/battery power. From where I set, this looks very attractive. Having a generator wired into a Sol-Ark also gives you a lot of redundancy for low battery, cloudy, type conditions. I know you might not get clouds much where you live but still Sol-Ark with generator, solar, and battery is a strong solution.

 

[Risky Rob]

He knows exactly how many amps he needs. If I recall it's 57@230V. My best advice is to not buy the conventional pump that contractor is offering. Instead get a specialty solar well pump, and carefully design the entire well system to allow you to pump water with an inverter.

 

[MichaelK]

He knows exactly how many amps he needs. If I recall it's 57@230V.

Well, no. I pulled the 57A from the chart I posted. So, that number is my approximation of what I think it would be. I agree with what DThames in that you should get a clamp meter on the pump, start it with the generator, then determine what the actual starting surge is.

Here is an affordable clamp meter that can read inrush.

UNI-T UT216C 600A Digital Clamp Meter NCV BackLight T AC DC Multimeters + Clip 6935750532164 | eBay

Model UT216C. NCV,VFC function. Jaw Capacity 30mm. LCD Backlight √. DC Current (A) 60A/600A ±(2.5%+5). AC Current (A) 60A/600A ±(2.5%+5). AC Current Frequency (Hz) 40Hz ~ 400Hz. AC Current Frequency (Hz) 40Hz ~400Hz.

www.ebay.com

I used this meter to determine the inrush of my own pump. I also compared it to a far more expensive Fluke inrush meter and the two readings vary by less than 1%. So, the 216C will get the job done.

I would also agree with working with the pump in place rather than replacing it. I have pulled a pump from 400', and it is NOT fun work. 600' will just be worse. I would recommend first getting the data on running your actual pump, then design your system around it. Or, as DThames mentions, use a generator to supplement power just at startup, then use just the inverter to carry the running load.

Keep in mind though that some inverters are very fussy about the quality of power they receive from the generator. The inverter looks at voltage, Hz, and maybe waveform to "decide" if the generator is "qualified" to supply power to the inverter. My XW+ is that way, and will reject the generator power if it is pushed higher than ~2000W.

 

[OffGridForGood]

If the pump is existing (as it seems is the case) then it makes sense to find the in-rush-current and then design around this as your peak load.
The comment above -"what size generator runs the pump now" is an easy starting point. It will give you some idea of the peak, even before you get your hands on a decent Amp meter. I also agree with the comment by DThames about parallel inverters: In my own system I have twin MPP6048 inverters, I started with one, then paired in a second one a year later. I had originally thought I would need a third unit to run large shop equipment (3Hp cabinet saw) but with only two, the saw starts and runs, so I have not purchased a third inverter in my case. In your case maybe you need a third inverter, but as DThames says, you could actually start with two and try it out, add a third (or even a fourth) if and only if you actually need it.
When you search for an inverter, you can check the specs on how long it will handle over-current, and how much over; not all inverters are the same.
If you could 'live with' the generator just for the well pump to fill your tanks a few times a month, you could save a lot of $$ since your other loads are so much lower. Another way to look at it, may be, use the generator for the short term, while you build out the rest of the PV system and later expand (as DThames suggests) with parallel inverters, eventually being able to remove the generator from the system, but avoiding needing to purchase a full system up-front.