Invert first, pump later...

nyarelathodep · October 2016

Hey all, been awhile since I've needed to probe the collective perspicacity of the solar sages here on NAWs. I'm ready to upgrade. Here's the system as it stands:
225ah 24v bank (T-105 RE)
500w of panel
Samlex SA 600w inverter
Classic 150
Iota 25a charger
Yammy 2000is
Briggs 5550 Genny

This system has performed flawlessly for about two years now, the only issue being that of water pumping. Which leads me here. I have been, up till recently, been getting by on water via the Briggs to power my old Gould's 1/3hp submersible to fill a15 gal drawdown pressure tank. Typically once, and no more than twice a day, would get us by. Living in Maine, water is generally plentiful, but this year has seen the worst drought in recent history and my shallow well had been bone dry for near 4 months now. And I've had about enough... So time for an artisan, and proly a new pump. And to go with that, a bigger inverter.

Inverter shopping has been trying, to say the least. I'm a buy quality, buy once sort of guy, and I'm interested in only that which I need and best fits my situation. That being said, it seems like unless you are interested in buying cheap Chinese inverters of dubious ratings, when your in the market for bigger inverters these days, they come with all sorts of bells and whistles which use unnecessary power for what I need it for, and the new style of hybrid ones have replaced the old standbys which I was considering a few years ago (looking at you, VFX3524...). I can't justify a no load 34w just to pump water a few times a day. I'm totally off grid, I don't need a generator interface... Much less 16 million digital algorithms constantly running in the background waiting to seamlessly switch to grid power which will never come. I also don't need a built in charger...80a won't be doing my small bank any favors, I'm sure. So where does that leave me?

To fulfill all my criteria (durability, extreme quality, affordable, no frills), my search has been narrowed down to... One. The Exeltech 2000xp. With a no load draw of but 12w, and what appears to be high precision PF, and a x2 rating surge which is sustainable for a full 6 seconds, this seems like the obvious choice. The internal brushless fan and the fact that you can apparently drive a truck over it doesn't hurt either. And they will service any inverter they have ever produced, which is reassuring. Here's my question:. Now that I've settled on the inverter, what sort of submersible 2 wire,120v pump can this handle without pushing it too hard? The depth of the well is an unknown at this point. I know that doesn't help in fielding the question much, but it's likely to be less than 100', and less than that horizontally. I'm looking for a quality pump to charge the pressure tank.(40/60). Any input on my options would be greatly appreciated.

Aguarancher · October 2016

If your artesian is reference for an artesian well, all that I have seen flow at the surface? If you have some place where you could install say a 250 gal water tank you could then use a small pump for your pressure tank. Until you figure out your water source it will be hard to upgrade your system.

nyarelathodep · October 2016

I have no available space for a reservoir that size. Space is at a premium around here. Yup... Misspelled artesian, heh. Drilled well, 4"casing. Let's just say it's equal or less than my aforementioned distances.

Aguarancher · October 2016

take a look at Grundfos SQF pump

nyarelathodep · October 2016

Anything less insanely expensive maybe?

Aguarancher · October 2016

not for 100',120v. that's why i said 250 gal tank, small pump to your pressure tank and use your genny for the big fill..

Aguarancher · October 2016

i see these around all the time for cheap. compact for a tight space.. http://palmsprings.craigslist.org/for/5815892976.html

nyarelathodep · October 2016

For that exorbitant price, I could go with twice the inverter and wire it to a sub panel and put a two way toggle switch in place, and only power it when running the pump, I suppose... But it would still be limited to 120v (unless I was to somehow get a 240v inverter wired in the same fashion... But that's sketchy territory for my skills). On the other hand, I guess it's a possibility to place a large reservoir container in my now useless 4 tile shadow well and use a smaller pump from there? What then might I ask is the practical depth limit for a 2 wire, 120v pump running on 4kw max power?

Aguarancher · October 2016

convertible jet pump. link for info only.. http://www.sta-rite.com/ResidentialProduct_sr_ws_jt_FLC.aspx

westbranch · October 2016

The issue with any motor is the startup surge, you need to know this first ! then you can choose the inverter to do the job...

fyi re depth, this link is for Goulds pumps, I have had 3 so far as the well was deepened 5 times, the 1/3 hp worked to 120 feet but I dont think they still make it, probably have to go 1/2 hp min.

http://www.gouldspumps.com/ittgp/medialibrary/goulds/website/Pump Selection System/PSS_UserGuide.pdf

this might give you a better start to your search http://documentlibrary.xylemappliedwater.com/wp-content/blogs.dir/22/files/2014/11/GSSPEC-R1.pdf

But I would recommend getting ahold of a well driller locally, and see what he can supply...

nyarelathodep · October 2016

Thanks WB. I actually have an older Gould's with a Franklin 1/3hp... It's in my shallow well and still works. I had called Gould's last year to try and get info on the surge rating, but as the writing on the unit was badly defaced, they couldn't help me ascertain even a guess. Question? Was your unit also 2 wire, 120v? Additionally, if anyone is aware of a bigger (3-4k), reliable inverter to do the job which meets my above mentioned criteria, that would be a help too. If Exeltech made an inverter in that range that was available, I would go for it, but no one seems to vend thier military spec ones, and their modular Mx units are really expensive.

westbranch · October 2016

mine are 240V 3 wire, but I was told the 2 and 3 wire motors are the same physical size and interchangeable.

So if you pump is still working why not use it if you get a shallow drilled well?
How deep are your neighbours? (More than 1 or 2) we ended up at 305 ft. and 30 GPM still producing but static level dropped.

nyarelathodep · October 2016

I probably could use it, and if it was shallow enough, that was on the table... But if that pump went, I wanted something big enough to handle a 1/2 hp one. Also, I'm uncertain the 2000xp will handle the one I have. My only neighbor is my brother, and he has a dug well, but he lives right at the bottom of the valley and gets all the runoff, though his water is not great, and I'm about 60' more elevated from him. I have a guy coming next week to poke around and see if a dug well in a better location is feasible... If he can find water in this drought, then I will be ok, but I'm trying to plan worst case scenario.

westbranch · October 2016

They still make Franklins AFAIK

mike95490 · October 2016

They better still make Franklin's.
Costs, Either in the inverter or in the pump.
I went with a conventional 3 wire pump. Avaib in 240 and 120VAC. 3 wire has the starting control Capacitor in a topside box, the 2 wire packs all the stuff down the hole with the pump. Having the extra wire length and a more robust capacitor topside, also means easier starting for the inverter

nyarelathodep · November 2016

Greetings again. So after having to move the well another 240' from where it was, now I have tons of water. After pulling the pump, I was able to get enough info from it for a Franklin tech to furnish me with some useful information, and hopefully with that, I can ascertain what size inverter I'll need to run this thing.

1/3hp 115v 2 wire motor with a max amperage of 8.9, and about 48a surge with a PF (at full load) of 53. The total distance horizontally if approximately 380', with a depth of only about 8 foot into well, and total head of no more than 20'. The wire running to it is 12/2. Any guesses as to what size inverter I'll need of I want to use this pump?

jonr · November 2016

Some people say ~3000 watts surge and some say use the LRA x V (suggesting a 5500W surge rating). My guess is that the Exeltech XP2000 is about right. Your wire is significantly undersized.

https://www.solar-electric.com/residential/inverters/off-grid-inverters.html?manufacturer=Exeltech

http://www.buypumpswholesale.com/files/1928173/uploaded/wirechart.jpg

nyarelathodep · November 2016

The pf augments the surge, I've been told. Is this correct, and if so, what is the formulae?

jonr · November 2016

The PF means that the LR amps don't pull as many watts as one would normally calculate. But to use that confidently, you would need to know a) the PF while starting and b) the behavior of the inverter in terms of how it handles surge volt-amps vs surge watts.

A PF of 53 makes no sense - perhaps you mean .53?

nyarelathodep · November 2016

Yes, sorry, I figured the decimal point was unnecessary, given the total range it could be. Tech told me that was starting surge. In the case of a surge rating, is a closer to 1.0 better than a lesser number? I know the Exeltech handles 4kw... That might be a bit too low, perhaps. In the process of tracking down a vfx3524 if not...I figure that will handle it.

BB. · November 2016

Surge for an induction motor is generally have a very poor power factor (probably closer to 0.1-0.2 vs ~0.67 to 0.80 PF when up to speed and under load).

Generally, for typical AC inverters (and non-commercial AC gensets), you can assume that their rated output (continuous and surge) does not care (Watts peak = V*A peak). Where:

Power (Watts) = Volts * Amps * Power Factor

The power drawn from the battery bank (Watts) is less with poor power factor loads (power factors less than 1.0, see equation--Closer PF is to zero, the lower the AC output power is, and therefore lower DC input power from battery bank). But from the inverter point of view V*A is high--High current=high internal losses/heat/saturated magnetics.

-Bill

nyarelathodep · November 2016

The pf value I was told must be for the up and running stage of the motor then, I'm guessing, which leaves me back to where I started in terms of sizing an inverter. I'm starting to wonder if it's more with my while to get some kind of DC shallow well pump like a dankoff and dispense entirely with the idea of uprising an inverter solely to charge a pressure tank.

jonr · November 2016

I see that the XP2000 lists a maximum surge of 45A output. Once you figure in wire losses (even with properly sized wire), you can't exceed that. So my opinion is that it is a safe choice - no matter what the starting PF is.

nyarelathodep · November 2016

So you can start it with less than the listed rating? Ie; 43a to start a motor with an LRA of 48a? Or perhaps I'm not understanding this correctly? Because that inverter is my first choice all day.

jonr · November 2016

Yes. Your supply wire resistance adds to the locked rotor motor impedance with the result being lower amps than the rated LRA. Below is someone who reports using a 1000W inverter with a 1/3 HP Franklin pump. Sounds quite marginal to me, but it should provide some confidence that a good 2000W inverter isn't pushing the limits.

http://www.homepower.com/articles/solar-electricity/design-installation/ask-experts-running-well-pump-grid

nyarelathodep · November 2016

Oh snap! Didn't know that... Thought underpowering the motor at start up would lead to damage eventually. Thanks Jon... That helps a lot.

Invert first, pump later...

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