Water Pump question

nyarelathodep

Hi all... Quick question. I have a 1/3 hp goulds submersible pump 115v 2wire model with a max surge rating of 8.9 amps and I plan on using an outback vfx3524 inverter for my system. My question is would 4 6v golfcart batteries (24v configuration) be sufficient to handle the starting surge? Would I be much better off with a bank of 8? The pump will be in a shallow well with a static water level of 12' and the total distance is about 60' with no more than a 20' vertical lift.

vtmaps

Re: Water Pump question

nyarelathodep wrote: »

Hi all... Quick question. I have a 1/3 hp goulds submersible pump 115v 2wire model with a max surge rating of 8.9 amps and I plan on using an outback vfx3524 inverter for my system. My question is would 4 6v golfcart batteries (24v configuration) be sufficient to handle the starting surge? Would I be much better off with a bank of 8? The pump will be in a shallow well with a static water level of 12' and the total distance is about 60' with no more than a 20' vertical lift.

Startup surge: no problem. The running load may stress the batteries if you run the pump at high pressure and for prolonged times. Four of those GC batteries holds about 5280 watthours, but that assumes you are drawing 264 watts from them.

--vtMaps

Cariboocoot

Re: Water Pump question

nyarelathodep wrote: »

Hi all... Quick question. I have a 1/3 hp goulds submersible pump 115v 2wire model with a max surge rating of 8.9 amps and I plan on using an outback vfx3524 inverter for my system. My question is would 4 6v golfcart batteries (24v configuration) be sufficient to handle the starting surge? Would I be much better off with a bank of 8? The pump will be in a shallow well with a static water level of 12' and the total distance is about 60' with no more than a 20' vertical lift.

Yes.

I have the same inverter. My batteries are slightly larger at 232 Amp hours but there's only four of them and it handles my 1/3 HP water pump no problem. It also handles all my power tools, some of which are pretty healthy in the current department (some 2 HP motors). The septic pump has soft-start and the air compressor has an unloader valve but their running current is higher than the water pump's start demand.

Should not be a problem.

nyarelathodep

Re: Water Pump question

Ah, thanks so much gentlemen. That was the only thing left to plan out and good news for me! I'm not sure about the pressure issue, but the usage times are very conservative and I plan on a pressure tank to save wear on the pump as well as provide consistent appropriate psi to the tankless water heater. Considering my power needs are no greater than yours, Coot, I'm pretty happy knowing now that four batteries will do the trick for me

waynefromnscanada

Re: Water Pump question

Where did you get the info that the MAX surge is only 8.9 amps? Just wondering. Sounds very low for a 115 volt sub pump.

westbranch

Re: Water Pump question

I'll wager that is the rate printed on the pump, my Goulds 1/2 hp is a hair less at 8.6A

waynefromnscanada

Re: Water Pump question

westbranch wrote: »

I'll wager that is the rate printed on the pump, my Goulds 1/2 hp is a hair less at 8.6A

That 8.6, is that the rated operating amps? In which case the start surge would be much higher.
I have sub pump with Franklin Electric 1/2 hp motor, 115 vac, rated amps (running) is 12 amps. Start surge is much higher.
Have another, 220 VAC, rated 4.8 A / 5.9 S.F. Amp. I'm convinced the start surge is far higher than 5.9 Amps from the surge loads they used to put on the generator I used to have. Don't use either one on inverter power, too much for the Xantrex 1800 PS, and it's rated if I remember right, +40 amps surge.

nyarelathodep

Re: Water Pump question

Wayne, it was the rated maximum amps on printed on the unit. Was thinking that meant the maximum amps it would draw (ie; surge) but perhaps I assumed incorrectly? If it ends up being too much for the system, any insight into what would be a viable alternative (without breaking the bank)?. My back up plan is a 1.8 amp sump pump.

Cariboocoot

Re: Water Pump question

Why are we having this "it won't work" discussion when I've already said it will? Based not on conjecture or whim but the real-world fact that I do exactly what he is asking about?

The pump start-up surge is barely a momentary blip, not some minutes-long battery-destroying death current. You won't even notice it (unless you're trying it from a Honda EU2000i; that doesn't work).

waynefromnscanada

Re: Water Pump question

Cariboocoot wrote: »

The pump start-up surge is not some minutes-long battery-destroying death current. .

Was not suggesting it is, rather my concern was and is the inverter's ability to handle the start surge. Been there.
Cheers.

Cariboocoot

Re: Water Pump question

waynefromnscanada wrote: »

Was not suggesting it is, rather my concern was and is the inverter's ability to handle the start surge. Been there.
Cheers.

The VFX 3524 can handle it, no problem. I've yet to fault that thing even though it's surge rating is "only" 7kW.

waynefromnscanada

Re: Water Pump question

Cariboocoot wrote: »

The VFX 3524 can handle it, no problem. I've yet to fault that thing even though it's surge rating is "only" 7kW.

OOPS, Obviously I didn't read, or realize he had a 35/24 inverter. My bad.

nyarelathodep

Re: Water Pump question

Thanks for the reassurances, Coot . Ordering the inverter this week. Can you suggest a good guide for wiring the components together? Can't afford a pre-wired assembly at the moment, and will be getting the panels and charge controller at in the not-so-distant future ( a month or so), so initially it will just be the bank, inverter, and generator. Also, i notice Sams Club has duracell golf cart batteries (6v 215ah) for $85... Half the cost of the trojans i was looking at. Considering this is my first set of batteries, would it be advisable to learn on these or are theya waste of money, I'm wondering?

Cariboocoot

Re: Water Pump question

Several people have done fine with the warehouse GC2's. No reason I've heard why you shouldn't give them a try. Especially at half the price of Trojans.

Wiring guide. Ah. Inspected or not inspected? If it's inspected you have to follow the rules that will allow it to pass. If not inspected you only have to follow the rules that will allow it to work safely.

Outback has a lot of wiring diagrams for their equipment. Spend some time reading the installation manual (available on-line; they don't even ship hard copy anymore it seems). It's a really good idea to familiarize yourself with it before attempting the installation. Running current of the 3524 @ 24 Volts nominal is about 150. If you will be operating in that range you'll need at least 1/0 wire for the DC side. And don't forget the fuse or breaker.

Also don't forget you will need a MATE of some version to program the VFX. Do not use the default values as there is a high probability they won't be right for your system (gen input limits, max charge current, LVD to name three critical items).

nyarelathodep

Re: Water Pump question

Ahhh... Very glad i asked because i was looking at those earlier and wondering how essential they might be. Would getting the mate3 over the two be beneficial for a starting out guy like myself, or just complicate things needlessly? Concerning the wiring, I'm way off grid and the only code the town seems to have cared about was septic, which took them forever to go check on (no one looks forward to making that trek to my property it seems, heh), and there's no insurance issues to worry about either. Thanks ever so much for all the information you've walked me through. If it matters, concerning the mate2 or 3, i will most definitly be taking your previous advice on using the midnite kids for my panels. Assuming there is no real reason for me, with my loads, to go 48v even with the batteries being so cheap, it will be 24v.

mike95490

Re: Water Pump question

nyarelathodep wrote: »

..... Assuming there is no real reason for me, with my loads, to go 48v even with the batteries being so cheap, it will be 24v.

Except, you may be close to the limits of easy battery sizing with a 24V system. 24V 400ah system is same amount of lead/acid as a 48V 200ah system. Same total watt hours, but you can use smaller wires, and the system will handle larger surges.

Cariboocoot

Re: Water Pump question

I would pick the MATE or MATE II over the 3 because the latter is more expensive and has features which you won't be making use of (as opposed to a system with Outback FM controllers and/or Radian inverters).

I would not worry much about the differences between 24 and 48 Volts either. There's a downside to the higher Voltage as well as an upside, as with anything. For one thing you need fuses/breakers/disconnects that can handle the 60+ Volts of a 48 Volt system. That limits your choices in that department.

One of the biggest problem with systems is they do not expand easily, so it helps to know what kind of power you need going in and what limitations there are to the equipment you first pick. This is both for maximum Watts and Watt hours stored.

nyarelathodep

Re: Water Pump question

Yea, my inclinations were to stick with the 24v system. I wish I could run out of questions at some point, lol, but...speaking about water pumps, my brother had a question which im tossing out here. Does anyone happen to know the surge rating of the Shurflo revolution 115vac pump, by chance? Cant seem to find it anywhere, including a call to the shurflo tech department (!?) He has the MS suresine, and wanted to know if that inverter could handle that pump. its max amp rating is 1.0, but I know the start surges are typically much higher than the max amperage listed.

Cariboocoot

Re: Water Pump question

He'd be better off using the 12 Volt Shurflo direct from the battery rather than run the 115 Volt version through the inverter. Less losses, and the 12 Volt appears to be more dependable than the 115 AC version.

I'm not sure what the motor is inside the 115 VAC Shurflo, but the high start surges we talk about are usually found in induction motors (high torque) which have run & start windings. Brush type motors have minimal surge demand.