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bldginsp
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# Posted: 2 Aug 2014 06:54pm - Edited by: bldginsp
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Will I burn up my generator if I use it to power a water well pump on continuous use for hours at a time? So, the question is, what is the reality of the capability of these little gasoline generators?
I'm going to drill a well soon, I'm planning what kind of pump to use. Can't make a final decision until I know exactly how deep the water is and at what rate the well will produce water, but at this point I'm guessing that I will have about a 350 foot head to pump water into my 2500 gallon tank (no pressure tank- gravity feed). I will probably choose a one horsepower pump at about 8 amps 240 volt single phase, or perhaps 1-1/2 horse at about 12 amps. So, depending on flow rate, I may need to pull 2,000 to 3,000 watts on the pump for one to three hours depending on how much the tank needs to be filled.
I have a Briggs and Stratton 10 horsepower 5000 watt construction-type generator which claims to provide 8000 'starting watts'. But it is designed, supposedly, to provide 5,000 watts continuously. But pulling up to 3-4,000 watts for a few minutes and pulling 3,000 for several hours are really two different things. I already killed one 2500 watt generator with construction saws, don't want to kill this one with too big a pump.
So, what's your experience with these generators- what can they really do on a serious continuous basis, aside from the advertising hype?
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toyota_mdt_tech
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# Posted: 2 Aug 2014 09:26pm
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I would say if its rated for that continuous, you should be OK. Maybe a little more wiggle room, maybe a 6500 continuous.
I have the Honda EU6500is and it ran my household during power outages, ie hot water tank (electric) range, dryer, septic pump, all electric. No issues, did it on eco mode even.
How far about the well head will the tank be and how far away (in feet)
I'm looking into a solar well kit, with a smaller 1/2 pipe, runs about 2 gallons a minute off solar power. With the 1/2" pipe, it isnt pushing a heavy column of water, its slower, but you could run it most of the day to fill your storage tank. The solar livestock well kits dont even use a battery, just straight solar panels.
Just some more ideas to consider.
http://www.solarpumps.com/
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bldginsp
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# Posted: 2 Aug 2014 11:01pm - Edited by: bldginsp
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Yeah, Toyota, I did look at the solar pumps, but it kind of got complicated fast- here's my thought train-
A solar pump will operate off of only a few panels, with no charge controller, batteries, inverter- straight from panel to pump. I plan to put a small solar power system on my cabin for just lights and gadget recharge, so, can I use the same panels for that system for the well? That would mean using a transfer switch to transfer the panel power from the battery charge controller to the pump circuit. That would work, if the voltage and amperage of the panels could work for both systems. Otherwise I have to buy twice the number of panels and have two separate systems.
If I did have the transfer switch, and two systems powered by the same panels (but not at the same time) then for at least part of the time at the cabin the system would have to be switched to the pump to fill the tank. Then the batteries would run down. Ok so maybe I need to get twice the number of panels and have two separate systems.
I may eventually get grid power, in which case I can't use the solar pump on grid AC, and I don't want to replace the pump, ever, if possible.
The solar pumps are an as yet untested technology, I don't want to have to replace them every 5 years at a cost of $1000 each time.
So putting in a time-tested 'standard' well pump operating on AC seems, for now, the wisest and less expensive option. Could be in the future I'll have a grid tied PV system and so, will in effect, operate the well off solar.
This is complicated by my well depth and head height which will certainly be over the 200 foot limit of most solar pumps. There is an Italian deep well solar pump, they don't advertise the price, I doubt it's even close to a comparable AC deep well submersible.
A lot to consider.
Back on the generator question, I'm not sure i have my math right- a one horse pump rated at 8 amps at 240 volts should pull about 2000 watts (volts x amps = watts) but they list the unit as .75kw, or 750 watts. Maybe 8 amps is start current, I don't know, but I'm sure my generator would be quite fine at 750 watts.
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groingo
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# Posted: 2 Aug 2014 11:54pm
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Any reputable generator will have overload protection but it has been my experience if in doubt and even without doubt I never run my generator un monitored, I am always checking engine temps and even pay close attention to the sound, is it laboring, surging etc., and finally if your really on the edge rent one.
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toyota_mdt_tech
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# Posted: 3 Aug 2014 12:38am
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bldg, I also bought a Flo Tech 220VAC well pump, its rated for 10 GPM, my well produced 15GPM, so I didnt want to run it dry. My well depth is 178 feet. I dont know how deep the water is, maybe 160 or less. I have not installed it yet, ie used 1" water line. I figured it would be setting submerged for years and would degrade, so havent trimmed out the well as of yet. I am 1/4 mile from buried power. If I move there, I will be hooked up to the grid.
It appears you can buy a new 12 or 24VDC pump for 300-600 dollars.
I think in your case, the 240VAC pump and your generator would work fine, I was going by your 4000 watt number is why I suggested more. But it appears your pump would consume less. You should be fine.
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bldginsp
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# Posted: 3 Aug 2014 03:09pm
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Groingo- you're right it's necessary to monitor these small generators, in my case if I ran it for two hours to pump 1000 gallons I'd be wondering if the stator would heat up too much after an hour or so. But it should handle it.
Toyota- the 8-12 amps I was looking at before, giving wattages of 2-3000 must be starting amperages. When running, a 1 horse AC submersible pump will use about 1000 watts or less, so my generator should be fine.
If reliable DC deep well pumps are available in a price range comparable to AC pumps, I think I'll research it more. The ones on the link you sent are in the $1000 range, including 200 feet of wire, and only good to 200 feet depth. I will probably need over 200 feet depth, and a total of maybe 500 feet of wire to get to the panels. At 24 volts, the wire size is going to be probably #8 or #6, hopefully not #4, which will cost a lot. I'll parse it out and re-post. I'd prefer to have solar, if it can work.
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toyota_mdt_tech
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# Posted: 3 Aug 2014 03:29pm
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Not sure what size wire for the 12V system, but if it was a 24V system, the wire size can be smaller (technically half the size to do the same work). Most of those low voltage DC well pumps are in 12 or 24V, I think there is even a 36V one too. But I'd say 24V would be better.
I'm just starting to look into this also, so I'm still in the learning stages too (have been researching it for about a month now and kinda slowed down for now). If you find out anything else ie information, post it up.
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bldginsp
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# Posted: 3 Aug 2014 03:43pm - Edited by: bldginsp
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Here's more info on the solar option from Northern Arizona Wind and Sun:
http://www.solar-electric.com/wind-and-water-products/sodcwapu/grsoposuwapu.html
they have a variable voltage Grundfos deep well submersible pump that will operate at higher voltages, allowing use of smaller wire. No idea on price.
So, with 4 of their 80 watt panels in series at 130 volts total I could pump 2 gallons a minute in full sun at a pump height of 375 feet using #10 wire. Very impressive, I'll price it out.
Edit- did some more reading- this pump can be operated with DC or AC, and can be used as solar with generator backup. But they are pretty pricey- only price I found on the pump was over $1500.
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Truecabin
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# Posted: 3 Aug 2014 05:13pm
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1 hp motor draws about 750 watts i wouldnt think even twice about a 5000 w generator putting out 15% of its continuous rated capacity continuous
besides 5000 w generators are all over craigslist for $300 you are wasting your time worrying
your gen can put out 2500 per leg but the pump you say is 240v so its drawing from both legs equal thats good
note that a 2500w (if 240v) gen might only put out 1250 per 120v leg so you can run into trouble with 120v power tools running on a 2500w/240v gen
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bldginsp
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# Posted: 3 Aug 2014 06:36pm
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yes, Truecabin, I did kill a 2500 watt generator with power tools, then I bought the 5000. You are right- it's plenty for the pump- I misunderstood the ratings at first.
But now I'm seriously considering the solar option, so I don't have to use gasoline at all to get water.
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