Yes, this is OT, but you folks seem to know everything...<g>
I need to get an automatic backup generator, but my needs
The fully automatic units I can locate are all in the range
I need something on the order of 5-10KW. So, compared to the
"standard" residential backup unit, the one I am looking for
is really tiny. But, anything over that (approximate)
capacity would just be money wasted.
Might any of you suggest sources for such a small (but fully
Very sincere thanks,
Indeed, my numbers were all screwed up... 'sorry.
I need to drive only a sump pump, and a small fan in a
direct vent gas heater. The units I have seen are in the 7KW
range, and I need a small fraction of that.
Thanks to all for your comments,
Seems to fit -- I'm not sure I see the problem here... <g>
If all you really need to power is a sump pump and a small fan, then an
automatic backup unit seems to be overkill; is there a reason you can't use,
say, a 1500-watt portable generator?
Consider a sump pump with an alternative power source, too, such as Basement
Watchdog or Ace in the Hole.
Doug Miller (alphageek at milmac dot com)
On Tue, 20 Nov 2007 23:06:14 GMT, email@example.com (Doug
I could use a small generator... In fact, I have, but...
We travel a fair amount, and living in rural New Hampshire,
outages are not all that rare.
We would be in trouble if we had an outage while we were
Beyond that, the standard "battery backup" units for the
sump pump seem to have a run time on the order of 15-20
hours and I recall an ice storm in which we lost power for
more than 96 hours.
Thanks for your thoughts,
To borrow from the endless threads on rebuilding battery packs for tools,
why couldn't you extend the on time of the sump pump with additional battery
In fact I knew somebody who used deep discharge marine batteries for
something like this. He got the batteries from a charter fishing service who
used them for trolling motors.
Just an idea. I am not sure how practical it would be in your situation.
Further threads provided additional info RE: Application.
Years ago, we sold a mini SCADA unit designed spefifically for this
You would monitor the incoming power.
If it would fail, a contact would close, then call you and announce
the power was out.
It could also close a contact to electrically start a generator.
Found a lot a application in Canada for monitoring telecommunication
facilities out in the boonies that were only accessible by helo in the
This is at least 20 year old technology and had about a $3K cost back
Today, the net will have revolutionized SCADA systems.
Try a Google for SCADA and see if small systems are still offered.
I wonder if a solar or wind powered charger would be sufficient for the
battery backup on the sump pump. 15-20 hours is quite good by itself, then
add to that changing from solar power during the day...should be enough to
keep the sump pump running intermittely for a long time.
If his pump is cycling every 30 seconds and draws say 2 amps then
that's a 110 watt load---if it's winter then triple that because the
days are short and you've got 330 watts worth of collector required,
plus losses due to various inefficiencies. Not considering air mass
and average cloud cover at his location and suchlike, I'm pulling 500
watts out of my butt as a number. At the 8 bucks a watt that I'm
seeing in various places, that's $4000 worth of collector alone, then
you have to add inverter, batteries, etc.
He said that he had seen times when that happened, and also times when
he had had an outage for 96 hours--that makes for an engineering
spec--has to run the pump at 50% duty cycle for 96 hours plus whatever
margin one wants.
I dont think Kenneth said his pump was recycling every 30 seconds..If it
was, I would agree with the poster that said he needs to invest in a back
hoe and some drain pipe.
He said his pump would last on backup batteries for 15-20 hours. My
thinking is that would be increased three fold if the batteries were
recharged using solar cells during the day.
IMOHO, I wouldnt trust a generator starting automtically and running while I
was away if it was a critical application. Too many factors involved.
Better than staying home all the time! A standby generator is often the best
choice. Sure the genny could fail, shit happens sometimes. But then the sump
pump could fail to. It gets to some point where you have to put some faith
in something, or stay home 'cuz you are to paranoid up to leave!
Quoting one of his posts:
A battery backup and inverter is a possibility, but we have
had outages as long as four days, and also have had
situations in which our pump cycled on and off every thirty
seconds or so for a week.
If those two situations were to coincide, I would need quite
a pile of batteries to stay dry.
Sincere thanks, as before,
Also he didn't say that his pump would last on backup batteries for
80W solar panels are less than $500.
T-105, 6VDC, golf cart batteries are less than $65.
A small inverter is less than $500.
Assume the sump pump requires 2A and operates on a 50% duty cycle
which would require 240W/hour.
I use 50% efficiency of solar cells for estimating, thus (80W)50% 40W.
240W/40W = 6 panels or about $3,000.
T-105 are rated about 235AH.
If you cycle them between 70%-90%, they provide about 47AH/pair at
240W/47AH = 5 sets of batteries minimum, I'd probably use 6 sets or 12
Use $5000 as an estimate to achieve total independance from an
Plus the added advantage of "no moving parts' <g>
Less than he would spend on a auto start generator (yeah...right!), auto
transfer switch, etc. that would all work flawlessly while he was away.
Me..I would gamble on the solar thing first<g>
Use $3,000 as an estimate to achieve total independance from an
For that money, just to power a sump pump, I'd certainly go the route of a
Guardian standby generator. You can buy one heck of a whole house generator
for that kind of money. Keep a couple extra propane tanks around and switch
tanks over every 50 hours of runtime. Enjoy life as usual. I feed my whole
house on a simple 8,000 W gas generator, but it's not an automatic setup.
The Guardians are really nice units. I've installed several of them and one
of these days I'll put one in myself.
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