OT- Small - Automatic - Generators...?

[Kenneth]

Howdy,

Yes, this is OT, but you folks seem to know everything...

I need to get an automatic backup generator, but my needs are unusual:

The fully automatic units I can locate are all in the range of 7000KW.

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 automatic) generator?

Very sincere thanks,

[J. Clarke]

Home Depot?

Try

KW wouldn't be a residential unit, it would supply 200 amp service to more than 100 houses.

[Nova]

7000 KW!!!???

The one's I've seen are in the 7 KW range.

[Kenneth]

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,

[Doug Miller]

???

7000KW = seven megawatts.

You might want to check that again... or quit looking at industrial equipment.

Actually, 5 to 10 KW *is* a standard residential backup unit.

7000KW is high-end industrial size.

[Kenneth]

Hey, lighten up... I was only off by a factor of 1000...

The units I have seen are in the range of 7KW, and I need something on the order of 10-20% of that.

Thanks,

[Doug Miller]

[snip]

[snip]

Seems to fit -- I'm not sure I see the problem here...

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]

I figured something went astray somewhere....

I don't think you're going to find an automatic unit much smaller than that, to be quite honest -- maybe 5KW, but I can't imagine anybody making an automatic unit as small as 700 watts.

[Doug Winterburn]

Not sure about the automatic part, but Honda might have the answers. They make damn good generators:

I saw a water powered sump pump as backup on "This Old House" several months ago. The house water supply pressure drove the thing when the power was out for the regular sump pump. Wouldn't solve the fan issue though - I'm guessing you're trying to prevent a possible freezing problem? Do a google on "water powered sump pump" and you'll get lots of sources.

[Dave Hall]

It would seem that the switching equipment required would far outweigh the generator cost. Were you looking for natural gas? I would think that would be hard to find in that size as would something with a large enough fuel tank to make this an extended use item.

Not fully knowing your issue I would suggest considering a battery system sized to run your items for the immediate term (a few hours at best) supported with a standard portable generator that you would have plenty of time to set up in the event of a power outage. However, if this is for something that you are going to be absent from for days on end this isn't going to be an answer, but neither is a non-natural gas generator. If the battery system backed by a generator seems like a possibility, then you might take it further and look into whether capacitor banks exist that will run the pump and fan for the immediate term (2 to 3 hours maybe?). I don't know if they make those for a residential purpose, but I know that where I work we installed a capacitor bank to run all of the site lighting (many street lights and pole lights) for emergency egress of an 8,000 person stadium as it was less expensive than a hard piped generator sufficeient for the same use.

[Nova]

The transfer switch arrangement would be cost prohibitive for such a small load. Depending on the average run time required you may be able to get away with battery back-up using an "Uninterruptable Power Supply" (UPS). Check out Tripp-Lite's web site for an idea of the prices.

checked a one for a 700 Watt draw , 10 hour reserve at about $850.

[Kenneth]

Hi 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 away.

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,

[Kenneth]

I appreciate your thoughtful comments.

Please see my response to Doug.

The main issue I confront is time. We have had 4 day outages, and were we away, we would be in a tough spot.

Thanks again,

[Kenneth]

Hi Doug,

Yes, freezing is (half) the issue.

I have a second (unused) flue in our chimney and could easily install a gas heater using it, but...

It is my understanding that those heaters must have electricity (to run the fan).

The water powered sump pump confuses me though:

If we had an extended outage, we would not have any water pressure (or at least would not have it for very long.)

If I had electricity to pressurize our water supply, I would just use it to power the pump I now have (unless I am misinterpreting your comment about water pressure.)

You will see other issues elsewhere in the thread.

Sincere thanks,

[Doug Winterburn]

I misunderstood - I thought the sump pump was to prevent flooding. It sounds like the pump is for a well, not a sump? The water powered pumps work if you have city water and therefore water pressure independent of your power. They are a solution to prevent flooding of a basement for example if the power is out for the electric sump pump.

[Kenneth]

Hi again,

My desire for backup electric power IS for a sump pump, to prevent flooding. I regret any confusion. We are in a rural setting, and have our own well. So, no electricity means no water pressure...

Thanks again,

[Lew Hodgett]

Forget the automatic transfer part of you spec.

An automatic transfer switch will cost more that the engine-generator set alone.

Based on the loads above, you will have time to start eng-gen before the world ends.

Since this is for infrequent use, consider a 10HP-5KW, "Contractor" generator.

Noisy as all get out but biggest bang for the $, for a short time application (8-10 hours at a time).

Lew

[d.williams]

[Lee Michaels]

"Kenneth" wrote

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 packs?

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.

[Lew Hodgett]

"Kenneth" wrote

Further threads provided additional info RE: Application.

Years ago, we sold a mini SCADA unit designed spefifically for this type application.

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 winter.

This is at least 20 year old technology and had about a $3K cost back then.

Today, the net will have revolutionized SCADA systems.

Try a Google for SCADA and see if small systems are still offered.

Lew