Emergency generators. [telecom]

Some years ago we had a windstorm (or hurricane) that knocked out power for days--a week for some people. This is not an uncommon problem in Maryland and the Eastern shore. Summer thunderstorms can knock out power for days.

Anyhow, the problem was getting power into the house to run the computer (I was on deadline at the time), the refrigerator, and maybe a light or two. I don't own a generator, and for events that happen only once or twice a decade, that seems an excessive expense. Then I remembered: I had two cars, each of which had a generator with battery backup. A quick trip to a nearby truckstop (if two counties away is nearby) and I owned two inverters. These cost about $100-125 each. (Truckstops are the most likely local sources, but Wal-Mart sometimes has them. Or, there is the internet.)

I connected the one with the nominal rating of 1000 watts (continuous) to the battery of my Ford, which had the larger battery and generator, using large crocodile clips (like jumper cable clamps), and ran an extension cord into the house. I plugged in the refrigerator and "POWER". The one with the nominal rating of 750 Watts could not run the refrigerator, but attached to the battery of the Honda it did just fine on the computer and printer. I had the cars idling, so the batteries had a chance to recharge (IIRC, modern alternators deliver full power even at idle). There is no way this arrangement could supply full power to the house. I think the Ford had a 65 AMP alternator, which means 780 Watts at 12 volts, less the losses. However, the battery supplied any surge that the alternator could not. (When an electric motor, like the one in the refrigerator, starts, it draws perhaps double its usual load for a fraction of a second.) Electric stoves, air conditioners, electric heat just won't work with such small alternators, though you could probably run the fan in a forced-hot air furnace.

This arrangement would also work for camping at events [or evacuations] where you can leave your vehicle reasonably close to your tent.

***** Moderator's Note *****

I don't know how to calculate the startup load of a refrigerator: you are right, of course, that the starting demand is much higher than the running power that's needed, but I'm not sure how to calculate it. I'm told that the worst case power-demand is from an air conditioning system, but I don't know why.

If anyone has a pointer to an EPA or other site that gives the procedure, please send it in. I'm very interested in getting information about the running costs of various fuels, as well: I read that Natural Gas is much more expensive than gasoline. TIA.

Bill Horne Moderator

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David Chessler
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