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Low voltage

I mentioned last week that the temperature in Vermont in June is unpredictable.   Case in point: last week we had several days of days so cold that I had to run the furnace to keep the trailer warm enough for me to type, and now for the past four days it has been between 85 and 90 degrees at the lake. It’s the temperature equivalent of “feast or famine,” except it’s “roast or freeze.”

The current “roast” phase means the people inland, and especially up in Vermont’s “Queen City” of Burlington, where pavement abounds, are really suffering.   It’s always hotter away from the lake.   We’ve got 55-degree heat sink about three miles wide and 400 feet deep right in front of the house, and it takes a bit of the edge off.   Lots of cool green lawns help too, but the humidity is horrible.   People talk about Florida humidity, and I agree it’s intense, but try a summer in northern Vermont sometime.   I have to be careful not to inhale too deeply, lest I drown.

So today I finally broke down and tried to fire up the air conditioner.   (I’m working in the Airstream all day because it is quiet and free from distractions.) The problem is that we are on the end of a 50-foot extension cord from the garage, and that garage outlet is probably at the end of a long line of electrical code violations.

The Dometic air conditioner installed in our Airstream, and most other late-model Airstreams, requires a minimum of 103.5 volts.   Any lower than that and you’ll burn out the compressor motor, and that’s an expensive mistake.   Last summer I bought a digital voltage meter which stays plugged into an outlet on the wall, specifically so I can watch suspicious campground voltage and find problems before they cost me money.

You might be surprised how often campgrounds have inadequate electrical service, but far worse are the courtesy parking situations.   After all, most people don’t build their homes to with dedicated electrical circuits for visiting RVs, and that means low voltage is often a problem.   Since homeowners rarely have a clue what sort of power they can supply, it’s sort of a “moocher beware” situation.

The problem with the voltage meter is that it can only tell you what the voltage is at that exact moment.   It can’t predict what the voltage will drop to when you put a load on it, like an air conditioner.   Think of voltage like water pressure from a hose.   There might be lots of pressure in the hose when the faucet is closed, but when you open the faucet, the pressure could quickly bleed off and leave you with barely a trickle. Turning on an appliance that uses electrical energy is just like opening that faucet.

So my technique to avoid expensive problems is to switch the air conditioner on and watch the volt meter carefully.   When the A/C compressor fires up, the voltage will drop.   If it drops to no less than 104 volts, you’re theoretically OK (although I am always leery of getting even close to that number; my personal limit is 109 volts to allow for variations in line voltage).     If the voltage is unacceptable, I snap off the A/C switch immediately.

No surprise that today the voltage was ridiculously poor, in fact the worst I’ve ever seen.   The moment the compressor started the voltage dropped to 89 volts, struggled up to about 95 volts after a second or two, and then I shut it off.   No air conditioning for me!

Considering that we are coming here annually and staying for weeks at a time, I could see installing a 30-amp dedicated plug for the Airstream, as we did in Arizona.   But the location of the power meter would require us to bury a new line under the driveway and install a subpanel on a post.   Beside the mess and expense, it would be a big psychological step for our fiercely independent family, since having our own power outlet would almost akin to moving back into my parents’ house. It’s probably asking enough that we are leaving an antique Honda next to their garage for the winter.

And really, all that trouble for air conditioning just for a few days each summer?   Maybe I should just go jump in the lake to cool off.   I’m sure that’s what Dad would say.   He’s probably right.

5 Responses to “Low voltage”

  1. Dirk Says:

    Rich, we really enjoy your posts and tonight as I’m chuckling over your prose about the air conditioners and low voltage I just decided to send you an atta boy. You have a real gift for expressing the joy of travel. And sometimes the travail of all the other things that impact on it. For example, your piece on the Discover card nonsense about them “serving us better” cha, cha, cha. Been there, done that. But hey, Airstreams are possibly just the demographic of Discover executives that might just see the error of their ways! Not!

    Keep up the great work here and on the fine magazine. Stay cool.
    Happy trails, Dirk

  2. Roger Says:

    I have an item for my A/C, that I haven’t put in yet, that is a ‘hard start’ kit. It is essentially a bigger capacitor and some other circuitry that builds up a better oomph for the initial hit of the compressor. The extra circuitry delays the start until the cap is full, I think. I got it to help the startup when we are running off of our two EU2000’s.

  3. Rich Says:

    Another possible solution is the Hughes Autoformer, which boosts voltage (by trading off amperage). I’m looking into them now.

  4. Airstreamer in Phoenix Says:

    Definitely Rich: Go jump in the lake!

    ; )

  5. Tom Says:

    I put in a Hughes Autoformer last year. A bit pricey but cheaper than replacing an air conditioner. I have been suprised how many times it has activated itself.