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raferguson

Sep 15, 2004, 1:25 PM

Post #1 of 6 (748 views)

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Voltage Regulator vs. Transformer

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The topic of voltage regulation is an interesting one for me. On a recent RV (Recreational Vehicle) trip to Mexico, I found that the power available was over 135 volts (in this case, off the meter that I had with me). I was reluctant to plug in my RV at what was probably 140 volts, figured it would overcharge the batteries, and perhaps cause other problems. When I showed the campground host, he found a voltage regulator rated for 10 amps that he loaned me. That put me in business for the most part, but I could not have started and run the air conditioner on 10 amps.

When I got home, I researched these voltage regulators on the web, but the highest capacity that I could find was 10 amps.

I was thinking of buying a buck/boost transformer for $100 or so, which would have more than a 10 amp capacity. But the discussion of voltage fluctuation made me realize that a buck/boost transformer is only good in a more or less stable voltage situation, since you have to manually set up the taps to get the voltage change that you desire. The advantage of a transformer is higher current capacity, and the fact that it should accept short-term current overload to let the air conditioner start up. The advantage of the regulator is automatic adjustment for fluctuations in voltage. Buck/boost transformers are kind of exotic things that I would have to special order, and perhaps find a case to put it in. Voltage regulators are more readily available, especially in Mexico.

Are there voltage regulators with more than 10 amp capacity? (15 amps would be enough, I think, although I am not sure how much current the air conditioner pulls when it starts up).

I will take a standard digital voltmeter on my next RV trip to Mexico, and plan to do something to deal with voltage problems, just not sure what would be best to do. As an RVer, you travel around, so my milage will vary. ;-)

Any comments?

Richard

http://www.fergusonsculpture.com

Rolly

Sep 15, 2004, 2:18 PM

Post #2 of 6 (741 views)

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Re: [raferguson] Voltage Regulator vs. Transformer

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You can buy a voltage regulator that will power your A/C and other loads, but you will pay dearly for it. You need to talk with a professional power equipment dealer. Here is a good place to start: http://www.thomasregisterdirectory.com/...ators_0047264_2.html

Rolly Pirate

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sfmacaws

Sep 19, 2004, 9:16 AM

Post #3 of 6 (700 views)

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Re: [raferguson] Voltage Regulator vs. Transformer

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We've had the same problems if we try to plug in while in Mexico, I've measured current as high as 142. I also tried to find a voltage regulator that could handle that and found it would be really expensive.

We have a Power Surge box that we always plug between the power pole and the RV and it cuts off the current if it goes over about 135. This protects our AC and other appliances but cuts us off regularly. It will allow the current through again after 2 minutes if the voltage falls within its acceptable range so we often have the juice going on and off. Usually we find that it will go off during non-use hours (middle of the night) and back on in the morning when use is higher.

It's fairly irritating so we rarely plug in while in Mexico, only if it is so hot that we are willing to go through some hassle to get the AC working for awhile. We could just let it cycle on and off except that when it is off we need to get up and open some windows, turn on fans, etc then do the reverse if it comes back on. Not worth it when you are sleeping.

If you find a cheaper solution, I'd love to hear it.

Jonna - Mérida, Yucatán

raferguson

Oct 4, 2004, 3:10 PM

Post #4 of 6 (675 views)

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Re: [raferguson] Voltage Regulator vs. Transformer

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I bought a buck-boost transformer, and wired it up, seems to work fine.

More info at my website below.

http://peregrino.home.att.net/camper/transformer.html

Richard

http://www.fergusonsculpture.com

johanson / Moderator

Oct 4, 2004, 4:45 PM

Post #5 of 6 (666 views)

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Re: [raferguson] Voltage Regulator vs. Transformer

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Hey great idea. Although my voltage goes up and down a lot here in Ajijic. (I keep a radio shack voltage meter plugged in all of the time, usually it only varies from 118 to 228. However I have friends in other communities where the voltage has been about 128 to 140 since a recent upgrade one year ago.

I recently picked up a rather expensive HDTV 60 incher and would hate to damage it. I will add your suggestion to my list of options. I wonder if it makes sense to use a step-down transformer that only decreases the line voltage by 5 to 8%?

raferguson

Oct 4, 2004, 7:58 PM

Post #6 of 6 (652 views)

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Re: [johanson] Voltage Regulator vs. Transformer

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I think that I would have gone with the voltage regulator if I could have gotten one rated higher than 10 amps for a semi-reasonable price. I wanted more like 15 amps continuous rating, with the ability to provide more current to start the compressor on the air conditioner. Transformers deal with short-term overloads much better than solid state solutions. One could get a large transformer and adjust the voltage for the entire house!

The 10 amp voltage regulators are readily available and under $100, so probably the best way to go for electronics, etc.

These buck-boost transformers can be wired in many different configurations to get many different voltage ratios. The manual shows more than a dozen different schematics. For example, they show one configuration that changes 240 to 225 volts, so I think that configuration would take 128 down to 120 volts.

Richard

http://www.fergusonsculpture.com