autoformer

[pianotuna]

Hi,

I've decided it is time to get serious about an autoformer.

Can I get one that would cover only the roof air (nothing else worries me brown out wise)? Or am I better with one that does the 30 amp service?

Draw on the air conditioner was a whopping 1900 watts. The campground breaker did flip off twice.


I did find a few days last summer where I was at a 30 amp RV campground where voltage was lower than I'm comfortable with. I did switch off the water heater, turned off the converter and moved the fridge to propane, but still had low voltage issues.

What autoformer would you choose (link please) and why?

I wonder if there is a way to use the Magnum inverter to do voltage support?

[wa8yxm]

TechWriter wrote:

MrWizard wrote:

You just can't convince some people that using l.p. for fridge,wh, or heat
Is better than a low voltage "Brown out"

I'm guessing that most RVers don't even know about low voltage.

I know more about Low Voltage than I care to know (And no, not due to having fried a compressor).

But I look at it this way, the park where I am parked, charges one rate for 30 amp, and another for 50

I am paying for 50

I am thus entitled to use it.

That said, in the park I am in the wiring is up to the task, The only time I have had a "Low voltage"issue it was a NO-VOLTAGE issue (Power fail park wide due to incident elsewhere).

But in many parks... well the park was built back when 30 amp RV's were rare and 50 amp rigs were not even on the drawing board,, The wiring is NOT up to the task and has not been upgraded,, Aluminum feeders now 50-or more years old have deteriorated to the point where any load is too much.

But when I pay for 30, or 50 amps, I expect to be able to use it, I think I have a right to expect to be able to use it.

What some folks do is run 2 or 3 cords.. Now that (in most cases) is excessive (Sometimes I run a 2nd line just for my Wi-Fi Modem, (Depends on where the park pedestal is and where I park the Modem) but well.. single digit wattage is not really a concern.

[pianotuna]

Hi mlts22,

I don't know how to set the Magnum to do that sort of voltage support. It will supplement only when I exceed the amperage.

Would one limit the shore power amperage on the Magnum remote?

[TechWriter]

MrWizard wrote:

You just can't convince some people that using l.p. for fridge,wh, or heat
Is better than a low voltage "Brown out"

I'm guessing that most RVers don't even know about low voltage.

[mlts22]

I've wondered about using a Magnum Energy MagnaSine MSH3012M. It functions similar to the Victron by using the battery and supplementing voltage if the 120VAC coming in is sagging.

It is no replacement for an autoformer (especially for consistantly long times at low voltage which would deplete the batteries over time), but it guarantees the proper voltage, regardless of surges or sags.

[MrWizard]

Many people pull in to a park or campground, and put all appliances on electric, fridge, wh, then use the a/c and MW, and when too many people do this, the line voltage drops

You just can't convince some people that using l.p. for fridge,wh, or heat
Is better than a low voltage "Brown out"

[Gonzo42]

OK, I was intrigued by the name 'autoformer' and suspected, now confirmed that this is what I learned to call an 'autotransformer', which I have used in a lab extensively.

So now that I know what it is, I look forward to advice on the use or necessity in RV parks.

[TechWriter]

camper19709 wrote:
I am also shopping for a AutoFormer. I have found the Hughes and the Power Master. Both have good reviews. But, I also found the Surge Guard RV Voltage Regulator with no reviews. Does anyone have any personal experience with the Surge Guard?

Yep, works fine. I bought the Surge Guard over the other brands because the SG "plays nice" with my RV's Surge Guard EMS.

[time2roll]

For just the air consider Tripp-Lite LC2400 for about $200usd.

[Pirate1]

I have had a powermaster 50amp wired inplace for over 5 years. Works great I guess as I never have low power issues.

[MEXICOWANDERER]

Edited to correct poor eyesight and clumsy fingers on a smart phone




Don, I TORTURED my 20-amp tortilla and it just laughed go outside and look at the power pole transformer. Whether in Regina, Reno, or Raleigh, that transformer is made in Mexico.

If we can work out the details I can pick up a 20-amp model and mail it to you when I go north for medical in February. Place the box INSIDE the coach and feed the AC from the box. It really needs a 20-amp receptacle, and some MOVS & transient voltage diodes soldered inside to make it sneer at one of the conventional RV autoformers.

Mexico, Canada, and Canada are all part of NAFTA so there should be ZERO import duty on this item. Sticker on side clearly says HECHO EN MEXICO.

[pianotuna]

Hi Fred,

Thanks for the suggestion about "roll your own". I would want the voltage protection to cut in (and out) automatically.

I don't understand why the Mexican product is so much better and at the same time so much cheaper.

I guess it boils down to Hughes, Power Master, and Surge Guard.

[HTElectrical]

Golden_HVAC wrote:
Pianotuna,

While most will not have the technical skills to wire up a voltage booster, you can save some money by doing it yourself. I built one with a 500 watt 'buck/booste' transformer. It is rated at about 42 amps at 12 volts. They also sell a 16 volt version. I figure that if the voltage input is 108, then the increase is about 11 volts, to bring it up to 119 - give or take a little.

When I was living on a ranch, with the main electric panel about 300' away, I was plugged into the well house, and that wire was about #8. So voltage drop was about 1 volt per amp that I would draw. So unboosted 120 volts became 132 volts, and it would drop by about 12- 15 amps depending on if the microwave or air conditioner was running. I used solar for the batteries, and never charged them in the summer with shore power.

I plugged in my refrigerator directly to the power post - so it will never be boosted, because high voltage is REALLY bad for the refrigerator electric heater. 132 volts will take the typical 2.5 amp heater up to about 3A X 132V = 396 watts! That is enough to crack a heat exchanger ammonia line.

You will have the skills to wire up this booster transformer. It comes with line drawings, and when I wired mine up the first time, I got output of 108, so I had to move a couple of wires to get 132 volts.

http://www.grainger.com/product/SQUARE-D-Buck-Boost-Transformer-WP157564/_/N-/Ntt-buck+boost+transfo...

Mine will not change voltage automatically, but I have a three way switch on the outlet, so I can change from boosted to input line, depending on my needs. I do unplug it before making the voltage change. I bought a 12" long 30 amp cord from Camping World near my home, and a 30 amp receptacle and deep metal box from my local Home Depot. I had the couple of feet of #10 wire to use inside the box and to to the transformer from the plug and receptacle.

Basically the input neutral goes to the output receptacle, and the high voltage on the transformer. Then the input black wire goes to the 3 way switch and high voltage input on the transformer. Low voltage on the transformer also goes to the three way switch. Other side of the low voltage goes to the input black wire (and other side of the input high voltage). So the input black wire + 12 volts (or +16 if you select that model transformer) goes to the 3 way switch, and to the black output side of the receptacle.

Good luck!

Fred.

The last place you want to buy a Buck Boost Trans form is Grainger. They rape you! Purchase off of Ebay, Amazon etc... any brand will do , you do not need to go with Sq. D, I have used over 15 of just about every brand and in 20 years have only had 1 Acme 2 KVA go bad!

[camper19709]

I am also shopping for a AutoFormer. I have found the Hughes and the Power Master. Both have good reviews. But, I also found the Surge Guard RV Voltage Regulator with no reviews. Does anyone have any personal experience with the Surge Guard?

[JesLookin]

I had a Franks, it was inadequate. Now have a hardwired PowerMaster, it works perfectly. I never know if it is boosting - it switches automatically. I do look every once in awhile, sometimes it is boosting sometimes not.