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 > Drop in voltage with increase in heat

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down home

south

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Posted: 08/10/20 10:36pm Link  |  Quote  |  Print  |  Notify Moderator

Right now at 9:30 pm it is 91 outside ad 75 inside and voltage meter is right at 115. It will go up to118-120 later....but in the heat of the day 110 or so the voltage goes down to 110 or so and we won't use the convection/microwave oven etc as it drops down to 105 or so.
That is on the generator or on 50 amp plug in.
Anyone have an idea what to investigate, a fix?
I'm not sure how long this has been the situation...but I don't remember encountering it in years past.
We did replace the front roof heat pump late last year with a little larger capacity pump.

pianotuna

Regina, SK, Canada

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Posted: 08/11/20 12:04am Link  |  Quote  |  Print  |  Notify Moderator

Hi down home,

There is nothing to fix. It is perfectly normal for demand from the air conditioner to increase as temperature rises outside.

Mine start off at 1200 watts. By mid afternoon, on a hot day that increases to 1900 watts.

At the local campground, that causes the voltage to be lower than I'm comfortable with. I solve that with an autoformer.

You could, in theory, add one. But 110 is quite adequate to run the roof air. I've always believed that is better to not fix something that is not broken.


Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp hours of AGM in two battery banks 12 volt batteries, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

valhalla360

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Posted: 08/11/20 05:53am Link  |  Quote  |  Print  |  Notify Moderator

For shore power, voltage sag mid day and resultant increase in amperage drawn, that's pretty normal. If it's dropping below 110v, an autoformer is a great option unless it's extreme.

What's a bit concerning is the voltage is dropping while on the generator. Ours doesn't change noticeably when on the generator and hangs at around 118v. (this is once it's running, obviously, there is a surge for a second when it starts).


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cavie

Port Charlotte Fl/ Hindsdale MA

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Posted: 08/11/20 06:01am Link  |  Quote  |  Print  |  Notify Moderator

do NOT us the A/C below 109 volts.


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CA Traveler

The Western States

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Posted: 08/11/20 06:42am Link  |  Quote  |  Print  |  Notify Moderator

valhalla360 wrote:

For shore power, voltage sag mid day and resultant increase in amperage drawn, that's pretty normal. If it's dropping below 110v, an autoformer is a great option unless it's extreme.

What's a bit concerning is the voltage is dropping while on the generator. Ours doesn't change noticeably when on the generator and hangs at around 118v. (this is once it's running, obviously, there is a surge for a second when it starts).
X2 Something is not right with the gen or wiring. Do you have 105V on both legs?


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cavie

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Posted: 08/11/20 07:52am Link  |  Quote  |  Print  |  Notify Moderator

CA Traveler wrote:

valhalla360 wrote:

For shore power, voltage sag mid day and resultant increase in amperage drawn, that's pretty normal. If it's dropping below 110v, an autoformer is a great option unless it's extreme.

What's a bit concerning is the voltage is dropping while on the generator. Ours doesn't change noticeably when on the generator and hangs at around 118v. (this is once it's running, obviously, there is a surge for a second when it starts).
X2 Something is not right with the gen or wiring. Do you have 105V on both legs


That should be 115/120

Darryl&Rita

Grande Prairie, Alberta

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Posted: 08/11/20 08:53am Link  |  Quote  |  Print  |  Notify Moderator

Loose wire connection onboard your RV. Time to do some tightening.


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ksg5000

Oregon

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Posted: 08/11/20 05:03pm Link  |  Quote  |  Print  |  Notify Moderator

No expert but I think all the above answers maybe correct. Depends on the generator/altitude etc. Std hard line hookup will reduce power when park/city loads increase .. air conditioners tend to demand more when temps are higher .. and my generator tends to put out less when I am at higher altitude. Loose wire connection will create similar issues. Combo of high temp and high altitude put close to max on my last trip.


Kevin

down home

south

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Posted: 08/11/20 10:06pm Link  |  Quote  |  Print  |  Notify Moderator

After reading your replies it strikes e that the only common source of electrical power is the transfer switch. Hopefully it is only a loose connection. Not much chance of corrosion here in 110 heat

wa8yxm

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Posted: 08/12/20 05:08am Link  |  Quote  |  Print  |  Notify Moderator

There is the possiblity of a poor connection some where .. Recommendation is to use your voltmeter at as many test points as you can starting with the generator's output connection box or outlet.

But as the heat rises. pressure in the A/C increases In fact there are charts that tell you how much.. As the pressure rises the compressor works harder and harder to pump the refrigerant through the lines.
Now there are two (really several) types of electric motors for this post
Series and Shunt wound
Series (As I recall. note I may be mistaken) as the load increases the motor slows down a bit. as it slows down it draws more and more and more current. The starting current oh these can be downright impressive

The other type attempts to run the same speed no matter what
But again the harder it works the more current it draws.

So it does not matter which type the Compressor is... As the pressure increases. SO DOES THE CURRENT DRAW.


Home is where I park it.
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