50amp to 30amp adapter question

[Streetloaf]

All of the RV parks I have been to have had a 30amp hookup.
My coach is 30amp.
2004 Itasca Sunova.
The place I am at today has only 50amp hookup.
Ok fine. I have an adapter.


With a 30amp hookup, normally when I run both my A/C's I see on my display that I am using 26-27amps consistently.
This place, with the adapter on the 50amp hookup, my display tells me I am only using 19-20 amps with the same A/C usage.

Not sure what to think of that.
Any idea as to why the 50amp hookup with a 30amp adapter shows a lower power usage?

[Jim_HiTek]

I suspect that the newer 50 amp outlet in today's typical RV park has a solid 120 Vac at the outlet whereas the 30 amp outlet voltage sags when you run both ACs, giving lower voltage, causing higher current drawn by the motors. Mainly because the 30 amp infrastructure is older and likely the parks you visit already have low voltage because of all the other RV'ers drawing power from 30 amp outlets.

Suggest you always use 50 amp outlets in future. Especially in the heat of the summer. For example, they are predicting a 111 F day and over 100 all this week here in what used to be a nice cool valley near Walla Walla Washington. The offset is that there are 250 wineries within a 50 mile radius of Walla.

Edit: I will mention that many older RV parks charge a premium for 50 amp, but you are a 30 amp RV so no premium! Yea! Your rig is different then millions of 30 amp RVs because most cannot run both ACs on 30 amp, your high current draw shows why. What happens when you turn on the MW? Does one of the ACs get shed? Anyway, that high current is very close to popping an old worn out shore power breaker too. Another reason to plug into a 50 amp outlet whenever you can.

[j.m.jackson]

If the park with the 50A plug is running at 130v, you'll lower your amperage. higher voltage = lower amps. What voltage was at your coach?


I installed an inexpensive volt/amp/HZ meter between my transfer switch and house panel so I can see what's currently going on, whether I'm on gen or shore power.

[Streetloaf]

Originally Posted by Jim_HiTek

I suspect that the newer 50 amp outlet in today's typical RV park has a solid 120 Vac at the outlet whereas the 30 amp outlet voltage sags when you run both ACs, giving lower voltage, causing higher current drawn by the motors. Mainly because the 30 amp infrastructure is older and likely the parks you visit already have low voltage because of all the other RV'ers drawing power from 30 amp outlets.

Suggest you always use 50 amp outlets in future. Especially in the heat of the summer. For example, they are predicting a 111 F day and over 100 all this week here in what used to be a nice cool valley near Walla Walla Washington. The offset is that there are 250 wineries within a 50 mile radius of Walla.

I just spent a month in Vegas. Temps were over 113 on several days. Brutal.

[Streetloaf]

Originally Posted by j.m.jackson

If the park with the 50A plug is running at 130v, you'll lower your amperage. higher voltage = lower amps. What voltage was at your coach?


I installed an inexpensive volt/amp/HZ meter between my transfer switch and house panel so I can see what's currently going on, whether I'm on gen or shore power.

I haven't metered anything. I just got here couple hours ago. Flagstaff AZ.

[Jim_HiTek]

Flagstaff used to be one of my favorite places to spend a few months. But Black Barts is a mess, my favorite RV park became a 'buy your site' place, the other park outside of town was good but expensive, and the one neat park outside of town didn't have Wifi. Most of the other parks I crossed off my list due to reasons. So it's been off my radar for a few years. But I just checked the weather and now I no longer need Wifi because I have unlimited cell phone data so that one park might be a good choice for a few months stay next time I'm in the area.

Where did you end up parking it?

[Streetloaf]

Originally Posted by Jim_HiTek

Flagstaff used to be one of my favorite places to spend a few months. But Black Barts is a mess, my favorite RV park became a 'buy your site' place, the other park outside of town was good but expensive, and the one neat park outside of town didn't have Wifi. Most of the other parks I crossed off my list due to reasons. So it's been off my radar for a few years. But I just checked the weather and now I no longer need Wifi because I have unlimited cell phone data so that one park might be a good choice for a few months stay next time I'm in the area.

Where did you end up parking it?

Black Barts. I am only here overnight. Isn't that bad here. Easy to get to. Check in took 5 minutes. At least there are some trees. Better than anything in Vegas.
Lot of permanent residents here. Spent a month in Duck Creek in Vegas.
Talk about ghetto.

I was going to park at the truck stop across the street, but they make it clear you can't park an RV there. I am not camping. I am traveling. Gas prices killed my plans for roaming. I am just driving a straight line to my new house in TN.

[LETMGROW]

Have you ever tried the dog bone in a 50 Amp service before? Perhaps your dog bone is defective or the post is wired differently than most.

[Streetloaf]

Originally Posted by LETMGROW

Have you ever tried the dog bone in a 50 Amp service before? Perhaps your dog bone is defective or the post is wired differently than most.

It's new. I just took it out of the package.

I mean, everything works fine in here. Like others have said, maybe the voltage is higher here?
I know their water pressure is extremely high.
Def need a regulator at Black Bart's.

[LETMGROW]

Originally Posted by Streetloaf

It's new. I just took it out of the package.

I mean, everything works fine in here. Like others have said, maybe the voltage is higher here?
I know their water pressure is extremely high.
Def need a regulator at Black Bart's.

Who's to say the adapter isn't defective right out of the package. If it was me I'd walk around and find someone else who is using a dog bone and strike up a conversation with them. They might offer to let you try theirs to see if everything works correctly or you might find they are experiencing the same issue you are. Maybe even take your volt meter along if it's portable.

[Sweetbriar]

To get that much of a amp change would require a big change in voltage or a reduction in watts being consumed.

If your normal demand of 26-27 amps is at 120VAC that would equal 3180 watts of power being consumed. With a drop in amps to 19-20 and the same 3180 watts the volts will need to increase to 163VAC. Normal utility power can very as much as +/- 6% is North America so even if your normal 30 amp service was at the low end (112.8VAC) and the 50 amp was at the high side (127.2VAC) you'll only see around a 3 amp difference.

I wonder if one of the A/C's was in a de-icing mode at the time you checked power. This would be fan on but compressor off which could drop the power demand by half for that A/C or 2385 watts combined which would drop the amps to 19.8 at 120VAC.

Seems plausible.

[twinboat]

If you were using a bad dogbone, the ACs would have burnt up by now. It's 120 volts or 240 volts, nothing in-between.

If its notably cooler then the last time you ran both ACs, they will each draw less amps.