Disappearing voltage?

[OntMont]

100 ft of 16/3? I'm surprised it did not melt on the spot. You really need a 10/3 RV cord. The plugs on U-ground cords are only rated for 15 amps (maybe 20 in some cases). I'm sure that is the root of your problem.

[dsprik]

How many amps does that main AC pull?

[kdeiss]

quote:Originally posted by OntMont

100 ft of 16/3? I'm surprised it did not melt on the spot. You really need a 10/3 RV cord. The plugs on U-ground cords are only rated for 15 amps (maybe 20 in some cases). I'm sure that is the root of your problem.

I agree this is your problem look no further

[OntMont]

The main AC must pull about 15-20 amps, probably more on start-up.

[richfaa]

Daved ..according to our PT 50C the main A/C pulls 14 amps..the bedroom 10.5. I have no idea what the start surge might be.

[NCFischers]

Your 16/3 cord is your problem. Get rid of it. I'm also surprised that you haven't burned it up already. Get a 10/3 50 foot cord and your problem will go away.

[Tom S.]

If all you are running is the front air, a 50ft 12/3 will work but it is the absolute lowest you should go. A 10/3 would be better, especially if you ever have to run more than the ac. The best would be to either A) put a 50 amp outlet near the trailer (that's what I did) or B) buy or make a 50 amp extension cord. The 50 amp extension cord isn't a bad idea since it could come in handy when camping (I have one and used it twice when we went to Alaska). 50 amp cords are very expensive but if you watch ebay you may score a deal on one.

[dsprik]

Sorry, didn't explain why I had an extension cord hooked up to the Montana at the house. It is basically to keep the converter running to keep the battery charged. Fridge, water heater, mw, all switched off (Breakers). We occasionally go inside and need to turn the lights on. We go inside to clean and work on projects inside it.

I only ran the AC to check if I had a problem with it. I understand that the extension cord is not made to run the rig. Wasn't meant to. I was hoping that with everything else off in the rig, that it should run one AC at least. Guess I was wrong. No wonder my electric bill in the winter in FL is so high...

Thanks for the good info. I believe I am OK on my electrical. The CG electrical we were at was the problem. We will find out the next time we go camping.

[bigmurf]

Hey Dave: Could be that dead animal in your ceiling. g Devil made me say that.

[dsprik]

Thanks for bringing that up, Murf!

He may be lying across a couple of those AC wires up there perhaps... But then again, I really haven't smelled any cooked squirrel, so maybe not...

[firetrucker]

Dave, get a voltage tester and plug it in next to the extension cord, as OntMont suggested. That will help you isolate the problem to the power cord or inside the Monty. Make sure all the wire ocnnections behind your breaker panel are tight, too. You could swap the breaker to check its operation.

Bob

[dsprik]

Thanks, Bob. I will do that. 95 here today in N. MI (records being set all over), so I will have to wait for the heat to lessen. Breaker panel wiring is OK. Just something about this doesn't feel right. Is there something that could happen inside the Monty that would increase my voltage draw?

Would a weak/bad breaker cause this voltage drop problem? Thanks for your help.

Jim, does anyone sell a 10/3 extension cord, or do I have to buy that in wire only wire?

Tom, I looked into running 50 amp service for my rig at home and unfortunately my power service comes into the opposite end of the house from where I have to keep my Montana. This 125' run became very expensive - even with electrician friends. I put that little project on hold for now, but it is the ideal situation. Looked at 30 amp service, but by the time I get that paid for, I might as well wait until I can put in the full 50 amp run.

~On Edit: Jim, I did find 10/3, 50 ft @ Home Depot for $55 - not bad. Now if my house wiring will handle it. 1980 Ranch style house. Should be OK?

[NCFischers]

Dave,
That's a good price for the cord. Your house wiring will be fine, it's not that old and the wiring that was used in the 80's is good. The reason for the 10 gauge extension cord is to lessen your voltage drop to the trailer. Shortening the extension cord from 100 feet will help also. It won't have any effect on your house wiring. You will still only have the amperage that your house circuit breaker has but you will have less of a chance of heating up the circuit and tripping the breaker.

[firetrucker]

Dave, a lot of the voltage drop can come from the connections, and the connectors, too. The standard straight blade plug is good for only 15 amps, no matter what the sizof the cord. As jim said, a larger guage cord will reduce the voltage drop for longer runs, but will not increase the maximum current limit set by the plug, and may tempt you to overload the house circuit.

One quick way to check the cords is to start your A/C and put your hand on the connectors to see if they are getting hot. If they aren't, then the problem is most likely in the Monty. Voltage checks on either side of the connector is the best way to confirm the problem, but not always the easiest thing to do.

Besides checking the voltage at the house receptacle, you could also check across the main circuit breaker and the bus bars in the breaker panel, and then at the output of the breakers for the A/C's. Wherever you see the voltage drop first, then that segment is where the problem is.

Bob

[dsprik]

Thanks, Jim and Bob. This is great info and I really appreciate it. I have a voltage tester, but I am not that adept at using it. I will try to get my BIL over here in the next day or two to follow your "map" that you have here. Going to Home Depot tomorrow.

Went in to the Monty this afternoon - very hot inside and the converter was running on high. No battery drain at all that I can imagine. Will that just kick on that high on it's own to keep the battery charged in this heat? I was going to try to pull the panel, but I didn't want to shut down the power with the converter running that hard. It was over 100 in there anyway. Wasn't planning on staying in there for long...

[Tom S.]

quote:Originally posted by dsprik



Tom, I looked into running 50 amp service for my rig at home and unfortunately my power service comes into the opposite end of the house from where I have to keep my Montana. This 125' run became very expensive - even with electrician friends. I put that little project on hold for now, but it is the ideal situation. Looked at 30 amp service, but by the time I get that paid for, I might as well wait until I can put in the full 50 amp run.

~On Edit: Jim, I did find 10/3, 50 ft @ Home Depot for $55 - not bad. Now if my house wiring will handle it. 1980 Ranch style house. Should be OK?

You are right - running a sub panel that far would cost a lot - even doing it yourself. Copper isn't cheap and I don't like aluminum. My plug is only about 25 feet from the sub panel for my arc welder, which made it a nice and easy run, plus I happened to have everything I needed including the wire.

Your 10/3 should work just fine. You house outlets are probably wired with 12/3 and rated at 20 amps, but you can check your breakers to be sure. If they are 15 amp, you are wired with 14/3.
With 12/3, your loss over the 50 foot 10/3 will be minor and you will be good as long you don't go crazy! If you have 14/3, you will still be good for one ac unit and a few lights.

[dsprik]

Great! Thanks, Tom!

I still wonder why my converter has been running hard all afternoon. Just went out and it is still running, but now just barely. But seems that it has been really working hard all afternoon in this heat. Does that do that just for charging the battery when it is hot out??? No drain on the battery - that I know of.

Checked my battery and it seems OK. Water in all cells, none fizzing though with the converter running wide open. Is that normal? Maybe my converter is causing some excess drain on the rig electric?

[Tom S.]

By converter running, I'm assuming you are hearing the fan, which is heat regulated. Load on the converter causes it to heat up and thus the fan runs. If the outside air is already hot, the converter fan could come on sooner/easier. You might want to check and see if you had something left on that drew the battery down while you were unplugged though. Just one light can drain a battery if left unattended for a few days, especially an older battery. BTW: Cooling fans are a good thing. I thought the cooling fan in our converter was super quite. Turns out the darn thing wasn't running at all, which I'm sure is why the converter died a premature (as in just after warranty expired) death.

[dsprik]

Boy, Tom, I am positive there is nothing on that would draw from the battery. Would that cooling fan come on high with out the converter actually doing any work. Maybe simply a cooling system to keep the converter cooled off - whether the converter is actually working of not???

In other words. If that compartment gets hot and there is a current to the converter, the fan may be triggered by a thermal switch and come on by itself to try to keep the box cool even though its not doing anything? That would explain the fan running so hard most of the afternoon today even though the battery was not being charged...

[Tom S.]

No, if there is nothing on and your battery is in good shape, the converter shouldn't have kicked on. My new one only runs when I have a bunch of 12 volt stuff on. My only point on the heat was if the converter fan kicks on when the converter reaches a set temp, say 130 degrees, and the temp inside the compartment it sets in was already 100, it would not take as much to heat it up the additional 30 degrees as it would if the temp was only 70 to start with.

Sounds like you may have other issues.