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Old 07-05-2016, 06:22 PM   #11
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Originally Posted by JD and Beastlet View Post
Yes, I understand that. But saying "Power loss is proportional to the square of the current" sounds like a formula, and any such formula would have to take into account the length and gauge of the extension cord, would it not?
Yes you are correct see my voltage drop calc that I posted above.
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Old 07-05-2016, 06:54 PM   #12
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Originally Posted by JD and Beastlet View Post
Yes, I understand that. But saying "Power loss is proportional to the square of the current" sounds like a formula, and any such formula would have to take into account the length and gauge of the extension cord, would it not?
Yes. But you don't need to do the calculation to know what you need to do.

Power is equal to current squared times the resistance. The wire in the cord develops a certain resistance per foot. This resistance is related to the material of the wire and the diameter of the wire. Since most cords are made of copper, the resistance is then proportional to the size of the wire. Smaller wire, more resistance per foot. Longer cord, more feet, hence more resistance in the cord.

Current is proportional to the load you put on the end of the cord. If you operate something that consumes more watts (A/C, water heater, toaster, fridge), then the current it draws goes up.

So ideally, you want large wires, shorts cords and low wattage. If you change one in the "wrong" direction, you need to change one or both of the others in the "right" direction.

Consider your 30 amp RV cord as "adequate" for running most things. But if you start adding extra, smaller gauge extension cords to it, you need to start dropping the wattage of whatever your running.

Now, all that being said, in my driveway I've run my A/C with a 100 foot "normal" (not sure of it's gauge - probably 14awg) extension cord and have had no problems. BUT, I haven't run anything else, either.
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Old 07-05-2016, 09:25 PM   #13
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So I'm good to run just the fridge?


2015 Cherokee 284bf limited
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Old 07-05-2016, 10:35 PM   #14
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So I'm good to run just the fridge?


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Most likely yes for just the fridge.

Get you one of these and plug it into an outlet in the RV this will tell you for sure. I have the digital one. Also won't hurt anything after you have this turn the AC on for a few min with your 100 foot extension and you will see what happens to the voltage drop. Again won't hurt nothing unless you left it on running for hours. Most likely an 100 foot 14 AWG extension cord connected to an RV and running the AC will melt the extension cord in a few hours.

https://www.amazon.com/Prime-Product...dp/B000BRFTH6/

https://www.amazon.com/Prime-Product...dp/B002P48KLK/

We just traded campers and when I get a new one I pretty much tear it part adding upgrades I want. I also find alot of issues from the factory and fix them as I go.

Here is the thread I started on the new camper.

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Old 07-05-2016, 10:57 PM   #15
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Most likely yes for just the fridge.

Get you one of these and plug it into an outlet in the RV this will tell you for sure. I have the digital one. Also won't hurt anything after you have this turn the AC on for a few min with your 100 foot extension and you will see what happens to the voltage drop. Again won't hurt nothing unless you left it on running for hours. Most likely an 100 foot 14 AWG extension cord connected to an RV and running the AC will melt the extension cord in a few hours.

https://www.amazon.com/Prime-Product...dp/B000BRFTH6/

https://www.amazon.com/Prime-Product...dp/B002P48KLK/

We just traded campers and when I get a new one I pretty much tear it part adding upgrades I want. I also find alot of issues from the factory and fix them as I go.

Here is the thread I started on the new camper.

Traded Flagstaff 25KS for a Catalina 253 RKS

Mine never got hot. Maybe it's 12 ga, but doubtful.
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Old 07-05-2016, 11:16 PM   #16
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I fried my fridge mother board. I was temporary using the trailer for a week at my home while we were moving. I only was using a few lights and tv, and fridge. I was to far away from my 30 amp RV home connection. So I plugged into 15 amp using the trl heavy gauge 30 plug, I used and adapter and I think 14 ga wire extension cord that was about 100 feet. Needless to say my adapter melted and now my fridge is fried. Two lessons for me, don't use 14 gauge wire with adapter for long periods, and I have a progressive EMS and I didn't use it because I though at home there was no need.


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Old 07-06-2016, 09:57 PM   #17
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I will be plugging it in tomorrow so we will see how it goes!!!


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Old 07-07-2016, 07:38 AM   #18
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http://www.cerrowire.com/files/file/voltagedrop.pdf
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Old 07-07-2016, 07:41 AM   #19
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The trick is to ensure the battery is charged already or disconnect the battery. The charger will also heat up when trying to charge with it's input amperage low. Be sure not to try the ac or water heater.
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Old 07-07-2016, 07:55 AM   #20
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Quote:
Originally Posted by kendive View Post
Yes you are correct see my voltage drop calc that I posted above.
Geez, I missed that completely. Thank you.

Quote:
Originally Posted by rockfordroo View Post
Yes. But you don't need to do the calculation to know what you need to do.

Power is equal to current squared times the resistance. The wire in the cord develops a certain resistance per foot. This resistance is related to the material of the wire and the diameter of the wire. Since most cords are made of copper, the resistance is then proportional to the size of the wire. Smaller wire, more resistance per foot. Longer cord, more feet, hence more resistance in the cord.

Current is proportional to the load you put on the end of the cord. If you operate something that consumes more watts (A/C, water heater, toaster, fridge), then the current it draws goes up.

So ideally, you want large wires, shorts cords and low wattage. If you change one in the "wrong" direction, you need to change one or both of the others in the "right" direction.

Consider your 30 amp RV cord as "adequate" for running most things. But if you start adding extra, smaller gauge extension cords to it, you need to start dropping the wattage of whatever your running.

Now, all that being said, in my driveway I've run my A/C with a 100 foot "normal" (not sure of it's gauge - probably 14awg) extension cord and have had no problems. BUT, I haven't run anything else, either.
Thanks for the explanation. Between the information I've received and the voltage drop calculator link I have a better understanding.
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