15 Amp Power Cord

[John Padmore]

Since I bought my coach with nothing in it (except the 50 amp cord) I need to outfit it with various adaptors and a good 15 amp power cord to plug in while at home. I purchased a 50 to 30 and a 30 to 15 adaptor. I read somewhere that I will need a heavy duty 15 amp cord. Any recommendations? Thanks....


John

[Karl Welhart]

John,

I would be very careful about plugging into a 15amp service.  It must have good voltage and do not run more than a 30' extension (30am cord is best).  Before you plug in, make sure all the heavy loads are turned off.  This would include AC, electric hot water, charger (and inverter), and your frig...  Then, after you plug in to your 15amp service, you can only turn on the charger.  After you are fully charged, you may be able to turn on the frig, but watch carefully to your voltage.

[LarryNCarolynShirk]

John,

It is best to run out your 50 amp cord to plug in your adapters to the 15 amp receptacle.  If you can not reach the receptacle with the 50 amp cord, use the largest gauge cord available to reduce voltage loss.

Larry

[Joel Ashley]

John-

Karl is right about watching how many devices are on in this scenario.  If the batteries are fully charged, you can fudge a bit, and turn on the fridge to prep for a trip;  but watch it if you want to add electric-side hydronic heat for example, or turn on the microwave or something.  The longer the extension cord the more the voltage drop, which can damage some component induction motors on startup (they need 120 volts but are getting only 105, and burn up from working too hard).  I use a 25 ft. 12 guage from my 30 amp house RV outlet.  I have a big 30amp RV cord stored in the coach for campground situations if needed, but at home I don't use it, as the 12 guage is fine.  If I was going to put up guests overnight or longer in the coach by the house, I'd switch to the 30 amp extension so they'd have more household use.  

In my case I have a 30 to 15 adapter at the 30 amp house outlet, then the 12 guage cord with a 15 to 30 adapter at the female end, into which plugs a 15 inch yellow 30/50 pigtail, and the coach 50 amp cord goes into that.

If you are plugging into a 15 amp outlet at home, you can skip my first adapter of course.  I used to run a 14 guage cord, but after its high resistance resulted in a burned adapter once, I went out and got the much larger yellow 12 guage cord, and you should also.  The shorter you can go there the better... and less spendy, too... 6, 12, or 15 foot - whichever will minimally reach for you.  Bigger guage, shortest length = least resistance to easy current flow, less voltage drop, and a cool cord and adapters.  Be sure your adapters are high quality as well - don't skimp on price there.  Inevitably, those little black adapters are what will melt and fail.  That and the nifty handles are why I splurged on a nice 50/30 yellow pigtail last summer.

In my coach, I also set my Magnum inverter/charger panel for 15 amps to control things, but you may not have that option on your rig.

Joel

[Bill Sprague]

Sorry, I guess I should have mentioned that I only want to keep the batteries up....not run a bunch of appliances.

When you buy a cord for this, spend extra for one that says it is made with 14 gauge wire.  It will be imprinted on the cord itself.  That is typically what a house is wired with for 15 amp outlets.  Lowes, Home Depot, Ace and Tru-Value typically have them.  

If you plug in directly with adapters, your motorhome can fool you a little.  On mine, if the inverter/charger is set to defaults and the batteries have been used, the charger wants to start with about a 25 amp charge and tapers off over time.  Obviously that will trip the 15 amp breaker in the house.  On mine there is a choice on the inverter/charge control panel to tell it I have a 10 amp limit.

My prefered alternative when limited to 15 amps is to use a standard automotive charger hooked directly to the batteries.

[Bill Sprague]

I stored outs alongside the house for some time using adapters from 50A to 20A without any issues.  One does need to watch the amps pretty carefully though.  Fridge on propane if needed and HW heater off, and set power share on the inverter to 10 amps.  I could run one AC unit if needed along with lights so it wasn't all that bad.  Recently I had a 50A box installed which was much easier and cheaper than I had anticipated.

Dick,

I have too.  My point of using the charger directly to the house batteries is that you don't have to carefully watch the amps or the volts.

It is like indefinite Quartzsite style dry camping without the need to run the genset once a day.  Through the inverter, you can use everything at will except AC.  

Another place it works well is where the power is suspicious, like an old state park that was built for old travel trailers.   Instead of risking power spikes to the Beaver, the relatively cheap charger can take a hit and be sacrificed.

I have a friend that has a favorite scenic campground in Mexico where the power is terribly unreliable.  Rather than risk the circuitry in his rig, he uses an autoparts store charger direct to his battery.  

[John Padmore]

Dick, I plan to install a 50 amp box in the future. Can I just get a box on ebay (50 & 20 amp) and have it hard wired into the system? I don't see why not.

On another subject, my coach as 2 house batteries. Should it have 4? Thanks....

John

[Gerald Farris]

John,
If you are talking about wiring in a 50A box at your home for the coach, Yes you can get any weather proof 50A receptacle box and wire it into your home breaker box. You can purchase a 50A box at Home Depot for a little over $20 plus the breaker and wire.

As for batteries, your coach came with two 12V group 31 chassis batteries and four 6V golf cart batteries that were wired in series in pairs to produce 12V. If your coach only has two house batteries, they were probably changed to two 12V batteries (probably 8D), which is OK, but only if they are true deep cycle batteries. If you have two 12V cranking batteries, they will not last, or if you have two 6V golf cart batteries, you do not have enough capacity.

Gerald

[John Padmore]

Gerald, I believe they are 2-12v group 31 chassis batteries. They are definately not 8D - I know these from my boat. When I installed a 2500watt inverter on the boat I installed 4 - 6v golf cart batteries and had ample power. Looks like I will need to do that again.

Good to know Home Depot will have a 50 amp box. I will pick one up next week. Thanks.....

John

[Dick Simonis]

Dick, I plan to install a 50 amp box in the future. Can I just get a box on ebay (50 & 20 amp) and have it hard wired into the system? I don't see why not.

On another subject, my coach as 2 house batteries. Should it have 4? Thanks....

John

John, that's exactly where I got mine.  Looks just like an RV pedestal box with breaker and an outlet.  The location on the outside garage wall was right beside the 200 amp service entrance and I had an electrician come in and install  50 breaker, run the conduit, mount the box and wire it up.  Total cost for everything was ~$300.00.  In retrospect I would have gone with a bit more upscale box containing the additional 30A and 20A outlets for and additional $30.00 or so.

Be careful that you don't just get a 50 amp receptacle with no breakers as that will not meet code.  You need breakers at both the receptacle and in the panel.

[John Padmore]

Thanks Dick, good to know!

[Joel Ashley]

I know Bill recommended going up to a 14 guage cord, but my recommendation, as I stated previously here, is 12 guage.  My error was not mentioning that cords come in all colors and that just because it's yellow on the retailer's shelf doesn't mean it's 12 guage;  I've seen yellow 14's too.  Just look for the shortest 12 guage that will reach for your circumstance.  It should say 12/3 SPJT or some such nomenclature.

Both 14 and 12 guage (the smaller the guage number the larger the 3 copper wires inside) are rated 15 amps.  But the issue here is voltage drop, and the larger diameter 12 guage is more capable of carrying maximum voltage through to coach components over the same distance.  As I said, it was a 14 guage extension cord and cheaper black adapter that failed on me once before.  

I agree with Bill in that you should spend the $ for heavier duty, and enjoy knowing any circumstance is better covered.  I would just bump it up one more notch to a 12 guage.  

Joel

[Bill Sprague]

You don't need four expensive deep cycle batteries if you don't dry camp much.  If only you dry camp once or twice a year almost any battery will work.  You might run the genset more, but it is good for it's longevity.

[Steve Huber Co-Admin]

John,
You should check your inverter setting for battery capacity. With only 2 6V 200amp batteries hooked in series to get 12V, your inverter current capacity should be set to 200 amps. If you add 2 more 6V batteries in series and then parallel them to the existing 2, you will still have 12V but the current capacity then increases to 400 amps. Leaving the inverter set at 200 amp capacity will boil the batteries dry.
Steve

[Stan Simpson]

I have been watching this thread because we sold the house with the 30 amp outdoor receptacle, and need to install one at the new house. This time, the distance from the power cord bay to the outlet will be around 50 feet. Our 50 amp cord is 36 feet, and then we have an adapter that brings it to 30 amp that is about 3 feet long. Will a new 20 foot 30 amp adapter be sufficient, or will there be significant voltage drop?

Thank you for the help.

Stan