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Old 05-28-2020, 01:34 PM   #1
Grizzlyjim660
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Inverter help ?

I’m trying to install a 1600w inverter in my 2015 carbon m-31, i watched a video on YouTube and this guy simply went from the batteries to the inverter then took an extension cord made it to have 2 male ends on it then plugged one end into the inverter and the other end into any outlet in the RV, and it looked to be working.... my question is does that create a “loop” with the converter that charges the batteries ? And if so how can this be avoided ? Could the breakers on the converter be flipped off like the main and the a/c and leave the rest on ? Trying to figure this out without putting some kind of switch that i have read about but dont really understand. Thanks !!
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Old 05-28-2020, 01:42 PM   #2
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Yes, it works by creating a "feedback circuit" in the trailer. The converter will form a "continuous loop" that will be "charging the battery while drawing power from the battery" so the converter circuit breaker needs to be turned off.

The problem, one that can be deadly, is the male end has 120 VAC on the pins. Anyone who might unexpectedly unplug that extension cord could be electrocuted. Even if the "adults around the camper" are smart enough not to do it, the visiting toddler that happens to be following a butterfly into the passthrough could be killed by that type of "inappropriate electrical modification"...

I'd advise that if you're going to do it, just run the extension cord (with a male end and a female end) under the trailer and plug it into the shore power receptacle on the trailer. It's safer, prevents an electrical hazard and you still need to turn off the converter.
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Old 05-28-2020, 02:05 PM   #3
Grizzlyjim660
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So just flipping off the main converter breaker will stop the loop ? I would probably have to flip off the a/c as well but then everything else would work like all the outlets and microwave ?
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Old 05-28-2020, 02:49 PM   #4
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Essentially, it's that simple, but you'll need to do an assessment of what you want to power and what you want to not power. If your battery bank is not "extremely robust" (also defined as "nearly limitless) you'll also need to make sure the water heater electric element is turned off, the refrigerator is changed from AUTO to LPG (to prevent automatic switching to electric operation). As for the air conditioner, realize that if you don't set the thermostat to cool, the A/C won't come on.

Your microwave is a "power hog". At 900 watts@120 VAC, it is going to require roughly 75 amps of 12VDC to operate. Running the microwave for 1-2 minutes would deplete a GP24 battery to near the 50% limit, so use it sparingly !!!!!

Essentially, operating a 3000 watt transformer will require a multiple battery bank, I'd suspect somewhere around 4-6 GC2 golf cart batteries for an "overnight experience with microwave use for a bag of popcorn or to heat a meal.

The "problem" becomes, "How do I recharge the batteries every day" ???

If you're looking for a "modest, unsophisticated" way to watch TV and charge phones/devices, then a "small 150-300 watt transformer, located at the site of power need" is much more practical and SIGNIFICANTLY less expensive.

To operate a 3000 watt transformer on a battery bank will require an initial investment of several hundred dollars (think at least 500 for batteries alone) plus the cost of the inverter and "some means to recharge the batteries"... So, likely close to $1000 or maybe more for a 6 battery system, inverter and generator/solar to recharge the system. And, that cost is with the "cheapest HF or knockoff 2000 watt generator. If you choose to go with a Honda or Yamaha generator, you can expect to double that initial investment to somewhere slightly above the $2000 mark.
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Old 05-28-2020, 02:59 PM   #5
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Great !! Just so i fully understand .... if i flip off the MAIN breaker on the converter the rest will work ? I did purchase a “ suit case” portable 100 watt solar panel which I have yet to try, for charging during the day. I also have a onan generator onboard but am trying to lessen the use of it. I will be doing a lot of boon docking. Your advise and help is greatly appreciated !!!
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Old 05-28-2020, 03:24 PM   #6
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Originally Posted by Grizzlyjim660 View Post
Great !! Just so i fully understand .... if i flip off the MAIN breaker on the converter the rest will work ? I did purchase a “ suit case” portable 100 watt solar panel which I have yet to try, for charging during the day. I also have a onan generator onboard but am trying to lessen the use of it. I will be doing a lot of boon docking. Your advise and help is greatly appreciated !!!
I suggest you re-read John's post and do a lot more research. I don't think you are really getting the jest of what he's trying to explain. I may be wrong but from your replies I have a vision of a kid you call in the house, tell them not to play in the street and they nod their head say o.k. then bolt out the door and run into the street.
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Old 05-28-2020, 03:38 PM   #7
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First i don’t appreciate your sarcasm. But very much do appreciate Johns help !! To rephrase my question, if the MAIN breaker is flipped off does that prohibit ANY juice to flow through the RV ? I’m not an electrician, which is why I’m here asking questions. Thanks
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Old 05-28-2020, 04:03 PM   #8
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Originally Posted by Grizzlyjim660 View Post
First i don’t appreciate your sarcasm. But very much do appreciate Johns help !! To rephrase my question, if the MAIN breaker is flipped off does that prohibit ANY juice to flow through the RV ? I’m not an electrician, which is why I’m here asking questions. Thanks
For every suggestion John made you came back with basically the same response so it appeared to me that you weren't absorbing the information. I think you need to do some more research and find out how much energy you plan to use and how you plan to replenish it. A 100 watt solar panel may produce 100 watts on the equator with unobscured sky for a few hrs per day.

So let's say you use the microwave for 10 mins then most likely you will run out of daylight long before you replenish the stored energy (battery) used. The thing is, when dealing with electricity a mistake can be a deadly mistake. Get all the information and be safe. Asking the questions and learning is key.

If you don't understand that the main breaker Kills all the 120 vac power to the panel (just like in a house) then I think connecting an inverter and wiring it in will be beyond you comprehension at this time. It's a go from A to E and skip B,C &D.

Whatever your opinion of me I'd urge you take John's first advice and don't just rig a double male plug to "backfeed" electricity. That's like laying a loaded gun down in the pass thru.
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Old 05-28-2020, 04:09 PM   #9
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Quote:
Originally Posted by Grizzlyjim660 View Post
First i don’t appreciate your sarcasm. But very much do appreciate Johns help !! To rephrase my question, if the MAIN breaker is flipped off does that prohibit ANY juice to flow through the RV ? I’m not an electrician, which is why I’m here asking questions. Thanks
There are TWO electrical systems in every RV. The first is the 12 volt (battery system) and the other is the 120 volt (shore power/generator/inverter system).

The two are not interconnected, however the converter does provide both 12 volt power to the trailer systems AND charging power to the battery. The converter uses 120VAC to produce 12VDC for the trailer systems. Other than that "converter function" the two systems are not connected or inter-related.

If you turn off the "main breaker" you turn off all 120VAC to the trailer, stop the converter from operating and cause all 120VAC at the outlets, all appliances to stop functioning.

So, if you connect a 1600 watt inverter to the battery and plug the output into the trailer shore power connection, you'll be powering the entire trailer 120VAC system. Turn the main breaker to OFF and you stop powering everything in the trailer's 120VAC system. The battery would still be powering the inverter and the inverter output would still be going to the trailer shore power connector, into the trailer power center, but would not travel past the main breaker.

In previous posts, I attempted to explain that attempting to power your RV's 120VAC system with a 1600 watt inverter would require an extremely large battery bank, especially if you intend to operate the microwave. Operation of the microwave" will deplete a typical battery bank in one to two minutes of operation on high power. In other words, pop a bag of popcorn and you'll deplete the charge in a typical GP24 battery.

It's not going to be as "simple as buying an inverter and an extension cord to run it back to the trailer shore power connector. You'll need to consistently "turn off electrical items to prevent overloading your inverter and discharging your batteries. You'll need an extremely large (and equally heavy) multiple battery system to provide power, and even then, you'll need a reliable and "campground friendly" means to recharge the batteries every day after a "night of popcorn and TV"....
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Old 05-28-2020, 04:23 PM   #10
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Great thanks !!! That answers my question, and i have learned that using the microwave is not going to be An option. Also i appreciate the safety suggestions and will DEFINITELY not make that mistake. I was referencing a you tube video and that was used there.
I mainly wanted to use it for tv, dish, computer. Maybe a fan. And wanted to do this the least invasive and simplest way. Thank you again !!!
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Old 05-28-2020, 04:48 PM   #11
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If what you're wanting to operate on the inverter is, as you say, "tv, dish, computer. Maybe a fan." then you can do that very easily with a 300 watt "point of use" inverter. You'll need to run two "heavy gauge wires (I'd say 8 ga stranded cables) from the battery to the point of use. Connect them to the inverter and plug the TV/DISH into the two inverter outlets. If you want to use the fan or the computer, then unplug something to plug in something else.

An LED TV consumes about 80 watts,
A laptop consumes about 120 watts,
A DISH receiver/satellite consumes about 200 watts
A small 10" box fan consumes about 40 watts

So, your inverter would have 2 outlets and you can "pick and choose" between the 4 items above, 2 outlets, 2 items..... Easy LOL

Now, as for batteries, you'll need "AT LEAST" a pair of 6 volt GC2 golf cart batteries. That 100 watt solar system will, on a bright sunny day, replenish about 1/2 of what you use each night. On a cloudy day or if camped under trees, etc, even less replenishment. We carry a 2000 watt Champion generator with us when we "boondock" I've found that in northern Michigan, the sunshine is not as dependable as "regular unleaded".... with the generator and enough gas, we don't need to rely on the sun....
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Old 05-28-2020, 05:14 PM   #12
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The only benefit you get from backfeeding the converter output into your existing 120V network is the convenience of local outlets all over the rig. The risks of the practice far outweigh this.

You have to remember to shut down every item in the rig that eats too much power to run off the battery (if it didn't, it would have been DC already as a boondocking convenience). Miss one, kill your battery.

This includes anything you may have plugged into an outlet anywhere in the rig and forgot to unplug. Including the outdoor socket(s).

If you plug your backfeed into the "far" side of a GFI circuit, you lose electrocution protection.

You have to remember to shut off the converter loop and manually put your fridge on gas. Oops, don't forget the water heater.

You have to remember to disconnect the shunt cable before using shore power ("or else a large occurrence," as Dave Barry warns).

In short, you vastly multiply the risk of doing something you didn't want to do, with consequences ranging from a dead battery to a smoking cat.

If I were going to do this, I'd mount a very limited strip of inverter-powered AC outlets in a single place in the rig, and use that. That way, I could police exactly what was attached and know where my power is going. Also my daughter wouldn't absent-mindedly try to use her hairdryer when she was out of sight of everybody else in the shower.

My benchmark is that using the (DC) furnace for one night off the battery pretty much depletes it. There's simply not a lot of power to be had there.
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Old 05-28-2020, 05:58 PM   #13
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John's post #11 is your best option in my opinion. Some more food for thought ... anytime you go from 12vdc to 120vac there is a loss of power. The inverter is not 100% efficient. So if you have a cell phone charger that plugs into a standard "house outlet" and you charge your phone with the inverter it's a very inefficient method. You would be going from 12vdc to 120vac then the phone charger would take the 120vac and change it to 5vdc to match the USB on the phone. You would be much better off installing a 12vdc outlet with USB ports (like this https://www.amazon.com/Cigarette-Lig...e%2C148&sr=1-3 ) and plug in the phone with a USB cable. Laptops also run on a DC battery and some brands offer a 12vdc charger for the car.
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