Confused about Converters

[DanielB]

I need a converter. It seems the Intellipower (I think that is the name) 9200 series is popular, the price is ok, and it has the built in stage charging brain thing.

What I don't get is this: Lets say I have a 30 amp plug on the trailer. Of what value would a 45 amp converter be over a 30 amp converter.

[wasagachris]

Apples and oranges Daniel. The 30 amp plug is 30 amps at 120VAC and the 45 amps from the converter is 12VDC.

[DanielB]

I get it.. So with a 30 amp 120VAC plugged into a converter, is there a maximum amps that can be produced from that input?

[wasagachris]

I'm not exactly sure but I think the converter will be connected to only 15amps on the 120VAC side and it will supply the maximum amps on the 12VDC side as is stated by the converter. I.E. 45amps=45amps, 60amps=60amps and so on.

[overlander63]

Maximum amps at 120 volts input would be about 10, putting out maximum 45 amps at 12 volts. Those are both maximum (short time) ratings.

[DanielB]

So if you plug in a 30 amp cord then you can have 30 amps input to the converter? Then could a 60 or 70 amp converter output that much from a 30 amp input?

So from a 30 amp input only 10 of those will be going to the Converter? and from that 10 the max output will be 45?

[Mexray]

Give Randy a call @ bestconverter.com - he'll give you the straight scoop - it's his business!

[DanielB]

I'm gonna do that. Thanks.

[Dwight]

Let's say you plug your RV into a 30 amp electrical supply and you only use 120 volt appliances. You're using available amps from the 30 amp electrical supply for whatever 120 volt appliances are running, but the converter is drawing almost 0 amps because you're not using any DC accessories. It will use a small amount for items like the LP gas leak detector, clocks or maybe an aisle light, but not enough to really affect the amperage you are plugged into.


Your RV converter is rated for a certain amperage i.e. 30 amps, 45 amps, 55 amps. In other words a 45 amp converter is capable of running 45 amps worth of 12 volt appliances in the RV. When your RV converter is working at its maximum capacity, which in this case is producing 45 amps for 12 volt appliances and accessories, it is drawing around 5 amps out of the 30 amps available from the campground electrical supply.


Let's say you're plugged in and you're using a couple of 12 volt overhead lights (2 amps) and a ceiling fan (4 amps). In this case your converter is drawing very little from the campgrounds 30 amp electrical supply. In another scenario let's say you're using a lot of 12 volt overhead lights (8 amps), you're running the furnace fan (11 amps), water pump (4 amps), 12-volt television (5 amps), range hood fan (2.5 amps), and the battery is being charged by the converter charger (3 amps). Now, when the converter is running close to its full capacity it draws the full 5 amps from the campgrounds 30 amps, leaving you with 25 amps for other 120 volt appliances and accessories. As you can see it's unlikely that all of this would be happening at one time. The bottom line is the converter amperage draw will fluctuate depending on the 12 volt demand placed on it.

[TG Twinkie]

In electrical systems there is a term called WATTS. When you take the voltage (ie 12 volts) and multiply it buy the current (ie 45 amps) you get 540 watts. This is the maximum amount of power that a 45 amp converter will be able to produce. Up to this point everything is on the 12 volt DC side of the system.
In order for your converter to produce the 540 watts of power it needs to be plugged into a 120 volt AC power source. The electrical demand (power required) to run the converter at full capacity will be 540 watts divided by 120 volts = 4.5 amps. Since the converter is not 100% efficient it will draw somewhere around 5.0 amps on the 120 volt AC side of the electrical system.
The original 12 volt systems in your trailer will not consume anywhere near the 540 watts that a 45 amp converter can provide. So it is more than sufficient for the original needs of the trailer.
If your trailer has Air Conditioning it will require a 30 amp service from your house power panel. This power is provided through a cord (called a shore power cord). The shore power cord must be rated for 30 amps. The shore power cord plugs into a special and specific type of receptacle with the appropriate matching plug on the shore power cord.
You trailer is wired for 120 volts AC (alternating current). Do not plug your trailer into a 220 volt power source.
Your shore power connection capacity is 3600 watts. 120 volts x 30 amps.

[DanielB]

I think I got the idea.. Watts=Volts x Amps

From a 30 amp shore plug available is 120x30=3,600 watts max
A converter output of 45 amps at 12v draws a max of 12 x 45 = 540 watts of the 3,600 available.

[garry]

You have it right.