| Just when I thought we thoroughly covered RV | | | | of 12 volt overhead lights (2 amps) and a ceiling fan (4 |
| electrical systems I get another good question about | | | | amps). In this case your converter is drawing very little |
| something I failed to discuss in my previous articles. I | | | | from the campgrounds 30 amp electrical supply. In |
| received one of these good questions the other day | | | | another scenario let's say you're using a lot of 12 volt |
| and thought there would be many other RVers who | | | | overhead lights (8 amps), you're running the furnace |
| would like to hear the answer. | | | | fan (11 amps), water pump (4 amps), 12-volt television |
| Question: In one of your previous articles you list the | | | | (5 amps), range hood fan (2.5 amps), and the battery |
| RV converter as drawing 5 amps. Since, I believe, the | | | | is being charged by the converter charger (3 amps). |
| converter is operating any time you plug into a 120 volt | | | | Now, when the converter is running close to its full |
| AC system (30 Amp), does this mean that in reality | | | | capacity it draws the full 5 amps from the |
| you only have 25 amps to work with (30 minus 5 = 25, | | | | campgrounds 30 amps, leaving you with 25 amps for |
| and not considering clock draws, etc.)? I am developing | | | | other 120 volt appliances and accessories. As you can |
| an electric amp chart to hang inside a cabinet and I | | | | see it's unlikely that all of this would be happening at |
| need to resolve this question as this would make a | | | | one time. The bottom line is the converter amperage |
| significant difference. | | | | draw will fluctuate depending on the 12 volt demand |
| First of all let's talk briefly about what your RV | | | | placed on it. |
| converter does. When you plug your RV into an | | | | Another question I was asked was; I know my |
| electrical source, or when you use the onboard | | | | converter is also a battery charger so why won't it |
| generator, the converters job is to reduce 120 volts | | | | bring my discharged batteries back to a full charge? |
| AC down to 12 volt DC to supply power to all of the | | | | RV converters do provide a charge to your RV house |
| 12 volt appliances and accessories in the RV. If you | | | | batteries, but only a small portion of the converters |
| weren't plugged into an electrical source your RV | | | | amperage rating is used for this. Normally 3 to 5 amps, |
| battery(s) would supply the power to all of the 12 volt | | | | which are not nearly enough to charge batteries that |
| appliances and accessories in the RV. The converter | | | | are discharged. |
| basically prevents your RV battery(s) from draining | | | | The converter battery charger is designed to keep the |
| when you're plugged in. | | | | house batteries topped off with this trickle charge. |
| There are two types of amperage draw concerning | | | | Another problem with older RV converters is they |
| your RV. The AC amps we are using and the DC | | | | charge at a fixed voltage in the range of 13.5 volts. If |
| amps we are using. I'll try to explain. When you plug | | | | your batteries are fully charged this can be too much |
| your RV into an electrical source and use 120 volt | | | | for a float charge and over time it will deplete the |
| appliances like the roof air conditioner, the microwave | | | | water level in the batteries cells. This is why it's |
| and a TV you are drawing amps from the available | | | | important to check the water level in your batteries on |
| supply at the campground, usually 30 or 50 amps | | | | a regular basis, especially when you leave the RV |
| depending on your RV electrical system and the | | | | plugged in for extended periods of time. You need a |
| electrical supply you are plugged into. When you're | | | | three stage charger that can provide a bulk charge |
| plugged into an electrical source and you use DC | | | | then an absorption charge and finally a float charge. |
| appliances and accessories like fans, lights, pumps or | | | | Newer RV converters on the market are capable of |
| the TV antenna booster you are drawing amps from | | | | charging the batteries this way. |
| the converter. Are you more confused now than | | | | Now, to help you out with your amp chart I am |
| when we started? Let's try wording this a little | | | | including some typical amperage draws for appliances |
| different. | | | | and accessories commonly used in RV's. Keep in mind |
| Let's say you plug your RV into a 30 amp electrical | | | | I'm not an expert on electricity by any stretch of the |
| supply and you only use 120 volt appliances. You're | | | | imagination. This is just a basic guide to assist you in |
| using available amps from the 30 amp electrical supply | | | | how many amps you are using at any given time. If |
| for whatever 120 volt appliances are running, but the | | | | you need to know exact amperage ratings you can |
| converter is drawing almost 0 amps because you're | | | | check the data plate on any motors, appliances or |
| not using any DC accessories. It will use a small | | | | electronic equipment you are using. If you can't locate |
| amount for items like the LP gas leak detector, clocks | | | | a data plate with this information check the appliance |
| or maybe an aisle light, but not enough to really affect | | | | or electronic equipment owner's manual. This |
| the amperage you are plugged into. | | | | information might provide wattage requirements rather |
| Your RV converter is rated for a certain amperage i.e. | | | | than amps. Here are a couple of simple formulas to |
| 30 amps, 45 amps, 55 amps. In other words a 45 amp | | | | help you convert some common electrical terms. |
| converter is capable of running 45 amps worth of 12 | | | | Wattage % Volts = Amps |
| volt appliances in the RV. When your RV converter is | | | | Amps X Volts = Wattage |
| working at its maximum capacity, which in this case is | | | | One other thing to keep in mind is many RV appliances |
| producing 45 amps for 12 volt appliances and | | | | require more amps to start the appliance than they do |
| accessories, it is drawing around 5 amps out of the 30 | | | | to run the appliance. A roof air conditioner can draw 16 |
| amps available from the campground electrical supply. | | | | amps to start, but may only use 13 amps once it is |
| Let's say you're plugged in and you're using a couple | | | | running. |