RVs by themselves are pretty complicated. But there’s one more thing in RVs that confuses newbies quite a bit – it is the electrical service of the RV.
30 amperes, 50 amperes – what do these numbers even mean? How do you find out how much power you will need to run your RV’s appliances?
Let’s be fair, this isn’t a topic that is too easy to grasp, but once you wrap your head around it, things become pretty simple.
Today, in order to make you more proficient in the RV electrical stuff, we are going to overview what the 50-amp service even is. Then, we’ll dive deeper into power generators and will describe how to choose a proper one for your RV.
So, what size generator for 50 Amp RV? We would recommend a 4,000 watt generator at a minimum, but your requirements might differ based on how many appliances you’re using at any one time. If you’re running a microwave, TV, refrigerator, AC, while charging a laptop, you might find your wattage requirements are higher. Read on for more in-depth analysis.
What is a 50-amp service?
RVs with 50-amp service have a plug with 4 wires – two 120V wires, a ground wire, and a neutral wire. When you connect the plug to a power generator, you can draw either 120V or 240V (2 x 120V).
For some perspective, let’s have a look at 30-amp service as well. 30-amp service not only has a weaker amperage but also has a slightly different plug structure. A 30-amp plug has 3 wires – one 120V wire, one ground wire, and one neutral wire.
Now, what does this difference mean for power delivery?
One of the definitions of the ampere expresses it through the relationship amperage = wattage/voltage. With both 50-amp and 30-amp services, we know the amperage and the voltage (2 x 120V for the 50-amp and 120V for the 30-amp service). By rearranging the formula, we can calculate the maximum wattage for them.
So, the wattage of 50-amp service is going to be 50A x 2 x 120V, which is 12,000 watts. The wattage of 30-amp service is much lower- 30A x 120V = 3,600 watts. This is crucial for understanding what we are going to describe next.
Can you plug a 50-amp RV into a 30-amp power source?
Campgrounds very often have power sources prepared for RVers, but they mostly are rated at 30 amperes. So a common question among newbie RVers is whether or no they can power their 50-amp RV with a 30-amp power source.
Well, if you have an adapter, the answer is yes. But even with an adapter, you won’t be able to use the potential of your 50-amp service fully.
Remember the wattage of the 30-amp service? It was 3,600 watts. And if you have RV appliances with a total wattage of 12,000 watts, what do you think, is a 30-amp service going to deliver the required power?
Needless to say, the answer to this question is no. So when hooked to 30-amp service, you are severely limited to what kind of appliances you can use in your RV.
The circuit breakers on most campgrounds are designed with a tolerance of plus/minus 20%. With such tolerance, it would take between 2,880 watts (80% of 3,600 watts) and 4,320 watts (120% of 3,600 watts) to trip the breaker.
What this means is that at campgrounds with 30-amp service, you shouldn’t forget that you can’t use all the potential of your RV’s electrical system. Plus, if there are other people hooked up to the campground’s service, you will be getting less power than 2,880 – 4,320 watts.
So no matter how much you need all of your appliances, you will have to run them one by one (or alternatively in small groups) in order not to destroy the campground’s electrical system.
What size generator for 50-amp RV to go for?
Now, we’ve determined that 50-amp service can work with up to around 12,000 watts. But does this mean that you need to buy a 12,000W power generator? No, you don’t necessarily need to buy such a powerful unit.
The required power of your generator will depend on the kind and number of electrical devices in your RV. Plus, whether you will be using them all simultaneously is going to also matter.
For some perspective, let’s have a look at the following chart made by Honda:
|Appliance||Starting wattage||Running wattage|
|Microwave oven, 650/800/1,000W||1,000/1,300/1,500||1,000/1,300/1,500|
|RV air conditioner:|
These are some general numbers just for reference, and you shouldn’t completely rely on them when choosing the best generator for your RV. You will need to consider the starting and running wattage of the equipment that will be actually running in your RV. Instead, we will use these figures to explain a couple of key things.
How to choose proper generator wattage?
Before going forward, we think we should clarify this starting and running wattage thing. This confuses a lot of newbies out there, and you should understand what the difference between them is.
Equipment almost always consumes much more power at startup than when running. Electric appliances need a lot of energy to start up, which is why startup wattage is higher than running wattage.
This is a thing that you will need to consider when choosing a power generator. Even though the appliances won’t need as much power when running, your generator must be able to provide the necessary startup wattage to your appliances in order to turn them on.
This is why buyers are advised to base their decision more on the startup wattage rather than on the running wattage.
Now, let’s get back to choosing generator wattage.
Some people may think that to know the necessary generator wattage, you just need to add up the wattages of the equipment that your RV has. This is one way of going about choosing a power generator, but it is extremely inefficient.
Let’s consider the following example. Suppose your RV has these appliances:
|Appliance||Starting wattage||Running wattage|
|Microwave oven, 650W||1,000||1,000|
|Flat 46 inch TV||190||190|
|11,000BTU air conditioner||1,600||1,010|
Now, it would make sense to just add up the starting and running wattages and get the minimum power rating that your generator should have. In this example, if we were to simply add up the numbers, we’d get about 3,840W starting wattage and about 2,830W running wattage.
This isn’t too much, so it actually may be feasible to just get a 4,000W power generator and not think about power optimization too much.
Now, what if you have a second AC unit with BTU of 15,000? Or what if you also want to buy a grill? Well, if we add their numbers to what we’ve just calculated, we’d get 8,790W starting wattage and 6,480W running wattage.
These numbers are much more serious. A generator with such power ratings would be much more expensive, bulky, and costlier to run than a 4,000W generator. You may even be unable to find a generator with such a rating and be forced to run a two-generator setup, which isn’t always the best option in terms of space and noise.
So what could you do in order to optimize your RV’s power consumption and get a more reasonable generator for a better price?
You’ve probably noticed that when we calculated the starting and running wattages, we basically assumed that all of the appliances are started up and running simultaneously. However, this isn’t a thing that actually happens a lot when RVing.
Think about it, are you going to run your microwave all day? Or the laptop? Heck, the only thing that you will be running all day will probably be the RV refrigerator! And thanks to this, you may be able to go for a much cheaper and more compact generator than you would if you based your decision on the plain total of your stuff’s power draw.
So, to make a more efficient decision, you would need to approach the issue more intelligently
Let’s suppose that you absolutely need to run your RV’s refrigerator and AC unit at all times. As for the rest of the equipment, you don’t really need them all the time, so you can use them only when necessary.
First of all, you will need to consider the starting wattage of your appliances. It is more efficient to start up appliances one at a time. So, unless you need to for some reason start multiple appliances at once, take the appliance that has the highest startup wattage.
In our case, it is the AC unit with its 1,600 watts of startup power. If your generator has 1,600 watts of power, it will be able to start up any appliance one at a time. It will even be able to give power to start up multiple less powerful appliances, but it won’t start up the AC and the refrigerator simultaneously.
At the same time, when running, your AC and refrigerator will consume around 1,190 watts, so a 1,600W generator is more than enough to also run them. However, if their combined running wattage was more than 1,600 watts, you would need to get a beefier generator.
In our case, 1,600 watts still wouldn’t be enough to start any of the other devices, even one by one. We need to do some adjustments to our calculations to do so.
Among the appliances that are left, find which one consumes the most power at startup. In our case, it is the microwave. If your generator can start it while the AC and the refrigerator are running, then you will be able to start any of the other appliances one at a time or even in a bunch.
If you will be starting the microwave up while the AC and refrigerator are already running, you will need 1,190W (the combined running wattage of the AC and the refrigerator) plus 1,000W (startup wattage of the microwave), which is 2,190W.
So, in order to make the described configuration work, you would need to have a 2,2KW power generator.
If you have a generator that delivers these figures, you can technically run your AC unit & refrigerator with anything else. With the remaining power, you could start and run the microwave. Or use your laptop. There would even be enough power left to run your TV, satellite receiver, and laptop simultaneously!
Of course, when calculating wattage, you would need to consider the wattage of your appliances, in what sequence you will be starting them, and how many of them will be running at the same time.
Leaving extra room for appliances
In our last example, we figured that the generator must have a wattage of 2,2KW. While this technically is enough to run your configuration, you should get a generator that can deliver more than that.
There is this thing called a power spike. And when it happens, the power draw of your equipment can suddenly jump up. And if your generator isn’t able to provide the appliances with power at this moment, its circuit breaker will trip.
You can go and restart everything, but a better option would be to have a generator with some spare power. We’d recommend you to have a spare 500 watts in your generator.
Parallel generator operation
Did you know that you can connect several generators with each other to receive more power? Well, this is a thing that can be very useful for RVs with 50-amp service since it’s pretty difficult to make use of their full potential with just one generator.
If you find that you do need more than one generator to satisfy your power requirements, then look for generators that support parallel connection. Otherwise, they just won’t work with each other. Plus, keep in mind that usually, no more than two generators of the same model can be run in parallel.
Not all generators are made equal. And when choosing one, you should make sure that it has a 50-amp receptacle on its output panel. Otherwise, you will have to get an adapter to be able to hook your RV’s 50-amp plug into whatever your power generator has.
Now that you hopefully understand what 50-amp service is and how to read wattage, you should be able to pick the right power generator for your needs. Remember to follow our guidelines, do the research to find out how much power your appliances need, and make a proper choice.