Let's talk about Generators!
What a fitting topic to talk about, post hurricane Beryl. How did everyone do? We just got our power at the house back on last night (7 days) and the shop on Friday (5 days). We can do a few topics on this, I suppose since there's so much to go over. Yes, I know, I do blogs every Monday on automotive stuff, but every once and a while, let's stray from that topic.
Ohms Law
I suppose the first thing we need to talk about is Ohms Law. Well, why? Because this is going to determine what size generator you need, and how much stuff you can run off of it.
Ohms law will let you figure out what wattage, voltage, and amperage is all about, and how to calculate them.
Example- I have a 3,000 watt/3500 watt surge generator. A typical small generator.
How many amps can I use? Well, the watts (3000) divided by 120v power (what comes out of the plug on your wall) equals 25 amps.
The surge (when a motor is started it pulls more amps then when it's running is 29 amps available.
So lets think about that in other ways. You look at your appliance/fridge/whatever and on the sticker it says it uses 10 amps. 120v x 10 amps is 1200 watts.
As long as you have 2 of the 3, you can calculate the other. This is important!
When it comes to bare minimum things you need to run, lets just think basics. In my opinion, the refrigerator is the only thing that really needs to be run when the power's out- you can go a long time without power if you can keep food cold and fresh. While the fridge is running, you can charge your batteries and phones up.
Perhaps (depending on the time of the year) a window unit a/c or a portable air conditioner may be another thing that most people would consider "essential".
To run a fridge and a window unit, you need to calculate the total wattage requirements of both appliances.
The Bare Bones:
Refrigerator:
- Average wattage: 300-500 watts
- Starting wattage (surge): 800-1600 watts
Window Air Conditioner:
- Average wattage: 500-1500 watts (depending on size)
- Starting wattage (surge): 1000-3000 watts
Combined Requirements:
- Total running wattage: 800-2000 watts
- Total starting wattage: 1800-4600 watts
Recommended Generator Size:
- A generator with a running wattage of at least 2500-3000 watts and a surge/starting wattage of 3500-4500 watts should be sufficient to handle both appliances simultaneously, if they both came on at the same time....
But this is just a general suggestion, not the rule.
领英推è
I'll give you an example on this, based off the generator I'm using and the fridge/window unit that was running on it.
The generator is an old Champion generator I picked up at a pawn shop because it didn't work. It was a project. It's rated for 3K watts/3.5K watts surge. It has a 20 amp plug on the front of it. More on this later.
I was running an LG portable air conditioner, that is 1270 watts running (unknown starting wattage) and a Whirlpool fridge that takes 1000 watts to start (remember, electric motors take a lot of power to start!) and 120 watts while running. I looked these up by the model number to find the specs on it.
So, in my case- the only thing I really needed to worry about was resistance- i.e. the quality of my extension cords. As resistance goes up (cheap/small/undersized extension cords) the amperage/wattage increases, causing additional strain on the load you're putting on the generator.
I would start the generator, get the fridge plugged in and running, then plug the air conditioner in and I had plenty of reserve power from the generator to run a fan or two + charge my electronics. Easy peasy. The generator didn't struggle to run, and only could be heard under load when one of them was turned on.
Running a House
When considering running an entire house, the generator size will depend on the specific appliances and systems you want to power. Here are the typical wattage requirements for common household appliances:
The problem with this is the variables on what size the house, appliances, and usage is. This is where you have to put into consideration of what is important to you. It also takes a little time to look at what you're going to use, and tally up the consumers to ensure that your generator is sufficient.
Common Household Appliances:
- Refrigerator: 600-800 watts
- Window Air Conditioner: 500-1500 watts
- Central Air Conditioner: 2000-4000 watts
- Electric Water Heater: 4000-4500 watts
- Microwave: 800-1200 watts
- Electric Stove: 2500-5000 watts
- Lights: 60-600 watts (depending on the number and type)
- Television: 100-400 watts
- Computer: 300-600 watts
Total Running Wattage: ~5700 watts Total Starting Wattage: ~10,000+ watts
You could get away with something as small as a 5 or 6K watt generator, or may need something that's 10-13K watts, depending on your needs.
What are your thoughts on this topic? I'll go over a few more things I think are relevant in the next few blogs.
If you need help with your generator, we may be able to help. We have an ultrasonic cleaner that cleans those little carburetors out really well- which is usually the issue with small engines that don't want to run right.
832-797-9114