Renting A Portable Generator? What You Should Know ...

By Eric Morse, Two Rivers Marketing | September 28, 2010

When renting a generator there are many things to keep in mind. Portable generators come in all shapes and sizes with all kinds of bells and whistles. How do you cut through the inflated claims and unnecessary options some generator manufacturers offer? Well, it's easier than you might think. Every contractor knows what is needed and what is not to get a job done, and the same is true with portable generators.

First, determine how powerful your generator has to be. Most portable generators available today run between 5 kilowatts to 2,000 kilowatts. An easy way to decide how much power you need is to take an inventory of what machines will be running off the power the generator will be providing. Next, add up the wattage of all the machines you will be using. Remember to calculate the extra wattage for the starting of electrical motors. Electrical motors require four to 10 times the normal running watts to start. Machines like space heaters and fan blowers have G-type motors in them. G-type motors may need four times their normal wattage to start up. L, M and N motors found in air compressors and water pumps may require 10 times their normal wattage to start up. Rental stores should have a chart showing the wattage for certain products. To get the most accurate reading, check the wattage required on the product label.

To find the most economical generator, add up the running wattage of all the machines and then add the starting wattage of the most powerful engine. Make sure you do not start more than one motor at a time. If this is not possible, add up the starting wattage of all the machines and this will give you more than enough power to run your machinery.

Even though you may only have the generator for a short time, it's a good idea not to run your machine too hard. Be sure to add 15-percent to 30-percent more kilowatts than you think you need to reduce the generator workload. This will also reduce downtime because you will be able to continue working instead of waiting for your generator to be serviced.

Next, make sure your rental store has a quality maintenance program. Reliability of equipment is usually proportional to how well it is taken care of. Most stores will offer some type of maintenance program. If a store does not maintain its own equipment, try to find a qualified mechanic who will. Components that should be checked include: cooling system, fuel system, fuel filter, air filter, air intake, exhaust system, oil, oil filter, and the bearings of your machine should always be properly lubricated.

Portable generators run on all types of fuel — diesel, gasoline, propane, and more. For construction applications diesel is suggested. Diesel can sit for long periods of time without losing its initial quality and in most cases also offers more power. The downside to diesel is that it is the most expensive fuel and can cost up to 10-percent more in construction applications.

When comparing generators you will see claims of long run time. This means low power output because the generator in most cases is not consuming as much fuel as high-power generators. High-power generators use a lot of fuel, but usually have fewer problems. However, the fuel filter in high-power generators can cause downtime because of their high consumption rates. Be sure to check the fuel filter often in high-power machines. Also you can improve fuel filter life by filtering the fuel before you put it in the generator's fuel tank. If you are using fuel from an on-site tank this would be a smart move to ensure the cleanliness of the fuel you are using.

Exciting new options are available on most generators. Warning lights for oil pressure and coolant temperature are recommended because they give information about the most critical liquids in the machine. The user has more options than ever when choosing a generator to rent.

Loud generators are less expensive. But is the cut in price worth the hassles? Loud generators cause problems with residents living near a construction site. For this reason, manufacturers have made generators quieter in recent years and more tolerable to work with. This is especially important in construction applications where noise is a sensitive issue. Most generators come with impressive mufflers that dramatically reduce noise pollution. If you are looking for a super quiet generator check to make sure you are renting a machine that is not less fuel efficient because of its noise-reduction equipment.

Keep in mind that renting a generator is a trade off — your needs versus the amount you want to pay for benefits. You have to choose between high and low kilowatts, power versus run time, generator motor size and fuel consumption, and finally cost versus noise. The best way to decide is to look at what generator can help you help your customers.

Information Provided By: Ingersoll Rand, Mocksville, North Carolina