Truck Topics

Power Your Truck

By Jeff Jensen, Editor
Posted Nov 21st 2006 1:11PM

trucking-inverter.jpgOn any given evening, in truck stops across North America, you'll find the driver relaxing in his cab or sleeper with many of the comforts of home. 

That includes his TV/DVD, microwave, coffee pot, crock pot, and the ever-present laptop computer, to name a few.  What do they have in common?  They all run on AC power. 

As a matter of fact, AC-driven appliances in all the latest colors can be found at any discount retailer, whereas the less powerful DC counterparts found in truck stops have been replaced by the home appliances that have migrated into the trucks.

The key to this evolution has been the acceptance of the inverter.  The inverter takes stored battery power and converts it to AC power to run appliances like TVs and coffee makers located in the sleeper cab. Inverting power from a battery bank is a quiet and environmentally friendly alternative to idling the engine to supply power to the cab.

Once a novelty, inverters are now mainstream over-the-road equipment. Expedited fleet owners use them as a recruiting incentive and to retain good drivers. Truck makers offer them as factory-installed options. Anti-idling laws and the hours-of-service rule have made them more practical.

Of course, drivers who use shore power hook-ups on a regular basis might not need an inverter. Or, the expediter who has made the investment in an APU or generator might not need an inverter. 

Those who have adequate 12VDC equipment (TV, radio, etc.,) and don't feel the need to run micro-wave ovens and similar AC items might not.

But for those who need/want to use microwaves, large TVs, VCRs, stereos, kitchen appliances and power tools, AC power is the only choice.  An inverter can actually pay for itself when used for these purposes.

What inverter do you need?
Many people base their buying decisions on power and price.  Unfortunately for many people, this simplistic approach to purchasing can lead to disappointment and frustration, usually because they undervalue quality or underestimate their AC loads.

When considering your inverter purchase, it's wise to keep some parameters in mind:

Output Power- measured in watts
You'll need to get an inverter capable of more than the max watts you'll use at one time.

Surge Power-
This should range from about 2 times output power to 6 times output power. You need this to start heavy loads, capacitor-start motors and the like.
 
Idle Current or No Load Power Drain-- An important figure if you'll leave it turned on (idling) so that it automatically delivers full power when an appliance is turned on. This can equal nearly 20 watts of 12-volt power in some brands. (20W at 12V = 1.7Amps). You don't want an idling/standby inverter to constantly drain over an amp-and-a half from your battery. Quality inverters draw only a fraction of an amp (as little as a tenth or much less, of an amp) at idle.

Efficiency- Is a critical figure. It should exceed 90% overall in [most] inverters. It should not vary much from partial to full loads. Beware of inverters that advertise 90+% overall efficiency but may drop to less than 50% at some load levels.

Ray Lawrence is the owner of Espar of Michigan in Romulus, Michigan.  His company represents the Tripp Lite line of inverters and power products, both for sales and installation.

He says, "Tripp Lite manufactures a full range of inverters from the little 300-watt models that plug into your cigarette lighter to the RV-style inverter/battery chargers - very elaborate systems."

"The models that we use and install most often are the 1000 watt model, an 1800 watt model and, on occasion, a 3000 watt model." 

"It's important to remember that an inverter is simply changing DC voltage to AC voltage.  That power has to come from the truck batteries, so we strongly recommend that a cargo van driver uses an auxiliary battery if he plans to use an inverter."

He tells us, "We've sold and installed a few of the 3000 watt models but it requires a lot of battery capacity and heavy-duty installation.  For most people's uses, an 1,800-watt inverter will do the job just fine."

He gives some power requirement examples:

13” Color TV                  80-100 watts

Laptop Computer           100 watts

Microwave oven             800-1000 watts

Coffeemaker                  1000 watts

Toaster oven                  1000 watts

Laser printer                   800 watts

*These power requirements are estimates.  Consult individual appliance info for accurate power requirements.

Can the inverter installation be performed by your average do-it-yourselfer? 

Lawrence says, yes, but... "We recommend that the inverter installation be performed by a professional because you're dealing with battery power.  In our installations, we use large-amperage fusing and wire looms to protect the wiring from chafing." 

"For a 1000-watt inverter, prices will range from $199-$329.  Installation will probably run around $200."

"You can find cheaper inverters in the truck stops or big-box stores, but these are (to be kind) not as robust as the Tripp Lite or major name brand."

Inverter Sources

Espar of Michigan
www.esparofmichigan.com
800.837.3900

Xantrex Technology
www.xantrex.com
408.987.6030

Black & Decker
www.theinvertorstore.com
888 417-8673