On the Wash Front - June 2009

Hydraulic vs. Electric —
There are Pros and Cons in Either Approach
By Anthony Analetto

Sometime around 1940, electric-drive conveyorized car wash equipment hit the market. Sometime in the mid 1970s, the industry shifted to hydraulically driven motors. Now, every other day or so, I get asked the question, “Which is better, electric or hydraulic drive?” It brings to mind the classic joke — “Why did the chicken cross the road?” My favorite answer has always been, “To get to the other side.” But just like car washing, there are many responses that can make a straightforward proposition more complex. Before going down the path of deciding between exclusively using either electric or hydraulic drive components, first define what it is you need to find on the other side of the road to maximize the profitability of your business. The choice may just be a means to an end, but it’s no joke.

As with most engaging arguments, both sides have their pros and cons. However, in consideration of hydraulic vs. electric use in a conveyorized car wash, the strengths and weaknesses change as different variables enter the picture. Although this makes for a lively debate or discussion, it’s often confusing when trying to select the best equipment for your car wash business. So, let’s take “best” to mean the solution that delivers the highest quality product, at the lowest possible cost, with the least maintenance and greatest reliability — and examine the choices.


The first tunnel car wash that my dad built had an electric drive conveyor, wraps, side brushes, and wheel brushes. These were still the days when a brush was simply called a brush and the only computer managing the wash was its owner. Needless to say, this wash also predated today’s advanced Variable Frequency Drive (VFD) motor controls, sealant technology, and other engineering improvements that make electric-drive technology relevant to the modern car wash operator.

Our back room was stocked with spare electric motors, sprockets and chain. The ratios of the gearboxes were limited, so different size sprockets, and torque convertors were used to set the speed of the equipment. At 17 years of age, commuting to my local college, I would often remove and replace a motor between 6:30 and 7:30 am, go to class, drop off that motor and pick up the one that had just been rewound before returning to the wash. If you ever have a chance to visit the Henry Ford museum in Naples FL, you’ll see a fully operational machine shop from the early 20th century. One main electric motor is driving many pieces of equipment via an ingenious series of leather belts and pulleys. Speed was adjusted by moving the belt to a larger or smaller pulley. Seeing the whole thing run reminds me a lot of the early electric car wash equipment.

I know some of you veterans may be laughing at your own memories right now, but these early wash systems really highlighted the underlying truth that electricity and water just don’t mix well. With the introduction of hydraulic motors to the car wash industry in the early 1970s, operators began converting to the then new technology in droves. A single hydraulic power pack could be located in the equipment room away from the wet environment. This configuration was more reliable, easier to maintain, and improved the safety of the wash. One power pack could be sized to drive multiple pieces of equipment at different speeds with the ability to adjust them with the turn of a knob. Toss in the fact that the initial purchase price of a hydraulically driven component is normally less than a comparable electric-drive component and it’s no wonder that to this day, hydraulic is still the preferred technology for most car wash operators.


If hydraulic were perfect, there would be no debate. The first drawback is energy loss. As a rule of thumb, it takes 1.5 horsepower from an electric motor running a hydraulic power pack to deliver 1 horsepower of energy to a hydraulic motor. Second, hydraulic motors can leak oil into the surrounding environment when not properly maintained. Although water-based hydraulic fluids in part nullify the latter weakness, the energy loss issue is an inescapable fact. Until recently, the additional electrical cost of hydraulic motors was relatively minor and easily justified by their lower purchase and replacement price. The new reality is that utility prices are rising, dramatically in some areas. Another consideration is that many municipalities have imposed escalating impact fees for larger electrical service capacity. That means that if a location is able to run the wash with a smaller incoming service by using electric instead of hydraulic, there is a potential savings not only on monthly consumption, but also on the service connection itself.


What’s spurring the comeback of electric drive components to the car wash? Mainly the dropping prices of variable frequency drive (VFD) technology. These drives allow us to adjust the rotational speed of the motor driving the gear box which directly adjusts the speed of the brush, conveyor, or dryer without changing gears or belts in a way that’s reminiscent of equipment in the Henry Ford museum. When combined with rising utility costs, VFDs, once too expensive for the car wash industry, are becoming increasingly popular. There are also a growing number of motor gearbox combinations that are IP 66 rated. These sealed components feature windings that are coated in an epoxy, urethane, or double varnish that makes them much less susceptible to shorting out the motor.

Based on some research with these manufacturers and a number of customers using electric drive components, the greatest risk remaining, and most prevalent source of failure, is at the point of connection. No amount of technology can eliminate the fact that water and electricity don’t mix well. Despite tremendous advancements, the harsh environment of a tunnel car wash seems determined to help water wear down a path to sensitive electrical components. Constant motion, varied detergents, and drastic temperature fluctuations continue to frustrate many attempts to prevent water intrusion, so the number of short circuits and problems remain significant.


There’s no question that those of us with long memories and livelihoods in this industry have a natural tendency to shy away from placing electric motors in our tunnels. That said, there’s more benefit to using today’s VFD-controlled electric drive components than a slightly reduced monthly electric bill. The other side of electric-drive energy efficiency is an overall reduction in electrical requirements of the entire site. There are many reasons to add wash equipment to a tunnel after its original construction. Whether you’re looking to eliminate labor or improve wash performance and consistency, often the first barrier to adding equipment is that many locations are already at capacity for the electric service in the building. Rather than upgrade the service, it is sometimes more economical to convert some items to electric drive to free up service for the additional components.

Additionally, this is also a popular path for the increasingly common conversions of in-bay automatics to mini-exterior tunnels. It’s often possible to drive all the new tunnel equipment electrically with the existing electrical service. This allows the operator to modify their business model with minimum cost and plan the next expansion when it is affordable.


Although a true admirer of the engineering advancements and potential of using electric-drive components in a conveyorized wash, I’ll never be able to escape the belief that what can go wrong, will go wrong. To me, the risk of using electricity at a car wash goes up as you get closer to the ground. I believe it’s nearly inevitable that one day the conveyor pit will not drain correctly —and there is no reasonably priced electric motor that I know of that will survive complete submersion. For operators looking to add equipment without increasing their electrical service, VFDs offer a great opportunity; just make sure you plan for additional training. Being able to keep your car wash open for business demands having the ability to perform routine maintenance and make emergency repairs. Working with three phase electric power in a wet environment presents real risks and liabilities. It should be done by a licensed electrician or certified personnel. At 17, I was very well trained, but I’m not sure that I would let my own son do what I used to do without an actual license. I would, however, keep the back room stocked with spare motors.

Good luck, and good washing!

Anthony Analetto has over 26 years experience in the car wash business and is the president of SONNY’S The Car Wash Factory’s Equipment Division. Before coming to SONNY’S, Anthony was the director of operations for a 74-location national car wash chain. Anthony can be reached at (800) 327-8723 x 104 or at AAnaletto@SonnysDirect.com.

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