The argument for electric ground support equipment is pretty strong. The cost of the electricity to power a vehicle is about 25 percent of the cost of diesel fuel. And the total carbon footprint of the electric vehicle is about 15 percent of its diesel counterpart. This is why there has been so much attention given to electric vehicles and why they have become increasingly more common on the ramp, largely in the form of bag tugs and belt loaders. Ironically, not much attention has been given to the device that actually produces the electricity — the battery.
Today’s modern electric ground support equipment is typically powered by a lead-acid battery — a battery invented in the 1859. In simple terms, a lead-acid battery creates a chemical reaction between lead oxide and sulfuric acid to produce lead sulfate and electricity. That electricity then powers the vehicle’s electric motor. The process is then reversed, returning the battery to its original fully charged state. A high-quality, well-maintained battery can last well over five years and 1800 charge cycles.
Lead-acid: It’s Come a Long Way
Let’s give the lead-acid battery some credit. It’s the original rechargeable battery and it still today delivers the most power per dollar of any other battery technology. Fortunately, it has come a long way in the last 150 years and there are many variations and options:
Flat-plate batteries are the standard duty battery. They are the most economical of all the batteries and provide good performance and life.
Sealed “maintenance-free” batteries do not require water. They use a gelled electrolyte or sometimes a glass mat to absorb the electrolyte. This prevents the battery from losing hydrogen and oxygen during the charging process, and therefore eliminates the need to add water. However, they have a huge downside — they can cost twice as much and last half as long as a comparable “flooded” battery.
Tubular batteries use a tubular-shaped plate to create more surface area for the chemical reaction to take place. This provides more total power and better vehicle performance. These batteries also tend to provide better throughput and cycle life.
High-capacity batteries provide even more power in the same cubic space. This is a great choice for heavy-duty applications where a bigger “gas tank” is needed for higher-power consumption or longer run times. These batteries are not cheap. There is more cost for more kwh’s and often the price per kwh is higher, too.
Low-maintenance batteries require less-frequent watering. Labor savings can be significant, reducing the number of waterings from 50 times per year to 12, or even six times per year. Watering is the most important part of maintaining a battery, so making sure the battery always has sufficient water is critical. Anticipate longer life because the risk of damage from under-watering is minimized. This is a great choice for GSE.
Fast-charge batteries are built to handle the added current and heat generated by a fast-charging application. Typically, the battery’s conductors, such as cables and inter-cell connectors, are larger and the steel tray is vented for cooling airflow. These batteries may cost more or may have less power capacity, but they could be necessary. Too much heat kills a battery just like too little water.
In addition to choices of battery technology are choices of add-on options. Some are as simple and inexpensive as flip-top vent caps instead of the standard quarter-turn caps, or a water de-ionizer to filter out impurities. (The basic rule of thumb: If the water is good enough for a human, it’s good enough for a battery.)
Single-point watering system: This is a highly recommended option. The device installs on the battery and provides a single quick-connect fitting that plugs into your water supply. This allows a user to fill a battery in one minute instead of 30 minutes, and water each cell to exactly the perfect level. With proper watering being the most important thing maintenance personnel can do, this system should be on every battery.