Designed as a supplemental power source, super capacitors like this KAPower unit extend battery life and are particularly helpful in extremely cold temperatures. Photo: Kold-Ban International


Even low-tech batteries last longer with proper maintenance.

Most batteries last three to four years, but some absorbed glass mat (AGM) batteries can last twice that long.

Dirt and corrosion can create a circuit that allows a battery to slowly discharge, and corroded terminals also drain batteries. To keep either from happening, brush disassembled posts and terminals with a baking soda paste and then flush thoroughly.

Temperature extremes shorten battery life. Too much heat can cook the water in the electrolyte out of a battery.

Be careful to avoid overcharging. Smart chargers use computer chips to measure state-of-charge and cut back amperage to avoid overheating.


Adding power takes more effort than just plugging in.

Capacitors offer undeniable benefits in terms of power capacity, quick charging, and cold-weather reliability. But do your homework before investing in the new equipment.

“If you make the move to capacitors, you have to have the right infrastructure in place,” says Bruce Purkey, owner of Purkey's Fleet Electric in Rogers, Ark., and a member of the American Trucking Associations' Technology and Maintenance Council.

Although capacitors can discharge as much power as four batteries, they require different maintenance than flooded cell or absorbed glass mat (AGM) batteries. “You can't just buy a capacitor and expect it to take care of itself,” Purkey warns, “or you'll end up with a very expensive boat anchor.” He advises taking the following steps:

  • Ask the right questions. What's the right size capacitor for your operation? Does the capacitor need to be charged or discharged when not in use? Does the manufacturer offer testing equipment?
  • Understand the warranty. Some manufacturers claim their capacitors will last up to 20 years but offer far shorter warranties. Be sure to follow proper procedures in case you need to meet the terms of a warranty. “You can't assume it won't fail,” says Purkey.
  • Invest in an electronic package. Ask your supplier what additional equipment you'll need to charge the capacitor, disconnect it from a battery, protect it from discharging, and test it.
  • Provide training. Be sure operators know how capacitors differ from traditional batteries; and how to charge, discharge, maintain, and test them.