September 2008, Work Truck - Feature
Can Neighborhood Electric Vehicles Work for Your Fleet?
By Mike Guardabascio & Chris Brown
How do I best maintain the batteries?
The greatest amount of maintenance, preventive or otherwise, involves the batteries.
There are two types of lead-acid batteries: flooded lead-acid (FLA) batteries and valve-regulated lead-acid (VRLA) batteries. The single biggest battery maintenance chore involves checking FLA batteries and "watering" them if fluid levels are low. This should be done weekly.
If they are not watered, FLA batteries will dry out and fail prematurely. VRLA batteries are sealed and require no watering, though they are a few hundred dollars more expensive.
Protective covering should be used when watering batteries. It should be done in an area that can contain any acid that may drip from the batteries during watering or when the batteries are charged.
Check for battery corrosion. A cleansing additive called Charge It dissolves the lead sulfate on the battery plates. Properly maintained batteries should provide at least a three-year battery life.
What other steps can I take to prevent premature battery failure?
Like all lead acid batteries, those in your NEV will hold a charge longer by using and recharging them regularly.
NEVs have a parasitic load that can drain the battery even when the vehicle is turned off. If the vehicle is not used frequently, this load can discharge the vehicle battery in less than two weeks to a "zero state of charge," and damage the battery.
Look to see if your NEV has a battery disconnect switch for times when the vehicle will be inoperable for more than a few days. Don’t leave batteries plugged in longer than necessary.
What other types of maintenance issues might I experience?
A 2006 government study of NEVs in fleets found these recurring problems:
- Onboard charger failure, especially for vehicles operated frequently and charged for extended periods every day. Many failed because of exposure to the environment.
- Motor controller failure.
- Motor overheating during missions that required high power for hill climbing or carrying heavy loads.
- DC-DC converter failure because of water splash to circuit board and fuse connections.
Any tips on charging?
For small NEV fleets, charging from a standard 120-volt convenience outlet is generally sufficient. However, large numbers of vehicles aggregated at the same location for charging can overload a circuit. Additional charging outlets are recommended at NEV parking locations.
- Buy a timer to charge on non-peak electricity grid hours.
- Make sure the charging cord is the proper gauge to prevent overheating.
- New batteries will likely not charge to full capacity until after 20-30 charge cycles.
- FLA batteries may have considerable gassing; therefore, it is recommended to charge outdoors. Gel-capped VRLA batteries do not need such ventilation.
- When charging outdoors, make sure you have an outdoor-safe outlet and plug that can withstand inclement weather as well as direct sunlight.
- Fast charging can provide an emergency backup when vehicles do not receive an overnight charge. Fast chargers recharge a battery pack at about a mile for every minute charged.