High Efficiency, High Frequency Battery Chargers

Forklift battery chargers. (Courtesy: Maria Giorgio at flickr.com)
Forklift battery chargers.
(Courtesy: Maria Giorgio at flickr.com)

Keeping the battery charged on each forklift in your fleet is essential when it comes to efficient operation. Battery chargers are used to achieve this. Warehouse managers and forklift fleet managers understand that for the charging process to take place, the charger needs to match properly with the battery.

However, many charger experts point out that managers or fleet operators often choose the wrong charger and don’t know it. The purchased charger appears to charge the battery properly and the forklift operates for a full shift. But it is still possible that the charger being used is not providing the best charge.

The idea of selecting a charger in the past may have contributed to the problem of selecting the wrong charger today. Several years ago conventional charging was the most popular and affordable means of charging a battery. It was much easier back then to select the proper charger because the options were limited.

Silicon controlled rectifier chargers were the best option under some specific applications and ferroresonant chargers were the best option under other specific applications. People who needed to select a charger had only those two options.

Now there are many different charging alternatives and selecting the wrong option can affect the quality, length, and efficiency of the charge.

For example, a new charger technology to consider and that has been making headway in warehouse-forklift applications is high-efficiency, high frequency chargers. These devices feature a switch mode power conversion technology that permits switching at higher frequencies.  As a result, chargers are much smaller and weigh much less than chargers of the past. These chargers have lower transformer heating and power dissipation and thus perform a lot more efficiently.

Although it is true that conventional chargers and high-frequency chargers report high efficiencies greater than 90 percent, there are peak efficiencies measured at power levels greater than 60 percent. For conventional chargers that operate below 60 percent of rated power, especially during the latter stages of the charge cycle, the charging efficiency actually drops and reduces the overall charge efficiency to less than 90 percent.

The high-efficiency, high frequency chargers feature technology that includes improvements in the electronic circuit design and microprocessor controls. So these chargers feature a very high charge cycle efficiency of better than 90 percent and offer high efficiency over the entire charge cycle. As a result, there is a 6 percent or greater energy savings.

The high-efficiency, high frequency chargers cost more than conventional chargers. However, they can save as much as 4 percent to 5 percent of energy which means savings on energy costs. The savings in energy costs will more than pay for the higher cost of the charger.

Other factors that can influence your selection of chargers include:

·      Time needed to reach a full charge.
·      Equalize charge regime
·      AC voltage tolerance
·      Service support.

How these factors are affected depends on the operation of the forklift, the number of shifts the lift runs, the length of each shift, ambient temperature of the warehouse, local utility, and more.

The next time you’re in the market for new chargers and/or batteries consult with your local charger dealer or sales representative and seek his help in selecting the proper charger for your needs.