SMART IDEAS FOR YOUR BUSINESS
®
INDUSTRIAL BATTERY CHARGERS
FACT SHEET
Thousands of forklifts, golf carts and other electric
vehicles hum busily along in industrial or business
settings each day, quietly going about their daily work.
Forklifts are indispensable in today’s warehouses and
golf carts have traveled far from the course.
The battery chargers that power these electric vehicles
have been reliably charging batteries for decades,
practically unchanged since they were first introduced.
Durable and dependable, they are also not as efficient as
the new generation of chargers.
Upgrading your battery chargers can save your
organization thousands of kWh and hundreds of dollars a
year in electricity costs per charger—and Smart Ideas for
Your Business® incentives can help you make the upgrade.
BATTERY CHARGER BASICS
There are four primary types of battery charger
technology in use today: ferroresonant, silicon controlled
rectifier (SCR), a hybrid of the two and high frequency.
Tests have shown high-frequency chargers to be more
efficient than those built around the other technologies.1
Ferroresonant battery chargers are the workhorses of
industrial battery chargers. They have been charging
flooded lead-acid batteries for decades. “Ferro” chargers
supply a regulated output relatively independent of AC
input voltage fluctuations due to the special qualities of
ferroresonance. They operate without any advanced
electronics, making them durable and strong.
Ferroresonant chargers are also bulky and
unsophisticated. They can damage modern sealed
batteries like NiMH and Li Ion batteries.2 That’s where
silicon controlled rectifier (SCR) battery chargers come
in. SCRs charge NiMH, Li Ion batteries and flooded
lead-acid batteries. They use a standard transformer to
ComEd.com/BizIncentives
reduce the AC voltage input and a diode rectifier to
convert AC to DC. An SCR controls the charge output
current and can be interfaced with a microprocessor to
perform different charging profiles.
Overall, SCRs are slightly less efficient than ferro
chargers. Enter the hybrid battery charger, which uses
the best of both technologies, and improves efficiency.
Today, there’s an even more efficient battery charger.
High-frequency chargers (also known as switch mode,
MOSFET or IGBT3 chargers) offer improved energy
efficiency and are smaller and lighter than ferroresonant
and SCR.
1
Testing took place at PG&E Applied Technology Service laboratory, San Ramon, Calif., and
SCE Electric Vehicle Test Center in Pomona, Calif. Experimenters measured energy efficiency
on multiple chargers from each technology. 2009.
2
NiMH: nickel-metal hydride battery. Li Ion: lithium ion battery.
3
MOSFET: metal oxide semiconductor field effect transistor.
IGBT: insulated gate bipolar transistor.
HOW HIGH FREQUENCY CHARGERS MEASURE UP
Energy waste occurs in the battery and charger system in
three main areas: power conversion efficiency, charge
return and standby losses. Tests have shown that high
frequency battery chargers are more efficient overall4:
» Power conversion efficiency measures energy lost during
conversion from AC to DC: energy out of charger versus
energy into charger. High-frequency chargers attain
levels of 92 percent, while the other technologies are up
to seven points behind.
» Charge return (overcharge losses) measures energy out
of the battery versus energy into the battery.
Overcharging to some extent keeps batteries healthy,
but energy is wasted when it’s excessive. Again, the
high-frequency charger comes out on top.
» Standby losses occur when the charger is plugged in but
not charging. Like cell phone chargers, whenever they’re
plugged in, they are drawing power. In general, standby
losses for all chargers were minimal.
If your company is in the market for new or replacement
battery chargers, consider high-frequency chargers. With
ComEd’s Smart Ideas incentives, you can shorten your
payback while benefitting from this new technology.
4
Testing took place at PG&E Applied Technology Service laboratory, San Ramon, Calif., and
SCE Electric Vehicle Test Center in Pomona, Calif. Experimenters measured energy
efficiency on multiple chargers from each technology. 2009.
Smart Ideas® is funded by ComEd customers in compliance with Illinois Public act 95-0481.
© Commonwealth Edison Company, 2012
CONTACT US
For more information about Smart Ideas for Your
Business, including applications and incentive amounts,
visit www.ComEd.com/BizIncentives. You can also
reach us by phone at 888-806-2273 or email us at
SmartIdeasBiz@ComEd.com.