Lithium-ion batteries are quickly emerging as a popular engine-start system in the light-single helicopter market, replacing larger and heavier nickel cadmium or lead acid batteries in several new types.

True Blue Power, a subsidiary of Wichita-based general aviation avionics supplier Mid-Continent, has received a supplemental type certificate (STC) to install the 17.5Ah-rated TB17 battery in Robinson R44 light piston, says True Blue Power director Rick Slater

The same battery also will be used as the engine-start system for the Bell Helicopter 505, the light-single turbine that notched its first delivery on 7 March at Heli-Expo.

Another STC application is being reviewed by the US Federal Aviation Administration to install the TB17 battery in the Robinson R66, the established rival of the 505 in the light-single market, says Kurt Robinson, chief executive of the Hawthorne, California-based helicopter maker.

Helicopters are a natural fit for the advantages of the lithium ion battery. As a power source, True Blue Power advertises the TB17 as one-third the weight of a lead-acid battery in a highly weight-sensitive aircraft category. The higher power density and lower maintenance costs offset the main drawback, which is a typically higher acquisition price for lithium ion batteries compared to older products.

The STC and forward-fit approvals also suggest lithium-ion batteries are shedding a reputation for safety concerns, particularly in the wake of the three battery over-heating incidents involving Boeing 787-8s in 2013.

True Blue Power emphasises the inherent safety of the TB17 battery architecture, which uses commercial available, iron phosphate cells made by A123.

“We’re seeing now that people accept the fact that if you do it the right way it can be done safely,” Slater says.