Solar panel technology developer has another $5.2 million in the bank after hitting a benchmark in its technology development.

The Charlotte-based developer of photovoltaic modules and so-called “thin film” solar panel systems said Wednesday it had produced cells that delivered higher sunlight-to-electricity conversion efficiencies.

The benchmark of 7 percent under testing conditions triggered a $5.2 million investment from The Quercus Trust and Michael Draper of Equinox Securities.

“The efficiency target was a critical milestone that demonstrates the viability of the Viper(TM) manufacturing platform for low cost solar panel production," said Sencera Chief Executive Officer Rusty Jewett.

In September, Sencera said it had closed on $15.6 million, with $10.4 million to be received as technology milestones were hit. The initial funds are to be used to build its first factory, which will be in Charlotte.

Funds also will be used for development of modules based on microcrystalline silicon.

Reducing production costs is a challenge for the emerging solar power industry.

The new funding follows $3.6 million that the company secured from Quercus Trust and Michael Draper of Equinox Securities. They also provided the additional funding.

Sencera was launched in 2003 with an initial focus on so-called thin-film transistor and integrated circuits.

The company hopes to employ 75 people by 2011.

In July, Sencera announced its plans for the plant with a pledge to invest more than $36 million over three years. The company received a $62,000 One North Carolina Fund grant along with local incentives.