Battery energy storage company Prudent Energy takes its total raised since mid 2010 to $61.5m, lining up a large consortium of Asian and US venture firms after it picked up the assets of Canada-listed VRB Energy in 2009.

Mitsui yesterday led the latest $29.5m round raised by China and US-based battery energy storage company Prudent Energy, which has a technology used by clean energy companies.

The Japan-based conglomerate was joined by venture firms Vangoo Investment Partners, Idinvest Partners, Asia Clean Energy Limited and an unnamed Korean based strategic investment group. Venture capital firms Draper Fisher Jurvetson, DT Capital Partners, Northern Light Venture Capital and CEL Partners, all existing investors in Prudent Energy participated in the financing.

The company has raised $61.5m since mid-2010, although the amount raised for its first two rounds is not known. Mitsui Ventures, the corporate venturing division of Mitsui, also backed the company’s $32m series C round last year, which was also backed by Jafco Asia and many of the investors in the latest round. Other investors listed on Prudent Energy’s website are venture firms Sequoia Capital. The company’s chief executive is Johnson Chiang.

Prudent Energy in January 2009 acquired "all patents, trademarks, know-how, equipment, and bulk of material it owned or controlled" of VRB Power, a publicly traded company in Vancouver, Canada, sold, according to the company’s website. In November 2008 VRB Power had announced it was curtailing its operations.

Draper Fisher Jurvetson and DT Capital Partners were investors in Prudent Energy at the time of the VRB acquisition.

Prudent said the fundraising would be used to bring down the costs of delivering its energy storage systems and to increase its sales in Asia, Europe and North America.