BOULDER — A pair of venture-capital firms in Boulder have made a “sizeable” investment in SunTech Drive LLC, a Boulder-based clean-tech startup that has developed a new class of electronics for powering electric motors that pump water using off-grid solar power.

The controller systems are smaller and lighter than traditional controllers and use 50 percent less photovoltaic panel capacity than other controllers on the market, the company said, representing a 40 percent cost-savings for a solar project, making solar a cost-effective alternative to diesel in the off-grid market.

UPC Capital Ventures led the round with Highland Ventures Group participating.

The amount of the investment is a moving target. John Wallington, founder and managing director of UPC Capital Ventures, said the amount is dependent on a series of follow-up commitments.

UPC Capital Ventures is backed by Chicago-based UPC Energy Group, a global renewable-energy development company with wind and solar development operations around the world.

“We are excited to close this Colorado-based deal with SunTech Drive,” Wallington said. “The company captures the essence of the Boulder entrepreneurial spirit, a major reason we decided to open an office in the region. … The strong emphasis on the environment, sustainability and efficiency within the Boulder startup community makes for a unique investment environment.”

John LoPorto, SunTech Drive’s chief executive, said the new capital, combined with a $250,000 Advanced Industries grant received in December from the State of Colorado, “will have an immediate benefit to our existing operations allowing us to make necessary capital and personnel expenditures to accelerate development of our product line and distribution channels.”

SunTech Drive has had successful demonstrations domestically and internationally. It has a solar pond-aeration and water-pumping installation at Keeton Industries in Wellington. Overseas, the company has had successful demonstrations in India for aquaculture and agricultural solar-powered water pumping, which has led to orders for the product.

Other demonstration sites include a village-scale drinking water installation in Kenya, two other sites in Bangladesh and a solar water-pumping demonstration at an avocado farm in Chile.