By Rosalba O'Brien

SANTIAGO (Reuters) - Lithium Power, the latest company keen to capitalize on Chile's vast reserves of key battery ingredient lithium, is planning to start drilling by September and ramp up to commercial sales by 2020, the chief executive told Reuters.

The Australian-listed smallcap, which already has projects in Australia and Argentina, announced last week that it was forming a joint venture with local partners to develop the Maricunga project in northern Chile. Lithium Power is going to fund the development costs starting with a $2 million loan.

The project had been deliberately chosen for the regulatory classification for parts of it that allow for immediate exploitation, said Martin Holland, the chief executive of Lithium Power. Maricunga has an initial resource of 574,000 tonnes of lithium carbonate.

"We expect to look at doubling that resource in the upcoming drilling program that we're doing in September," said Holland in an interview on Monday.

Foreign investors are flocking to South America's so-called 'lithium triangle', a region of brine lakes home to over half of the world's resources of the mineral that powers the rechargeable batteries used by electric cars and consumer devices.

Lithium Power's project is in the triangle, near assets that state copper firm Codelco [COBRE.UL] also wants to develop.

The Australian firm's local partner, a venture headed by Chilean businessman Martin Borda, has had "many discussions" with Codelco over the years, said Holland. He said he had also met a number of times with Chilean mining officials.

But he added that the company was unlikely to add more projects to its portfolio.

"We're pretty much done now, we feel like we've diversified across hard rock spodumene in Australia and quality brine assets in Argentina and Chile," he said. Hard rock is more expensive to mine, and "once supply meets demand in the'd rather be in the brine," he said.

(Reporting by Rosalba O'Brien; Editing by Diane Craft)