http://www.dcvelocity.com/articles/20150716-the-allure-of-lithium-ion/

Earlier this year, the snack maker Mondelez bought li-ion batteries and battery management systems from Electrovaya for its Toronto DC, and the Norwegian wholesaler Europris reported that in a six-month trial, batteries from GNB Industrial Power "significantly" lowered its forklift fleet operating costs.

In Carlin's opinion, the fact that forklift manufacturers are hiring employees specifically to support lithium-ion and other new technologies suggests that they believe acceptance will grow. "I would expect that over the next five years, testing will continue, and as people become more confident in the overall benefits of the newer technologies, lithium-ion will be embraced as a major alternative to lead-acid," he says

An often-quoted 2013 report by Navigant Research estimated that li-ion batteries cost around $400 to $700 per kilowatt-hour, compared with $150 to $400/kwh for lead-acid batteries. Prices fluctuate, but currently, price differentials are "in the range of four to five times the cost of lead-acid when calculated on a watt-per-hour basis," estimates Steve Dues of Crown.