power time of LP E6 Full charge Canon Battery in Plate?

does anyone tried the LP E^ battery bracket plate by ikan? how many hours does a fully charged battery of a LP E6 battery will last in BMCC?

I've heard anecdotally they provide 45-60 minutes worth of power

I'm interested in making use of my Canon batteries too, while waiting for my v mount gear to arrive.
Are there any issues with voltage with these batteries, and what solutions are people using for using the Canon batteries with BMC (other than Ikan)? I see adapters meant for monitors on ebay but they have different connectors.