It's so much easier to just take conventional 3s or 4s RC LiPo, zip tie or whatever to your starter(try that witha Ryobi battery) , charge it once in a while and fly. No cords, easy charge on your hobby charger(try that with a Ryobi battery), and go fly. Last I looked the Ryobi batts(I own 2 of them for my cordless tools) are $80 a pair. How many lipos can you buy for that? (Remember it only takes one for a starter).

For all that, just take a 7ah 12v hobby battery and use it... The Ryobi is 4ah... seriously in this day and age there's thousands of batteries to choose.. make it simple or make it hard. I'm glad the original poster made it simple. Wasn't that easy? Good luck with the new battery system.