The battery pack itself takes a decent amount of time to fully charge (6-9 hours) pending how low the battery is when you begin charging.
With that being said, I had the fan inside the unit just to test the battery and after 14 hours the pack still had (2) of its (5) indicator lights on and could have ran for another 1-2 hours I’d say. Very happy with the performance of both and believe it will add a little help with the overall yield.
A friend of mine is letting me use the battery pack during my grow. Mentioned their father purchased it as a gift for them, but never mentioned from where or the cost associated. I circle back and if I can get any updates information I’ll let you know.