Quantum Instruments turbo sc battery pack

[Hopopotamus]

This is my first post on DPS so I'm not sure if this is the right place.
Friend of mine is selling Quantum turbo sc battery pack about 2 years old. I know that he used it for no more than 15-20 events only. He is videographer so his photo gear is collecting dust most of the time. I'm planing to use it on Canon 580EX II.
Here are the questions:
1. How many hours/photos can I take when it's fully charged?
2. How many charges can I expect from this battery pack?
3. Do you think 2 years is old for battery pack?
4. What is the cost of replacing the battery?
5. Do you think Cannon battery pack is better value?

I have no experience with battery packs in general so any info or opinion is appreciated.

[zona5101]

Hi and welcome!
I have an older Quantum Battery 1. it is probably 20+ years old and I bought it used. It still works like a champ...so durability is good. I have used it on as SB24 and now on an SB-600. Number of flashes is going to depend on the power output of the flash. "Hundreds" would be fairly accurate but beyond the quantity of flashes where it shines is in recycle time. The turbo is even faster than the Battery 1 in this regard. Quantum will replace the battery cell. You can go to their website and get a price. My Battery 1 is $60 iirc so the turbo is probably in that same ballpark. All that being said I only use it for events where I know I will be pounding out a lot of flashes, like weddings. Other than that it never sees much daylight as fresh batteries in the shoe mount flash do a fine job of keeping up and I don't have to deal with all the cabling and weight of the pack. ymmv.