It is one of several external batteries I have. Why ask someone else? If you don't need it, you don't need it. Up to you whether to sell it. Personally, I need the fast recycling. I attach an external battery for the times I need that fast recycling, such as processionals, outdoor shots in bright sun, or dark receptions, where I am depending on bounced, almost full power flashes. If I don't need the fast recycling, I use the camera and flash without the battery.
I would infer that you are using it for a Canon flash. If that is the case I would suggest using the Canon battery pack. I used the Turbo, the Black Box, The Digital Camera Battery, the Turbo SC, the Dynalite Jackrabbit battery and then .... tried the Canon battery pack.
The battery pack was more reliable, gave terrific recycle and lasted seemingly forever with good 'aa' batteries.
when i use quantum turbo packs on canon 550 it goes all day. when i am shooting canon i have about four of those things available to me.
i know that one of them has an attitude and starts to falsely say that it has no charge.
plug it in for five minutes and its ready to rock for the rest of the day.
so, that one has a problem, but they are all old and i never see any other problems. i probably work with those guys a couple of times a month so i see that gear regularly.
I have owned the same Turbo battery for about 15 years and I is still going strong. It provides power to either my Metz 45CL or my Metz 54MZ, and greatly decreases recycle times. And when I was actively shooting weddings with film the battery would certainly be more than enough to make over 300+ exposures and still be ready for more. (I have not shot weddings professionally for a while, so I haven't tried out the greater shot demands of using digital.) On a cost per year basis, the price of buying it has made it dirt cheap.
