No worries wells, it’s actually a little bit difficult in the beginning. I fly quadcopters so I use them quite a lot. I would be lying if I tell that I didn’t have to read a lot to feel comfortable with the subject, I’m sure there’s still things that I don’t know
By the way, one of them is actually a LiPo (2500, note “Polymer” in the name) and another is a Li-ion (6600).
A rough calculation throws that
6600 should take around 8 hours at 1A
2500 should take about 3 hours at 1A
It’s long, but it is like that. If you get a charger that can do 3A, it will take about 3 hours to charger the 6600, don’t use this one with the 2500 as it is rated to be charged at 1.2A only, so the current charger is good enough.
If it’s taking you 10 hours for the 2500 make sure that your power source can provide a good 1A of current, better if you have it hooked to a 1.5-2A power source.