New User bike light/flash light

Hi all I'm new to the forum I have a few cree torches and head torches but I'd say my knowledge is low. I've bought a cree light for my bike which is just a short flash light it has an 8.4v battery pack but its terribly low will last 30 mins it has 4x 18650 which are not branded all my others I use green samsung official ones. My question is i go for long rides so i need something to not last mins but hours. Is there any way I could get say 10 x 18650 but not exceed 8.4 and not fry my light.

Please feel free to be blunt I've got to learn somehow

Your solution can be met by looking into Exposure Lights rather than more batteries. I ve used em in the UK off and on road. I d recommend the Toro but there are others.

sure, you could wire 2s5p. ,

To be honest I understand I can switch but the light is incredibly light and the spread is exactly what I need its just terribly short battery life I actually wanted to run 3 lights off one big battery pack but I've searched for companies that could do it but it's just not something people do. I dont mind working hard to learn it myself but I just dont know where to start.

most likely your cells are complete garbage, also keep in mind to properly charge 2 or more li ion in series, like you have, you need either balance charger, or balance circuit in your battery pack, idk what light you got, but generic inexpensive lights sold all over e bay, amazon,,etc do not have either,