i did notice the 880 pack has more of a square connector rather then just the circular one but i dont think it will be much of an issue i could always cut it ane make it work.
The issue is pretty clear if you look at the connectors
Doesn't seem too bad to modify, but apparently it is possible to modify the standard female connector to fit the mj-880. I won't link to another forum, but I am sure your google skills are sufficient to search for modifying standard connector to fit mj-880.
i believe the y cable i would use to power both the headlight and tail light would take care of that
The only thing to watch out for is that the Y-cable has a reputation for using very thin wires - exactly what you do not want when you are running high current draw with a tail light and a double xm-l light.
Perhaps a better option though is to use a cable designed for the mj-880 which should have slightly thicker wires and comes with
Input: MJ-880 male connector.
Output 1: MJ-880 female connector, to be connected to MJ880 bike light or MJ-880 ext cable.
Output 2: Traditional magicshine female connector, could be connected to a tail light.
All you need then is to modify the female connector on your battery
Again a google search for mj880 y-cable should give you plenty of options
Now i have heard of these hobby chargers and thats my main concern is how to charge this pack once i mod it, but i have no clue how i would charge it, theres the pcb board for one and the 4 cells. Once i solder em in i will have to use the existing cord on the pack, any idea how to go about this?
Yep - that's how they are charged. What I did was cut the cord off the junk charger that came with the battery and put a suitable plug on the leads. I got a Turnigy Accucel 6 & could use either banana plugs or XT-60. I chose XT-60 because they can only go in with the correct polarity.
If you wanted to go fancy you could also wire in a balance lead & plug, but it should not be necessary with good quality cells like the panasonics.
A hobby charger needs a bit more care in use - you need to set both the voltage & the charge current, plus it has two good safety features - a timer and capacity limit which helps to stop overcharging cells in the event of a fault.