Originally Posted by Jsheng
Someone said that as long as I use semi auto, or full auto but no longer than 5ish seconds, the gearbox will be fine. Others suggest to buy 7.4 lipo instead.
On 11.1V in semi-only you'll be okay for a short while but black deposits of carbon (I think?) start to form on the contacts pretty much from the very first shot, and continue to accumulate with every single shot. The Marui v2 contact design is really less than ideal for handling high voltage, high discharge situations.
To give you an idea of how quickly these deposits begin to form:
Last night I took down a team member's brand new
G&P C8 MRE to downgrade the spring/swap out the all-metal piston/shim/improve seal. The contacts were absolutely clean when I first opened it up. To do my initial tests after reassembling the gun, I grabbed the battery I had handy, a Turnigy 1300mAh, 11.1V 25-50C stick. Fired only a quarter of a mag of shots into the chronograph. Because the piston I had put in was too fat for the G&P gearbox, I had to open up the gearbox again. When I did, the contacts already had a nice layer of black stuff on them.
If you want to run an 11.1V battery in any gun you will require a MOSFET, which will enable you to have your main power bypass the trigger assembly altogether, and have only a very tiny current go through the contacts.