I don't think running at 5V would be a big deal. That's about as low as I go before I recharge my AAs. The only thing you may suffer is range. Might actually be a benefit as it will remain consistent. Not a bad idea.
I recently added an exterior antenna to mine too. Popped the stub off the top and fitted a piece of plastic with the SMA on it. Used a 5" Ufl/SMA whip that came with a wifi card. One day I'll get to a range test.
Looks like mine:
My range has improved significantly and not only that but the signal actually "goes through" objects better now. I flew to an area about 300 meters away behind some trees and shrubs usually my tx starts beeping and rssi drops to 0 and it'll failsafe but this time I was able to keep flying with rssi about 20-30%
Also using a 650 mah 3s battery it lasts like a month on a single charge! I'm loving these mods, should've done them years ago lol.
Yep we gotta mod these things they simply are not good enough as they are lol.
Regarding the jumper t16 pro ribbon cable issue there is a facebook group dedicated to the jumper t12/t16s and like every single problem people have is related to the ribbon cables. Seems like every time I turn mine on it needs to be opened up and cables need re-seating. Really sucks because now I can't use my crossfire module.
I've head the newer t18s went back to the jst connectors.
Liked it so much I had to have it.
Unfortunately only getting 4.88v. The manual says low voltage alarm is at 4.2 though so I think we're fine. Gonna keep my eye out for a 6v regulator though.
The 2S had a short in the balance lead, and worked out perfect after re-soldering & gluing.
Look for "adjustable buck converter" on any big online retailer and will find a little board with potentiometers (voltage output adjust knob) on it just check the input and output range, buck converters are more efficient than linear voltage regulator but typically the latter are much smaller since single chip.