I rebuilt a i167 battery for 300 bucks.
 

So I bought a i167 with bad batteries and rebuilt it. Pretty easy and works perfectly now. Just soldered in 120 new 1.2v Sub C 3300 mAh Ni-mh batteries. I rode it 5 miles first day no problems and still had tons of battery left!

I posted a video on youtube about my repair if your curious. Search "Unbox Warehouse Segway"

Nice job!

I made my own battery welder from a lead acid battery, starter solenoid and cheap timer..works a treat.

I watched this video just before getting my new Segways, I know this was quite some time ago, but great work! I agree with you on the whole, "secret-sauce" bit and know that in the newer packs they're just 18650 Batteries wired in banks. Great job!