no-solder swappable batteries. the gray battery is the original, the green is a panasonic $15.00, the purple ones are chinese 2 for $12.00. i soldered micro bullet connectors on the batteries and wires, just plug em in and go. theres not a big difference in performance, but the panasonic does...
that battery in the link is too big (69mm) for the pax. you can use an unprotected battery, because the pax has it's own internal cutoff. you have to watch the battery size (65 mm-66mm). some protected batteries are longer, because of the chip (like yours).
Do you have eBay? most of the stuff on there is free shipping, or really cheap. lots of choices and good deals.http://www.ebay.com/itm/170511157772?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
my replacement runs great. i got the flashing orange light once or twice on the newer unit, but it was quickly fixed by clicking the mp a couple times.
my original pax got returned for flashing blue lights and death. ploom told me it was a thermistor problem, whatever that is.....here's what wiki says..A thermistor is a type of resistor whose resistance varies significantly with temperature, more so than in standard resistors.
all my batteries take roughly 1:10 from dead flat to green.but i don't know if that is fully charged. maybe if i get bored, i'll do some testing with the multi-meter.
i agree with mr krinkle, the battery indicator can be very wonky. Also, every user is different. A person who is constantly turning the pax on and off will drain the battery faster than a person like me, who prefers longer sessions, because it takes more amps to heat up the oven than it does to...
im thinking a lot of pax's internal problems are bad batteries. ive been using my pax as a guinea pig, trying out different batteries, and it has no problems whatsoever. I get 2 hours of continuous high (red) setting on a panasonic 18650. I only get about an hour and a half out of cheap chinese...