What wattage is she using for TC? If you lower it to where it comes up to temp but doesn't hit the limiter you will also save some battery life.... 4click when in TC get you the watts setting. Works the same as stop and go driving does with gas mileage and your gas tank.
I find I like to use about 5-10 watts more in TC than I do when using VW.. So I get better life with VW. So Far.
Great minds must think alike...lol. 'Cause, that's pretty much what I did for her.
She has 2 mods on TC, the Pico (75 watt) and a Cloupor mini+ (50 watt). Both would slam full wattage into the coil, overheat it and then the temp control would kick in and lower the wattage but it would swing back and forth.
The Pico was also randomly burning the 32 gauge nickel coil wire out like a fuse.
After lowering the peak allowable wattage to just over what is needed to heat the coil to set temp, no more blown coils, battery life has increased dramatically and the wattage doesn't swing wildly so the TC is more accurate. It also takes noticeably longer for the battery to charge as well.
She also started having a problem with the Pico saying "Device too hot", even though it was cold. It turns out is doesn't like button top batteries, a switch to flat top and that problem has never returned. I can't get my head around how the button top vs flat top could make a difference though... but it does.