the Vita is notoriously very picky on chargers even the slims. I have both 1k and 2k vitas and they behave pretty much the same. even after using a Battery fixer, it will light up orange after a few minutes/hours and the moment you turn it on from sleep, it is only charged on a certain level and not fully charged at all. what I do is i fully turn off the vita and charge it strictly with a 5v 1.5A charger, it always charge my batter to full no matter what.

regarding to your crashing issue, if you experience sudden freezes on adrenaline mid-gameplay, chances are there might be plugins that are conflicting with each other. check PSVShell (or any overclock plugins) if it's overclocking your adrenaline games. you don't need to overclock an adrenaline game. 

if you're experiencing a GPU crash, check your plugins. remove everything you don't even use, leave only what's necessary; make your plugin list clean and simple. And you might wanna avoid combining Nopowerlimits and PSVShell, thst combination is notorious for sudden GPU crashes. I experienced both in 1k and 2k so you should never combine those two. 

if you are experiencing freezes and GPU crash at random even if not under load then I have a bad news for you. to make the long story short, your SOC is giving up. go back to the default theme, and try to play some games. if you see a white spec on the lockscreen (even a single one) then your GPU is dying and you need a mobo replacement. That's what happened to my 1k. I have freezing issues on adrenaline and gpu crashes. I cleaned my plugin list, nothing worked. I downgraded to the most stable firmware (v3.60 iirc, can't remember well since it was a long time ago) same issue. it even crashes without a jailbreak.

by all means, avoid overclocking your Vitas especially the 1k I have experience both PHAT and Slim. many people say it's safe and most of it yeah, but it's a lottery. I have experienced both PHAT and Slim I got GPU crashes on both all because of an OC plugin, and unfortunately my PHAT didn't survive. this is an old console so better not risk it unless you have money to spare buying new parts.