Get a SkyRc MC3000 Charger (4cells) or a megacellcharger https://www.megacellmonitor.com/MegaCellcharger (16 cells)or an Opus BT-C3100(cloned/fake alot too) or the Opus BT_C3400 (4cells)I want to buy one of SkyRc product, imax b6ac
The imax b6 is one of the most cloned (fake) charger out there. I have an imax b6ac clone I read up on how to spot an fake imax b6 and still I managed to buy a SkyRc imax b6ac clone. Slow testing single cell at a time.
Also get an IR checker most any of the YR series. I use an YR1030+. Good thing about a portable IR checker is that it is well portable.
Wolf has tested 4 slot testers and the megacellcharger, IR meters and written comprehensive reviews on just about anything related to testing 18650's. all posted here.
Later floyd