I had the same issues, and bought this kit: ( OCR 2.5mm Pitch JST SM Connector... https://www.amazon.com/dp/B071HFPXBD?ref=ppx_pop_mob_ap_share ) and I highly recommend this tool to get the proper crimp. ( Flytuo Open Barrel Crimping Tool,... https://www.amazon.com/dp/B096NN52GP?ref=ppx_pop_mob_ap_share ). Use the 2.5mm notch.