200pack, UY Wire to Wire Connector K1

Q: Will these 'uy wire to wire connector k1' work with 18 awg wire?

These are designed to be used with 26awg telephone wire. It is unlikely that you will be able to use these for 18 awg wire. Amazon sells the following products that should work for you: https://smile.amazon.com/Connectors-BearMoo-Automotive-Waterproof-Electrical/dp/B073LZC2B3 or https://smile.amazon.com/MUYI-Connector-Insulated-Electrical-Connectors/dp/B075S6PJTK I use the latter, most often, however, it takes a crimping tool to get the best connection with these. Good luck with your project.