I mostly ride at night. For night safety ,I choose Antac advance led stip. I attach this USB powered led strip to my xiomi power bank. led strip cost me nearly $8. It also have on / off switch for convenient.
Step 1: USB Led Strip
I buy this 6 led strip for $8 from amazon.in attach it to cycle rear bar. or where ever you want
Step 2: Attach USB PowerBank
I use my old xiomi powerbank