I volunteered to be a ham radio bicycle mobile for  a city RACES event.  A year prior I had purchased a Blackburn Flea 2.0 Combo Front + Rear USB Rechargeable Lights.  The white front light worked, after sitting in my kit, but the red tail light failed and would not charge.  The white light did not last the 6 hour event.  I had to resort to using Serfas White LED Long Lasting front handlebar light.  The Serfas lasted the 6 hour event and still was working.

I do not recommend Blackburn Flea 2.0 Combo Front + Rear USB Rechargeable Lights.  I will never again buy a USB charge bicycle light, a seemingly silly concept.