My Sola 800 didn't want to accept a charge after sitting for a few months. Seemed like it didn't want to start charging. I don't recall exactly how the lights were blinking, but it never settled into charging mode.
Initially, I also had no luck rapidly tapping the charging contacts to the light, but then I attempted flipping the charger plug over and tapped the light a few times. In essence, tapping the Positive charger terminal on the Negative contact on the light (and vise versa). After tapping a few times, I flipped the charger back to normal and plugged it in normally. Viola, the light started accepting a charge.