It took 3 or 4 times seeing this happen before I figured out what’s going on, but I don’t see any docs for the biscotti-like 12 mode firmware in my S21A that indicate this behavior, so it’s a little surprising.
I keep this S21A in mode group 7 with mode memory on. It has lived on the handlebar of my commuting bike for the last few weeks. After about 5-6 hours of riding, bike strobe stops, and it just goes to a medium-ish solid on. The first time, I thought maybe I had bumped the button and changed the mode, so I tried to get back to bike strobe, and it wasn’t there. After I charged the battery, it was back to standard modes for mode group 7.
I’m playing with it again now, and it has a L-M-H (probably all lower than normal), party strobe, and beacon. No bike strobe. It was in bike strobe when I started my ride to work this morning. $10 says after I charge the battery, mode group 7 will return again.
I don’t see any docs that say LVP has a limited set of modes (and maybe even depends on the current mode group). Does anybody else’s S21A do this? I don’t see beacon in any of the normal mode groups, so I guess it’s a bonus you only get when you let your battery get to about 3.1 volts.
I put the battery back in at 3.5 v, and the “beacon” mode is a battery level indicator mode, I think. Instead of 1 flash, it’s now 3 flashes. And bike strobe is back already.
Bet you haven’t measured it under load though, only its resting voltage. Sounds like the correct behavior since before the low voltage warning it reduces to low output.
Yep, just in the charger. It’s usually still around 3.1 volts, actually, when I charge it. But that’s sometimes after quite a bit of riding on “medium” or something.
No SOS mode, but apparently a battery level mode, at least when the battery is less than 100%. The cheat sheet is just copied from Biscotti, but it looks like there are some changes that aren’t documented.
yeah my S21A also did that… i figur it out when the batt is 50% and lower… bike stobe is just like 50% flat… maybe when strobeing its goes beyond 100% power… so its preserve batt when 50% and under
How do you change modes on the S21a…I just got one with the Osram led and it’s got 5 leveled of brightness then a strobe, beacon and something else then back to lowest level. How do you change modes & does it have a battery voltage check function?