noglider 

Yeah so these are for your kids, huh? Good thinking. I know someone else here who knew his kids would not switch on their own lights so he got them dynamo lights. But dynamo tail lights are not as good as battery powered lights, and if you like blinking, you pretty much need a battery light. I'm glad you're doing this, because automatic lights are great for many folks. I love my dynamo headlights and prefer battery tail lights so I still switch them on and off. If you find a good tail light that is substantially bright, please report back.

chaadster

As a follow-up, I did get a pair of Cateye Reflex Auto lights, and I like them! They’re not perfectly what I wanted because they don’t have automatic capability for daytime flashing, but given the alternatives I could find, these are quite satisfactory.

The unit is rather big with a clear edge all the way ‘round, making for a big, bright surface that both broadly diffuses light from the multiple LEDs and provides a lot of reflector for vehicle lights.

The mounting options are good; it comes with both large and small clamps for seatpost and stays, and two shims of different thickness. It also includes a rack mount adapter, which is nice.

The function is either manual with choice of four or five light modes, or automatic with the same four or five light mode choices. A long push of the single button toggles between manual or auto function, so that’s easy, and a quick push toggles light modes. The auto works on a combo of low light and movement sensors, and there is no choice to use, say, just motion activation. I’d wanted the lights to turn on anytime the bike is moving, but that is not possible. Auto only works when light is low and the bike is in motion. The good news is that it does not have to be dark, just low light. Opening my two car garage door in daight with the bike inside but near the door was enough to fire it up, so I think it’d work when moderately overcast and certainly by dusk.

The flash brightness is good, and very nearly day-bright. There are several LEDs, but only one high power one, located in the center. It projects a pencil beam, so not great for off angle viewing, but again, pretty much day bright when viewed from directly behind. In combination with the smaller LEDs and big lens, this provides quite a bit of light source surface and intensity which I think is excellent for low light and darkness.

Flash patterns are also good, with a wild, full disco pattern being my favorite. It also has simple flashing, pulse, steady, and a pattern flash all of which look great.

Twin AAA power the thing and are included.

The one vexing moment I had was when, after the lamp started as we rolled out of the garage, it stayed on for our daylight ride, but after we stopped for awhile leaving the bike outside in the daylight, it would not restart. To be expected, given it needs both low light and motion for auto start, but I tried to start it manually and could not. I figured the included batteries were cheap, old, and dead, however, returning to the garage, after parking it I went to move it after awhile and it fired up again! I dunno if I didn’t long-press it enough or if it was a malfunction, but it was a little goody either way. It seems to be working properly still, so I guess I’ll chalk that up to user error, and just accept that daytime flashing ain’t happenin’. I’m fine with that, though, as I’d rather have some auto coverage rather than relying on my 9 year old to turn a manual light on/off. Once, I rode by his school during the day and saw his light flashing with is bike parked on the rack, so I know he forgets. Hell, I forget sometimes!

In all, I think the Cateye Reflex Auto is a great light and an amazing value at $14. It’s perhaps better suited to kids and those who ride on slower secondary roads rather than commuters on main roads because the brightness is marginal for daytime running, but that’s fine tradeoff in my application for automatic functionality.



Cateye Reflex Auto taillight