I'm trying to figure out my taillight setup for the shortening daylight hours. I was thinking of a Knog Blinder 3 front and rear, but I'm wondering if the tail light should be on the rack rather than the seat post. I'm thinking that maybe my pannier and saddle bag might block some light from a seat post mounted light. What are your thoughts? Any recommendations for a rack mounted light?

Yes, the back of the rack is better than the seatpost. I'd recommend my taillight, but it's a generator powered one...

No-brainer, Busch & Müller Toplight on the rack.

I agree with Kingston. I have a Busch & Müller Toplight Line on my rear rack, and it is perfect.
Busch&Muller battery powered bicycle lights

I recently got a Portland design works tail light, it comes with a seat post, rack, and seat stay mounts which is handy for multiple bikes, it also has a reflector which is nice. I run the rack mount on my daily and put the seat post mount on my back up.

https://www.ridepdw.com/goods/lights/radbot-1000

+2 for the B&M Toplight (I've got an older 4D). I like it because it's noticeable without being blinding.

I have two of these lights and I like em a lot. It would be cool if PDW made it in a USB rechargeable version.

Dinnotte

i run a knog blinder 4 on the rear. it's talk and on flashing red illuminates through the British fog quite well. i run it on the seaport up high.

it's probably been on and off the bike between 150 an 200 times in the first year without incident.

i probably get about 4hrs flashlight the front and rear.

check out my Bso thread and you'll see pics.

feel free to ask any questions

on old mobile story for typos.

I run 2 Cygolite Hotshots, IMHO the best bang-for-the-buck light you can buy. Many people say the Hotshot is very directional, and it is, but from 50 yards to 1/4 mile and even farther away, these lights *WILL* be seen by approaching motorists behind you. I have one mounted down low on the left seat stay, and the other on the rear of my Topeak rack (with the separately-purchased Hotshot rack mount).

The Hotshot recently had some improvements made to the included seat post mount, and also now include a dedicated seat stay mount. It uses 2 separate screws, one for tightening the clamp around the stay or seat post, and the other for securing the angle of the mount bracket. It's a really nice improvement over the original version (I have one of each). Also when charging, the old version used a separate internal flashing LED to indicate charging. The new one uses the main 2-watt LED in extremely low power mode to indicate charging. The new version also indicates when battery power is low by strobing the LED for a couple seconds at very low power, either when you turn the light on or off.

Why not get something very bright like a Knog Blinder 4 for your seatpost and get another light for your rack?

These reviews might help you decide.

They were reviewed from the point of view of being practical and AFFORDABLE for the average commuter. The Hotshot was 2012 pick and still a strong contender in 2013 with the Solas 2W edging it out due to better side view, as Patrick mentioned the Hotshot is quite directional.

not another steady versus blinking, battle, please..

FWIW Here's a LED taillight, set inside the seatpost [If no saddlebag is to be left on a parked commuter bike)
?25.4mm LightSkin seat post with LED rear light - silver · EpicBike · Online Store Powered by Storenvy

I have a B&M 4D toplight senso plus, and 2 toplight line plus taillights (plus is dyno hub powered )

the older 4D design uses a pair of AA batteries to power its 4 diodes
senso Feature allows you to just leave it in that mode,
it will turn itself on when you start rolling , and off after a couple minutes ..

great for those who forget And leave their battery light on & and find the battery drained when they come back..

the non Plus has an off position , the Plus the off position is the dynamo power, it goes off when you stop.

the newer ones the capacitor charging is the battery for the standlight. it comes on quite quickly when the dynamo turns..

mine is on the rack so I never have to worry about a load blocking a light on a seatpost. when I was commuting I also had a rear facing reflector. my current bike doesn't have a reflector. for added courtesy room from the cagers I added a strobe to my left drop bar and yes, it makes a difference

The rear rack is definitely the place to put it. It doesn't get blocked by bags, nearly all rear racks have specific mounts for lights on the back of them.

While it seems to me like the B&M Toplight is the best dynamo light you can buy, I'm hesitant to say it's the best rear light you don't have a dynamo. The biggest problem is just that it doesn't blink.

I use a Planet Bike Rack Blinky myself, I liked it because it has a fairly consistent blink pattern and a built in reflector. I've been considering, though, whether it would be safer to use 2 smaller blinkies on the rear rack. I always try to have 2 blinkies, run one on steady and one on blinking, because since the light is behind you you can't tell if the light goes out. I've had it happen - battery ran out, battery got knocked out of place, and arrived home to find I had had no rear light for who-knows-how-long on the ride. Most rear racks have mounting for 1 larger rear light, or 2 smaller rear lights.

PB lights are really inadequate, IMHO, being only 1/2 watt. There are other 2-watt lights out there that are WAY brighter, for usually only about $10 more, and many of them USB rechargeable.

Agreed. I also use two Hotshots. One mounted to my rack and on one the seatpost. they're around $30 each and usb rechargeable. Pretty hard to beat.

Lots of great suggestions, thanks! I'm going with the PDW Danger Zone for the rear rack. I also have an old PB tail light mounted on the back of my helmet, I think it's called the Mars. I like the high/low combo of lights, and honestly I can't feel the weight of a small light on my helmet... probably too many years wearing heavy helmets in the army

Just finished washing the bike, time to add some reflective tape to the rear rack while it's still clean.

I just put one on my commuter this week. Nice light, and a bit cheaper on Amazon.

Robot Check

I really like having a light mounted to the back of the rack. I wrote a blog post on a couple of DIY mounting solutions:
ROAM: Back Rack Light Hacks
(#shamelessselfpromotion)

^^^THIS^^^

Rechargeable is an firm requirement. I cannot foresee ever owning a battery powered light again. I know that I'd be money ahead within a year buying a second light over feeding a battery muncher.

My experience is limited to a half dozen or so of the higher rated sub $40 battery burners. I sold every last one of them on eBarf. YMMV

I use rechargeable AAA batteries in my PDW Radbot 1000s. I run two of them flashing. I don't commute every day, so I just swap the batteries for fresh charged ones every couple of weeks. I run them day and night. Also a steady on tail light powered by my generator hub. I'm really not paranoid, I just ride all the time on rural 55 mph roads. Even a Planet Bike Superflash (hope I got the model right) is visible from over half a mile away into a rising sun. I look for stuff like that when I'm driving: what helps me to see bicyclists.