I use it for EDC & dog walking. No streetlights around here. It's got a wide beam and is pretty floody, doesn't get too hot on high outdoors (6 x 7135 XM-L U2 1B) and I think would do well as a bike light.
It's as good as my motorcycles 5.75" headlight.
I’m curious about the cut-outs in the side of the head on the S4.
Do they help cooling? Do they reduce waterprofing?
The 3C and 4C tints are nice but not really warm enough especially for rainy conditions. The best bang for the buck is the T5, 5C XM-Ls. My main light is a 4C, XP-G not bought from fasttech and it has the same tint as the T5, 5C LED. I have a S3 in T5, 5C and the colour is beautiful!! (sorry, sleepy… not all that coherent.)
The S4 stays dry walking in the rain, and it only gets comfortably warm walking outside. I've only used tailstanding on high for long enough to take a shower, and it gets reasonably hot doing that.
If there’s some ambient lighting along the roads, I would recommend not getting too bright a light as it will screw up your night vision. I learnt this the hard way when I had over 1000 lumens on my bicycle. Turned into a corner at speed but could not see a parked bike in mid-corner. Had to bail at last moment and cost me a fractured rib 
Nowadays, I ride with about 200 lumen light. But, OTOH, if it is on pitch dark roads, I would say as bright and floody as you can get.
Good point. But not much ambient lighting on these roads.
Thanks. The Convoys all have a mode selector, so a bright one can be turned down a bit.
I’m inclined to go for the 2100ma driver, so that it doesn’t overheat on high.
I’m a bit put off by the S4’s requirement for a 65mm (length)*18mm (diameter) 18650 flat top battery, which I presume means it will have to be unprotected. So I’m leaning towards an S3 to allow me to use a protected cell, because AFAICS the S4/S5/S6/S7 all require small flat-tops.
I think the Roche F12 is similar to the S4 and fasttech claim the roche takes long 18650s. No experience with either lights, I was just browsing them some time back.
I prefer to mount my flashlight/torch on my helmet;
so I can direct the light in the specific direction I want.
If you mount your lite on the handlebars; the first instinct
is to mount it on top of the bars. But I think mounting it
at the bottom of the bars would give a better balance.
You can use specifically made clamps, or just use strips
of an old inner tube.
1nterceptor: I def. agree with mounting flashlights under the bars, have done it with both my Nitecore EA4 and BLF A8.
Much easier to balance them and much less bouncing…
I don’t use a helmet 
Can you see all the pot holes on your route with this light? I’m guessing the video can be a little misleading. Looks like a bright hot spot, but not much spill. It only takes one missed pot hole to take you down at the wrong time.
The Convoy S3 looks like it is similiar size as the S-Mini, which was going to be my helmet light, suplementing a main light on the bars. Now if I can figure out how to compare the pair. Thanks for the comparison.
Thanks!
I have just ordered one Convoy S3 Cree XM-L T5-5C AMC7135*8 (2800mA)
Now all I need to sort out is the mounts. On another thread, I found some links to recommended mounts on dx.com: a velcro mount and an all-plastic mount. At only $5 for the pair, they look worth a try, but dx.com repeatedly times out when I try to register an account
I’d go with these:
http://www.fasttech.com/products/0/10002597/1193005-universal-flashlighttorch-mount-for-bicycles
available on DX but probably more expensive.
They are very stable and very quick to use.
Thanks, John. I’ll try one of those.
At $1.38 each, it’s a bargain if it works, and no great investment if it fails.
“Can you see all the pot holes on your route with this light? I’m guessing the video can be a little misleading. Looks like a bright hot spot, but not much spill. It only takes one missed pot hole to take you down at the wrong time.”
I’ve been using the same light(generic SSC P7 flashlight) for more than 2 years now.
I commute to work(4PM-12AM) 4 times a week, about 5,000 miles a year. More than
a third of those miles are in the dark. No night time crash, yet. I ride in an urban area,
so there are plenty of light sources. Street lamps, store fronts, cars in front and behind,
etc. I don’t have any problems seeing potholes, glass, sticks, etc.
i plan on trying one of these, slightly more investment, but should be more adaptable
http://www.fasttech.com/products/1315501
I got one of these: http://www.fasttech.com/products/1630/10000946/1079100-universal-bicycle-swivel-mount-for-flashlights-and - it seems to work fine with an Olight S-10.
I like a straight two fish with th e dualling velcro .
I didn't like the one like Bort linked to since the bolt rusted and it became garbage in less than a season .looks handy but really a lame set up . There are really good discussions on BLF about this stuff if you use the search and look under bike lights or mounts .. I used to use an old 501B p60 with a Bright xpg in it very successfully but I ride slowly too :P
https://budgetlightforum.com/t/-/8339
two lights always seemed smart to me one with more flood and the other with more throw .
gotta love a back up