Convoy S21A (Short Technical Review)

I have always wanted my driver manufacturer to write programs similar to crescendo, but I have been too busy recently. I think I will be free in a few days.

I don’t have experience with Crescendo but I read on BLF :
Crescendo has hidden strobe , and ramping, for flashlight with regular switch (not e-switch).

That’s pretty good!

Light painting photographers like strobes (single frequency strobes). They can be hidden as long as once selected they can be memorised! It is quite a big market, one light painter has over 300k followers on insta.

I just did a little more reading about Crescendo. It’s very good!
Simon, if you make Crescendo driver available for S21A and S21B that will be great.

There are no discreet brightness steps in Crescendo. As an optional UI, yes, but I would hope not the only UI available.

Yup, as an optional UI.
the Biscotti (12-group) is also very good.
It’s good to have options. People can choose what suitable to their need/desire.

seems like spring bypass is not very high quality, after short time it just ripped off on all 3 s21a which I had

I guess its because of low quaility insulation on that cable used for bypass, which will become just too stiff(plastic like, instead of rubber…) due to heat damage

If I look at the runtime graphs then it looks like the light no longer steps down around 630 lumen, ~35%

So my ideal would be something like:

- 35, 15, 1%

  • hidden turbo, 35, 15, 1%

Just got an S21a today from the sale mohrlumens.com was having. Nice to be able to buy from a US source now that Mountain seems to be not selling lights like they used to. Came in the standard mail pouch. Hand written note inside telling me some extra parts I ordered were hidden inside the light for protection during shipment.

I got the 5000K version. The UI is fine. I’d rather have steps than a ramp in most hand held lights. I’ve got mine set for .1, 1, 10, 50, plus the blinkies. No memory, so it always starts in lowest mode. This is setting 7 if I recall correctly.
The strobe is very attention getting and I like the bike mode. Both of which I will probably never use.
I haven’t gotten a chance to put it to the oscilloscope or the lumen tube yet.

I like the beam pattern. I wish the spill was a little wider. There is some ringing at the very edge.
White wall hunting, I find the S21a to be noticeably warmer than the Samsung LEDs in the SP36.

The rear spring has a bypass. The front spring does not.

Fits the hand really well. Got a holster/pouch along with the light. The holster is really stout and seems really well made.
Unfortunately it doesn’t fit! The flap is way too short to close on the S21a. It’s also too short to close on a S2+.
Oh Well….

A little too big for a EDC pocket light (as are most). But for a coat pocket or a bag light? Just right. I like the extra run time the 21700 gives.

I’ll take a look at the PWM of this driver sometime soon.
For $18 plus shipping? Can’t go wrong. Got the stuff during the 15% off sale.
By the way, shipping for the light, two other S21a bodies, and a driver was $8.59 (I think).
All the Best,
Jeff

I agree, while the size is good for the cell size, it’s not ideal.
I agree with this thread’s OP: Review: Convoy S21A (21700, SST40). Seems, there is no use of old S2+ anymore.

3% (82lm) - Indoor use and simple outdoor walk.
30% (692lm) – Excessive for indoor use. Often not needed for regular outdoor needs.

When I buy another light, I look for advantages over my current lights that I actually use.
For me that’s:

- Tool 2.0 AA. I have this one in my pocket 95% of the time. Even during daytime.

  • DQG Tiny III 26650. Certain walks. Work light.

Obviously a 21700 packs a lot more power than the AA/14500 that powers the Tool. So at equal lumen, the Convoy has far better runtimes.

But do I really need that? No. A runtime of >240 minutes is good in my book.

Tool with 14500 gives me 360 minutes runtime at 85 lumens.
For me that means I don’t need the Convoy for “Indoor use and simple outdoor walk.”

Tool with a 14500, at its peak matches the Convoy’s 30% @ 650 lumen.
The 33 min runtime is way to low.
Swapping cells every 2 or even 1 hour would be acceptable. But not half an hour.
So that’s where the Convoy clearly has the edge.

I mostly use my lights for looking for stuff, for not tripping in the dark.
I do forest walks, but they are mostly “simple walks”, because rarely I need to see far away.
So even then 85lm suits my needs, with perhaps a brief high/turbo, using a 14500 cell.

Using an AA in the tool would give me:
360 mins at 85lm.
150 mins at 140lm. (requires a spare cell)

So…. do I really need it? No.
It’s so cheap I might try it anyway.
Because I don’t like stepdowns and 500-600lm is the turbo sweetspot for me, what really holds me back is the mode spacing.
Something like 3, 15, 50, optionally hidden 100, would make my choice much easier.
I fully get it, to suit everyone’s needs a light would need 500 mode groups.
That’s why ZebraLight’s approach is nice. 4 modes which each can be selected from a total of 16 (I think) values.

EDIT
I hope like the S2+ there will be options on how many drivers the light has. That would at least take away part of my reservations.
7135*3 output current 1050mA
7135*4 output current 1400mA
7135*6 output current 2100mA
7135*8 output current 2800mA

Recently picked up one of these with the 12 mode grouping.

Seems that whatever mode I choose it will at some point in the future randomly reset to the first mode (ie. 0.1 , 1…blinkies etc)

I recall there being something about driver memory wearing out if left in config mode for too long (which i haven’t) but it makes me wonder if this is an inherent bug with the driver, or do i simply have a buggy item.

Any ideas would be welcome. Thanks.

pls contact me any time if there is problem with the driver ,my friend

Check Convoy S2+: the selected group is reset after battery disconnect

At present, the manufacturer has replied. This is because the mode group is not saved at the moment of power failure. At present, the manufacturer has fixed this bug by modifying the program.
If some users need me to mail a new driver after one month, please leave me a message,

Odd, the S21A has been on the market for a while, but I feel like I’ve only started reading about these memory bugs in the past couple months.
Was the manufacturing process changed at some point recently? I’ve got one in the mail, so fingers crossed that it doesn’t exhibit similar bugs…

Are you sure it’s power failure? The mode memory on mine has never been affected by opening the flashlight. It will just randomly reset at some point in the future. There does not seem to be any particular cause.

same for me, once per like month it will simply change mode group for 1st one

I dont know what cause it, as it happen very rarely

I have one of the new 8A buck drivers with 12 mode group firmware and I’ve had this happen once as well.

anyone can chip in whether there are any safety concerns when the bypass cable snaps?

Probably not. But, the light can be run at a lower level. I have remade the bypass with a larger wire due to this happening on some of my S21As, too. At first, I was surprised it happened because the stock wire looked ok.