[Review] Convoy C8+ || OSRAM KW CSLNM1.TG , 1x18650 || Output, Power Regulation Graph, Beamshots

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bilakos10
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[Review] Convoy C8+ || OSRAM KW CSLNM1.TG , 1x18650 || Output, Power Regulation Graph, Beamshots

The flashlight was sent to me by Convoy for review.
Here's the product's link: Convoy C8+ w/ KW CSLNM1.TG & Lighted Switch


The Convoy C8+ comes in a variety of colors (desert tan / black / silver / orange / green).
The overall fit and finish is excellent.



Its body contains some knurling for added grip.
The head and tail incorporate an anti-roll design, which prevents the flashlight from rolling over.



The head of the C8+ comes with some thick heat-sinking fins for better heat dissipation.



The front glass lens of the flashlight is protected via a metal bezel which is slightly crenulated.



This specific variant of the C8+ comes with an OSRAM KW CSLNM1.TG emitter and a smooth reflector.
The emitter is perfectly centered thanks to the centering ring.



As with all Convoy flashlights, the C8+ can be easily taken apart.
Removing the front bezel gives us access in the reflector and emitter MCPCB.



Here's the OSRAM KW CSLNM1.TG emitter and its copper board.
Plenty of thermal paste is in place.



The driver is seated in the rear part of the head and is secured in place via a brass retainer.



The tail of the flashlight houses its mechanical switch.
I decided to install a red illuminated switch, as such color complements the black body of the flashlight nicely.



The illuminated switch kit also includes a translucent tailcap to allow the light to shine through.

 

The tail uses a thick copper spring and the PCB is held in place with another retainer ring.



Here's the tail assemble taken apart.
As said, I've installed a red illuminated tail switch.



Here's the illuminated switch board (left) compared to the standard board (right).
As expected, the illuminated switch contains a couple of resistors and emitters mounted in the sides of the main switch.



The rear threads are square cut and anodized, which allows the flashlight to be mechanically locked out.



The head's threads are also square cut, but come with no anodization.



User Interface

There are two different firmwares that the C8+ w/ KW CSLNM1.TG can be ordered with:
1. Simple 4-mode : 0.1%-3%-30%-100%
2. Biscotti (12 mode-groups) 

I chose my light to use the 12 mode-group driver, as it allows for better flexibility.

Here's a diagram demonstrating all the features of the 12 mode-group driver.
Please note that since posting this diagram, Convoy has increased the numbers required to access the config mode to 20 taps (was 10 taps originally).



The 12 mode-group driver includes Low-Voltage Warning and Low-Voltage Protection.
Additionally, as can be see in the previous diagram, mode memory can be toggled on and off through the configuration menu.

Output
Here's my output measurements along with the respective current draw.
The measurements where recorded using a Samsung 25R cell.



The Convoy C8+ w/ KW CSLNM1.TG pushes more than 1000 lumen at startup.
Such output is very impressive, considering that the emitter is 1mm^2.

Power Regulation
Here's a power regulation graph I created for the Convoy C8+.



What we can see in the graph:

  • Turbo (100%) is linearly affected by the input Voltage.
  • Medium (35%) is fully regulated down to 3.3 Volts.
  • Low(10%) and Moonlight (1%) are fully regulated for the full span of the battery's life.

Outdoor Beamshots

Here's a few outdoor beamshots that I captured with the Convoy C8+ w/ KW CSLNM1.TG

 
 

Edited by: bilakos10 on 05/31/2021 - 15:37
JaredM
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Great review. Surprised to see that the driver doesn’t regulate much better than this. Vf of nm1 emitter at 1.9A is only 3.2V and 4.3A comes at about 3.6V. I’d expect to see regulation go much deeper than this.

tatasal
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Is there any coupon code?

and btw, I don’t see any photos

ggf31416
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Thanks. I wonder whether the illuminated switch could have higher resistance than the original switch.

captainkirk
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ggf31416 wrote:
Thanks. I wonder whether the illuminated switch could have higher resistance than the original switch.

Original switch in that model is bypassed from the factory so it should have less resistance.

This space for let.

Jack Kellar
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I have one of these, only in desert tan w/ no lighted switch and the 4-mode driver. DAMN does it throw far.

I should also point out that the host warms up pretty quickly on sustained higher modes, so the assembly is definitely wicking the heat away from the emitter nicely.

bilakos10
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tatasal wrote:
Is there any coupon code? and btw, I don't see any photos

I think Simon from Convoy provides a coupon code for all BLF members.
I'll double check with him and keep you updated.

Regarding the photos, I've hosted them in imgur.com
In the past I remember hearing from a folk living behind the Great Firewall of China having similar issues.
Could this be the case with you too?
bilakos10
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Jack Kellar wrote:
I have one of these, only in desert tan w/ no lighted switch and the 4-mode driver. DAMN does it throw far. I should also point out that the host warms up pretty quickly on sustained higher modes, so the assembly is definitely wicking the heat away from the emitter nicely.
The throw of this light is indeed amazing Smile Now I am waiting for the 18350 tube to arrive. The long throw / short body size combo is definitely going to be very interesting!
JaredM wrote:
Great review. Surprised to see that the driver doesn't regulate much better than this. Vf of nm1 emitter at 1.9A is only 3.2V and 4.3A comes at about 3.6V. I'd expect to see regulation go much deeper than this.
You're correct. I was also expecting a bit deeper regulation in the 35% mode judging by the low Vf of the emitter. (Please view post #10 - Had some technical difficulties with my PSU's leads Big Smile
EasyB
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bilakos10 wrote:
JaredM wrote:
Great review. Surprised to see that the driver doesn’t regulate much better than this. Vf of nm1 emitter at 1.9A is only 3.2V and 4.3A comes at about 3.6V. I’d expect to see regulation go much deeper than this.

You’re correct. I was also expecting a bit deeper regulation in the 35% mode judging by the low Vf of the emitter.
It’s not a deal breaker, but the more regulation we can get out of a driver, the better.


Were you measuring the voltage right at the driver? Maybe you didn’t account for voltage losses between the power supply and the driver?
bilakos10
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EasyB wrote:
bilakos10 wrote:
JaredM wrote:
Great review. Surprised to see that the driver doesn't regulate much better than this. Vf of nm1 emitter at 1.9A is only 3.2V and 4.3A comes at about 3.6V. I'd expect to see regulation go much deeper than this.
You're correct. I was also expecting a bit deeper regulation in the 35% mode judging by the low Vf of the emitter. It's not a deal breaker, but the more regulation we can get out of a driver, the better.
Were you measuring the voltage right at the driver? Maybe you didn't account for voltage losses between the power supply and the driver?


You're absolutely correct. Thank you very much for the suggestion!

Backtstory
I use pretty thick leads for my power supply leads, so voltage drop isn't as issue at such current draws.
I took your advice and decided to also get the voltage readings right at the driver, where I observed a 0.22v voltage drop @1.91A...
This is when I noticed that the half of my PSU's positive lead strands where ripped off from my U-shaped terminal connector yell

Patched up a new terminal lead, and here's the corrected power graph.

As you can see, the regulation for the 35% mode is down to 3.3V
Also, the max current I recorded also got bumped to 4.76A, which is completely aligned with the ratings reported by Convoy!
tatasal
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bilakos10 wrote:

tatasal wrote:
Is there any coupon code? and btw, I don’t see any photos

I think Simon from Convoy provides a coupon code for all BLF members.
I’ll double check with him and keep you updated.

Regarding the photos, I’ve hosted them in imgur.com
In the past I remember hearing from a folk living behind the Great Firewall of China having similar issues.
Could this be the case with you too?

I ordered the green one, my first green light.

Btw, now I can view your op photos, for what reason, I don’t know.

NeutralFan
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captainkirk wrote:
ggf31416 wrote:
Thanks. I wonder whether the illuminated switch could have higher resistance than the original switch.

Original switch in that model is bypassed from the factory so it should have less resistance.

The new lighted switch should also be bypassed in this flashlight. Not too hard to do, but should be done since the current is over 3 amps.

Nice review bilakos10!

I’d rather use my flashlight around the house than turn on the lights.

bilakos10
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tatasal wrote:
bilakos10 wrote:

tatasal wrote:
Is there any coupon code? and btw, I don’t see any photos

I think Simon from Convoy provides a coupon code for all BLF members.
I’ll double check with him and keep you updated.

Regarding the photos, I’ve hosted them in imgur.com
In the past I remember hearing from a folk living behind the Great Firewall of China having similar issues.
Could this be the case with you too?

I ordered the green one, my first green light.

Btw, now I can view your op photos, for what reason, I don’t know.

The green one looks fancy Cool
Did you get one with the OSRAM CSLNM1.TG emitter?

EasyB
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bilakos10 wrote:

EasyB wrote:
bilakos10 wrote:
JaredM wrote:
Great review. Surprised to see that the driver doesn’t regulate much better than this. Vf of nm1 emitter at 1.9A is only 3.2V and 4.3A comes at about 3.6V. I’d expect to see regulation go much deeper than this.
You’re correct. I was also expecting a bit deeper regulation in the 35% mode judging by the low Vf of the emitter. It’s not a deal breaker, but the more regulation we can get out of a driver, the better.
Were you measuring the voltage right at the driver? Maybe you didn’t account for voltage losses between the power supply and the driver?


You’re absolutely correct. Thank you very much for the suggestion!

Backtstory
I use pretty thick leads for my power supply leads, so voltage drop isn’t as issue at such current draws.
I took your advice and decided to also get the voltage readings right at the driver, where I observed a 0.22v voltage drop @1.91A…
This is when I noticed that the half of my PSU’s positive lead strands where ripped off from my U-shaped terminal connector yell

Patched up a new terminal lead, and here’s the corrected power graph.

As you can see, the regulation for the 35% mode is down to 3.3V
Also, the max current I recorded also got bumped to 4.76A, which is completely aligned with the ratings reported by Convoy!

I think there is still something fishy with the measurement. From djozz’s test the voltage of the NM1 is ~3.35V at 4.76A. So that means there is a 0.85V drop somewhere. In my experience the voltage drop across a linear driver like this is a lot less than that, something like 0.2V. If you measure the voltage at the actual driver input that should be more accurate.

Your measurement is suggesting that there is zero regulation time in high mode, and I think that is incorrect.