s21b sst40

s21b sst40 Led Torch Flash Light Portable Lanterna

Feature s21b sst40

Material: Aluminum Alloy s21b sst40
LED: Luminus sst40 6500K white tint and 5000K neutral white

Convoy s21b sst40
Convoy s21b sst40

Now we offer another driver version, which has a simple 4 modes for switching, which is very suitable for ordinary users.
modes : 0.1%-3%-30%-100% max current output is 6000mA
Its biggest advantage is that no frequency can be seen in any mode, and there is temperature management.
It can control the flashlight temperature not to exceed 55 degrees Celsius

If the flashlight temperature is below 55 degrees Celsius, it will output full current. If it is above 55 degrees Celsius, it will constantly adjust the current so that the flashlight will not overheat.


The Convoy S2+ flashlight / torch has been around for over half a decade,and is a massively popular with flashlight enthusiasts, and “in the know” consumers. Is this light useful for light painting?

Convoy s21b sst40 is a very popular Chinese budget flashlight manufacturer, run by flashlight guru Simon Mao. The Convoy S2+ has been around for half a decade, and the original S2 has been around for even longer. Despite it’s age, it is still a very popular flashlight, mainly due to keeping pace with new LED emitter options, whilst keeping the core basics the same. It is also very cheap, at around US$14 to $20 more most models, and sometimes available from third party retailers for just $10.

The S2+ is an 18650 tube light, with a head and body diameter of 24.1mm, and length of approx. 118mm. It is compatible with both Light Painting Brushes and Light Painting Paradise systems, and also Light Painting Tubes if a side clip is included (Clear S2+ model) or purchased as an optional extra.

Details s21b sst40
Details s21b sst40

The LED and reflector (smooth or orange peel) depends on the chosen model. The tail switch is also either metallic or rubber, depending on the model. The light has 3 sections that can be unscrewed – the head, tube, and tail cap. Unscrewing either will mechanically lock out the light. Whilst the light is easy to modify, you can’t remove or change the lens without removing the driver and LED board.

The battery tube has springs at both ends, accepts rechargeable li-ion 18650 batteries, either flat or button top. However, I have found the tube to occasionally be too narrow for some protected batteries. Thus I can only be confident that unprotected 18650 batteries will fit – I use Sanyo/Panasonic NCR18650GA 3500mAh. I also find that if you shake the light heavily, the battery shuffling inside can cause the mode to advance – so best not used with fiber optic brushes! There is no internal charging, but that is expected at this price point.

For the very low price, the Convoy S2+ is impressively well built, with reported failure rates in line with flashlights from big name manufacturers such as Klarus, Nitecore, and Fenix. However, warranties from Chinese retailers can be a hit and miss affair, and getting replacements may depend on your negotiation skills. Its waterproof-ness is also debatable, but my S2+s have survived multiple accidental drops (or rolls) into water, so I would rate it as IPX4. There are no instructions included, however they are available on the product pages on Convoy’s web store.

Overview s21b sst40
Overview s21b sst40

The Convoy s21b sst40 is available in 22 different items from Convoy’s own AliExpress store (as at October 2020), and there are also various other versions available from many Chinese electronics retailers. When you add in all of the possible combinations for each item, there are hundreds of possible S2+ configurations. This is the list of custom models and options available (as of October 2020).

LED Emitters

– Cree XM-L2 – floody and bright (up to 1,000lm at 2.8A). 5 colour temperature options – 7A 3000k, 5B 4000k, 4C 4300k, 3B 5000k, 1A 6500k.
– Cree XP-L HI – throwy and bright (up to 950lm at 2.8A). 4 colour temperature options – 7A 3000k, 4C 4200k, 3A 5000k, 1A 6500k.
– Nichia 219C – high CRI, floody (up to 750lm at 2.8A). 2 colour temperature options – 4000k, 5700k. 4000k can have a green/yellow tint. 5700k is almost pure white “midday daylight” like tint.

Flashlight s21b sst40
Flashlight s21b sst40

– Luminous SST-20 – high CRI (2700k, 4000k only), throwy, but less efficient (up to 650lm for high CRI, or otherwise up to 950lm at 2.8A). 4 colour temperature options – 2700k, 4000k, 5000k, 6500k. Can have a green tint, particularly at 5000k. 2700k is a lovely “sunset” like colour temperature.
– Luminous SST-40 – bright (up to 1,000lm at 2.8A). 2 colour temperature options – 5000k, 6500k.
– Samsung LH351D – high CRI, floody, and reasonably efficient (800lm at 2.8A). 4000k, 5000k, 5700k. Can have a green tint, particularly at 5000k.
– Osram KW CSLNM1.TG – Green emitter (presumably for hunting).
– LG UV 365nm
– Nichia UV 365nm

User interfaces

Biscotti (x7135) / 12 Mode (5A) – programmable user interface, with 12 mode group options, and memory can be turned on or off. Alternating frequency strobe. Full press on/off, half press advances mode. PWM is not visible. 12 Mode (5A) has temperature controlled step-down.

3/5 Mode (x7135) – 10/40/100%, SOS, and 10Hz strobe. 3 second mode memory timer. Full press on/off (will advance mode if on time was less than 3 seconds), half press advances modes. PWM may be visible.

4 Mode (5A) – simple mode groups 0.1/3/30/100% and no strobe. The 12 Mode option is better for 5A driver S2+. PWM is not visible. Temperature controlled step-down.

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