4Greer WS1


I do not know where this light comes from, the 4Greer website does not contains much information, except about resellers. It is a single mode AAA light with support for LiIon. The light is made of aluminum with hard-anodized (Type 3) finish.

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The light is delivered in a plastic box with a paper wrapping. The wrapping contains all the specification and also works as a warranty card.

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The contents of the box are the light, two spare o-rings and a split ring.

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The light uses a XR-E led placed in the center of a small OP (Orange Peel) reflector.

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The head has a logo on it and also some groves to improve grip when twisting the light on /off. The location of these groves is not optimal I would have liked them closer to the front of the light.


The light uses the standard on/off for twisties, a ring on the circuit board that is connected to the battery tube when it is screwed down.


The battery tube has treads and a o-ring seal. The threads are anodized and the connection is done at the end of the tube.


In the bottom of the battery tube is the classic spring allowing for some length variation on the battery.


The battery tube is smooth, and has a clip that prevents the tube from rotating when twisting the light on/off. The clip is designed for front end down carry on thin fabric and it keeps most of the light below the carry point.


The backend of the light allows for easy tail standing, except when the split ring is mounted in the hole for it.


This is the parts I could disassemble the light into without using tools.

This is a simple light that always runs at full power with a short runtime, the construction is fairly standard. It is a strange design decision that stabilization only works with LiIon, but the light is missing LiIon protection.

Technical specification and measurements


This light is designed for any AAA sized batteries (Alkaline, NiMH, Lithium, LiIon).

Measured size and weight:
Length: 78.7 mm
Diameter: 14.7 to 17.4 mm
Weight: 37.5 gram with eneloop

The light uses a Cree XR-E Q4 WC led.


In the above table I have used 800mAh eneloop and 350 mAh LiIon batteries for measuring and estimating the runtime. The estimated lumen are based on the specified 100 lumen (Assuming it is valid in the stabilized range) and then scaled according to measured brightness.
It is interesting to see that the power consumption is the same with the two batteries, but the brightness is not, i.e. this light will get hot on either type of batteries, but LiIon gives more light.
The specified runtime is probably measured until the light goes out, not while it is giving any useful light.


The voltage scan show that the light is stabilized but only for 1.8 to 3.8 volt, i.e. the stabilization will only work for LiIon and only when they are not full.
This graphs also shows that the light is without any LiIon protection circuit, i.e. the LiIon battery must include the protection.


The runtime on this light is short, when measuring to 50% brightness and it is also obvious that the stabilization does not do anything with alkaline and NiMH batteries.


The light always runs at full power and does not need any way to reduce brightness, i.e. no pwm. But the regulation has some high frequency noise that depends on the voltage. At 1.2 volt it is 330 kHz, falling to 17 kHz at 3.7 volt, this is not visible to the eye.

Comparison to other Flashlights

Tiablo E3A Exquisite NiMH, Tiablo E3A Exquisite LiIon, 4Greer WS1 NiMH
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4Greer WS1 LiIon, LiteFlux LF2XT Custom Ti NiMH, LiteFlux LF2XT Custom Ti LiIon
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For the full comparison to other lights with graphs and beamshots see here.