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Brando - Mini Dynamo Keychain 2-LED Flashlight

provided for review by
As the name suggests, Mini Dynamo Keychain 2-LED Flashlight is a mini windup 2 LED based crank flashlight. The flashlight is highly economical to own and to operate. Build quality can generally be regarded good. To keep the cost to a minimum, LED's used in Mini Dynamo Keychain are generic 3mm white LED's. The flashlight also uses internal tabbed NiMH battery pack which consists of a stack of 3 NiMH button cells. This allows operation of flashlight for short duration without continuously cranking / winding. The batteries are charged using single diode based circuit and current generating dynamo. LED's are directly driven by the battery and are connected in parallel. Use of NiMH battery allows direct drive and yet the output of light will maintain regulation. Dynamo in the Mini Keychain is single phase and is driven by an assembly of series gears. Flashlight is capable of operating even with fully depleted battery. As long as the user cranks, the dynamo generates electricity and the flashlight provides illumination. Considering its size, we may very well call this flashlight as one of the worlds smallest wind up dynamo based flashlight with integrated rechargeable battery and charger.

Light Features:
  • Internally Dynamo
  • Internal Rechargeable NiMH Battery
  • Simple Drive Circuit (Direct Drive)
  • Simple Charging (single diode based)
  • Can operate even if battery is completely discharged (use dynamo)
Light Operation & Output:
Light Operation: Slide switch forward for switching ON. For switching OFF slide it backwards. If the internal battery is discharged, start winding and you will see light.

Charging Internal Battery: Put the light is in switched OFF position. Hold the flashlight in left hand with LED's facing away from you. Open the lever and crank/wind in clock wise direction for 2 to 5 minutes at a pace of 45 revolutions per minute. In simple terms, you should revolve / wind the lever roughly once per second or so. Little slower will be better.

Light Output: Below is the chart showing total output levels* for internal NiMH battery.

Mini Dynamo Keychain 2-LED Flashlight
Output 45

*The total output levels are based on custom built Integrating Sphere with Gossen Mavolux 5032 Class B USB Light Meter as photometer. To convert total output readings in to approximate Lumen readings, simply divide the total output by 10.
Light Info: In Progress
In-Depth Review & Pictures:
Packaging: Mini Dynamo Keychain 2-LED Flashlight comes simple hard paper box. Exterior color of flashlight included is handwritten on the box. Inside the box, you will find the flashlight wrapped in simple reseal able P. E.

Size comparison of the package with standard AA battery.

Size Comparison: Pictured below on the left is AA Alkaline battery and on the right is brando Mini Dynamo Keychain 2-LED Flashlight. As you can see, the flashlight is smaller in height than AA battery.

Viewing from side, we can see that the thickness of the flashlight is almost equal to the AA battery. In such a small size, you will find a dynamo/generator, NiMH battery pack, operating switch, series of gears, electronics and LED's. Now, you can imagine including all that in such a small package. We will talk about this a little later. Let's continue comparing size with one more flashlight.

Comparing the size with LRI Photon Rex Micro Light in center, Mini Dynamo Keychain is tad smaller in height.

Comparing the side view of Mini Dynamo Keychain 2LED on left with LRI Photon Rex Micro Light in center, AA battery on right. It does not appear too thick or too big when compared to Rex Light.

Body: Mini Dynamo Keychain 2-LED Flashlight has small rounded rectangular matchbox shaped body. One one side there is operating switch.

On the other side there is folded cranking liver.

Here it is from another angle.

On one of the corner there is a mini keychain attached.

Bezel: The first look at bezel of Mini Dynamo Keychain 2-LED shows rectangular faceplate with two 3mm LED recessed. Entire faceplate has mirror finish, but we may not call it as a reflector as it does not take active participation in light management. There is no additional protection to LED's. The LED's in Mini Dynamo Keychain do not protrude out of the body.

From the front view, the LED's are almost parallel and direct all light in same direction.

The 'reflector' as such does not take active part in light management, rather it is just there to improve cosmetic appearance of the flashlight. Although, we must say that some of the side spill does in deed get reflected from the side walls of the face plate. As such, intrinsic lens formed due to LED shape is entirely responsible for lumen management.

Crank Lever: As mentioned previously, the crank lever is placed on right side of flashlight and is folded inside the flashlight.

Handle to rotate also gets easily accommodated inside.

Here is a view of crank and handle unfolded. There is a arrow placed on lever indicating direction of rotation. The direction for rotating is clockwise.

Components: We opened the flashlight for you just to show what's inside and to subdue your curiosity in opening up the flashlight. Please do not try this at home. The flashlight can be opened using micro philips + screwdriver by unscrewing screws. The flashlight opens up in two half's. Each component inside is held together using these two half's. If you plan to open the flashlight, please be careful in doing so. The gear assembly is placed very delicately and can fall off easily. Without further delay, here are few pictures in full glory.

In the above picture, you can clearly notice that there is a small arrow mark on the crank lever indicating the direction of rotation for the lever.

Mini Dynamo Keychain 2-LED Flashlight consists of seven main components, generator, NiMH battery, operating switch, gear assembly, charging diode, PCB hosting 2 LED and the 'reflector' faceplate. The arrangement of these components is a very compact. LED's are connected in parallel and are directly driven by either by battery or by the generator / dynamo. Gears appear to be made of high strength plastic.

Here is the top view of Mini Dynamo Keychain 2-LED Flashlight Components. As you can see from the top view, there is a series of 5 gears that multiply the rotational energy multifold. This provides enough speed / revolutions per minute to rotate the shaft of dynamo / generator to drive LED's or to charge the battery. All gears have metal axles / studs.

One of the most surprising aspect of this flashlight sample is inclusion of proper NiMH battery pack. While most other flashlights of this category and price point contain alkaline batteries which are very deceptive to users. This flashlight is actually the one that in deed uses a real rechargeable NiMH battery pack. This battery pack has industrial packaging with tabs. Individual cells in pack are held together by green insulating sleeve. Generator / dynamo is directly connected to battery through diode. When switch is in OFF position, winding up the crank charges the battery. When switch is in ON position, winding up supplies current to the LED's and the battery.

Operating switch used in flashlight is of sliding type and will last at least for 2500 ON - OFF cycles.

Beam Shots:
Here is the Beam shot Matrix shows Mini Dynamo Keychain 2-LED Flashlight with fully charged internal NiMH battery. The as generic low cost LED's are used, the beam pattern is although has smooth flood pattern but the beam has a overly distinctive blue tint. This tint is due to result of overdriving LED's. All beam shots are taken at f/8 aperture with varying shutter speed.
Mini Dynamo Keychain 2-LED Flashlight Max (L-01)

Extreme Closeup Pictures: Mini Dynamo Keychain 2-LED Flashlight
Since there are not much structural features to demonstrate, we did not capture the high resolution.
Equipment Used: Custom built Integrating Sphere with Gossen Mavolux 5032 Class B USB Light Meter as photometer. Mavolux 5032 B USB is high precision, high accuracy and high quality light meter with conformance to DIN 5032-7 and CIE 69 standards. Utmost care has taken to ensure that the light measurements are accurate.

Test Scenario: We performed 3 runtime tests for Mini Dynamo Keychain 2-LED Flashlight. The first test was for cranking of about 2 minutes, the battery was not discharged completely prior to that. Next two tests were carried out after charging the battery with more than 4 minutes of cranking / winding.

NiMH Internal Wind 1: The runtime for Mini Dynamo Keychain 2-LED Flashlight after two minute winding is 2 Minutes and 21 Seconds to 50% of light output. Yes, you read it right, the time is in Minutes and Seconds. The light output starts upwards of 4 lumens. Not surprisingly, the light maintains output in regulation for the first two minutes and then there is a sharp drop in output. This is typical of NiMH battery, which inherit has a flat discharge curve. The overall runtime is less simply because of the battery capacity for such a small battery is less.

NiMH Internal Wind 2: The runtime for Mini Dynamo Keychain 2-LED Flashlight after 4+ minute winding is 5 Minutes and 2 Seconds. Here again, the light output starts nearly at 4 Lumens and maintain the regulation till entire runtime.

NiMH Internal Wind 3: The runtime for Mini Dynamo Keychain 2-LED Flashlight after 4+ minute relatively slow speed winding is 5 Minutes and 12 Seconds. As expected, although the light output starts nearly at 4 Lumens, during the runtime, the light output is lesser than the above test, yet it maintain the regulation for entire runtime.

Based on the sample provided, we can conclude that overall, the Mini Dynamo Keychain 2-LED Flashlight one of the smallest rechargeable windup, economical and generally good quality flashlight. You never have to worry about replacing the battery to get illumination. Simply windup when the battery is depleted or when illumination is needed. The output of 4 Lumens is decent for its size. We recommend the flashlight for general purpose non mission critical use. Light output has blue tint which is mainly because both the LED's are overdriven in direct drive more. Tint could be improved by using better LED's. Using high quality LED's such as Nichia or Cree would impact on increasing the overall cost of the flashlight.
Buy Mini Dynamo Keychain 2-LED Flashlight Flashlight at gadget.brando.com
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