Cree Archives - A Leslie Wong Blog

February 19, 2019March 11, 2022

Malkoff Devices E2/Scout 2-3 CR123 Head

When I started thinking about writing this post in 2013, Malkoff Devices had just expanded their product line with a few LED conversions designed for use with Surefire E-series lights and Surefire Scout Light Weaponlights.

Malkoff M61 in a VME Malkoff Valiant Concepts Head and Malkoff MDC LMH
Malkoff MDC LMH and Malkoff M61 in a VME Malkoff Valiant Concepts Head
Malkoff E2/Scout 2-3 CR123 Head on a Vital Gear FB1
Malkoff E2/Scout 2-3 CR123 Head on Surefire E2D flashlight body

Now the Malkoff E-series/Scout light range spans nine heads from superthrow, high output heads to a specialized Bodyguard V2 head (with greater than 1000 lumens for 10 seconds) and a three mode LiIon rechargeable battery powered head.

My early E2/Scout head has an input voltage of 3.4-9 volts. I run it on a Vital Gear FB1 or my Surefire E1B with a RCR123 battery. I compared it to my Malkoff M61 in a VME Malkoff Valiant Concepts Head, which is also designed for an input voltage of 3.4 to 9 volts. My M61 uses a Cree XP-G LED, compared with the current M61 which uses the XP-G2. The M61 has a slightly larger hotspot and in my sample while the E2/Scout head’s beam was slightly more neutral.

My Vital Gear FB1 has gone through several evolutions, first with a Veleno Designs E-Series tower module, then with a modded Malkoff M60 in a VME Malkoff Valiant Concepts head and finally the Malkoff E2/Scout head.

Currently, I carry a Vital Gear FB1 or Surefire E1B with the Malkoff MDC LMH. With three modes (15 lumens/80 lumens/400 lumens), the LMH is a little more versatile. It’s also slimmer than the Valiant head with the M61 and I can carry it clipped inside my front pants pocket.

April 7, 2013July 26, 2021

Cree LED Light Bulb

I’m a big fan of Cree LEDs. I use them in almost all my flashlights. Last month, a Cree LED light bulb was introduced that replaces a 60 watt incandescent bulb. (Cree Press Release) The bulb retails for $12.97.

Specifications from Cree:

9.5 Watts (84% less energy)
800 Lumens brightness
25,000 Hour rated lifetime
$1.14* Annual energy cost
Lifetime savings: $139*
Warm color temperature: 2,700K
Lights instantly, omni-directional
Mercury free
Safety-coated glass
Dimmable
10-Year Limited Warranty
UL damp rated
Fits most lamps
Diameter: 2.4 inches
Length: 4.6 inches

*Cree’s calculation of $1.14 yearly operating cost is based on 3 hours/day and $0.11 per kWh. Cree’s lifetime savings calculation is based on $0.11 per kWh when compared to 60W incandescent and 25,000 hour lifetime.

It seems that the Cree LED Light Bulb is only available so far from Home Depot. I bought my bulb online from Home Depot and with $1.17 sales s surprised that the light bulb’s envelope felt like it had a rubber coating. It has a standard North American Edison screw E26 socket. I replaced a 15W warm compact fluorescent bulb (CFL) that was in a table lamp with the Cree LED Light Bulb. The LED seems brighter.

When I removed the lamp shade to photograph the bulb, I noticed that the bulb was hot enough so that I couldn’t hold it – so despite consuming only 9.5 watts, it still gets very hot. There is a heat sink around the base of the envelope.

When I photographed the illuminated bulb, I set the camera’s color balance for daylight, so the yellow color of the light reflecting off the wall in the background is a good representation of what it looks like to the human eye.

For the chart below I used the following cost assumptions:
Incandescent bulbs: GE 60-Watt Reveal A19 General Purpose Incandescent Light Bulb (6-Pack) $8.77 ($1.46/bulb, 1000 hour life)

CFL bulbs: Feit Electric 15 Watt ( Mini Twist Dimmable Light Bulb (12-Pack) $104 ($8.67/bulb, 8,000 hour life)

LED bulb: Cree 9.5-Watt A19 Warm White (2700K) LED Light Bulb (1-Pack) ($12.97 25,000 hour life)

Cost of electricity from PG&E, about $0.13/kWh.

To get 25,000 hours with a 60 watt incandescent bulb, you would need 25 of them, at a cost of $36.50. The cost of 4 CFL bulbs for 25,000 is $34.68. The cost of the Cree LED bulb for 25,000 hours is $12.97.

There’s no question about the cost savings of the LED bulb versus incandescent. Total cost for 60 watt incandescent bulbs for 25,000 hours is $231.50. Total cost for 15 watt CFL bulbs for 25,000 hours is $83.43. Total cost for a 9.5 watt LED bulb for 25,000 hours is $43.85.

People who want to keep using incandescent bulbs may not be able to do the math or maybe they’re using them to keep their popcorn warm.

Incandescent vs CFL vs LED Cost Comparison

September 20, 2010March 22, 2019

Surefire E2E Flashlight Mods

I bought a Surefire E2E because it was a good deal. I didn’t realize until I received it how much smaller it is in comparison to the Surefire 6P flashlights that I have. It’s about the same size as my JETBeam Jet-I Pro.

The E2E uses an incandescent lamp, the Surefire MN03 lamp assembly, with an output is 60 lumens. The output seemed a little low so I started looking for ways to make it brighter.

Fivemega, over at candlepowerforums.com makes two nice incandescent options for the E2E, a bi-pin socket and a Mini Turbo Head.

I’d rather use LEDs and I found that Veleno Designs makes a good option fits in the E2E head. The Veleno Designs E Series LED drop-in is machined from brass, has great heat sinking and uses a Cree XP-G LED. I ordered a 3 mode cool white model and while the output was great, the tint was a little green. The manufacturer said that most people order a neutral tint so they don’t have that problem.

I decided to order some neutral tint Cree XP-G LEDs from DigiKey to replace the LED. After I soldered the LED to the board, I trimmed the board with a Dremel so it was a little larger than 3.5mm x 3.5mm, so it would fit on the Veleno pedestal. It still had a green tint.

In a few discussions on cpfmarketplace.com, it was theorized that the E2E reflector was causing the green tint and it was a lottery whether the factory reflector had the green tint. Instead of buying a new bezel/reflector, I tried re-silvering the reflector. The tint was still green.

Because of the work involved in putting another LED on the Veleno drop-in, I decided to try to find a deal on a Surefire KX2 LED Conversion Head. When I received it after a week, the tint on my new KX2 was also green. I had also taken a very long way to get to a E2L Outdoorsman.

Determined to get the light I wanted, I disassembled the KX2 using a heat gun to release the ample amount of glue that Surefire used on the threads to hold the head together. I unsoldered the leads from the LED board, removed the two hex screws holding the LED board to the drop-in and pushed the LED board out.

I then unsoldered the old Cree XR-E and reflowed soldered in a new Cree XR-E (R2 bin). I reassembled the KX2 using Arctic Silver 5 Thermal Compound underneath the LED board and when I first tried the light the hot spot was off center. I centered the LED and because the threads on the bezel that holds the Surefire Total Internal Reflection (TIR) lens were no longer glued, I was able to focus the beam to a perfect hot spot. And finally I have a neutral tint.

Now that the KX2 is open, I could use another driver, maybe try a McR-19XR reflector or an XP-G LED; but it’s been a long road to get here, so maybe I’ll wait a while.

September 19, 2010September 27, 2017

Soldering High Brightness LEDs

A year ago I saw this Youtube video where Steve Dahl at DigiKey demonstrates a method of soldering high-brightness LEDs to a Metal Core Printed Circuit Board (MCPCB) using a heat gun.

Though I’ve seen an electric skillet used for reflow soldering, I decided to try using the above technique when I wanted to replace an LED on a drop-in. I ordered some neutral Cree XP-G LEDs from DigiKey, some 16mm circuit boards and some LodeStar solder paste.

I don’t have an expensive heat gun – just one for removing paint. I thought if I used my infrared thermometer, I could measure the temperature at the tip of the gun and when it was maintaining the correct temperature, I would hold the board/LED in the heat.

I put dabs of solder paste on the contact pads where the LED would be soldered and placed the LED on the pad. It doesn’t need to be precise because the solder will only flow onto the contact pads.

The Cree XP-G specs (PDF) have 215 degrees C (~419 degrees F) for Peak/Classification temperature. When my thermometer read that, I put the board in the heat. (In the video, they use 600 degrees, which seems way out of spec and may be the reason the board turned brown). In a few seconds the paste melted and the LED centered itself, just like in the video. I immediately turned the heat off and kept the fan running to cool the board.

In the photo, the bottom board has been soldered. The upper left board shows the amount of paste I used. The upper right board has the LED on it before soldering.

July 11, 2009March 25, 2019

Ultrafire C2 modded with a Cree MC-E

In late 2007, I bought a couple of Ultrafire C2 flashlights. They were nicely made for an inexpensive flashlight and they used Cree XR-E LEDs (P4 bin).

Last fall, I modded one of my C2s with a Seoul Semiconductors Z-Power LED P7. The P7 is a quad die LED. I made it direct drive running off a single Li-Ion 18650 battery. There were mods that could be made for a circuit board to drive the P7 but I was too lazy to make one.

I recently found a 3-Mode Regulated Circuit Board for Cree MC-E and SSC P7 LEDs (SKU 1217) sold by Shiningbeam.com that advertises an output current of 2500 mA on high. It has only three modes: high, medium and low. The 17mm diameter of the board is a direct fit in many pills, including a lot of P60s and the Ultrafire C2. I used one of the boards to improve a DealExtreme P60 MC-E drop-in.

I had another of the Shiningbeam boards and a quad die Cree MC-E LED, so I decided to put them in my other Ultrafire C2.

I soldered the LED to a trimmed down DealExtreme Star Connection and Heatsink for Cree MC-E LED Emitters – Parallel (SKU 16545). I’m not sure why they call it a parallel board, because each die is separately addressable with the connections on the board. I soldered all the anodes together and all the cathodes together, so it would run in parallel.

With a fully charged Li-Ion 2400 mAh battery, I measured the current at a little over 2700 mA through the tailcap. After five minutes, the flashlight was hot, but not so hot that I couldn’t touch it. It also dimmed slightly from initial turn-on but it is still brighter than my P60 MC-E mod.

With a McClicky switch in the tailcap, this is a really nice, bright flashlight now.