Skylight's 8th BLF OL contest entry, modified flashlight [DDH ML778SL FINISHED]

Giveaways and Contests
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Final update: DDH ML778SL finished on 01/03/2021

Mon, 10/26/2020 First update: Host chosen, waiting for parts

I have chosen the host and leds that I will use for this modified flashlight.

I already have the host, ordered it one and a half years ago from Taobao, forwarded it with a Taobao agent. The flashlight is sold only as a host and is called the Dongdonghai D8A. I also have the long 8 18650 extension tube on order.

The DDH D8A is similar to the Astrolux MF01 but a little longer and with the head diameter of a Sofirn SP70. Below is a size comparison of the three flashlights.

I have planned since I ordered this host to modify it somehow instead of using the original configuration. To see how it works I put in a single XHP70 led with a TA driver. It works well and has a nice beam but it has not seen much use because I already have a few flashlights with a single XHP70. The DDH D8A is big enough for a more powerful configuration.

This is the host for my build, the DDH D8A.

With hot glue I made a transparent switch cover instead of the red one to let the light of the lighted switch through. I will need to replace it with a more flexible rubber because it is too stiff and gets sticky when warm.

These are all the parts of the host and a size comparison with the Emisar D4 to show you how big the reflector is. It has 80mm diameter and is 70mm high.

Some measurements

First, I wanted to use a quad or triple reflector with XHP70 leds but then this seven-leds-reflector appeared on Kaidomain. Now I want to fit it inside the D8A with seven XHP70.2. :sunglasses:

The reflector is a little too big for the front opening of the flashlight and the led holes are too small for the XHP70 leds. I will need to take away 1.5mm from the outer edge of the reflector and widen the reflector holes from 8 to 10mm. Then I need to build a copper spacer to fill up the empty 4-4.5cm of the longer reflector as the multi-led reflector is only 3cm high. Even if it does not fit yet, I already like the look of this seven-led-reflector in the D8A.

Currently I am waiting for the XHP70 leds and I will also order the copper for the spacer.

What I have

- Host Dongdonghai D8A

- 7x reflector

- Copper rod and 65mm plate for the spacer

  • Soldering paste, thermal paste, drill, metal saw, dremel and other material

What I need

- 7 XHP70.2 leds (3x 3000K, 4x 5000K)

- More copper discs for the spacer

- 8 18650 tube

- Maybe a Lexel driver? (with resistors, not sure if the 7135’s can handle 7 XHP70 or will overheat)

  • Aux led boards?

Thu, 09/17/2020 Original OP: entry, brainstorming

This is my topic for a modified flashlight for the 8th BLF Old Lumens contest.

I still have to decide which host to use and what leds and driver to put inside.

Could be a big host with optics and SST20 or a few XHP70 in a reflector, don’t know yet.

Stay tuned! :sunglasses:

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Build video

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OP: Choosing host and leds, parts list

Post#2: Build video

Post#12: Drilling reflector and switch retaining ring

Post#19: Seven XHP70 and long tube arrived, dremel reflector edge

Post#28: Drilling and filing, parts line-up

Post#28: Drilling copper plates, sawing copper rod, preparing copper spacer

Post#32: Fitting glass lens and measurements

Post#33: Preparing driver, modifying battery carrier

Post#42: Soldering MCPCBs to copper plate

Post#43: Testing and final assembly

Post#46: Beamshots and picture gallery

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Go for it :wink:
Good luck with the mod!!

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Well, I’m looking forward to it (and subscribed to the thread) :+1:

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Skylight, :smiley: Happy to see you are in the competition :+1:

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Looking forward to seeing what you come up with Skylight

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Thanks for your encouraging comments, MascaratumB, Scallywag, CNCman and pinkpanda3310 ! :+1:

After a month, I have made up my mind which host and led configuration to use in my OL contest modded flashlight this year.

I updated the OP with pictures of the host and the reflector. It will be a big host with 9cm head diameter and optional 8 18650 tube, a heavy copper spacer and seven XHP70.2 leds. :heart_eyes:

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Good to see you have the design nailed down Skylight. Looking forward to the mod. :+1:

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That should be some powerful light! :+1:

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He wants to make it a sky…light :smiley:

:sunglasses:

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Thanks for the nice comments, MRsDNF, MtnDon and MascaratumB. Sorry if I am replying late but here are the updates.

A few days ago I drilled out the holes of the seven leds reflector. I used a 10mm drill bit.

Before drilling

Half done with drilling

After drilling, I removed sharp edges and cleaned the reflector with air. It looks nice again and the holes are a little bigger now.

The switch retaining ring had to be drilled, too, to allow fitting a Convoy L6 switch cover. The self-made silicone covers did not work properly.

Switch retaining ring before drilling


After drilling and filing


Last Thursday five XHP70.2 leds arrived. I will use four of them in this flashlight. They are 5000K 90 CRI with N2 3C bin. I bought them at the HotRed Official Store on Aliexpress. XHP70.2 90CRI

Compared to a XHP70.2 P2 3A with 70 CRI (bottom right corner) it is clearly visible that these leds have the for high CRI leds typical orange phospor cover.

The four XHP70.2 look great in the reflector. The for now empty spaces will be fitted with three XHP70.2 P2 7A 70 CRI leds to achieve a rosy 4000K light.

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Someone likes walls of light :smiley:

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It would appear so. :heart_eyes:

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That is true indeed. Especially high cri and rosy walls of light. :heart_eyes:

But I hope it will give me a big hotspot with a little throw as well.

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This is gonna be nice ! :+1:

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Wow 4*XHP70 is going to be Sooo bright (and HOT) ;)

A bit off topic but what is your opinion on the Deko drill? seems like it is better than most crappy Chinese power tools.

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Thank you, Rdubya18. :slight_smile:

That’s for sure. I added some new pictures below where you can see that I will actually use 7 XHP70 with a big copper spacer underneath.

I didn’t want to make an advertisement for the Deko brand :innocent: but it is a great drill. It is one of the few drills on Aliexpress that is brushless. It is said that brushless motors are more efficient, stronger and better than brushed motors. The Deko drill is indeed strong with 58Nm torque and it even has an impact mode for drilling walls. It has a 40Wh battery that seems to last forever, two speed settings and a very handy percentage display on the battery pack.

I am not an expert in drills but compared to the old drill with Ni-MH batteries that I used previously this is a whole new world. So far, I found no flaws with this Deko drill and I would recommend it. [end of advertisement :wink: ]

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Last week the other three XHP70 leds for my project arrived, together with the long tube for 8 18650 batteries.

The four XHP70.2 5000K 90 CRI (N2 3C) and the three XHP70.2 3000K 70 CRI (P2 7A), in the right picture the configuration they will have:

The seven leds reflector is full now. :smiley:

Here is the long tube, together with the battery carrier:

What I did in terms of modifying was to grind away part of the egde of the reflector with my dremel to make it fit into the flashlight.

It went quite smoooth. I feared to scratch the reflector with the aluminium particles but they went outside and left the reflector untouched.

Before

During work

Almost there …

… and it fits.

The edge is a bit textured now but not too rough so I will leave it this way.

Current status

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Sweet light Skylight :sunglasses:
I really like this very challenging mod your doing. Great job and I’m looking forward to more pics :heart_eyes:
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