Thorfire S70S Mods, MTN FET driver, lighted switch

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JasonWW
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Thorfire S70S Mods, MTN FET driver, lighted switch

I bought an S70S because they were on sale for a very good price lately and I wanted to see their construction. I decided to post my mods as I haven’t really seen any other threads on modding this light.

First off, I really did not like the stock User Interface. I ordered a 30mm FET driver designed for the L6 from Mountain Electronics using the D4 UI or RampingIOS. Unfortunately the ramping is not so smooth due to using a single FET on a 2S driver. I’m thinking Richard doesn’t have time to modify the code to make the ramping perfect. It’s fine, though.

I trimmed the edge with a Dremel to make it 29mm. I’ve heard some S70S use a 27mm driver so verify which you need before ordering.

Here are the factory driver wires.

Make sure to label one of the white wires as there are 2 of them.

Here is where to attach the wires to the MTN driver.

In order to have a custom lighted switch I had to get creative. There are no outputs for a switch light on the MTN driver. I had to run switch light power directly from the positive side of the mcpcb. You can see the extra red wire here.

Don’t try running it from the main led black wire on the driver. It will cause a small current flow and the main led will glow when off.

Here is the stock switch pcb.

I removed the stock leds and used my own blue led on the 1000 ohm circuit where the green led used to be. This was too bright and had too much drain. I later went back and swapped it to the 5000 ohm circuit. Even 5000 ohms is too bright. I’m going to try a 24,000 ohm led soon to reduce parasitic drain even more. I also rotated the switch pcb so the light looks better.

Here is the final look.

Here are the notes I made along with performance data. I forgot to measure stock candela. After the driver swap I measure 125kcd or 707 meters.

Parasitic drain on the stock light is very high at 4.43 millamps. I think this is due to the particular green LED used and the small 1000 ohm resistor. When I installed the new driver I wired up the stock green led as a switch light. I know the MTN driver only draws 0.078 milliamps once the mcu goes to sleep. The green led drew 6.45 milliamps! I swapped to blue led and a 5000 ohm resistor and got the drain to 1.2 milliamp. I will try a 24k ohm resistor next to see if I can get the drain down to below 0.3 milliamp. (EDIT: I swapped to 24k ohm and get a 0.320 millamp drain. This still seems high considering the BLF Q8 can get 0.123 milliamps and that’s with 2 leds.)

The factory rating of 3800 lumen turned out to be a pretty low 2900 to 3000 lumen stock. The FET driver definitely wakes up the stock xhp70 to about 5,000 lumen.

I get a definite donut hole pattern with this light which is something I didn’t see with the stock Convoy L6. You would think the heavy OP reflector would blend it better. The stock centering ring height is 0.8mm. I tried shimming it up to 1mm, then 1.4mm with no real change. No biggie.

Edited by: JasonWW on 11/01/2018 - 20:59
ZozzV6
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Interesting that you got low factory lumens. I had about 5 S70S in my hands lately and all pushed 3800-4100 lumens. With an R100 bump one got 5100 lumens.

JasonWW
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Lumens are such tricky things to measure. Silly

Were yours drawing about the same amps?

CRX
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Cool Thumbs Up

ZozzV6
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JasonWW wrote:
Lumens are such tricky things to measure. Silly

Were yours drawing about the same amps?


The last arrived was the best of all I had. I still have it on shelf. Just measured now:
5.4A
4032 lumens
everydaysurvivalgear
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Hey Jason my S70 is from the first batch made and stock does like 6.5 amps at the tail cap. Its over 4000 lumens can’t remember the exact numbers i have it written down in a book but it scores higher than my stock L6.
Reason i say its from the first batch is because after the first run or first few runs they modded the driver to have slightly less output.

How does it feel compared to the L6? Did you get all the extras? Mine came with a spare lens and different tail caps and few other items? Hows the sling feel?

contactcr
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ZozzV6 wrote:
JasonWW wrote:
Lumens are such tricky things to measure. Silly

Were yours drawing about the same amps?


The last arrived was the best of all I had. I still have it on shelf. Just measured now:
5.4A
4032 lumens

Do either of you guys have any candela measurements, either stock or modded? I assume ZozzV6 has tried SMO with this too?

ZozzV6
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The L6 SMO reflector fits but not measured with it.
OP reflector measurements:
Stock S70S:
5A
3816 lumens
68900 cd

R100 resistor modded:
8.2A
5112 lumens
87800 cd

JasonWW
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everydaysurvivalgear wrote:

How does it feel compared to the L6? Did you get all the extras? Mine came with a spare lens and different tail caps and few other items? Hows the sling feel?

The L6 feels much better. I don’t like the battery tube design. It’s fairly slippery.

It came with the extra lens, etc…

I haven’t used the sling.

JasonWW
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contactcr wrote:

Do either of you guys have any candela measurements, either stock or modded? I assume ZozzV6 has tried SMO with this too?

I forgot to measure the candela of the stock S70S, but after the FET driver I get 125kcd or 707 meters.

It’s very peaky, though due to the beam shape.

JasonWW
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I swapped the switch resistor to 24k ohm and got 0.320 milliamp. Much better. It still seems high compared to the BLF Q8 which draws 0.123 milliamp and that’s with 2 leds. Question

I misjudged the resistor size. I thought it was 0805, but I think it’s 0603. No biggie, it still fits. I used hot air to try and simplify things.

It’s still plenty bright.

Here’s how it looks in real life. I adjusted the camera settings to match what I see in a semi dark area.


.

NeutralFan
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I’m surprised your green switch LED draws more current than blue. From the lighted switches I’ve done, green is 3 times more efficient than blue – green runs at 0.07mA vs blue at 0.21mA.

I’d rather use my flashlight around the house than turn on the lights.

JasonWW
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NeutralFan wrote:
I’m surprised your green switch LED draws more current than blue. From the lighted switches I’ve done, green is 3 times more efficient than blue – green runs at 0.07mA vs blue at 0.21mA.

There is more than one manufacturer of these little leds and they can be designed with different parameters. I’m guessing Sofirn, or whoever assembled the switch assembly, used a really low output green led. This is why they used such a small 1k ohm resistor.

I’ve got some lighted tail switches from Banggood or Gearbest that are blue and only use 330 ohm resistors and they are not even that bright. I think this is another example of a weak LED.