My first idea for a S2+ triple mod

Flashlight Modding and DIY Parts
1

Hello people from BLF, I’m new here and have been following some threads since I got my first Convoy S2+ a while ago. My idea is to build a high-CRI triple out of this host (or one of the others I’m awaiting delivery), and I’ve already done a bit of reading on parts. My checklist already has a high cri nichia 219C triple set/board, spacer and optics.

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But I need assistance with the driver. I see a predominance in the use of FET+7135 drivers, but for all I’ve seen, it’s not for me. I like the 7135*8 setup a lot, and my intention was initially to use the new convoy driver with biscotti firmware. The idea I had, thou, is to swap the attiny13 mcu with an attiny25 and go for the full bistro experience (clip and programmer also already on the checklist), maybe stack a couple more 7135 chips for extra regulated turbo punch, and if everything works, make the same mods to the drivers on my other lights.

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Is this possible? Is it worth it? Are 7135 drivers ok for this build (I see a lot of threads for fet, but few about 7135s for or against)? I’ve found only one thread here about swapping MCUs, but I don’t think it fully explained if the flashing of bistro was successful, I don’t know if bistro would work in this setup without modifications of if it would even work without heavy rewriting.

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EDIT: I thought I might add: Currently, all my 18650 cells are protected

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Help :smiley:

2

7135 chips get hot if not cooled properly, then they throttle output

also the heat transfer of stacked 7135 is not good
you also can get unpleasant result of temperature protection in Bistro with too much heat from the 7135s

Especially Nichia 219B have a low forward voltage which gets more heat to 7135 chips

3

I have my S2+ converted to a Nichia 219c triple (I used this product).
On a DD driver I get approx. 5-6 amps and, given the emitter profile, I would say I wish I had more. 219 with my bin/tint are not the newest and have more heat/less output. It is bright and looks great with high CRI though.

What are you going for, do you have a specific lumen output in mind?

ps: Welcome to BLF! I have been to Brazil once and I still remember what a beautiful country it is.

4

Have you seen the LD3 driver or H17F ? Both offer abit diffrent options then the normal fet or 8×7135 drivers.

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+1 for the LD-3 driver, you can choose from multiple outputs and additionally you can change your output yourself electonically, without the need to solder new components!

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I shall add I only have protected cells, thus another issue with FET, at least from what I’ve read so far

@MILSPEC
I don’t have a specific lumen output in mind, my goal is to have a bright high-CRI light, neutral to warm tint. I use my current light (xm-l2) in medium (40 of a 2.1 amp driver, will swap for a 2.8 amp driver eventually) most of the time and use the 100 turbo in short bursts. I’d like to have a similar medium, but have not much need for the same high. This is why I don’t think FET is the ideal for me, but I’m not exactly experienced in the topic.

One thing I know is that I’m not interested in super super high output turbo modes that get the light to hot to hold in 30 seconds, I’d like to be able to use turbo for more than a few minutes before either the driver steps down or I do because of the heat. I have a Nitecore rated 1000 lumen turbo that looks reasonable to me, I don’t know if this triple setup I wish to build could reach that

@Lexel
How bad of a throttle? I don’t intend to use highs for long periods, most of my use are around 1 amp on an xm-l2, would be a little higher if I had ordered the 7135*8 driver, rarely going for the turbo, with I estimate around 800 lumen

@Lowtech
These seem interesting, how feasible it is to get their firmware customized? H17F seems very cool, but very expensive also…

7

Why not JAXMAN E2L?

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Read all the info on the drivers, both seem to have great options.
But you cant change more then whats avalible to change in the setup.

But i have to say that a LD3 is probably a good option for you if you want to limit the output.
As you can buy them in a 3/6/9/12 A setup and then change it -/+1 A or something like it.

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@Serp
I’ve already got a Convoy light and already ordered a couple more, I’d like my remaining budget to be spent on the parts for this particular project (listed in the first post) as this is what I’m looking forward to having fun with

@Lowtech
Thanks for introducing these drivers, I like them very much, but just find them expensive (I already have a nanjg 105D driver and a couple of the new convoy drivers on the lights in the mail). Maybe overkill? I might try one of them them in the future once I have a budget for this kind of project again (and by then I will already have the LEDs and spacer from this project to reuse). That is one of the reasons for wanting to swap the MCU and try to flash a more configurable firmware like bistro on a 7135 driver, but as I read I see FET+7135 is not the devil I was making of it, just not a fit for my preferences.

I get since no one is encouraging me to pursue an MCU swap that it’s not a common thing to do. Maybe I’ll risk one of my drivers to clear a path and post my results once I get the parts, regardless if I reach my goal or not

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You could do an MCU swap to get the attiny25 and Bistro, but you will have to do some reworking of either your hardware or the FW or both. Bistro is a two-channel FW and will not work very well on a single channel driver without modifying the code to do so. If you are prepared to learn to alter code and flash FW it wouldn’t be too difficult to make it one-channel.

I will just mention that the FET+1 works very well. You don’t have to use the 100% turbo mode if you don’t want to; you can use any mode. The fast PWM works very well to dim the brightness. As mentioned above the 7135 chips can generate a lot of heat which could cause problems for them. With the FET you don’t have to worry about that.

However I won’t discourage you from going the many-7135 route. With the FET the brightness goes down as the cell voltage drops, though if I’m being honest this is not a big deal in actual use. The current might drop by a factor of two going from 100% to 15% state of charge leading to the brightness falling to ~60% of the original brightness. This is significant, but dropping 40% is not a huge amount and you still get good output for most of the battery discharge. The 7135 chips also only regulate for part of the battery discharge, depending on the output you use.

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@EasyB
“With the FET the brightness goes down as the cell voltage drops” - this is one of the things that make FET not my type, but if this is not as dramatic as I imagined, it might not be as big of an issue. The MCU swap is becoming more of a fun project (I have a little experience with javascript, so I’m no stranger do programming logic). It is looking more interesting to use it for my single emiters and I might have been to eager to make the 2 projects into 1 (the triple high-CRI + a custom driver)

On mountain electronics there is a fet+7135 with a bistro option but the pictures show an Attiny13A. Should I assume the bistro version will come with an attiny25?

And I’d like to thank you all so far (and everyone that drops their 2 cents afterward) for your tips! This project is getting more interesting, even if it ends up not exactly what I had planned initially

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The brightness falling with a FET is not so dramatic IMO, but with your planned triple 219c, which would have a very low Vf, a regulated driver makes more sense for your needs. As long as the 7135s can handle the heat. Have fun with the mod!

Yes, the bistro version comes with the 25.

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H17F. Very granular control, excellent temp control and associated tuning. A great UI.

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Parts ordered!
They’ll take a long time to get here (specially the programming equipment from aliexpress) but I’ll come back here once they start arriving and’ll start the process of:

- Modding a convoy biscotti driver into bistro by swapping the attiny13 mcu with an attiny25 mcu, and replicating the process in other convoy drivers if I’m successful (the firmware source has instructions for single channel driver). This is the “have fun” part of the project.

- Making one of my S2+ hosts into a high-CRI nichia triple, the easier mod since I only need to drill the pill and solder/de-solder the driver wires. This the practical part, since it will probably be my edc.

- Adding additional 7135 chips to the driver, aiming for 3amp max (+1 chip) for a single led light, maybe more if this driver end in the triple, and replicate this for other drivers if I’m successful. This will be the mix of practical and fun.

See you in something like 6 weeks :smiley:

15

Nichia triple mod done!

Adding 7135 chips in one driver done!

ATtiny13 chip removed from one of the drivers, ATtiny25 replacement in progress!

See here: What did you mod today? - #3296 by Persechini

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I built 2 tube lights (generic s7 aka 3 AAA or 18650 driven)

I used the 3x219c format and love the tint.

but

6x 7135 and 8x 7135 really don’t differ much (noticeable but barely).

and the turbo has almost never worked right. it acts like LVP but on any cells including fresh cells. one step down works fine but I did not know enough to deal with programmable options.

the LD3 sounds like the way to go.

.02

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Well, my adding of additional 7135 chips over existing ones so far was unsuccessful, I couldn’t solder in such a tiny space with my limited experience, so I think I’m retiring that idea.

I did manage to solder and ATtiny25 in my Nanjg sacrificial driver, but loosing 2 solder pads in the process, and until my usb programmer arrives I’m unsure if the driver is still functional (chip came blank). Any tips for when solder pads peel of?

On the plus side, I did 2 simple LED mods to 2 other flashlights, switching the Xp-L HI on my clear C8 and clear S2+ for a 5000k Nichia 219C (D320 bin 70 CRI for the C8 / D280 bin 80 CRI for the S2+). I prefer the 5000k tint on them over the 6500k of the Xp-L that came with the lights or even the 5000k from another Xm-L2 I had

I guess that’s all it until I can try reprogramming the chips. Desoldering the drivers from the pills has been my biggest peeve, as it makes a mess and I’d much prefer a retaining ring. I wish Simon sold brass pills for his lights and the corresponding retaining rings in his store.

I’m loving the nichia leds I’ve put on my lights so far, makes me wonder why more flashlights other than the one meant to be high-CRI don’t come with nichia leds. Any insights?

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TL:DR My triple XP-L lights are IMO much more practical in terms of output and heat.

I have some 219B flashlights that I like a lot and I even have a warm 219A triple that pleases me :slight_smile:

However IMO, my best triple is a 80+ CRI XP-L 5A3. You’ve mentioned not wanting to run at very high currents. Neither do I. The XP-L is much more efficient than the Nichia emitters and I believe I get much more output at the “pedestrian” currents (6A with long leads on the DMM) my light operates than I would with 219C emitters.

I have a 3A triple 219B that’s a very nice flashlight. Triple XP-Ls would be much brighter at 3A. The triple XP-L mentioned above is great on the medium modes and at 6 plus Amps on max has a nice kick to it that I really like. XP-L emitters give me very good output at sane currents.

19

A long time has passed since this idea of a mod first came to mind. A lot have changed in what I know, what I want and what I like from flashlights.

My S2+ triple now is the bearer of my FET+1 driver, with all other convoys having 7135*8 biscotti drivers.

If at first I had only a couple of protected cells because unprotected where expert batteries, now I have all but one. I have added a ton os laptop salvage batteries and a few unprotected 30Qs and GAs (or 35Es, thanks for the lack of certainty, liitokala) to the mix. The rewrapped panny Bs I have are now striped of rewrap and protection circuit, as are the 14500 sanyo that was inside the keeppower brand and a blue 14500 that was a nitecore, which I don’t know the OEM

Back to the S2+: with a bypassed spring this monster now drains 12Amps on turbo with a full 30Q, 10Amps in the liitokalas GA/35E, and as nichias usually do, generate an unbearable amount of heat. Turbo is just for show now, it heats up and becomes painful to hold in less than a minute, but with 5 mode, the second to last is basically what turbo was with the biscotti driver and still has some wow output but takes several minutes for the heat to make me want to turn it down. I tried calibrating the stepdown, but still haven’t gotten it quite right (to the point I could go turbo and it would step down before I’d do it myself)

But having such a monster (which will be having a monster brother when my D4 arrives) is ok. Now I know having a flashlight collection is not about having a lot of all-purpose lights. My single emitter 7135*8 S2+ can take it’s place as a more general purpose light. My nitecore HC30, despite not being the neutral white version I wish I had know about before purchasing it, combined with a skilhunt all elastic headband, get the 1st spot for my camping light.

I have also made amends with my inability to solder small components, and I’m struggling a lot more with flashing than I though I would. No biscotti to bistro mod for me, I guess, but maybe I’ll be able to flash andúril on my emissars, who knows

Anyway, this post is an ode to what I have learned and experienced so far, and for whatever my budget allows me to learn and experience in the future. The ride is a fun one.