OK I like to mod a SRK with 3 x nichia 219b high CRI emitters. At $2,20 each on a star reasonable priced.
I understand they are not very hot running so that is nice for the poorly cooling SRK host
But I do not want to blow them so how to proceed?
Put the leds in series to lower current through them?
I think about using the BLF V2 driver from the RMM group buy but have two V1 sets as well those need to be put together so it driver adaptation is needed maybe using this is easier, right? (Though I need info how to change it, still big noob here)
I would keep the leds parallel or you need a totally different type of driver, and the batteries can not be kept parallel.
The V1 version of Nichia 219b runs at a low voltage so it must be easy to get them at any current.
If you keep the original SRK led-board which is aluminium and non-DTP, I would keep the current/led under 2A, that is 6A total. If you go dtp-copper, you can run at 3A/led, so 9A. The RMM group buy driver is 11.2A, with copper ledboards you may just get away with that, or you can remove 7135 chips (350mA/chip) from it to lower the current.
At 9A, expect an output of ~1400 lumen, which is almost half of what cool white XP-L emitters put out. But with great tint of course
Yes, just take away 7135 chips until the desired drive current is achieved. As far as keeping the original SRK MCBCB, I do not think this will be possible with a 3x SRK anyway. All of the 3x LED SRKs I’ve seen have used XM-L/XM-L2 sized emitters and the MCPCB won’t be suitable for installing 3535 sized LEDs. Therefore you might as well use dtp-copper such as Noctigon or SinkPAD.
Thanks
Thought about putting the 219s that come on a copper star with the stars on the existing ALU plate, metal containing thermal grease at the place where it rests on.
219 are cooler in operation right?
Feels strange to remove chips from the carefully build V2 driver (and well I only have 3 of those and 6/SRKs to mod so full power is nice to keep.
Will post the link to the V1 version later because those are not put together yet.
Yes I understand the output of the light will not be super as can be, but a floody high CRI light seems very useful working at night/dark places or use as camping torch with a diffuser.
Cooler than what? (eg 219b @ 3A vs XM-L2 @ 1.5A?) I doubt that they are significantly more efficient (they are probably less efficient) so if you use a high drive current they will be hot!
Do you mean that your SRK lacks a shelf? I mean that the SRK only has an MCPCB which is screwed to the reflector. Is that the case? If so you’ll have to limit the drive current more. Flipping the stock MCPCB and placing it under the copper DTP stars will hold them in place, but it will not allow high drive currents.
I know and it is my understanding that the 219s are not high current LEDs, hence a good first modding project (first for modding and first SRK since cooling is less of an issue so less modding and practice for the second)
Djozz posted a graph above, please take a look at it. In an SRK with 4 fully charged batteries I would expect the 219b to operate at whatever drive current you provide. Saying that they “are not high current LEDs” is probably very misleading (to you) in this situation. Djozz clearly took the tested LED up to 5A - I doubt that 3x 219b will survive 5A with no shelf for long at all. Limiting the current to a low level at the driver will be required IMO.
Personally I don’t possess a shelfless SRK or have experience with “floating” LED stars. Hopefully someone else can chime in with some advice on how high a drive current is acceptable in that scenario.
aha, lol, ok well the V2 is going to be sued then.
Now this has an impressive amount of chips, how many should be removed?
There is 1 for the moonlight (the 2 o’clock inner ring if I remember correctly) that need to stay, but if desolder a few from the outer ring does it matter which?
With the copper boards I would aim for a little higher, 9A, so 24 chips. And there’s no current ‘loss’ with current regulators, if the input voltage is enough (which is very probably the case), they will push their rated current through the leds.
I did the same with a six XM-L SRK. all i did was cut a custom copper star plate ( 1/8th thick) and pressed it in the SRK head, then installed six 219B emitters, and used the JB driver with stock lead wires, ( only spring braid mods) its bright, and high CRI
Topic here: >> 2000+ Lumens from a Nichia 219B 92CRI ?
I would just use the stock driver and wipe everything off of it to use as a contact board. Then wire a nanjg three amp driver between the old driver and the emitters. Then wire the emitters in series. Easy peasy. Make sure they are on noctigons. The sideswitch works on the nanjg too you just have to solder it to the second pin on the MCU. Old lumens has a great post with pics for doing that.
I would also find someway to make a shelf. If this is one without the pill and floating in thin air you need to do that for sure. If it’s one that sits on the rim so it can transfer some heat that is probably going to be OK. Just make sure you use some good thermal epoxy and epoxy that big star down. Take that old big round star and flip it over to mount your new emitters on. Sand the other side down so it will make contact with the light for thermal transfer. I would even sand that little rim down so it’s bare aluminum instead of being anodized.
Thanks for all the input.
For starters I want to keep it simple.
So making a new pill or decent heat sinking is not something I see us do, where some soldering is feasible as rookies.
So the copper stars on the stock ALU shelf and some thermal grease to let that pass on more heat then it does now.
Because of the emitters this one does not need a super output just some nice good color rendering flood.
I think you made a typo, I’ve added strike-through in the quote. Series will not work - to use a Nanjg-105c/d type driver those emitters would be in parallel, just like with the stock configuration. Using a Nanjg isn’t a bad suggestion though. Slaving a second one would also be a possibility for a newbie (rather than stacking 7135s). EDIT: Actually that is a bad suggestion. If The Miller can’t flash the driver then The Miller will be unable to change the Nanjg from a clicky firmware to a momentary firmware. The clicky firmware wouldn’t be appropriate for an SRK.
You might just get away with using the stock driver and yup just use some good thermal grease on the shelf, metal to metal with a thin layer of grease or epoxy is best. You could even epoxy something from the inside if you want for more heat transfer. Go to your hardware store and see if they have some washers that fit inside, then epoxy that to the bottom of the star and if there is a gap between the washer and the sides of the light, jam something in there like copper wire or even tinfoil folded up really tight. Then use the screw hole to feed the wires through. There are more than one ways to skin that cat.
If The Miller can’t flash the driver then The Miller will be unable to change the Nanjg from a clicky firmware to a momentary firmware. The clicky firmware wouldn’t be appropriate for an SRK.