Luminus SFT40 test

283 posts / 0 new
Last post
Barkuti
Barkuti's picture
Offline
Last seen: 5 days 14 hours ago
Joined: 02/19/2014 - 14:46
Posts: 5635
Location: Alhama de Murcia, Spain

Pacolux wrote:
R010. Will this driver turn up the current by stacking resistors? I say it because for example in this Convoy driver6V 9,75 | Controlador XHP70.2 para una celda it does not

The link is wrongly done.

I'd be wondrous if people would steer from using the more limited simple post editor, and everything would be editor-unified, but this is another story which involves sb56637; it's not an straightforward task to convert quotes between editors.

 

Is it this XHP70.2 driver you are speaking of?

 

 

So what did you did with it? Big Smile

This driver is a switching, boost type driver. Technically speaking, these driver types are the ones which actually pull current. Others like this or that don't pull current from the battery, they just regulate or accurately limit the flow of current from the battery to the emitter, as they are regulated variable load devices.

These driver types or switching converters are usually designed with a power output in mind. The XHP70.2 driver claims 4800mA of output at the voltage of a 2S emitter (“6V”, or about twice that of a more standard 1S emitter like the SFT40 in this thread). I am sure it does it. However, bear in mind this already is a lot of power, and this driver will actually pull or try to pull a very high amount of current from the battery for it to be so. Let's do some math:

Pemitter = Vemitter × Iemitter = 6.5V × 4.8A = 31.2W

Pdriver = Pemitter / ηdriver = 31.2W / 0.9 = 34.6̅W ≈= 34.667W

Where P is power, V is voltage, I is current, and η is energy conversion efficiency (values used for voltage at the emitter and efficiency stem from XHP50 emitter tests and buck and boost driver threads).

I can't find any cut-off voltage in the driver's advertisement (bad practice), so I'll presume 3V. This means that, when the battery is discharged, the driver will pull up to Ilowbatt = P / Vcutoff = 34.6̅W / 3V = 11.5̅A = 11.556A for high mode, and with a full or close to full battery it may start from Ihighbatt = P / Vhigh = 34.6̅W / 4V = 8.6̅A = 8.667A.

And why did I use just 4V as voltage from the battery when the battery is full or nearly? Well, because there is resistance in between (battery, springs, a switch, etc.).

So, it is safe to say that such 4800mA “6V” or 2S boost driver requires between 8.5A to close to 12A from the battery to work in high, and depending on battery state of charge and other parameters like actual efficiency and etc.

Advice: take out that driver from the flashlight you stuck it inside Pacolux, undo the Wink shenanigan you did and restore its original sense resistor, and be done with it.

I say shenanigan because I feel you probably reduced the original sense resistor a lot. This is like taking a stock car to a tuning centre, and expecting its engine to deliver twice or thrice the horsepower just by reprogramming the control box. LMAO!

I do not mean to say that reducing the sense resistor won't work, but you have to understand what are the potential limits. I once built an SK98 with an H1-A boost driver among many major modifications (pill, switch and shaved XHP50 emitter). Emitter was driven at 4.2A maximum or so (I stuck an R050 over the stock R025 sense resistor, if I'm not mistaken), this is because the boost converter is limited to around 10A of input. I still have it by my side.

The H1-A which is sold now uses an 1.5μH inductor, this reduces its efficiency (they cheaped on it). Initial versions like mine employ a 2.2μH inductor.

djozz wrote:
People always talk about sense resistors, this should imply that a voltage is measured over the resistor and a feedback-loop is in place which makes the current constant. But in many drivers a fat low-value resistor in series with the output is talked about as sense resistor but it is not sensing anything, it is simply a dumb current limiter, and if nothing else happens in the driver, the current will go down with the voltage of the battery.

Not sure which one is the case in this driver.

Many drivers? Not that Wink many. Drivers which use low value resistors as voltage droppers are the least sophisticated, and usually super-cheap. You may find them in seedy flashlights, and also in some retailers (example: 2600mA 2-Mode LED Flashlight Driver Circuit Board @ FastTech). As a curiosity, I remember a driver I found in an SK68 flashlight, it was a low current output boost type driver which allowed the torch to work with AA cells (alkalines, Ni-MH, etc.), but it also handled li-ion cells. I am fairly sure that the sense resistor was used as a voltage dropper/current limiter in the latter case.

 

Fri, 08/27/2021 - 17:12

Please avoid fully quoting lenghty posts, namely with nested quotes. Trim quotes down to the essential. Helps with neatness and legibility. Thanks.

The human mind, and its programming, is at the forefront of a particular battle of The Light vs evil dark forces. Nearly every human being on this beautiful planet “Earth” has some sort of negative mind programming in its mind. And you better take care of your mind programming, or someone else will in this wicked world.

Pip
Offline
Last seen: 8 hours 11 min ago
Joined: 11/23/2019 - 05:56
Posts: 407
Location: Ohio

I reflowed my FT03 with an SFT40 and I think I have a new favorite LED. Current measures 9.63 amps with the HLY cell that came with the light, so I probably wouldn’t put a higher current cell in it. I dont have any way to measure the intensity so I can’t give any numbers on that but it looks impressive.

fogofwar
fogofwar's picture
Offline
Last seen: 1 day 4 hours ago
Joined: 08/19/2021 - 05:38
Posts: 301
Location: Shenzhen, China

Lurker turned into a new poster here. I live in China and I just got a 4x SFT40 Jin Heng JKK80 light. The light runs on 3× 18650 and the seller claims 28A max current draw.

Small black dots have already appeared on top and bottom emitters while a bigger black dot is on the right one. The left one so far looks perfect.

While unfortunate, because it is a 4 emitter flashlight, there is nothing I can see in the beam. I’m just wondering if the emitters will stay this way or get worse? I ran it on turbo a few more times after the black dots appeared (2 minutes at at time for about half a dozen times) but the black dots don’t seem to be expanding or increasing in number. I can live with the black dots as long as the emitters don’t get worse.

Tom E
Tom E's picture
Offline
Last seen: 1 month 3 days ago
Joined: 08/19/2012 - 08:23
Posts: 15065
Location: LI NY

Not sure, but may be a contaminant or particles causing the black dots. Hope it's not the high amps.

On Ali, this JKK80 claims SST40.2 LED's, interesting. I haven't seen/heard of SST40.2's yet, because we are pretty sure the SFT-40 is a domeless SST-40 new (2nd) generation part.

Did you get a "blue" output on max/turbo? If so, it could have damaged the LED's. I'd be surprised if a stock 3 cell/4 LED light this could happen but it's possible I suppose. Are the springs doubled up or bypassed, or better than average quality?

Funtastic
Funtastic's picture
Offline
Last seen: 3 hours 59 min ago
Joined: 06/26/2014 - 02:14
Posts: 2768
Location: New Zealand

I wonder if it’s from left over flux or other contaminate that wasn’t cleaned off. Someone else posted about this in the Convoy thread

Piercing The Darkness YouTube channel – https://www.youtube.com/c/PiercingTheDarkness

Funtastic
Funtastic's picture
Offline
Last seen: 3 hours 59 min ago
Joined: 06/26/2014 - 02:14
Posts: 2768
Location: New Zealand

Tom E – You bet me to it

Piercing The Darkness YouTube channel – https://www.youtube.com/c/PiercingTheDarkness

Tom E
Tom E's picture
Offline
Last seen: 1 month 3 days ago
Joined: 08/19/2012 - 08:23
Posts: 15065
Location: LI NY

Funtastic wrote:
Tom E - You bet me to it

smile Have you heard of SST-40.2's yet? 

Funtastic
Funtastic's picture
Offline
Last seen: 3 hours 59 min ago
Joined: 06/26/2014 - 02:14
Posts: 2768
Location: New Zealand
Tom E wrote:

Funtastic wrote:
Tom E – You bet me to it

smile Have you heard of SST-40.2’s yet? 

Fairly certain that’s just the same that’s currently being used. The gen 1 were burning the bond wires at 8.5A, but no reports of this happening in the Astrolux FT03 with bypasses at over 9A. I was told a couple years ago that the FT03 was using the gen 2

Piercing The Darkness YouTube channel – https://www.youtube.com/c/PiercingTheDarkness

Tom E
Tom E's picture
Offline
Last seen: 1 month 3 days ago
Joined: 08/19/2012 - 08:23
Posts: 15065
Location: LI NY

Ohhh, true - could be right there. From the pic on Ali, it does look like a standard SST-40 we all know now. A domed SFT-40 would have the same bond wires as the SFT-40 I'd assume.

 

fogofwar
fogofwar's picture
Offline
Last seen: 1 day 4 hours ago
Joined: 08/19/2021 - 05:38
Posts: 301
Location: Shenzhen, China

Thanks guys, no blue output – hopefully it’s just contaminants. I’m a little reluctant to open it up again since the flashlight originally had XHP 50.2 emitters but I decapitated them and took off all the phosphor with it.

I live in Shenzhen and I sent it back and the seller Old Jiang (the guy’s name and owner of Jin Heng) replaced my board with 4x SFT40s for 98 yuan.

fogofwar
fogofwar's picture
Offline
Last seen: 1 day 4 hours ago
Joined: 08/19/2021 - 05:38
Posts: 301
Location: Shenzhen, China

So I guess it’s bad news… I took it apart and used some compressed air on the leds. It seems like the black spots are from the emitter itself (see the clearer picture below). I actually don’t think the emitters were overdriven much but don’t have a great way to test. They should have received 7amps at the most while SFT40s are rated for 6amps.

The SFT40s should be from a quite new batch since Old Jiang from Jin Heng just had them restocked. Do you guys think it will get worse? I ran it for a few more times on turbo today without more damage. Although my batteries are no longer fully charged.

Pacolux
Offline
Last seen: 4 months 3 days ago
Joined: 08/14/2021 - 12:12
Posts: 48
Location: España

you have to clean with cotton buds and isopropyl alcohol, pressing hard without fear. Before mounting the reflector, look at the LEDs with a magnifying glass to make sure that there is no trace of anything left.

fogofwar
fogofwar's picture
Offline
Last seen: 1 day 4 hours ago
Joined: 08/19/2021 - 05:38
Posts: 301
Location: Shenzhen, China

I’m afraid of damaging the phosphor layer. I also don’t know what I’d be actually removing since I’m 90% sure the black spots were not there before running turbo. Anyone else try Paco’s method?

Funtastic
Funtastic's picture
Offline
Last seen: 3 hours 59 min ago
Joined: 06/26/2014 - 02:14
Posts: 2768
Location: New Zealand

Had some flux left on the LED which caused a burn mark, used a microfiber cloth and scratched away at it, worked without any issues afterwards.

Piercing The Darkness YouTube channel – https://www.youtube.com/c/PiercingTheDarkness

Pacolux
Offline
Last seen: 4 months 3 days ago
Joined: 08/14/2021 - 12:12
Posts: 48
Location: España

[quote=fogofwar]I’m afraid of damaging the phosphor layer. I also don’t know what I’d be actually removing since I’m 90% sure the black spots were not there before running turbo. Anyone else try Paco’s method?[/quote/]

the match has a nice silicone coating on top even though it may not look like it

fogofwar
fogofwar's picture
Offline
Last seen: 1 day 4 hours ago
Joined: 08/19/2021 - 05:38
Posts: 301
Location: Shenzhen, China

Got it, I’ll give it a while and try to clean it eventually. The Jin Heng flashlight boss also said that it should be no problem. I’ve never seen black spots before even with other flat emitters like Osrams or XP-L Hi. Perhaps the SFT40 surface doesn’t repel flux splatter as well as other emitters? It seems too coincidental that others have seen black spots as well on this emitter more than any others.

EasyB
Offline
Last seen: 4 months 3 days ago
Joined: 03/09/2016 - 15:24
Posts: 2250
Location: Ohio

The black spots will definitely get worse and will destroy the LED if run hard.

It can be caused by flux splatter or other debris. It gets hot from absorbing light and burns and chars which causes it to absorb even more light. If it continues it starts to burn the silicone then down to the phosphor. If the black spot doesn’t wipe off you can try digging it out with a fine tipped razor blade. Then wipe it down with alcohol. You want to remove all visible traces of the black stuff. I wouldn’t worry too much about damaging the phosphor because the LED is basically killed if you do nothing, anyway.

It’s a little surprising that it’s happening on 3 out of the 4 emitters. Could be a lot of flux splatter. If the thermal dissipation is very bad and the LEDs get very hot that can also increase the likelihood of phosphor burning.

ArtieT59
ArtieT59's picture
Offline
Last seen: 1 day 9 hours ago
Joined: 02/25/2020 - 17:55
Posts: 3564
Location: CT, USA

Pip wrote:
I reflowed my FT03 with an SFT40 and I think I have a new favorite LED. Current measures 9.63 amps with the HLY cell that came with the light, so I probably wouldn't put a higher current cell in it. I dont have any way to measure the intensity so I can't give any numbers on that but it looks impressive.

 

I did the same mod (as i think eve talked about), switching the sst40 in ft03 for sft40.. and i got 410 kcd measured with my lux meter at 5 meters. On a Lishen 9.6amp 5000 mah battery. 

 

Definitely an eye opening experience with the SFT40 in the FT03.. It out-throws my L21a sft40 and my ft03's beam isn't even perfectly tuned like the L21a is. 

[FLF] Five Light Friday https://budgetlightforum.com/node/78749

Check out some of my new lights (picture heavy) and quick first impressions of them here: https://budgetlightforum.com/node/77180

My Sft40 beamshots / comparison thread: https://budgetlightforum.com/node/78100

The BLF GT with SFT40 (2300lm, 2700m+ @ 30 seconds!)
https://budgetlightforum.com/node/79561

ArtieT59
ArtieT59's picture
Offline
Last seen: 1 day 9 hours ago
Joined: 02/25/2020 - 17:55
Posts: 3564
Location: CT, USA

Funtastic wrote:
Had some flux left on the LED which caused a burn mark, used a microfiber cloth and scratched away at it, worked without any issues afterwards.

 

I wish i could tag JaredM on this post-  i sent him an sft40 that he told me had black dots on the phosphor, which was probably from me when i was uninstalling it from my EA01... I wonder if he could save the LED.

[FLF] Five Light Friday https://budgetlightforum.com/node/78749

Check out some of my new lights (picture heavy) and quick first impressions of them here: https://budgetlightforum.com/node/77180

My Sft40 beamshots / comparison thread: https://budgetlightforum.com/node/78100

The BLF GT with SFT40 (2300lm, 2700m+ @ 30 seconds!)
https://budgetlightforum.com/node/79561

JaredM
JaredM's picture
Offline
Last seen: 7 months 1 week ago
Joined: 10/31/2011 - 13:33
Posts: 2645
Location: Pittsburgh, Pennsylvania

I attempted to salvage the emitter but there are little chunks taken out of the phosphor now that cause blue leakage. The cct is probably 10,000K or more now (hard to estimate as its exponential). It’s still installed in the TN31 waiting for a transplant. I never boosted the current up from the 7A I was running the PM1 at. I will swap the SFT40 from my incoming L21b to get the beamshots and readings I promised. I’ll turn the driver up to 9.5A as well. Trying to get my hands on a good camera and tripod. Thinking of picking up a Sony A6000 and a decent lens.

https://fundrazr.com/osturaband

No affiliation, just a fan.

ArtieT59
ArtieT59's picture
Offline
Last seen: 1 day 9 hours ago
Joined: 02/25/2020 - 17:55
Posts: 3564
Location: CT, USA

JaredM wrote:
I attempted to salvage the emitter but there are little chunks taken out of the phosphor now that cause blue leakage. The cct is probably 10,000K or more now (hard to estimate as its exponential). It's still installed in the TN31 waiting for a transplant. I never boosted the current up from the 7A I was running the PM1 at. I will swap the SFT40 from my incoming L21b to get the beamshots and readings I promised. I'll turn the driver up to 9.5A as well. Trying to get my hands on a good camera and tripod. Thinking of picking up a Sony A6000 and a decent lens.

nice, thanks for the info and for responding man. Looking forward to it!

[FLF] Five Light Friday https://budgetlightforum.com/node/78749

Check out some of my new lights (picture heavy) and quick first impressions of them here: https://budgetlightforum.com/node/77180

My Sft40 beamshots / comparison thread: https://budgetlightforum.com/node/78100

The BLF GT with SFT40 (2300lm, 2700m+ @ 30 seconds!)
https://budgetlightforum.com/node/79561

Funtastic
Funtastic's picture
Offline
Last seen: 3 hours 59 min ago
Joined: 06/26/2014 - 02:14
Posts: 2768
Location: New Zealand
JaredM wrote:
Thinking of picking up a Sony A6000 and a decent lens.

I use the Sony A6500 with a Sigma 16mm f1.4 lens. It’s one of the best low light lenses available. Matt Gill (Flashaholic) uses the same lens with his A6300 or 400, can’t remember.

Piercing The Darkness YouTube channel – https://www.youtube.com/c/PiercingTheDarkness

fxsniper
fxsniper's picture
Offline
Last seen: 5 days 3 hours ago
Joined: 09/11/2021 - 10:17
Posts: 42
Location: Spain

You think sft40 will be available again soon? And in 4000k or 5000k? I was considerning a Convoy S11 with sft40. But if it is going to delay too long, might as well just get it in CULPM1.

Natewar
Natewar's picture
Offline
Last seen: 1 week 1 day ago
Joined: 10/22/2019 - 20:52
Posts: 107
Location: Pennsylvania,usa

What happened to the SFT-40 led I cant find it in stock anywhere

Funtastic
Funtastic's picture
Offline
Last seen: 3 hours 59 min ago
Joined: 06/26/2014 - 02:14
Posts: 2768
Location: New Zealand
Natewar wrote:
What happened to the SFT-40 led I cant find it in stock anywhere

It’s in very high demand and sells out very quickly

Piercing The Darkness YouTube channel – https://www.youtube.com/c/PiercingTheDarkness

Umpi2000
Offline
Last seen: 3 days 7 hours ago
Joined: 03/15/2017 - 08:06
Posts: 444
Location: Durban, South Africa

Scallywag wrote:
Nice!

So previously, the choice for throw at 2000 lumens was the XHP35 HI. This appears to not just surpass that, but also be more convenient as a 3v led.

This would have simplified the GT back when it was made? 3v with all that room for batteries and heat disipation and a simple driver

JaredM
JaredM's picture
Offline
Last seen: 7 months 1 week ago
Joined: 10/31/2011 - 13:33
Posts: 2645
Location: Pittsburgh, Pennsylvania

Umpi2000 wrote:
Scallywag wrote:
Nice!

So previously, the choice for throw at 2000 lumens was the XHP35 HI. This appears to not just surpass that, but also be more convenient as a 3v led.

This would have simplified the GT back when it was made? 3v with all that room for batteries and heat disipation and a simple driver

Had this same thought the other day. In time I’m sure somebody will do this mod.

https://fundrazr.com/osturaband

No affiliation, just a fan.

Tom E
Tom E's picture
Offline
Last seen: 1 month 3 days ago
Joined: 08/19/2012 - 08:23
Posts: 15065
Location: LI NY

Same setup for the GT SBT90.2 upgrade, and same issue of not being able to re-use the big stock MCPCB (3535 to 5050). Carriers can get converted, driver swap, then the MCPCB/centering piece issues.

ArtieT59
ArtieT59's picture
Offline
Last seen: 1 day 9 hours ago
Joined: 02/25/2020 - 17:55
Posts: 3564
Location: CT, USA

Tom E wrote:

Same setup for the GT SBT90.2 upgrade, and same issue of not being able to re-use the big stock MCPCB (3535 to 5050). Carriers can get converted, driver swap, then the MCPCB/centering piece issues.

 

I don't own a gt, wish I did though.. someday.

 

It's too bad a 5050 mcpcb was never made.. the sft40 would be a GREAT one for it. But the sbt90.2 driver couldn't be used, could it? That's the only 3v driver for the gt right?

[FLF] Five Light Friday https://budgetlightforum.com/node/78749

Check out some of my new lights (picture heavy) and quick first impressions of them here: https://budgetlightforum.com/node/77180

My Sft40 beamshots / comparison thread: https://budgetlightforum.com/node/78100

The BLF GT with SFT40 (2300lm, 2700m+ @ 30 seconds!)
https://budgetlightforum.com/node/79561

ArtieT59
ArtieT59's picture
Offline
Last seen: 1 day 9 hours ago
Joined: 02/25/2020 - 17:55
Posts: 3564
Location: CT, USA

JaredM wrote:
Umpi2000 wrote:
Scallywag wrote:
Nice! So previously, the choice for throw at 2000 lumens was the XHP35 HI. This appears to not just surpass that, but also be more convenient as a 3v led.
This would have simplified the GT back when it was made? 3v with all that room for batteries and heat disipation and a simple driver
Had this same thought the other day. In time I'm sure somebody will do this mod.

 

where's my beamshots, JaredM ! Hah Wink

[FLF] Five Light Friday https://budgetlightforum.com/node/78749

Check out some of my new lights (picture heavy) and quick first impressions of them here: https://budgetlightforum.com/node/77180

My Sft40 beamshots / comparison thread: https://budgetlightforum.com/node/78100

The BLF GT with SFT40 (2300lm, 2700m+ @ 30 seconds!)
https://budgetlightforum.com/node/79561

Pages