GB BLF LuckySun D80-SE Need long tubes? -3/3/16

Well that’s interesting. Wonder how I can see almost half an amp of gain by bridging those pads and you see almost nothing. Could it be because you swapped your FETs? I don’t claim to understand the electronics theory as well as the rest of you guys, but I’m definitely seeing an increase in performance over here.

I don’t know the electronics either, I grew up in a lumber yard, an now a photographer, pretty much scared of electricity truth be told.

I know that the Vishay mosfet’s I put on the driver are the best that can be found. Wight backed me on that as have others. Wight is the one that told me what to look for in the spec sheets. When I added these, the difference was negligible. I got the most gain when I bridged the sense resistor bank.

And for what it’s worth, this driver is exactly as those pictured, 153 pair of resistors, 4 “000” sense resistors, and it had the A009T Mosfets. The spec sheets on my Vishay componenets show lower Rds On, but not by a whole lot. I used Vishay SOT-23 Si2312CDS, a side by side pair right out of the tape.

emarkd.

I believe, if I am understanding Dale correctly, that the ‘000’ resistors were already bridged.

The only change is replacing the 15K resistor (recommended by Sharpie and Del), which had almost no difference. Therefore, the 15K resistor is not the culprit either.

Dale…please correct me if I am wrong.

I shoulda known better than to make two changes before testing. That’s just bad science, no matter how you look at it. I can fix it though. :slight_smile: I don’t want to fool around with trying to put that little smd resistor back in place, but moving that ground wire back to the other side of the resistor bank is easy enough. So I cracked my light back open and did just that. My results: 3.92 amps at the tailcap.

In other words, on my light, on my workbench, on my meter, I got zero gain by moving that ground wire (equal to bridging that resistor bank) and almost half an amp of gain by replacing that 15k resistor with a solder bridge.

I can’t believe I’m carrying on with this — I swear I’m not trying to argue with Dale about flashlight modding. The guy probably forgot more about flashlights while eating breakfast this morning than I’ve ever known and I have the utmost respect for him and you both Krono, but I’m just not seeing the same results. Again, I don’t claim to understand it, I’m just reporting what I see.

I got my D80 today, I plopped a battery into it and turned it on. It didn’t work. I did the usual paperclip test, and got some light, so that narrowed the problem down to the tail cap. While I was visually inspecting the tailcap the entire contents of the tailcap fell out into my hand. I figured the retaining ring must not have been screwed in properly. While the tailcap was disassembled I took the oppertunity to clean off all contact points in there using isopropyl alcohol, lube the threads, and put it back together, screwing in the retaining ring properly this time.

I screwed on the tailcap on the body, turned it on, and the flashlight worked. However as I was screwing on the tailcap I heard a popping sound. When I unscrewed it again the retaining ring had came off it’s thread and the tailcap components fell out again. I’ve repeated this process twice more. It only happens when screwing it on with a battery inside. It appears that when I screw the tailcap on the pressure from the battery somehow manages to push the retaining ring loose. I’m not using excessive force when screwing it on. I was using a protected battery, 68mm long. I ordered some unprotected 30Qs around the same time that haven’t arrived yet, so hopefully when I get a shorter one the pressure will be less and the problem will be gone.

But still, what should I do about this? Just live with it and hope the shorter battery works? Try to get a new tailcap from gearbest? If the later, how would I go about doing that?

Survey says, it’s the emitter.

I pulled the brass post on the driver, put a solder blob on it and checked it. Marginal gain. So I wired the emitter, in the light, direct drive to the 35A cell. 4.99A. There’s just not much there to be gained if I was getting 4.83A to 4.86A from the driver. This is top end, pure and simple.

So, I pulled an old XM-L2 off an Aluminum star and put it on a SinkPad, put that in this light and put the brass button back on the driver. Bingo! 5.52A in the light. Same driver, same cell, different emitter.

Edit: Oh yeah, the funny thing. The older emitter pulls 5.52A but only makes 1383.45 lumens. So, we were getting top lumens with lower current draw… higher efficiency all along. Funny, huh? We get all caught up chasing the current when the output is right there in front of us all along.

EditII: I did check direct drive with the Star in the light, it hit 6.11A but wasn’t being pressed down against the emitter shelf with no reflector in place, it started to get hot. But that tells me the driver in sheer top end with this old emitter is costing some half an amp, might be in the 22ga wires on the driver or just running through the circuitry, don’t know. (test leads I used were 20 ga. but about 4” long each.) Still, it’s fully capable of making the power given an emitter that will take it. Maybe I’ll check it powering a triple or the SBT-70…

Hi kronos, Dale,

We are still obviously missing something. Problem is we are talking about milli-ohms here and there, it does not take much to move the readings around when driving a diode with voltage source (as opposed to a current source).

Regarding the 15k resistor:

Looking again at the datasheet of the AO3400 FET (this may not be the FETs we actually have, but the numbers are quite typical), we want the 'on' resistance of the FET to be a low as possible. For this we need the FET gate voltage as high as possible. This why only some FETs are suitable for DD drivers - we have limited voltage available.

With the stock driver, best case (FET not heated), we are operating between the two orange dots, gate voltage at 2 V and down to 1.5 V with the cell drained. We are off the trend line, the purple is just my (optimistic) interpolation.

Bypassing the 1st 15k gets us to operate between the two green dots, 4 V to 3 V.

It can only help.

Dale, do you normally wait for the LED to heat up when taking a current reading?

I tend to take it as fast as possible before the cell sags or when the mcpcb is floating. But I know the LED Vf will go down as it heats, pulling more current. Another variable not everyone is considering.

I agree with you chasing amps is somewhat futile. It is like tuning your car for maximum fuel consumption.
At the end of the day we should be measuring lumens.

Even measuring watts is better than measuring amps, W = V x I. Higher Vf lowers the current draw we can get from a single cell, but it does increase watts (and hopefully lumens) at the same time.

Andreas,

-Sorry, can’t help you, but I got 3 D80’s yesterday and I have the same issue.
I was using old 2400mah protected Trustfires, I thought may work to try the light out. I have unprotected cells that are in the mail, I’ve given up until they arrive. I won’t know until then if I’ll need the longer tubes mentioned in this thread.

I take the reading at start, if I take a delayed reading I also report that.

I went back to the bench and soldered a loop between the driver neg and Star, with the light assembled and no spring bypass it ran 4.67A through this new (old) emitter. (At the emitter) With the spring bypassed, it runs 5.21A at the emitter on a 35A. This is with my Vishay MOSFET’s on the driver and the resistor bank bridged and with the 100 ohm resistor in place of the 15K.

Thanks Dale. Also good info on the spring bypass. It is impressive how the steel springs heat up once you get to 5+ A. Not healthy for the switch or the cell. I was doing it with a power supply in constant current mode, in a light it probably self-regulates a little as the spring heats up and its resistance increases.

Re. The brass button and related driver pcb vias, I measured 7 mV across it while running 4.4 A. So as you said, not significant.

A lot of blood, sweat, tears, care and attention has gone into making it and its a shame that the numbers don’t match the prototype’s, but it’s still a nice bright light and can be modified to hit the numbers without a whole lot of effort :slight_smile:

Mine has arrived and the fit and finish are nice! I’ve only been able to measure around 2 amps at the tail end with a cheap multi-meter. With better / unprotected cells and better meter leads I may see more.

Today the D80 5A arrived, ordered on Jan-08. Fast free shipping - this time with Belgium Airmail Registered. No label for tint on box. What i got, as expected:

  • very good overall finish
  • warm tint
  • throw is in the middle of XinTD C8 and BLF X6
  • mode spacing / UI could be better, but Turbo is bright

2,7A, measured with a cheap multimeter with thin leads and a LG INR18650MH1. Some Samsung INR 18650-30Q are on my wish list.

This D80 might be my first modding victim (driver swap). But prior to that i have to extend my equipment and know-how.

The diffuser of an Olight M22 Warrior fits well.

I hope the D80 3C ordered on Jan-01 will arrive soon. Another shipment lottery. :smiley:

Thanks, Kronos.

It’s really a shame that it’s so difficult to measure actual out front lumens, as that’s really what matters. I wish there were a inexpensive light box for the masses so we could all get on the same page, that’d probably help more than anything to get more usable data and improve performance for the bigger picture.

These lights are doing a nice job, especially when you stop and consider they’re purchase price is virtually host price for most any other light. Great entry level purchase for sure. The direct thermal patch copper mcpcb is already there, as is a heavy duty Omten switch. Nice AR lens, some premium assets for a bottom line price.

Yes, I wish y’all were every one getting a 1500 lumen pocket rocket, that would make me feel a lot better as I was really looking forward to seeing your reactions. I think it’d be awesome to win the lotto, buy and set up a CNC system and get real rockets out the door to everybody! lol

Reckon it was missed that I ran it down to 2.65V on a cell…

Wow.

> electronics engineer …. I am one

Please, stick around and keep up the effort to educate us.

The emitter was making ~3 lumens at that point, which would be approx .01A (I was not taking an amperage reading at that time) The exercise was in answer to the question of Low Voltage Protection, which was on the original driver and got lost somewhere in the shuffle while this GB was taking place.

Apparently there were more than one thing lost in the shuffle, and we didn’t have an EE on the sample testing team to verify these things.

Perhaps you would like to volunteer to help us out in future Group Buys? It would be most helpful, as you can see, to ensure we are getting what we are expecting and promised.

Those of us on the testing team had more or less specific duties. I am known for pushing limits. I have a lightbox, so I test top limits and lumens, both of the provided sample as well as it’s capabilities when modified, as many of our members have plans to modify any given light. So my focus is on what a light does at max levels NOW and what it can do when tweaked. Other’s have their specialites, none of which fall in the range of Electrical Engineer. We have lost a few of those in the past months, running low in the specialty at the moment. Our driver board designers have dropped out like crazy and our current code writer is stressed. Lot of work involved in getting these long drawn out Group Buys to go according to plan and even then, well, you know that part already…

The ultimate goal is big picture, we REALLY DO want to get better lights in people’s hands.

I know there is a lot I don’t know. I also know there is a lot I know, but can’t remember. So by all means, feel free to point out where I’m failing and there’s a good chance I can retain that in the near future and do a better job. I mean to, intend to, and will research/learn/strive to that end.

Couple of years ago I couldn’t solder a speaker wire on. Maybe there’s still hope for me yet…

I had the mcpcb out to swap out the driver and emitter wires. While the mcpcb was free, I ran it again on the bench supply to compare numbers.

The mcpcb was sitting on a sheet of aluminum to keep cool. Measurements were taken ~5 s after power-up each time, without waiting for the current to stabilize.

FWIW:

Power supply [V] With stock driver [A] With mod. driver [A] No driver [A]
3.6 2.00 2.36 2.56
3.7 2.44 2.71 2.94
3.8 2.76 3.09 3.41
3.9 3.16 3.47 3.81
4.0 3.52 3.88 4.22
4.1 3.83 4.22 4.52
4.2 4.12 4.62 4.91
4.3 4.47 4.93 -

Column 2 is a repetition of the numbers from yesterday.

Column 3 is with the gate resistor and 000 pack bypassed.

Column 4 is with the power supply directly wired to the emitter.

(And all was done using the stock 3C emitter.)

For the visually inclined:

With the stock driver we are at 81-85% of true direct-drive numbers. The modification takes it to 91-94%. None of this will be very obvious in real use. So stop sweating the numbers and enjoy the light :).

Here’s a thought. Can someone try the pencil lead trick to do a quick mod of the gate resistor? It might help folks that don’t solder.

EDIT: I’m still waiting for my 5C light to arrive.