Billy X,DBCstm answered correct to your question.HKJ measured parasitic drain of ~42uA,not much.
With 4Ah King Kong,just shy of 1000 days.I think I can live with that.Thanks DBCstm and L4P.
I got something right!
<---victory dance
I did some high dissipation tests,in concrete case I set ~4.5Volts input voltage,and used luxeon T for test led because it has only 3.3-3.4Vf at 5 Amps.This caused very high dissipation in mosfet,around 5Watts,which caused desoldering of cathode wire from mosfet(that means >180C in maybe 10sec).High temperature protection didn't trigger because PIC was still <100C,reason for that is too fast heat generation and very small thermal mass of mosfet.Important note is that driver was in "open air" without any kind of cooling.
But with "advanced" heatsinking,something like alu or copper piece-heatsink glued with arctic alumina to mosfet and pic and if possible thermally conected to flasghlight also(potting, silicone sheets...) this would be a different story. Even just small copper piece glued on mosfet-pic would add significant thermal mass( and thermal mass in heat world works like a capacitor in electrical world-sucking extra energy and block spikes) and create much better thermal connection between mosfet-pic,and in that case if power dissipation is very high, high temp protection should work at time and prevent mosfet-wire desoldering.
So the point of the story is,use this stock driver for single xp-g2,xp-l,xm-l2,and if you really know what you are doing(heatsink it well),you could try,but at your own risk.
I know that this driver isn't fool-proof and it's far from perfect,but I'm continuously working on improvement,and only I can promise,it will be better and better.
Thanks for the test, that gives some perspective in how to use the driver :-)
While I like playing around with adding copper, I don't want to run these into the ground...so to speak. So I'll use them for their intended purpose and enjoy the high efficiency. :)
Thanks for the explanation, appreciate it. ;)
So for continuing the e-switch mode selection. if you have a conventional flashlight, you can set the mode, 1, 2, or 3 by pre-programming the driver before sealing it into a single main power switch host. Say you set it for ramping and then built the conventional non-e-switch light, the flashlight would from then on be a ramping mode flashlight. Is this line of thinking correct?
I don't think the UI groups for the e-switch affect the clicky. Could be wrong.
The issue is that with a mechanical clicky it's on/off. The MCU or whatever component is controlling it can't get a read on a soft press or long press, so the mechanical clicky just isn't capable of doing the same thing the e-switch is.
… i see some “add a e-switch” builds comming up…
What light do you guys see these drivers as being perfect for? I've got a Convoy L4 that has the e-switch disconnected with a BLF17DD piggybacked in. The switch is mounted on the driver board itself, still there, just not being used.
Also have the L2m shorty with it's 18350 that could really use the additional run time on the lower end.
And with run time being a premium, my Macro Chop AA MiniMag might be in need of an emitter upgrade to XP-G2 or XP-L...it uses an IMR14250 with a de-domed XP-E2 at 2.2A at the moment. Yes, it's REALLY short!
So there's 3 of my 4 spoken for....any thoughts or care to share your plans?
Ive got the prototype in a Convoy S-series light.
My Convoy L4 will most likely get one.
At least one of my "Convoy L5" will get one.
Maybe ill use it in the Yezl Y3 too..
The question will probably be, which single emitter, single cell lights in the future will I not use it in? :p
(Answer is probably, when I want a more specialized UI, or when I want to keep it more budget with a Qlite or something like that).
Once the "expander boards" becomes available I might order more drivers and those boards. Ill probably make a SRK type light with one too.
These drivers will be handy to have a few spares of since they are quite flexible. Should not be hard to find homes for them. :)
This driver is all about efficiency and nice UI, while having a great output as well. But for the real hotrods the BLFDD is king!
I swapped out a 'NANJG92' (=effectively a 17mmBLFDD with a tiny bit more resistance because of the thinner board traces of the +path) for the prototype LD1 in my Supfire A6, and lost 20% output on the high setting (in this flashlight I do not reach 5A), I guess the resistance in this driver is a bit more than the BLFDD (which is impossible to beat with those massive traces).
Could that be due to V-drop difference across the FET used in the LD1?
Probably one in a 14650 minimag and one in a Convoy C8. If he can get the two cell voltage expander done then some Mtg mods. Otherwise I’ll wait on some of the Buck efforts going on.
If I want to drive 2 XM-L2 LEDs wired in parallel, driven by a single 26650 cell, and I don’t need to go over 5 amps total (2.5 amps to each LED) will there be a problem? Would the thermal load on the driver be any different driving 2 parallel LEDs at 5A total vs a single LED at 5 Amps?
The thermal load would be significantly increased since the "effective" vF is now much lower with the two parallel emitters. To maintain 5A constant current with the same input voltage requires the driver to burn off more heat. Linear drivers like this one (this one is linear, just without PWM) work best where the Vin and Vout are pretty close together. The farther apart you get, the more heat has to be generated to maintain constant current output.
So, why does it run more efficiently at lower levels but this heat issue rears it's head between 1A and 4A?
I guess that wasn’t directly intuitive but it is a good point. At 2.5 amps per emitter (assuming XM-L2), the Vf is only ~3.25V and at 5A to a single emitter, the Vf is well over 3.5V (I lost the interpolation graph) so this is roughly another 1-1/2 watts across the FET.
I don't think the driver itself is much more efficient (if any), but I could be very wrong about that since I haven't measured it at a given current vs. anything else. I wonder how it pans out compared to a single 7135 at moonlight levels.
The LED is running much more efficiently due to the lower drive current. On a normal 7135 5A driver for moonlight you are still pulsing 5A into the emitter, which is still pretty inefficient. This is delivering a constant low current, which at the emitter level is definitely more efficient than a high current PWM'd.
The other big benefit to this driver is the lack of PWM. No noises, no flickering, even on the lower levels.
I had to dig up the post from djozz where he tested emitters at high power on different MCPCBs so I could figure this out.
At 2.5 Amps, he measured 3.25V.
At 5 Amps, he measured 3.60V
Under a 5 Amp load most cells are going to drop below 4V real quick, so:
- A single LED running 5 Amps, the voltage drop across the driver will be 4.0V-3.60V=0.4V. Power dissipated by the driver will be 0.4V*5 Amps = 2 Watts.
- Dual LEDs running 5 Amps total, the voltage drop across the Driver will be 4.0V-3.25V=.75V. Power dissipated by the driver will be .75V*5A=3.75 Watts.
Wow, that’s almost double the power across the driver. I didn’t expect that.