I often hear about the high currents measured on the DRY turbo mode, especially with the new driver, but these currents seem way too high and implausible to me to be genuine steady currents without damaging the LEDs.
In my own testing I have often found that in reality the reason why a higher tailcap current reading gives higher performace even if way over the max spec of the LED is that when the tailcap is put back on and the light is used in a normal situation there is much higher resistance and so any current in real use will be significantly lower than the DMM measurements without the tailcap switch in the circuit.
For example, on my Ultrafire/Manafont 3 mode (almost direct drive PWM for low modes) drop-in the difference is clear. With an IMR 18650 the drop-in current when measured through the tailcap (of a Solarforce L2x) is around 1A lower than without the switch, I measure 4.5A dropping to 3.3A depending on voltage when measured just at the tail end of the light, but 3.5A dropping to around 2.5A when I include the tailcap in the circuit. This result is the same with similar driver circuits measured with and without varying tailcaps. Although the specific amount of resistance each tailcap offers does differ slightly and depending on the current trying to pass through it.
Anyway, this seems to explain to me why such high currents measured with a DMM without the tailcap seem to provide such higher outputs in real use with the tailcap instead of just more heat, as in reality the currents to the LED are a certain amount lower than measured.
I know some users here do often measure through tailcaps too or measure outputs without the tailcaps replaced so in some cases this point won't apply, but I think in many cases it still does.
In the case of the DRY I am particularly interested in tailcap resistance (I have one lost in HK somewhere but technically on the way to me). I really don't like the reports of 4.5-5A currents on turbo, but I think that in real use through the tailcap this could be reflective of lower and more manageable currents on turbo, maybe 3.5-4.2A?
I would love to know if anyone has measured the current either going to the LEDs in the DRY on turbo mode, or at the tailcap both without and then with the switch/tailcap itself included in the circuit.
Sorry if this has been done already and I've missed it, a pointer to the results would be appreciated :)
Edit: I just smoked my driver doing this test this is the second one I burned up. These drivers are so fragile please be careful with your light one small short and poof the drivers toast.
My measurements were made using an induction meter over an 8ga wire, with the switch in the circuit. I did get slightly lower results than 2100 did on his DRY.
I wonder how hard it would be to do the same, but at the LED.
EDIT: Dang, E....you are HARD on these DRY drivers....
I just bumped the tail cap while taking the measurement and now it only pulls 1.7 amps in turbo mode. Luckily I have 2 more drivers on order and a functional strobe one I can use for now but I lost my Turbo mode and I haven't even had it a week.
Damn, sorry I caused you to risk that. I wouldn't have asked if I knew it would end up with you frying something. I'm glad you've got some coming to replace it though at least.
Thanks for the test anyway, what cells were you using?
It seems the switch doesn't give much resistance at around the 3.5A level, I wonder if it gives more at the high currents 2100 was reporting.
No biggie this is the second driver I smoked there is a reason they only cost 5 bucks they are the cheapest possible driver you can buy and the smallest short cooks them.
Ok, so you both only got below 3.5A through the tailcap and with AW IMR and Panasonic High current cells respectively? I'm guessing Chicago X's Warm version is not the newer Turbo driver? But that E1320's is? (was!)
Sorry to refer to you both in the 3rd person but otherwise it just gets confusing..
Not to defend the Dry driver (I have no first-hand experience of its fragility or toughness), but all electronic devices are "fragile" in that way. A short in the wrong place can kill a computer, a TV, a cell phone, a $400 calculator (this, I do have first-hand experience with!)... If you doubt this, I dare you to open up your favourite electronic device, and place a metal paper clip on the circuit board. :)
Sometimes, a momentary short won't damage anything. But you takes yer chances.
I did measure through the DRY switches along with a host of others from UF/Solarforce/Trustfire etc, drop of only about 0.2A. Same as the results above. So it is pretty indicative.
The DRY switches/tailcaps are one of the lowest resistance ones around.... pretty hardcore stuff here.
My highest readings come from the Sanyo 2600 unprotected, then Solarforce 2400 and also TF Flames 2400 (protected and unprotected). The Panasonic 2900/3100s are definitely below the Sanyo 2600.
Do note the driver has resistance in them too (obviously). I have a really "pure direct drive", as in the + and - wires directly goes to the battery disc (no driver) and it's very easy to do above 5A. That is with the SR3800. The SR3800 also has a very hardcore switch.
Wow very informative thread!! thanks dorpmuller for re-raising it. I was not aware the DRY turbo model had these reliability problems, I think I will scratch that one off my list... despite its BLF popularity overall.
My 4 DRYs are still going strong, actually i am using the DRY replacement driver in the SR3800. Just try to be careful i guess, well i shd have done driver swaps at least 10 times already..... LOL!
One of my lights, the T3 WW one, also has a power resistor in it as that was probably the earliest version (IIRC Chicago X and me were amongst the first to receive it here). Take it out.
I definitely would not avoid buying the Dry because of the driver. Just order it with the driver you want and it should not be a problem. The problem I had was using the Dry drivers on different lights and doing stupid things like shorting it out while taking tail cap readings. I think if left in tact it will do it's job for a long time, just don't take it apart and play with it and you will be fine.
I'm glad you've got some coming to replace it though at least.