New XM-L driver on DX, anyone getting one?

[kenwood96]

Looking at efficiency, may be 3 makes more sense...

Sent from my HTC Wildfire using Tapatalk

 

[Foxx510]

Since there has been some buggy drivers burning leds, is it possible to load test these on an incan globe first to test current and stability before hooking it up to a led?

 

[VegasF6]

I tested mine with power resistors, but it's still no guarantee.

 

[cmacclel]

I tested mine with power resistors, but it's still no guarantee.

Has anyone tried the new buck/boost 18v driver up on kai? I have a couple on the way.

Mac

 

[moderator007]

Hi Mac,
I would be interested in how the 3-mode driver turns out. When you get them could you possibly post up some findings.

 

[simplec6]

Which one is that mac?

 

[moderator007]

Which one is that mac?

KD 3-mode # S020121
KD 5-mode # S020077
I hope he is getting the three mode version. I would like to know how much current to the leds for each mode.

 

[simplec6]

The KD 3-mode S020121 lists the following specs (it is pretty pricy at 14.99):
This circuit comes with low voltage protection at 5.7V, so please use two or more li-ion for best result.
Input Voltage: 3-18V (recommend use of 2-4pcs 4.2V 18650 or 4-6pcs 3V CR123A)
Output current (single LED): 5A
Output current (3 or 4 XM-L LED wired in serial): 3A
Modes: Low - Medium -- Height


I'd be very interested in the current output in both configurations (buck and boost). This will be great if it does the advertised 5amps.

 

[Foxx510]

I started testing this DX 57779 driver a few days ago. It works well, but has a couple of issues. It runs really hot at 12v running a single MT-G, almost too hot to touch. It also wipes out FM radio reception in the near vicinity.

 

[Techjunkie]

Has anyone tried the new buck/boost 18v driver up on kai? I have a couple on the way.

Mac

The KD 3-mode S020121 lists the following specs (it is pretty pricy at 14.99):
This circuit comes with low voltage protection at 5.7V, so please use two or more li-ion for best result.
Input Voltage: 3-18V (recommend use of 2-4pcs 4.2V 18650 or 4-6pcs 3V CR123A)
Output current (single LED): 5A
Output current (3 or 4 XM-L LED wired in serial): 3A
Modes: Low - Medium -- Height


I'd be very interested in the current output in both configurations (buck and boost). This will be great if it does the advertised 5amps.

I've got one of KD sku S020121 on the way to replace DX 57779 in my bike light (3*MCE driven by 4*3.0V LiFePO4 D-cells). The DX driver has been rock solid and I thought that on a bike, strobe mode might have been desirable, but I find myself being annoyed when I have to cycle passed it. Also, there's no low V warning and the mode memory on that one is the worst kind, where it always goes to the next mode at next power on instead of the last mode. (It'd have been better if it always started on high or low - then I'd only see strobe if I wanted to.)

I'll give the KD one a shot and see if it pleases me more than the DX. I'm expecting less runtime, 'cause it'll increase in current drain as Vbatt drops below Vf, whereas the DX driver has no boost, so draw (and brightness) decreases as Vbatt drops below Vf.

 

[Garfi99]

The KD 3-mode S020121 lists

Hi,

I testet this driver in a SkyRay818.
First it seems to be a really nice driver. It really pushes nearly 3A to the XMLs.
In my lamp it works with 2 or 3 18650. If you use only 2 batteries it took 4.5A from the batteries.

But:
The driver is getting hot really fast. I found no special part on the driver which is getting hot especcially. The whole driver seems to warm up.
So the driver is going to reduce its power an the current to the leds will be reduced to nearly the half.

So you have to cool this driver.
Up to now I found no realley good way to do this in my SkyRay.
I filled up the space between the 2 pcp with conductive paste and tried to get a good contact to the case.
But this does not work really good.

If you find a way to cool the driver it might be really good.
But without this, it will reduce its power after 30seconds.

Nice evening.

 

[Techjunkie]

Hi,

I testet this driver in a SkyRay818.
First it seems to be a really nice driver. It really pushes nearly 3A to the XMLs.
In my lamp it works with 2 or 3 18650. If you use only 2 batteries it took 4.5A from the batteries.

But:
The driver is getting hot really fast. I found no special part on the driver which is getting hot especcially. The whole driver seems to warm up.
So the driver is going to reduce its power an the current to the leds will be reduced to nearly the half.

So you have to cool this driver.
Up to now I found no realley good way to do this in my SkyRay.
I filled up the space between the 2 pcp with conductive paste and tried to get a good contact to the case.
But this does not work really good.

If you find a way to cool the driver it might be really good.
But without this, it will reduce its power after 30seconds.

Nice evening.

Was just about to post with the exact same findings. I replaced the DX sku 57779 driver in my bike light with KD sku S020121 tonight and I have to say, I'm thoroughly unimpressed with the KD driver. I'm using a 12V LiFePO4 pack that at worst sags to 9V under load. To push the 2.5A to 3 MC-E in my light (as measured by clamp meter between driver and LEDS), the driver only has to maintain 10.2V to the LEDs. That's not asking the driver to do much at all. Nonetheless, after less than a minute of holding the leads at the tailcap, I can see the power consumption slowly fall from 3A to ~1.5A, and the light is visibly dimmer than another 3x MCE light that I have for side by side comparison.

At least the DX, buck only driver would maintain current as high as the pack would allow for the entire discharge, which is more than I can say for this driver, which is throttling back to less than what direct drive would provide. It would be far better if it could just switch into a bypass / direct drive mode when pack voltage is below Vf at the target current and the driver is overheating. The only good that's come from this is I now have 4 hours of runtime on high, but the medium mode would have provided at least that anyway.

I'd like to think that with my light being air-cooled by the ride and heatsunk directly to the handlebars, and the gummy heatsink sponge things conducting heat from the driver to the host, that driver might be kept cool enough to not have to throttle back as long as my bike is moving, but the truth is, I'm just being too lazy to switch the drivers again and the mode memory on the DX driver is a bit of an annoyance. If I switch back at all, it will be because I'll want the strobe mode back as a safety feature.

Long story short - the KD driver's specs are too ambitious, at least for 3 LEDs. It's only pushing 2.5A and short of being liquid cooled, can only do that for about a minute.

 

[Quest4fire]

Long story short - the KD driver's specs are too ambitious, at least for 3 LEDs. It's only pushing 2.5A and short of being liquid cooled, can only do that for about a minute.

:sigh: the search continues...

 

[bshanahan14rulz]

I tested mine with power resistors, but it's still no guarantee.

In the laser hobby, we use power rectifiers to drop the voltage, and a low ohm accurate power resistor to measure voltage drop across and calculate current. Diodes are great at simulating diodes ;-)

Also, VegasF6, thought I recognized you from somewhere else too...

 

[Techjunkie]

In regard to KD sku S020121 overheating, I am advised that potting the driver will allow it to overcome. I'll try the fujik silicone glue first, as I'd like to be able to chip it out of the light if it need be. If that doesn't cut it, I might move on to potting it in an aluminum sheet sleeve with a mixture of epoxy and aluminum oxide. I just don't want to cement it permanently into the light, and getting the sleeve to exactly the right diameter will be a challenge. I'll report back with findings afterward, but it will be a few weeks at the least.

 

[Quest4fire]

In regard to KD sku S020121 overheating, I am advised that potting the driver will allow it to overcome. I'll try the fujik silicone glue first, as I'd like to be able to chip it out of the light if it need be. If that doesn't cut it, I might move on to potting it in an aluminum sheet sleeve with a mixture of epoxy and aluminum oxide. I just don't want to cement it permanently into the light, and getting the sleeve to exactly the right diameter will be a challenge. I'll report back with findings afterward, but it will be a few weeks at the least.

Have you ever tried mixing AL powder with the fujik? It would still be removable but might add enough to the silicone's thermal properties to avoid the epoxy/heat sink route.

 

[Techjunkie]

Have you ever tried mixing AL powder with the fujik? It would still be removable but might add enough to the silicone's thermal properties to avoid the epoxy/heat sink route.

I've never tried the Al powder at all before - was too afraid of breathing it in / absorbing it through skin. I've decided to just go with the stronger solution and skip the fujik this time. On a less expensive driver that's easier to get to, I'll try the fujik next time.

 

[Techjunkie]

The jury has deliberated and the verdict is in. KD sku S020121 flat out sucks. I potted it today, using Alumina powder and Devcon 2-ton epoxy, and I don't think I or anyone else could have done a better job. Here's the procedure, followed by test results:

Procedure

1. cut a sleeve of Aluminum sheet the exact circumference of the interior of the Mag D neck
2. with driver already wired very closely to top of Mag switch, seal all areas on top of the switch with kapton tape where epoxy could drip down
3. mix equal parts of the epoxy with so much Alumina powder that it couldn't possibly pick up any more
4. while rotating the driver on its side, pour the toothpasty concoction into the space between the two boards of the driver and paint its bottom for good measure
5. wrap the Aluminum sheet around the top of the Mag switch and seal around the joint with kapton tape
6. coat the inside of the Mag neck and the outside of the Al sheet liberally with thermal paste
7. force the switch, driver, and Al sheet collar into the neck with the heatsink
8. pour in the homemade AAA concoction until the driver is completely submerged
9. push the heatsink down the rest of the way until the switch is in position
10. turn the switch on and test the + and - in contacts with a DMM for a short before the epoxy cures
11. if a short is found, pull the HS up a bit to stop the inductor coil from shorting on the bottom of the HS and tone test again
12. wait several hours for the epoxy to cure and test the much improved heatsinking

Test Results

With gummy sponge things provided by KD:
0-1 min, 3.1A draw at the tailcap
1-1.5min draw at tailcap quickly plummets to ~1.1A

Fully potted with homemade AAA:
0-2 min, 3.1A draw at tailcap
2-3 min, slow descent from 3.1A down to 1.8A draw at tailcap
test ended at 3 min. neck was warm to the touch, but not hot


Conclusion

Potting helped somewhat, but still did not keep the driver from throttling back after a very short period of time. Combined with metal to metal contact of the host to the hose clamps to the bicycle handlebars and all components air cooled by the ride, it might have been enough to keep the driver from throttling back to less than direct drive, however...

• Potting was expensive. It cost $8 for 4oz of Alumina powder and $5 for Devcon 2-ton. Granted, that's enough to do this about 5 times.
• It is very likely that I might never get all the components out of the host undamaged. Certainly it won't be easy. It's almost certain that I'll have to dremel cut the potted driver from the switch housing.
• NONE OF THIS SHOULD BE NECESSARY! Even if the results were that it worked perfectly, it's crazy to have to go through this trouble to get the driver to work as it should in the first place.

Not convinced that the potted sleeve was making the best possbile contact with the neck, and also to prove to myself that I could swap the DX 57779 driver back in, I removed it, wrapped the sleeve in foil and did some more testing. The results enough of an improvement for me to keep the driver, but in my estimation, not worth the effort.

Full details posted in the bike light build thread here.

 

[Quest4fire]

Wow! I wonder if you got a quirky driver TJ, or if they are all equally worthless. It will be interesting to see if others have similar experiences. Thanks for your exhaustive efforts with this driver and for sharing the results with the rest of us.

 

[dinac]

I just got new version of this driver :


it hasnt got that secon circular PCB on top like old drivers...

maybe someone has found solution where to tap resistor for full power ?
old PCB vs. new are different....