As you can see in the picture, one of those resistors was missing right from the start.
Those resistors are 0.43 OHM resistors and they were getting VERY hot (over 50 degrees Celsius) in less than 30 seconds. I replaced them with 4 parallel 1ohm, 1W through whole resistors and they were still getting just as hot quickly so I decided to replace them with a direct wire connection because I read that something like that would also help with the maximum light output. Indeed it helped. The 9926A mosfet pushed a maximum of 4.9A for 20-30 seconds and then it died. It's maximum rating is 4.5A so that is clearly why it died but with those resistors in place it's very likely the resistors would have burned.
Fixing this by replacing the 9926A moseft and getting some 1R 1W 2512 SMD resistors is not very attractive because the light output would still be significantly less than what I would like to get from a 10 LED CREE XM-L flashlight.
What would be a reasonable fix? Do you know where I could get some better drivers for the SkyRay King?
When reading the title I thought about mountain electronics bit you have found that.
How handy are you?
And how patient?
If you click on the second linknin my SIG you come to the Q8 and there is a driver in development for it
I have to look for the latest parts list and Narsil, the software is in rapid development and a bug is now addressed. So either waiting for a new version to flash or flash it later is logical, yet it might involve some parts to get rid of the bug so if youbare patient follow its progression in the AT25/45/85 development thread.
(Will give links later now on the phone)
But that driver you link to I have in use with moon and it is simple and useful in operation.
Not cheap so I ordered 3 and a LED because that did not raise shipping and divided it among the parts.
Richard the owner is BLF user RMM and is very nice, friendly and professional in answering questions and ships fast so I bet a lot of us BLFers are bummed not living in the US
The Q8 driver also looks really good. I am impressed with the specs of the SIR800DP mosfet. If I read the datasheet correctly it goes all the way up to 28A but I am sure I wouldn't want to go over 15A. What is the maximum current this driver will pass to the LEDs? If it drives the LEDs very hard, at least a bi-metal switch would be nice it it was possible to add, if not a proper temperature sensor. The way I see it, a flashlight should not go over 50°C.
Also, as far as I understand, making the Q8 driver implies ordering PCBs and parts. PCBs alone would probably be 20$ and the other parts probably also 20$ including shipping so it would be 40$ for the driver alone. That would be fun to build and all but it would be stupid to spend on the driver twice the money I spent on the complete flashlight, especially since the one that I have has a fairly modest thermal dissipation. :)
So, in conclusion, can I buy a driver for less than 20$ from somewhere now or maybe by the end of august?
I actually measured the mosfet in my driver and it is fine. The micro is shorted though and that's why it stopped working so it's pretty unlikely I will attempt to replace the micro.
I think the driver board must be ordered in minimum amount of 3 for $17 incl shipping
Tom has made a list with links where to buy everything in the AT25/45/85 development thread.
If you find two others and have the skills to put it together sure the three of you can work something out (hint Nicolicous two posts up )
Buy or build a much cheaper 17mm or 22mm FET driver with a firmware of your liking and piggyback it on your dead driver, like TomE did here
That way you have much greater choice for driver and firmware. Your old (stripped) board works as contact board, just ensure good heat transfer to the new driver.
Ahh, yep - my SupFire M6 mod, with the Indicator LED mounted tombstone style , aligned with a light pipe mounted next to the switch.
You got lots of options with an SRK clone driver because of the available space.
I love all the squiggle line traces on that stock driver! Poor man's resistors. Btw, that resistor pad was left blank very much intentionally - if they were to add another there, it would reduce amps to the LED's even further. They could have used R1, but bumper the values a bit to better spread the juice to 4, not 3 resisotrs, then maybe it would keep the temps downs. It's a real cheaply done driver.
)
, aligned with a light pipe mounted next to the switch.