The only problem with using 2 FET’s is that the resistors are setup for a single FET and using 2 will cause them to switch more slowly and increase the losses (aka, they will get hotter) and cause the ramp to change some in the low modes.
You can try it and see what happens though but a single SIR800DP should work fine. That is how the lights I built are setup.
Ok then I will use one.
Thank you for all your help!
interested …any reviews
I’m at work now. Covered the surrounding area of fet with kapton tape. Added solder paste. And reflowed the fet.
Now it is blasting again 
Now I’m at day shift so when I get hom remeasure output and finally do an intensity measurement.
I hope swapping the FET is all it takes to make it bulletproof.
So you got about 18k lumen stock. Was that the NW or CW version?
18270 lumens NW version.
I’m glad there’s a happy end to this story.
Hmmm, I guess that means the CW that I prefer is what, 3k lumen less?
Still, 15k lumen is nothing to sneeze at.
No. CW is usually has higher lumens output.
Glad it is an easy fix. Has anyone replied you on the spare FET pad question?
Really? I vaguely remember the lower forward voltage on the NW giving it a higher output.
I’ll have to check TA’s driver thread. Wait, I’m not sure what exact CW emitter the factory is using. I may have to wait for a comparison.
Yes! TA answered it. It is designed for one fet only. Two fet will switching slower.
If you use the same bin then the output should be roughly the same between tines minus the lux meter bias towards CW tints.
In the case of the MT09R, I am not sure what CW LED’s they are using now but in the last batch the CW LED’s were a lower bin then the NW and were a fair amount lower output. Around 20% lower IIRC (so around 3 bins lower).
It is possible that they upgraded to P2 bin CW LED’s like I suggested for this batch though.
Oh, I also heard that they will be discontinuing the MT03 after this batch is sold out. I really like that light, the best flooder I own. Tempted to get another one if I could justify it.
^ That’s odd. Seems to me that the MT03 is a winner, and a Haikelite flagship as well…
My guess is they are consolidating the production into just the MT09R as it seems more popular. I don’t think the sales of the MT03 are good enough since the MT09R came out to justify selling both.
Aaaaghhh!!! Having flashbacks to the FIRST group buy!!! Lookout!! Terry is about to jump out from behind a tree and blame all of you for this issue!!
OK, that was unkind. Still licking wounds. That being said…what the heck Haikelite?? They just can’t seem to leave well enough alone. I wonder if maybe they were a victim of their own country’s nefarious business practices and settled for a cheaper FET which actually ended up being a crappy knock-off.
As a follow up - my first generation TA rework of the MT09R with its aftermarket high bin led’s, TA driver and spring bypasses is still going strong! 22k of clean, beautiful light. It scares my neighborhood every night when I go on my walk/jog.
I am pretty sure this is the case, the more I have learned about how China works the more I realize just how Lucky we are in the USA. Some companies are simply not allowed to buy certain items, no matter what they do.
In this case I think they tried to get the same FET but ended up with another model due to not really understanding what they were doing.
I wish they had contacted me about it and let me find an alternative for them instead but I was so insistent on them using the correct components and what I have learned about how China does business (never ever say there is an issue until it can not be rectified), it makes sense that they didn’t want me to go through another round of testing to find an alternative FET. Not a justification but an understanding of why it happened.
It looks like the FET they are using is good enough for the stock light if you don’t bypass the springs and luckily it is a fairly simply fix if it does fail. Once replaced the driver should be like the ones I built.
Hi Freeme. Can I have the code please?
Thanks
Does Haikelite know about this? Do we know if they have plans to fix it?
I am saying “fix it” and not just “improve it” because if with just a spring bypass the FET dies, I don’t think that it will die only after spring bypass. It could die on flashlights with a little bit better soldered springs or with the randomly “better” springs of the batch or after 10 minutes use of an unmodified light, who knows.
I think that too many factors can add 5% power and too many factors can make some FETs 5% worse, that could be the 10% difference which kills the FET.
I wouldn’t use an elevator that has 100kg limit, if I was 98kg and at 102kg it falls and kills whoever is inside.
There is a big factor to keep in mind, while the lumen output might of only increased by ~15%, the current most likely increased by at least double that due to the law of diminishing returns.
A ~30% safety factor while far from ideal should mean that the majority of the drivers should not have an issue but yes, a higher then normal failure rate is quite possible.
Far as them fixing it, they have not said anything to me in some time so I am not really involved anymore. replacing the FET’s on the drivers that are already made in bulk is not practical, it would be more efficient to make a whole new driver on an assembly line then to pay people to replace FET’s by hand.