If it already gets blue at 4.5A, it could be thermal problems too, like a reflow gone bad. I can imagine KD selling lower bins than i.e. led4power, but that should not result in a different current handling, just a bit lower output.
I have 2pcs installed in two different lights that behave the same way. Convoy L21A & M21C
Postage from led4power was affordable sometime ago, just not now. Adding a 2mm² CSLPM1.TG on ∅20mm star makes me see an €12.50 (Premium Packet EU2) shipping fee, when in the past their lowest regular mail shipping fee was €2. On top of this add an extra €0.80 if your order is under €9. Thus, if I want to order a single 2mm² white flat on ∅20mm star I have to pay a whopping €20.90 to see it reach my mailbox. :facepalm:
Fri, 05/01/2020 - 10:57
It can’t be a thermal issue when it’s the second I switch it on. It would be over a longer time?
Thanks Barkuti.
I was thinking of testing one to compare. Sounds pretty high, might leave it
Actually, would I be getting a near accurate current reading using 12 awg wire, 20cm on my DMM? Someone else reported 7.5A using 2mm using my same driver and I measured 7.5A for a sec also. I’m guessing 12 awg is fine for this current.
No, because DMM adds resistance on its own.
Okay, time to order a clamp meter.
Any ideas on a decent model?
UT210E
Because of corona virus pandemic certain types of shipping are/were not available for some countries, Spain was one of them. Now situation is getting better, so cheaper shipping options are available again (standard shipping options are now available again for Spain), for some countries outside of EU restrictions still apply. The problem is my post office doesn't have list of countries with such restrictions, it's only visible to them in their system, I tried to get that list in "paper" format, but for now they so have it (or don't care).
Thanks for clarifying led4power, good to know. 
Here's what my latest L4P order has gone through. Weird it went from NYC to VA, where I'm only about 30 miles from NYC:
ROANOKE VA DISTRIBUTION CENTER, Arrived at USPS Regional Facility -> Your item arrived at our USPS facility in ROANOKE VA DISTRIBUTION CENTER on April 30, 2020 at 8:23 am. The item is currently in transit to the destination.
2020-04-25 09:48 ISC NEW YORK NY(USPS), Processed Through Facility
2020-04-25 09:48 Origin Post is Preparing Shipment
2020-04-25 09:48 UNITED STATES, USJFKA ISC NEW YORK NY (USPS), Receive item at office of exchange
2020-04-20 03:49 CROATIA, HRZAGB ZAGREB 10003, Insert item into bag
2020-04-09 07:21 CROATIA, HRZAGB ZAGREB 10003, Receive item at office of exchange
2020-04-08 13:12 CROATIA, 10004 ZAGREB, Receive item at location
2020-04-07 17:30 CROATIA, 10200 ZAGREB, Receive item at location
2020-04-07 13:02 CROATIA, 44105 SISAK, Receive item from customer
The delay in the office of exchange for 11 days is notable. Plus 5 days in US it took to ship it to the wrong place, apparently.
Shipping was 8.50 euro for a 33 euro order of LED's, MCPCB's, driver, etc. Hoping that shipping comes down in the future because it used to be real cheap - L4P had great low shipping costs, but I haven't placed an order in quite a while before this one, like 2 years.
By the way, this is just to comment that if there is one led emitter which could benefit from a 4040 footprint, that is the 2mm² white flat or CULPM1.TG. Its about power density.
Hello, with Convoy l21a original driver at 6A the heat will be the same as the sst40? Or the osram 2mm produce more heat than sst40 at the same amps? I saw your charts and there is a Vf difference and of course the emitter area. Thanks
You will not see much heat difference betwern the leds if they are driven by the same driver at 6A. The power/heat at the led will be somewhat different but with the driver being lineair, the overal power/heat by led+driver combined will still be the same.
my concerns are about the temperature control using the 2mm and how it will be affected. the idea is to keep the ntc for extended periods on turbo/high without risk of malfunction, but at the same time, prevent a shut down by the ntc. Reliable flashlights for sale to regular / inexperienced customers, with better throw.
I removed the NTC and did stack the sense resistor to crank up the current to about 7,3 A
It gets nice and warm after about 5 minutes, but i havent used it for very long extended/continuous times, so cant say something about that.
What resistor value for 7.3amps?
R50 on top of the original R10
I would avoid buying from Kaidomain for the moment until I get a successful reflow myself for testing. The 2mm has a slight purple tint even at 4.5A. djozz is thinking it may have been a bad reflow. It could be an entire batch as all 6pcs have the same issue.
My 30pcs 1mm do the same thing at 4.3A so I’m selling at 3.5A (650 lumens) with stacked 7135 chips
Next purchase will be from led4power