It has similar specs, nice modes and is smaller. Most interesting: whereas the LD-29 seems to underperform in single cell mode (only 2,5-2,6A), this is not mentioned with the LD-2C. So there’s still hope…
If you could test both, LD-29 and LD-2C, in comparison and in both voltage-ranges, would be great.
I’d gladly provide you with my new, unused, untouched LD-2C from IOS that came the other day. PM me your address if you want to use it. I wanted to fiddle with it myself but your rig is much better and results are comparable that way. Or PM me your PP-address, I second the idea of Matjazz.
Again, thanks for a good, informative report.
Strange that you have a 3.04A variant of the 105C. A variant that Fasttech should not have in stock (8x0.38A).
Thank you HJK for doing all this work! Your results for the Nanjg 105C confuses me though, could anyone please help me understand what’s happening here?
I have read forum members here (Old Lumens springs to mind for one, when he was modding the 3 and 4 AA to “D” battery carriers) trying to use three AA Eneloops to achieve 2.8A at the LED and finding that they weren’t getting anywhere near 2.8A but, when they used four AA Eneloops, they hit the 2.8A easily, and it remained “regulated” at 2.8A for a reasonable time.
Their driver would have been seeing something roughly around the 4.8 volt mark from four Eneloops under full load, but your graph shows that by 4.5 volts the output has apparently dropped back down to 1A? Why do your results differ so greatly from their real world results? Is it really just due to the heat build-up of the driver you tested?
This exact driver is rated from 3 to 4.5 volts. I realise that 4.5 volts is not their ideal input voltage, and a lot of that will get burnt off as heat, but why would it be rated to 4.5 volts if it couldn’t produce the required current at that voltage?
Please understand I am not trying to devalue the work you have done here!!! I just can’t quite make sense of it all.
HKJ, Did you get a sense for how fast the 7135’s overheat when not properly heat sinked?
I know it would depend on a lot of factors, but just wondering how fast current would drop in a worst case situation after light if flipped on with fully charged cells.
benz, the sag at higher voltages is likely due to heat. The driver is floating in space with no thermal contact. In a flashlight, the driver ring is sitting on the pill and this conducts heat away from the chips. The thermal tabs (big Gnd pin) is right there on the edge which will make a huge difference in board temperature.
With the drivers floating in the air there is very little cooling for such a small pcb, I believe that it overheated in maybe 30 seconds.
Mounted in a flashlight with prober contact to the aluminium, it will be much better.
This is one aspect that I cannot test properly. Even if I mounted a piece of aluminium on the driver, it would not be a prober test, because the actual cooling will depend on the actual flashlight and how it is mounted in it.
38P is 380 mA. That’s why you get around 3.0A in your measurements.
I wonder if all of their stock of that sku number is in fact 3.04A drivers. That would be an opportunity.
Don’t want to trust others experience without proof - eh?
To find specs you have to know the maker and find his specs sheets which I can’t.
But look at the V2 driver 3.04A at Kaidomain. You can’t see anything from the pictures but the 7135’s are marked “38K” the same way as yours “38P” (I have one in my hand right now). This is a common way to mark the bin and the letter is not relevant, but often a package code.
If you don’t trust me now that you have a 3.04A driver then it is your loss.
I do tend to trust datasheets more than random Internet postings (I do not know your level of experience). But I can see the one on FastTechs website is marked 35F, this does kill my date guess.
It is not really a loss for me, just some other numbers in my test. The "low" current version has the advantage that it runs slightly less hot, with many drivers close together it might allow it to run longer at full brightness.
I agree with HKJ, no one is saying your out to spread misinformation, but it does happen, there are many posts by people who did not understand something correctly and explained it to a new member with mistakes, or people who came up with wrong conclusions based on many factors, with no malicious intent or occasionally with intent.
When you have built a reputation as a respected member and a reliable source of information then people are more likely to take you at face value (there are many members who people trust for technical advice, including HKJ), but the adage trust but verify does also come in handy, and a datasheet is something that a company is using to drum up business so they are generally used as a source of verified information.
Correct, I have not rejected his specification, I would just like to see some documentation for it. In my first post about the AMC7135 I did link to the datasheet from ADD, where it specifies the A for low current version.
ADD might have changed the way they mark the chips (Datasheet is from 2006) or the 7135 might be from another manufacturer.
When I start to test all the drivers from intl-outdoor, I might be able to see what is correct (If some of the uses the low current driver).
Types:
Buck: Driver uses an inductor to decrease the voltage, input current is less than output current.
Boost: Driver uses an inductor to increase the voltage, input current is larger than output current.
Linear: Driver uses a linear chip (like 7135) to reduce the voltage, input current is the same as output current*.
Direct: No current regulation (except resistance) is present, input current is the same as output current*.
All driver types can use pwm for brightness regulation, the first 3 can also use linear regulation.
*Except for current for the control circuit.
It is possible to copy the table to a spreadsheet and sort on different columns.
Any comments?
Great work, very interesting, thank you. Is there a way to monitor the driver temperature during testing? I would be interested to see what performance drop there would be due to high temps, also the performance gains when heatsinked well. Or maybe point out which drivers are more temperature sensitive than others.
