Test/Review: LD-1 5A PWM-less driver - led4power (Tests in aYezl Y3)

It is a bit unfair to compare them at same current, the LD-1 will be brighter than the pwm driver.

If you compared it to a 5A pwm driver, then the lower settings will be about 50% brighter.

That’s a good point… perhaps if someone does this test, it should be compared at the same lumen level instead of the same current?

(seems like the current would probably not be a very interesting test anyway, since any two devices at the same current will tend to have similar runtimes regardless of what they actually do with the power)

Except that LD-1 can maintain full output to a lower battery voltage.

Agreed, I’m mostly interested in independent confirmation of efficiency differential at equivalent lower mode output modes.

As I wrote above, you get about 50% extra brightness compared to a 5A pwm driver. This is because the led has higher efficiency at lower currents.

You could also use a triple XPG2 as the test LED, to mostly avoid the high-Vf-limiting-max-current issue.

HKJ, I was agreeing that the comparison should be based on lumen output rather than just current but that does make for a more complicated test.

I also plan to do the comparison based on light output, but I’ve not receive my sample yet.

You can do a fairly good estimate without doing the test, but if you have a 5A pwm driver it is not that difficult to setup:

Mount the led and a luxmeter at some fixed position (A luxmeter with PC logging is preferred).

Run the test with the pwm driver.

Use the LD-1 in ramp mode and adjust it to same brightness on luxmeter.

Replace battery used for adjustment with fresh battery and run the test again.

It could be interesting to do, but I do not have a 5A pwm driver for it.

Hhmm, gotta check my driver stock. I could build up a Nanjg to ~5A, but I do have this driver from Richard: http://www.mtnelectronics.com/opencart/index.php?route=product/product&path=67&product_id=214, but it's 2-3 cells. Didn't realize you gained 50% over a PWM mode - I knew it was better, but not by that much - cool!

That is because the XM-L2 has low efficiency at 5A.

I wonder what the efficiency difference might be at 1.4A, or 1.5A, or 1.9A.

The 1.9A light I just put together with a Nichia 219B is really nice, and the PWM is fast enough it looks almost the same as full current control… but the runtime won’t be as long. I never really use it above 800mA or so (average), so I could reduce its overall power to increase efficiency, but it’s nice having a turbo mode once in a while. The higher power is also nice for strobes, because a 0.3ms pulse looks brighter at 1.9A than it would at 1.4A.

For a bike tail light, I went with 700mA because djozz’s measurements show that as more efficient than 350mA or 1050mA on a red XP-E2. I don’t need it that bright, but it should increase the overall runtime at the same brightness levels, even when using PWM.

The efficiency difference is because a 50% (or whatever) constant current requires a much lower Vf, compared to a PWM'ed 50% which is full current for half the time and none for half the time (assuming both drivers do the same current at 100%). The average current might be the same for both drivers but the voltage isn't and the total power used comes from both volts & amps.

Update added to OP. I'm probably not going to have time to do battery time tests, least not as thorough as I'd like.

Thanks for all the testing Tom E. You are trend setting here.

Im still waiting for mine. Nothing in the maibox today either. :_(

Getting my fix here in the meantime. No need to rush the review though.

Just fyi... I wasn't sure how turbo mode works. He is saying basically it's DD - very high amps, more than the 140% increase he listed. Basically turbo takes it out of current controlled/limiting mode -- this is a very nice feature!

Also, HKJ found an issue in high mode using higher powered cells that needs a cap to be replaced, and once done, fixes the issues that HKJ was seeing. So, I'm holding off more testing til I get the cap and can mod the driver. It's a tiny 0402 -- I never worked with a cap that small, so may have a "super tech" at work do the replacement. He would have no problem doing this, so less risk than me doing it Embarassed.

This HD2010, btw, is a total PIA for this experimenting because of the poor clearance for the bigger wires, big flat reflector bottom... Also the plastic LED alignment piece they ship with HD2010's now is too small for the opening, making it almost impossible to center the LED... Ugh. The older HD2010's I have didn't have this promleb- the LED alignment pieces fit much better.

Is this driver listed as something besides LD-1 on Intl-Outdoors?
I see 18 drivers there and don’t see this one.

Would this work well in a BTU Shocker host?
http://www.cnqualitygoods.com/goods.php?id=1818

Off topic:
Would a 60 Watt Weller temp controlled (700 & 800 degree F tips) soldering station work OK for reflowing LED’s?

It’s a new linear driver by Led4power that does not use pwm for dimming so it has much better efficiency at lower currents. No relation to IO.

Thanks Rufusbduck
Meant to put it in the original thread.

That where they talk about it being sold by IO.