Convoy T3 vs T2 efficiency on NiMH?

LED Flashlights – General Info 1 x AA / 1 x 14500 Flashlights
1
I've heard that the T3 uses a 90% efficient driver, while the T2 (4-mode LH351D version) uses a 75% efficient driver, so one expects the T3 to be more efficient as a whole. However, some data seems to suggest otherwise:
  1. According to ZeroAir reviews of both lights, T3 and T2 both sustain a high of around 100 lumens; however, the T2 has more than double the runtime.
  2. This BLF post contains the same observation: the T3 draws twice the amps around the same output.
If anyone here owns both lights, a comparison of output, runtime, and current draw on NiMH would be most appreciated!
2

Edit: I was wrong because I compared different chemistries.

In the reviews made by ZeroAir:

- T3 519a high NiMH - over 80 minutes ~200 lumens

  • T2 LH351D high NiMH - 160 minutes ~100 lumens

Because we know that to produce twice as much lumens we need more than twice as much energy and runtime is more than a half, we could draw a conclusion, that T3 519a high NiMH is more efficient.

3

Not quite! You may have been looking at the 14500 runtime graph, which does sustain 200lm for 80min. But not Ni-MH. It may be a bit confusing as the two reviews have different testing orders for NiMH and 14500.

4

Does the T2 still only come with the four mode driver? Simon’s 12 mode AA/NIMH/14500 driver is so much nicer its a no brainer for me.

5

I am not sure. The concern here is that the 12-mode driver might be a downgrade compared to the 4-mode driver, with only half the efficiency on NiMH.

6

I tested the t3 low modes with a 2300mAh — 10:12h, 1:3d16h.

I consider the t3 to be a nimh light with emergency 14500 compatibility. It is uselessly too bright for outdoor use at 1% with a 14500. I was worried about the efficiency as well, but it seems to be roughly in-line with others. Would have been nice if the 1% lasted 10x as long as the 10%, but those may be nominal percentages more than exact percentages.

7

I haven't tested my runtimes but guessed based on my current draw measurements, around 30mA for 1% and 180mA for 10%. Dividing 2300mAh by these numbers gives runtimes that are very close to your measurements.

The T3 efficiency on NiMH does compare to most other AA lights out there. It's even a bit more efficient than Acebeam Ryder RX, and significantly more than Skilhunt E2A SST20. But the extra +60% efficiency of the T2 would still be nice...

Another interesting phenomenon I observed is that the T3 current draw on high (NiMH) depends on the emitter. My original 519A 2700K draws more than 2A; after swapping in 519A 5000K, it never draws more than 1.6A. This affects mode spacing as well: the 30% mode was around 30% output before; after the swap it's more than 50% of the max output.

8

I found this review stating that T2 on the highest mode lasts only 27 minutes: Convoy T2 Review | Cheap and reliable AA flashlight - 1Lumen.com

Maybe there is a mistake in the ZeroAir’s test? (Convoy T2 14500/AA Flashlight Review - ZeroAir Reviews)

9

Thanks for sharing this--but this particular T2 in the review is actually the first-generation T2 that has a different driver from your LH351D-equipped T2. The user interface is different, and the old driver has a 400-lumen burst toward the end of the run.

I originally suspected a mistake on ZeroAir's part, but the runtime plots and lumen/current measurements are consistent, and I find it unlikely that both are erroneous.

10

This is very sad, I wanted the MAO version of T3 to be next, that I buy.

But Simon wrote that T2 is 70% efficient and T3 is above 90%. It doesn’t look like it, T3 is really underperforming.

ZeroAir’s Convoy T2 review

ZeroAir’s Convoy T3 review

I’ve been waiting for a long time for an honest T3 review, and it’s finally here. The result is very disappointing.

11

thanks for the data

162 minutes on the T2… :+1:
52 minutes on the T3, :confounded:

12

Thank you for embedding the images--it makes comparison a lot easier! If you are interested in the MAO T3 host, you might be able to ask Simon to make it with the previous 4-mode T2 driver.

13

Technically there are a few differences between the two--the T3 run is uncooled and uses a lower capacity cell. But one can rely on current measurements, which don't suffer from these disparities, and they indicate the T2 is around 60% more efficient than T3. The T3 is more efficient only on 14500, and I wish the manufacturer had made that clear.

14

“60%” is not entirely true, because those tests are performed on different leds (lh351d and 519a).

15

You’re welcome.
Of course you are right I could order it with the older driver, but I would also need the mode memory that can be turned off.
Earlier I was thinking of just buying a new driver, but now I’m going to drop the idea and look for another type. After reading about the fragility of MAO coating in several places, I think I’ll give up on that too.

16

You are right, but there is very little difference in their opening voltage and efficiency. Half the runtime of T3 cannot be excused, the new driver is very badly designed. In our country, 14500 is not a widely used battery, so for me it is secondary and less important.

I will never understand why these engineers don’t have two hours to test the circuit they have designed? In the meantime, who knows how many thousands of them have been produced. :person_facepalming:

17

Update for anyone who might be reading this thread: I now believe there is NOT sufficient evidence to conclude that the T3 driver is less efficient than the T2 driver on NiMH, everything else being equal.

It occurred to me the possibility that the same driver may have different efficiencies driving emitters that differ in electrical characteristics. Note that I mean electrical efficiency here, not lumens--that would be efficacy.

I recently swapped the 2700K 519A for a dedomed 519A 5700K in my T3. The maximum current drawn went from 2+ amps down to around 1.5. The comparisons so far between T2 and T3 all have the T2 in LH351D, and T3 in a Nichia emitter--219B and 519A. While the 219B and 519A have almost identical electrical characteristics (Vf curve), the LH351D has a much higher Vf at all current levels. I suspect this difference in forward voltage may have a sizable effect on the efficiency of the light.

If the difference in apparent efficiency can be accounted for by the difference in emitter Vf, it is possible that the T3 driver is not less efficient than the T2 driver. If that is the case, I owe Simon and the flashlight community an apology for prematurely coming to a conclusion without enough supporting evidence.

In any case, what really needs to happen is a test with the 2 drivers driving the same emitter (same model and CCT), with output and current measured.

18

So is T3 MAO still a good choice for the 14500 batteries?

19

If you intend to run 14500 most of the time, T3 has a less out than T2 but is more efficient--overall I think the T3 is better for 14500.

If you want to use NiMH, I don't have conclusive evidence about the efficiency of T3 vs T2 using the same emitter.

20

It doesn’t have a real low mode running on 14500. If that works for you, then it’s a good choice.