Jetbeam CE poor efficiency (compared to a Fenix P3D)

[regulator]

I have a Jetbeam CE from DX (I think one of the first models available - and slightly different from the ones from the emillion group buy). My light has a fantastic white beam and the finish is very nice as well. However, I am experiencing very short runtimes. I cannot even get two hours on medium. I tried different batteries with the same results. The light gets pretty warm on medium. The output is not bad though - it may be just a little less bright than my Fenix PD3 on medium.

I measured current draw and it pulls 1 amp on medium and appoximately 2 amps on high. I think this is too high and a result of a very inefficient converter. I know that runtimes have been posted with medium running anywhere from 4.5 (on a version from emillion) to over 7 hours (with the new 1.2 version). I wonder if the batch from DX had efficiency problems or maybe they are early models released to them due to the sales problems.

Again - the Fenix P3D which is slightly brighter on medium only pulls appoximately .137 amps (on a 4 volt lithium 17670). The Jetbeam pulls 1 amp at 1.25 volts on medium. The Fenix is about twice as efficient! I think Fenix did a good job with their new lights and efficiency.

 

[AFAustin]

I have a C-LE from DX. Likewise, nice white beam and good output. But, I got about 2 hr. 25 min. on high, and it never got too warm.

Kyle at DX stands behind his products, so you might want to arrange a return. He may be out of stock on the C-LEs at present, but probably has the new DX X.V, which may be the same as the C-LE.

 

[regulator]

Hey AFAustin,


Thanks for some comparison info. Mine would get very warm on high - almost hot. It does get pretty warm on medium. While the output is nice, I do not think it should be as warm as it gets - I would think it would run only slightly warm on medium. This caused me to take some current measurements. On low (which is dimmer than a Peak Pacific by about half) it is reading 212 mA's.

All other things considered it is a nice light - it just bums me out that there is something waisting power and cutting into runtime. It took over a month to get this light from time of purchase.

 

[MarNav1]

I have 6 C-LE's and have never noticed one even a little warm. I'll check one out
tonight and see what happens and report back.

 

[chimo]

What batteries are you running the C-LE on?

If they are Li-ion, you are essentially direct-driving the emitter. Efficiency would then be quite high (losses through the inductor, schottky and MOSFET). The current from the battery should be about the same as to the emitter.

My C-LEs top out at around 1A on the input for NiMH and Alkaline cells.

Paul

 

[x2x3x2]

Yup the JETBeam is about 50% as efficient even compared to the Fenix L1D CE.

With both running Eneloop cells the JETBeam thows about 370 lux for 4 hours while the Fenix throws about 790 lux for 4 hours.

 

[regulator]

I must have a defective unit then. I was running it on a NiMH cell. It would get really hot on high - and measures 2 A. This current reading seems correlate with my dismal runtime of about an hour on high.


Any other observations are appreciated. I would hate to have to wait for a return. It takes forever to get soemthing from DX and I don't even know how long a return shipment would take - almost seems not worth it.

 

[MarNav1]

Been running a random C-LE on a L-91 since my last post and it's not any warmer
than when I picked it up. I hope that helps. Oops forgot to say on med. I'll
run it on high if ya want.

 

[AFAustin]

I would say to contact DX. They have been quick recently on e-mail responses. I had a defective C-LE and got a pretty quick turnaround on the replacement unit.

 

[regulator]

Thanks for the info - it has helped me determine that there is something not right with mine. I ran it and the Fenix P3D on medium (both with similar output) and the P3D stayed cool and the whole Jetbeam light got warm. I will try contacting DX.

 

[flyingbrass]

If you contact DX please pass along what they say. Mine also runs hot with short runtime. I used 2400 batteries that came with my LaCrosse charger. 8 days earlier they tested at 2130 and 2140 mAh.

On medium it was noticeably dimmer at the 90 minute mark. At 2 hours it was very dim. 2.5 hours I could barely make out the spot on my ceiling, and I could look directly at the LED with no problem.

I blew a fan on the light while testing high. At 33 minutes I estimated it to be about half the original brightness. At 1 hour it was down to approximately the same output as the low setting.

Quite disappointing.

 

[regulator]

Hey Flyingbrass,

Yep - sounds like yours is doing the same like mine. I have not contacted DX yet. I wonder if it will still be taken care of since I recieved it a little over a month ago. The problem was not obvious since I did not run it often and it did perform well during short periods. It wasn't until I got curious to see runtimes that I discovered something not right.

I may try contacting them to see what they say - and please keep me informed if you do the same.

 

[LED_Thrift]

I have two C-LE's from the first group buy and they only get a bit warm on high. My runtimes are better than what you stated when I use NiMH, but I have not timed them.