Acebeam EC65 review (21700, 4x XHP35 HI, cool white)

Elmer, when you want to reply to a specific post or person, look at the bottom of their post and hit the “qoute” button.

I typically write my reply just below the quoted section. :+1:

Noted! Thanks!

Awesome! Looking forward to the update :slight_smile:

Thank you for your exemplary review maukka.

I can now safely cross this light of my list. There are several smaller things that are, in my opinion, not well executed or thought out and keep me from buy this light, but the biggest issue is the temperature limit. Why did Acebeam set it at 75°C ? That is just way too high. Sure it protects the electronics, but the temperature limit should be set according to the most temperature sensitive thing, the users hand. A limit of 50°C or 55°C (maybe 60°C) would be better.

Furthermore most Li-Ion batteries have a maximum operating temperature of 60°C, and bad things can happen when Li-Ion batteries get too hot.

To be fair, the high temperature limit is usually ok, since most of the time you will be holding the light in your hand and can just step it down manually when it feels too hot to touch (>50°C). I rarely (never) leave a light unattended for hours.

Usually when I do runtime tests I will start the fan when the body reaches about 70°C to protect the battery. This time I just wanted to see how hot the light would actually get.

I’m more disappointed about the single real turbo burst. Looks like toobadorz’s new sample was able to do it four times before stepping down to the lower turbo level though. So there’s some variation between lights and batteries. Still, the visual difference between the maximum turbo and the next level down is non existent.

That is of course true, but I would prefer a temperature regulation I don't have to worry about. Perhaps I am spoiled by the excellent PID temperature regulation of Zebralights...

Acebeam should at least have bundled the light with a higher drain battery, or better yet improved the driver so that turbo mode works down to a lower voltage (lets say 3,3 V or perhaps even 3,0 V).

Bad mode spacing is a constant source of annoyance for me. The brightest modes are too close together, and the low modes are too far apart (unfortunately that is way too often the case).

On the EC65 turbo is only 3526/1784 = 1,98 times as bright as high (a difference that is simply too small and, as you say, barely visible), on the other hand low is more than 20 times as bright as firefly (and of course a 12 lm mode is really not deserving of the name "firefly").

On an unrelated note: maukka do you have a central place with links to all of your reviews? It would make finding them much easier in the jungle of threads on this forum, perhaps a central thread or your signature.

Noir, it sounds like your expectations are higher than current technology allows.

I hope that in the near future Lexel will have his high powered boost drivers working with NarsilM. Then you can set your own levels and your own temperature limits.

I think his Bistro UI works on them, but I’m not very familiar with Bistro.

I think building your own light is the only way you’ll get it to your personal liking.

Hello maukka, your measurement indicates the max temperature of Mid is around 65°C, but with my new EC65, I got only 43°C (the max temperature measured around the side switch, during my whole Mid runtime test). My experiment is done under room temperature (25°C), with no cooling.

That is pretty weird, or maybe I should measure the temperature around the head instead?

Here’s the light at 25 minutes on mid. Already too hot to hold.

Thank you, maukka. I’m sure that my new EC65 can still be held after 30 mins of Mid. Its body tube was still under 42°C then, and I did hold it to feel if it’s too hot (it was not). So there are indeed some differences.

I don't think that is the case. A lower temperature limit is just a different value that is set in the firmware and has nothing to do with advancements in technology.

Technology is also not the limiting factor when it comes to improving the driver slightly. I am not talking about huge leaps like 5 A more in turbo or twice the efficiency, but small improvements that would allow the turbo to be sustained down to 3,3 V or maybe 3,0 V instead of just 3,5 V. Small things like for example double or shorted springs (lower voltage losses) would already help in this regard (for some reason Acebeam didn't bother doing this), or simply a slightly lower maximum (turbo) mode which can be sustained better.

As it is the EC65 (or rather its driver) is IMHO a bit too "on a knife's edge" (for lack of a better term).

Very true. If you want it done right, you have to do it yourself. One of the reasons I'm into modding .

Thanks for the great and exhaustive review!

Not sure if it was mentioned earlier, but the photo of the package you posted shows peak beam intensity of 10,600 cd.

That is for the Nichia version.

Good news, the Samsung 21700 30T not only didn’t break anything, it was able to cycle full turbo seven times before stepping down to the lower turbo level of 3150 lumens. Initial turbo lasts for 40 seconds before stepping down, which is quite a lot better than on one of my original Acebeam 21700s with 12 seconds.

The internal dc resistance of the 30T is only 13 mOhm.

I’m sure performance would be even better with that updated version like Toobadorz got. Have you talked to Acebeam about getting a replacement?

Mine is already a replacement after the first one broke on turbo, just like Toobadorz’s. I’m sure the difference in performance is due to the battery sample difference as that is already large between the two I have.

Okay, I must have forgot you mentioned it.

Is your turbo still at 3700 lm? Toobadorz said his was now closer to 4000 lm on the replacement light (for some reason).

I don’t have numbers for the first light. It could have well been lower than the 3750 on the new one.

edit: scratch that. The first sample was 3456 lm @ 0 sec.

I’m still thinking this light could benefit from spring bypasses.

I’m not an experienced tester and I’ve only ever tested one light that had a boost driver. I did however notice that as I was using a heavy wire across the tail cap and a clamp meter to measure the amp draw on turbo that it extended the turbo run time.

I further could watch the amp draw decrease as I compressed the driver spring.

Have you noticed any similar behavior?

Also, what battery do you think is best for this light.

The Acebeam doesn’t give much full power turbo runtime, but does give extra run time at lower levels.

The 30T gives a lot of full power turbo run time, but it’s 3,000mah capacity runs out pretty quick.

Maybe the Lishen/Liitokala 4000mah is a good compromise?

Also, that 20A protection circuit is the biggest I’ve heard of. To answer Noirs question, that’s probably why they set that 3.5v turbo stepdown limit. If they tried to set it to a lower voltage it would probably try to draw well over 20 amps from the battery and maybe burn up the driver in the process.