*new* Acebeam K70: max. 2600 lumens, 1300 meters throw

[kj2]

Also check eu dot nkon dot nl. Large choice on li-ion batteries.

 

[BLUE LED]

I use Efest IMR 18650, 3100 mAh (20A). Good quality high drain / high capacity cells.

 

[monkeyboy]

Acebeam told me, the K70 draws about 7A from the batteries so think the Sanyo's are the way to go.

It's definitely not pulling 7A though each cell! (Could be 2s2p).

You can do a rough back of the envelope calculation to estimate this:

The XHP35 HI is rated at ~12V @ 1.05A maximum spec. To achieve the lumen output of the K70, the LED would need to be driven at about 2A and Vf would rise to about 15V. So LED is driven at around 30W. Factor in say 80% driver efficiency and total power draw is ~38W. Current through each cell assuming it uses 4 x 18650 would be ~38/(4 * 3.7) ~ 2.6A.

So current through each cell would be approx 2.6A. Maybe 3.5A at the very most.

 

[scs]

It's definitely not pulling 7A though each cell! (Could be 2s2p).

You can do a rough back of the envelope calculation to estimate this:

The XHP35 HI is rated at ~12V @ 1.05A maximum spec. To achieve the lumen output of the K70, the LED would need to be driven at about 2A and Vf would rise to about 15V. So LED is driven at around 30W. Factor in say 80% driver efficiency and total power draw is ~38W. Current through each cell assuming it uses 4 x 18650 would be ~38/(4 * 3.7) ~ 2.6A.

So current through each cell would be approx 2.6A. Maybe 3.5A at the very most.

If 2s2p, then the driver is actually a boost driver, right? Would the 3.5A cover the overhead amperage needed?
If it is a boost driver, I wonder if acebeam determined that they can build it for 2s2p that is more efficient than a buck driver for 4 cells in series.

Edit: If like you said, 15Vf is needed for max output, then maybe it is a buck/boost driver?

 

[KeepingItLight]

I just dropped the dime on the wife about the purchase of the MH20GT and now you're wanting to have my cojones modified.

That's one way to make a parrot quack! oo:

 

[monkeyboy]

If 2s2p, then the driver is actually a boost driver, right? Would the 3.5A cover the overhead amperage needed?
If it is a boost driver, I wonder if acebeam determined that they can build it for 2s2p that is more efficient than a buck driver for 4 cells in series.

Edit: If like you said, 15Vf is needed for max output, then maybe it is a buck/boost driver?

If it is 2s2p, then yes it would have to be a boost driver as the XHP35 is only available in 12V. The current through each cell in 2s2p would be no different from 4s assuming the same total power consumption and that all of cells are consistent. 3.5A should be fine. The current through the tailcap would be 7A max, but 3.5A max for each cell.

Vf = 15V was more of a conservative estimate. Probably lower in reality. With 4s a buck/boost driver would be ideal, but they might also just use a buck driver and have the light go into direct drive as it falls out of regulation. A lot of lights are like this. The Acebeam K60 uses a 4s battery configuration with good regulation but they are probably using the 6V version of the XHP70 with a buck driver to achieve this. As far as I know there is no 6V version of the XHP35 so they would have to use a different method to achieve good regulation in the K70.

 

[Parrot Quack]

That's one way to make a parrot quack! oo:

..........................:green:

 

[Theodore41]

Which of the two batteries,is good for the K70 ?
https://www.akkuteile.de/?ActionCall=WebActionArticleSearch&BranchId=0&Params[SearchParam]=sanyo+NCR18650GA&submit_search.x=0&submit_search.y=0

 

[ven]

Can't tell off link but if Sanyo GA then fine for light.

 

[Theodore41]

I think there are with and without button top.Can you tell me please,which of the two,is good for the K70?

 

[ven]

Either should work as the carrier has a slightly raised + end, I prefer flat tops myself.

 

[Theodore41]

Thank you very much.

 

[ven]

No probs , Samsung 30Q flat tops will be going in mine.

 

[Lightups]

Hello all. Does anyone's K70 have inductor whine? Mine's have a very soft constant hum on max, and on strobe, where the hum matches each blink of the strobe.

I am currently using 4 brand new Lg Hg2. After a few minutes on max one cell is at 4.10, two at 4.11, and the fourth at 4.11/4.12. Is the 4.10 something I should be worried about? I charged it using the Nitecore D2, and all came off the charger around 4.16.

Thanks in advance.

 

[ven]

Just keep an eye on them, tolerances in the charger , what your measuring with , all have slight variables .

It's worth looking at upgrading the charger to a four bay , this will make life a little easier .

 

[ven]

Came in today and very impressive, nice balance/feel like the k60vn


Questions about cells, well to show the 3400mah Xtar with pany inside(protected) which is quite a looooong cell. Yes a tight fit!!! but it fits!


Better to go with



Brothers






Pointless close up hot spot pic..........just to show it basically


Weather and everything else going on dependent , will try and get some outdoor pics when i can!


Cheers

 

[kj2]

Nice pair ven!

 

[gyzmo2002]

You do not have long resisted the temptation ...[emoji6]

 

[ven]

Nice pair ven!

Cheers Kev, they do make a great couple!!! Just need some decent weather, darkness and most important..........time!!!

 

[ven]

You do not have long resisted the temptation ...[emoji6]

I can resist any time i want and for as long as i want