4500 lm for 25hs? Imalent MR90

"4500 lm for 25hs?"

LINK?

it was a video on youtube that seemed to be official… but now I see Imalent wrote 2:30hs

that makes more sense

Sorry.

Lets say it needs 40W of power for 4500 lumens using an efficient LED chip.
25 hours of light would require 1000Wh (1kWh)

One 5000mAh 21700 holds 18.5Wh.
You would need 54.05 batteries assuming no losses in the driver circuitry to make it happen.
Of course you can’t buy 0.05 x 21700 so 55 batteries. Considering inefficiencies you might need 60 x 21700 batteries to make this work.
1000Wh power banks tend to cost $1000-2000 and weigh over 50 lbs. Add in inverter inefficiencies on top of LED driver losses and you might need 1200Wh or more.

So the answer to your question is no, a handheld flashlight is not going to put out 4500 lumens for 25 hours.

That said ANSI requires it to stay above 10%.
So it can give you 30 seconds of 4500 lumens then drop down to 451 lumens and give you hours of that. For 451 lumens @ say 3W you might need 80Wh of power to make that work, 5-6 x 21700s might do the job?

Totally possible if you step down a lot.

That does mean it won’t be doing 4500 lumens of course lmao.

Anyway, it’s functionally impossible to get a sustained 4500 lumens out of even a 4x 21700 battery pack(max capacity of 72Wh, and the Imalent cells included are less than that).

Even at 300lm/W, that would only equate to 5 hours, and we all know the SBT90.2 at 4500 lumens isn’t anywhere close to 300lm/W :stuck_out_tongue:

@ marcosgg:

I looked all over your link (Imalent MR90 web page) but can’t find any runtimes.

It’s always best to be specific so the reader doesn’t have to dig for the info.

25sec. then stepdown. these tiny oopsies happen always with chinese ads.

This is a cultural phenomenon. Everything is in the factors of thousands, tenthousands, millions,…. all simply meaning “a lot” without intended precision.

It is on the images.

Please do post those images…

Regardless: Imalent and Acebeam are at lumen war. Their claims are not to be taken seriously.

As for this particular model, although incorporates fans and an innovative reflector design, the cost is beyond “budget” (ie, this forum). Also, for $300+ USD, caters to ‘professionals’ or ‘bourgeois’. Doubt an on-the-field responder would use an un-sustained light in his tote. As a show light, great self-indulgence.

As a first responder or technical investigator, I use a 3-minute (arbitrary) sustainability criteria. Most of manufacturers claims fail for the turbo levels. Some do work in the high mode – hence the turbo should be hidden from main sequence and not memorised.

https://cdn.shopify.com/s/files/1/0068/9271/6105/products/15_98b4f8fa-c9af-4456-9e1e-4fb09b11118f_2048x2048.jpg?v=1654052227

this video is wrong:

Well, that 1st link is “page 404 not found”
Taken from the second video:

Now that I have a picture, I see you are referring to the SBT90.2 emitter (“spot”).
Just a typo; probably – 0.25 hours (15 minutes) is my better guess.

And you don’t have to quote from the previous comment – just repetitive.

I have the MR90 here, and the manual says 2h30min... / 2.5 hours For the Spot mode.. (SBT90.2)

2.5 hs… 2:30hs…

Cool! What do you think about it?

Hmm, let’s do some maths:

From Djozz

Presuming some 10% over stated lumens (from Djozz’s own admittance), this LED consumes some 17.6 Amps at 3.3 Volts ≃ 60 Watts

Imalent states 16,000 mAh battery pack:

Using perhaps a better cell as the best scenario, the Molicel P42A:

Battery capacity 4 x 9.5 Wh (at 20 Amp discharge rate) = 38 Wh

Runtime: 38 Wh ÷ 60 W = 0.633 hours (38 minutes)

Assumption of direct drive. Buck/boost driver would fair a bit better. Could drain below the LED’s Vf.

And mind you not accounting for lens and reflector losses; that 2½ hours cumulative claim isn’t possible.

Here's the graph I made... red line is just the SBT90.2...

It's about 1850 lumens for most of its runtime

thanks

I received my MR90 yesterday,and unfortunately it was DOA. I tried to charge it,but in vain,the voltage remained 0.3V only.
Fortunately,I had an idea.I sawpped the battery pack of my MS12 mini,which is the same with the one of the MR90,and voila,the flashlight is shining furious,with its fans rotating in full.
So,it seems that the power pack only, is defected.I hope Neal arranges the isuue.

just a typo, or they really meant 25 hrs for Melting Righthand

@sidney stratton

"As a first responder or technical investigator, I use a 3-minute (arbitrary) sustainability criteria.."

So in the 'budget domain, some of the newer Convoy's thrower or flooder should make the list i presume.

Cheers