Acebeam X70 - 40000 lm - 8*18650 - Active fan cooling

Mortuus, you should know better. We don’t go by rated specs. We go by real world tests.

Let’s wait until it has been tested to see if it can do 6400 lumen continously.

BTW, this is still less than the 7000 lumen continous of the DX80.

Agreed, it’s all about real world tests. Advanced Knife Bro tested the DX80 at ~7000 lumens for 2 hours. Has anyone done a real world test on the X9R? I’d be interested in the results.

I haven’t seen any, although I haven’t really been looking. I’m sure we’ll see some tests soon.

TL:DR: It’s possible.

It looks like they are running the LED’s at max CREE recommended specs. Assuming that, the XHP35 is putting out 1830 lumens, the XHP70.2’s the other 38k. so 38,170/12 = 3,180 lumens each. If their 40k lumen figure is OTF and not emitter lumens, it would appear they are running the led’s at max factory specs, which CREE claims is 3,800 lumens for the XHP70.2’s and 1833 for the XHP35.

That’s 13 watts for the XHP35 and 29W for each of the XHP70.2’s. Total wattage in that case would be 361 watts. It’s commonly said that between 60-75% of the energy going into an LED turns into heat. Say 60% of the energy turns into heat going into the heatsink, that is 216W of heat. Around 200W+ of heat needs to be dissipated.

So, the LED’s can run very hot, you could run them at 150C Tj continuous, but of course the batteries and the flashlight cannot be allowed to get much above 60C. Decoupling the head from the body with stainless dowels or what not would allow the head to become much hotter than the rest of the light, or decoupling the heatsink more or less from the light is an option. Either way, the target temp for the heatsink can be considered independently.

The XHP70.2 has a thermal resistance of 0.9°C/W, the XHP35 is at 1.8°C/W but runs less than half the wattage so it comes out the same thermally. So if the XHP70.2 is being fed 29W, it is 26°C above the heatsink temperature. Combined with the ambient temp, this allows about a 100°C rise in heatsink temperature before the LED Tj is at 150°C.

What does a commercial actively cooled fansink rated for 200W heat dissipation look like? The MECHATRONICS LED ICE ULTRA is an example of this.

The datasheet says that this heatsink will have a 50°C temperature rise over ambient at 200W dissipation. With this heatsink, at 23°C ambient, the Tj of the LED’s would be 99°C. That heatsink appears to use a 90mm to 96mm fan and consumes 2.76W at 3,000 rpm. They don’t spec it, but it probably has an output of around 55-60 CFM and >0.15” H2O or so. The heatsink resistance is .25°C/W, so this means it could dissipate 400W of heat before a 100°C rise occurs.

What do their smaller heatsink models looks like? Two of their smaller ones are in this datasheet. The difference between the two heatsinks in this datasheet is 10mm in fin length. Their thermal resistances are .58° and .46°C/W between the two. Its about an inch shorter than the 200W heatsink, and the ~90mm fans are 1500 rpm rather than 3000, but the heatsinks are the same 100mm diameter. These fans should be putting out around 30 CFM and .04” H20 SP. The bigger of the two fansinks could handle 200W before a 100°C rise. They do not have tightly grouped fins, presumably so that dust is less of an issue, and this is appropriate for the fans which do not have high static pressure.

If the fans in the X70 are high rpm 30x30x10mm fans, which they definitely don’t look like 40mm fans, they are putting out around 8 CFM each and 0.380” H2O (94.6 Pa) static pressure. Static pressure can be additive as well as cfm, so you’ve got 24 CFM and ~1” H2O static pressure. It’s a decent amount of static pressure; I have a loud and powerful 40mm fan with those specs. This means that the fins of the heatsink can be thin and tightly spaced.

So, what is clear is that the heatsink and fan combination needs to have better than .5°C/W sink to ambient thermal resistance (aka theta sa) to keep the heatsink from rising 100° above ambient, if there is 200W of heat to be dissipated. .4°C/W theta sa would be better, with an 80°C rise.

After looking at a lot of fansinks and specs, it would appear that it is possible that there is a .5°C/W theta sa or better conventional fansink within the volume in the cavity of the head of the X70, especially if it’s copper. (example at .55 theta sa at 26 CFM)(example at .3 theta sa at 26 cfm) The questions are: is there a high density aluminum or copper heatsink of sufficient volume hidden within the cavity of the head of the light? Do the fans deliver 20+ cfm? Are they really feeding those LED’s 361 watts? And so on.

Wattage for the xhp35-HI might be double your 13W. So 26W sounds about right.

I calculated about 270-300 watts total.

I think we’re both in the same ballpark. If outside on a 70°F day with some wind it might be able to go continous full power without stepping down.

That’s not quite right, you can either parallel the fans for more flow or have them in series for more pressure, but not both. Great explanation otherwise :+1:

Based on the orientation of the three fans, I assumed the heat sink fins would be divided into 3 sections with one fan for each.

Imalent is shit

says stable 15k, so i wouldnt asume the 53000 is a very long runtime… i think the host must be alot bigger and beefy its just a rushed light to beat x70 on paper imo… and reading imalents past i would never buy a light from them for 600$ crazy… i prefer less lumens but a light built like a horse and good quality. time will tell.

Hold your horses my friend,are you sure about it? I,for example have one DX80 and it is 100% reliable after all.So calm down.

I don’t think so!

I agreed, been using almost everyday and never ever have any issue!

It cost around $650.00 the acebeam x70

It’s around 700$

$685.00

Welcome to BLF. :wink:

I would rather have this for $600 and take my girlfriend out to lunch with the remaining $50!

That is just over 1Million CD @ turn on and .988Million Cd[988Kcd] @30 seconds. It is also very easy to carry when walking my Husky,no need to hire a Sherpa and pack of Huskies!

That is a completely different type of light. It’s low powered, long range and only lasts for 2, maybe 3 minutes. No one interested in the X70 would consider the TN42vn as an alternative. Sorry.

Your right,It is completely different. Your wrong that it[TN42vn 90] only lasts for 2 or 3 minutes! It maintains awesome out put for more than 30 minutes! :wink:

It is more like the Flood monsters can last only 2 or 3 minutes,I do not care what kind of fan you use.How long are you going to maintain 40K lumens? 30 seconds?

That TN42VN can run turbo 30 minutes and not overheat? Wow, I don’t think it could.

The X70 could possibly maintain its 40k lumen for 30+ minutes. It depends on the effectiveness of the cooling system.

If not 40k lumen, then 25k to 30k lumen continous is definitely a possibility.

It loses output though because of direct drive. So the power and heat are also reduced continously.