Something fishy with the temp limit on the Emisar DT8 (Anduril 2)

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RollerBoySE
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Something fishy with the temp limit on the Emisar DT8 (Anduril 2)

I was playing around with the temperature settings on my Emisar DT8 (Anduril 2).

If I start from the default max ramp intensity it stops right on the max temp setting even when setting it low, like 35° C.

But if I start from turbo it overshoots the max setting badly with as much as 20° C before down-regulation gets a hold on the heat.

Is it a bug or something I just have to live with?

Am I doing something wrong?

(I did carefully calibrate the temperature reading.)
(Light is equipped with 4000K SST-20:s and I’m using a VTC6 cell.)

SammysHP
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In turbo it creates much more heat than at the default ceiling. The regulation can’t respond fast enough and it will overshoot.

Perception
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I’m sure there are a lot of contributing factors, but on turbo it probably generates heat so fast that by the time it hits the sensor and adjusts it’s already overshot and it has to overcompensate until it can stabilize.

Unheard
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The sensor is in the MCU if I’m not mistaken. It should get hot much slower than the body. But 20 Kelvin over the limit is quite a lot. Have not measured this on the D4V2.

Smile, you cannot kill them all.

RollerBoySE
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I also have D4v2, both in Alu and Ti, with Anduril 1.
And when starting them (also with SST-20 and VTC6) from Turbo it only overshoots with very few degrees.

Can the combination of Anduril 2 and the new driver in DT8 have something to do with the bad overshooting?

stephenk
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I’ve found 55C to be the optimal max temp for sustained brightness in indoor testing conditions. Default 45C (out of the box) and 60C both resulted in a bigger step-down, and lower minimum brightness.

thefreeman
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In turbo all the heat is generated in the LEDs and it has to transfer to the MCU on the PCB (as Unheard mentionned)
At the ceiling a significant proportion is generated in the linear FET, on the PCB and quite close to the MCU, so it responds much faster.

elendur
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I was also playing with the turbo on my Anduril2 nofet 7,5A e21a d4v2 at a 45º limit and it became so hot that I just figured that momentary turbo was not temperature-regulated… did I imagine reading about that somewhere?

thefreeman
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No I’m pretty sure I read that somewhere too.

SammysHP
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Yes, momentary is not temperature regulated.

RollerBoySE
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SammysHP wrote:
Yes, momentary is not temperature regulated.

Although I am talking about the double-click from ON that goes to flatout, but stays on.
Maybe it uses the same circuit and bypasses the temp regulation?
Who knows?
It would explain the behavior.

SammysHP
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2C from off goes to ceiling, not turbo. It has thermal regulation.

2H enables momentary turbo without thermal regulation.

RollerBoySE
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Just to sum up.

I think we have concluded that ‘turbo’ is a flat-out mode without thermal regulation.

‘Max-ramp’, even if set to max-max, HAS temperature regulation that works excellent.

It’s a truly great light by the way.

elendur
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Only momentary turbo is not thermally regulated. Momentary means that you have to keep the switch pressed down. When you release the swtich, it goes back to its previous mode. Th idea is that you hands do the regulation, you wouldnt let it burn your hands so you would let go of the switch (and drop the light if it’s really too hot).

RollerBoySE
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elendur wrote:
Only momentary turbo is not thermally regulated. Momentary means that you have to keep the switch pressed down. When you release the swtich, it goes back to its previous mode. Th idea is that you hands do the regulation, you wouldnt let it burn your hands so you would let go of the switch (and drop the light if it’s really too hot).

At least my DT8 doesn’t have thermal regulation in turbo, that stays on.

(Thermal regulation in max-ramp works excellent on the very same light)