Convoy M21B GT-FC40 thermoregulation not working?

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kokosnh
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Convoy M21B GT-FC40 thermoregulation not working?

Is Convoy M21B GT-FC40 thermoregulation not working?
Just yesterday saw this post on reddit, guy got 80C on fins, is it one off, or is there something wrong with thermal control on it.
 (https://www.reddit.com/r/flashlight/comments/qy72hy/she_is_hot/)
I'm planning to buy two of them for bike for off road trip (so I won't feel the heat, but I still can be burn, when trying to take it out, or to turn it off, after an hour or so of it working.
And well it can harm the battery Sad and led too

Edited by: kokosnh on 11/21/2021 - 17:20
d_t_a
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Hmm. Probably best to bring this to the attention of Simon (Convoy).

Simon is more active in this thread:

https://budgetlightforum.com/node/64374

Funtastic
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I answered this on reddit

There is an initial stepdown at 60°C, but unfortunately nothing happens further and so if a model has insufficient cooling at 35%, that’s when it continues to heat up

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kokosnh
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Thank you for explaining, now that I know how it works, I will just think this through if I want it in my use case. 

That pseudo thermoregulation should be explained thoroughly in the spec. Because now I know, I always want to mechanically lock it out, before transporting, just in case.

I already have convoy S9, that if I leave for too long on 100%, I have to gram gloves to turn off.

lfb
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The Reddit post is mine.You can only get those temps by reseting turbo, so no worry for bike usage. Also, with air cooling you will get way lower temperatures.
I would be more concerned about glare, unless you are going to use it for off road.

d_t_a
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Funtastic wrote:
I answered this on reddit

There is an initial stepdown at 60°C, but unfortunately nothing happens further and so if a model has insufficient cooling at 35%, that’s when it continues to heat up

Based from your tests, around how much power can the M21B host handle? (eg. stay at 55-60 degrees Celsius continuously, and not heating up much further)

I notice that Convoy has added many new LED variants for the M21B recently – previously, there are only the XM-L2, XPL-Hi, SST40, which uses no more than around 3-5 Amps (manageable on the M21B).

But now, there are the 8 Amp variants of the CULPM1 and SFT40 for the M21B, which produces more heat.

And then there’s the higher power GT-FC40 and XHP70.2 LED variants of the M21B, which uses something like 8-10 Amps on highest brightness (per my tailcap current measurement).

tactical_grizzly
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d_t_a wrote:

I notice that Convoy has added many new LED variants for the M21B recently – previously, there are only the XM-L2, XPL-Hi, SST40, which uses no more than around 3-5 Amps (manageable on the M21B).

But now, there are the 8 Amp variants of the CULPM1 and SFT40 for the M21B, which produces more heat.

And then there’s the higher power GT-FC40 and XHP70.2 LED variants of the M21B, which uses something like 8-10 Amps on highest brightness (per my tailcap current measurement).

I think you may be confusing M1 and M21B. They are similar, but two distinct hosts.

M1 is slightly smaller and uses an 18650. It’s the one that has the 3-5 amp options (SST20, XPL-HI, CSLNM1).

M21B uses a 21700 and has higher-powered emitter options (FC40, SFT40, CULPM1, XHP70, etc).