Convoy M21F turbo regulation

[BringMeSunshine]

I ran my M21F on turbo while on a walk outdoors in freezing cold conditions, about 3 Celcius. After 40 minutes it dropped down to a low level. I re-engaged turbo and after a short while it dropped down again. So I set it onto high, and it eventually gave up after about 50 minutes from when I started out. This is much earlier than expected. Fortunately I carry an emergency torch, so in this case I was not stranded on an unlit country lane.

So I repeated the test indoors, after about 3 minutes the turbo started to step down ending up at about 44 % of the initial value after a few more minutes. My readings are only approximate. It then continued at that level until after 60 minutes there was a small drop to 40 % of the initial value. I gave up through boredom at 75 minutes. This performance is pretty much as expected from the online reviews of this light.

What is going on?

My guess is that the turbo regulation is controlled by time and temperature. After a few minutes on turbo, the output drops down to a level that allows the temperature to remain stable and comfortable. When running the light in freezing cold air, the heat can dissipate more effectively, and hence the light can run at a higher output level, and hence the battery drains more quickly.

Can anyone confirm this?

It is an excellent light, very nicely made, but I need to be careful not to run it on turbo while out on an hour long walk.

 

[bluflaam777]

I don't know but I like to 'hear myself talk' LOL

But, that sound about right and logically so.

I have a few convoys (not that model) but they act similarly to that. Heat regulation plays a big part in their design. Thermistors do what thermistors do in different conditions.

 

[BringMeSunshine]

I don't know but I like to 'hear myself talk' LOL

But, that sound about right and logically so.

I have a few convoys (not that model) but they act similarly to that. Heat regulation plays a big part in their design. Thermistors do what thermistors do in different conditions.

I’ve done a bit more reading, and it would appear that it is pretty standard behaviour. Output graphs by different reviewers for the same light often produce quite different turbo results, no doubt due to the efficiency of cooling or lack thereof during the test. I guess it makes sense to drop down to the highest temperature that does not cook the light or the user.

 

[bluflaam777]

Convoy isn't the only one with that behavior.
Yeah, basically 'turbo' isn't something you can count on for other than temporary use (in some cases less than a minute), or just to brag about 'da lumens'. In some torches even high mode will scale down some. Even the type/brand of cells will play a role.

Always good to do some research. Always good to share what we learn.

 

[BringMeSunshine]

Convoy isn't the only one with that behavior.
Yeah, basically 'turbo' isn't something you can count on for other than temporary use (in some cases less than a minute), or just to brag about 'da lumens'. In some torches even high mode will scale down some. Even the type/brand of cells will play a role.

Always good to do some research. Always good to share what we learn.

You misunderstand. Of course turbo always steps down from UberSupaDoopahEggFryer lumens after a few minutes. Good lights will then maintain a constant level until the battery is exhausted. I am referring to that constant level. There are reviews of the same light with quite different values for that constant level, depending on whether or not the tester cools the light, and how well.

 

[bluflaam777]

You misunderstand. Of course turbo always steps down from UberSupaDoopahEggFryer lumens after a few minutes. Good lights will then maintain a constant level until the battery is exhausted. I am referring to that constant level. There are reviews of the same light with quite different values for that constant level, depending on whether or not the tester cools the light, and how well.

You're right, my apologies.

I like when 'testers/reviewers' note the ambient temps during testing. Also the brand of batts they used.
Noting pretty much anything that could affect performance or testing numbers.

What equipment did they use? Age of cells? Temps? How many times did they test? Even add some antidotal usage results as they can be useful to some ppl. etc etc etc
Most reviewers don't bother with that info and good tests can't account for all potential usages.
Warranties? Customer service? Can I fix it myself?

Immpossible to cover every base, but I'd still like to know the numbers and how they got them.