Relationship: Ampere <--> mass of flashlight

15 posts / 0 new
Last post
Andi
Andi's picture
Offline
Last seen: 9 months 2 weeks ago
Joined: 01/22/2011 - 08:08
Posts: 333
Location: Germany
Relationship: Ampere <--> mass of flashlight

I have 3 XM-L flashlights and testet 2 different drivers with all flashlights.

flashlights are: Ultrafire P10 / KD C8 / HS-802

testet drivers: driver from manafont p60 dropin / KD P7 driver

I always have much more A with same driver in the HS-802, as in KD C8. (e.g. with KD P7 driver: HS-802=4,1A / KD C8=3,2A)

In P10 Ampere are little bit less, as in KD C8.

 

Now i thinking, could the reason the mass of the body ???

 

brted
brted's picture
Offline
Last seen: 1 week 18 hours ago
Joined: 01/12/2010 - 19:44
Posts: 2371
Location: Atlanta

That is surprising. I would expect them to be about the same. If anything, it seems like more mass and heatsinking might draw more current because the heat wouldn't just build up but would be moving on. A hot LED isn't as bright, so maybe it is also drawing less power?

Andi
Andi's picture
Offline
Last seen: 9 months 2 weeks ago
Joined: 01/22/2011 - 08:08
Posts: 333
Location: Germany

yes, that could be.

but i measure cold flashlight, i get the Ampere measure in under 1sec., i mean, in this short time, the led is not really hot.

 

hansheng
Offline
Last seen: 1 year 2 weeks ago
Joined: 04/12/2011 - 03:01
Posts: 46
Location: singapore

this might be the cause of the resistance of the switch too, i rmb a thread about different type of solarforce tailcap switch being testing and some of the tailcap switches have a bigger resistance than the others and thus result in lower current draw.

hope this helps

okwchin
okwchin's picture
Offline
Last seen: 7 months 3 days ago
Joined: 01/07/2011 - 04:41
Posts: 1164
Location: Australia

I think its fundamental torch design, the weight is almost irrelevant enough to be ignored. Its more likely the contact quality, LED variation, driver variation?

Are you changing the driver only, or is the emitter and the driver combination the same in each different torch.

"like everyone else - I’m looking for my next “last” flashlight" -  ohnonothimagain

Andi
Andi's picture
Offline
Last seen: 9 months 2 weeks ago
Joined: 01/22/2011 - 08:08
Posts: 333
Location: Germany

yes, i chanched only the driver....that´s my other thought, that´s maybe the LED.

all XM-L´s should be a T6, but i´m not know, which tint, or if the leds really a T6.

whatever, i have ordered some XM-L U2´s Smile

 

...tailcap is impossible, because for measure i remove the tailcap Wink

 

Don
Don's picture
Offline
Last seen: 1 year 1 month ago
Joined: 01/12/2010 - 16:32
Posts: 6617
Location: Scotland

It's not really the mass but how that mass is used. A chunk of lead bolted to the tailcap (or even the emitter) will do little good - the thermal conductivity of lead isn't that good. A heavy chunk of copper or aluminium - preferably with the LED directly attached to it (Which requires a reflow oven) - will do very well. See here for how it ought to be done. 

http://flashlightnews.net/forum/index.php?topic=2543.msg32030#msg32030

 

The numbers from my light tests are always to be found here.

https://spreadsheets.google.com/ccc?key=0ApkFM37n_QnRdDU5MDNzOURjYllmZHI...

Andi
Andi's picture
Offline
Last seen: 9 months 2 weeks ago
Joined: 01/22/2011 - 08:08
Posts: 333
Location: Germany

thanks for answers.

now i know it´s not the mass of the body.

next i will chanche the led´s.

...but i must say, the heat transfer of the KD C8 is much better, as of my HS-802. The pill of the HS-802 is screwed in the body of battery.

the pill of the KD C8 is screwed in the much more massive head of the flashlight body.

 

fishinfool
fishinfool's picture
Offline
Last seen: 2 years 4 months ago
Joined: 03/09/2010 - 00:30
Posts: 4342
Location: Hilo, Hawaii

Aloha and welcome to BLF hansheng!

 

Don wrote:

"But as I said long ago, you are more likely to be killed by a dead fish dropped by a seagull in the Sahara Desert than by a lithium ion

hansheng
Offline
Last seen: 1 year 2 weeks ago
Joined: 04/12/2011 - 03:01
Posts: 46
Location: singapore

fishinfool wrote:

Aloha and welcome to BLF hansheng!

 

 

thanks! 

more to learn from you guys!

okwchin
okwchin's picture
Offline
Last seen: 7 months 3 days ago
Joined: 01/07/2011 - 04:41
Posts: 1164
Location: Australia

All emitters can very in their voltage drop. Variation is increased between different output bins, but even within the same output bin, there is still variation. Vf binning isnt common practice yet. 

 

Think of it more like, 

Tint bins vs output bins, their somehow related, but in essence their different entities, and can affect the outcome in its own way. In the same way, output isn't always related to the forward voltage of the LED. So regardless of what LED output bin you have, your likely to see small differences in LED forward voltage, and therefore differences in the power drawn by the driver board. 

There could also be lots of other things, like the wires, lengths, soldering quality, contact quality between the DMM and the torch, even the way the driver responds to the LED and the DMM.

 

Andi wrote:

yes, i chanched only the driver....that´s my other thought, that´s maybe the LED.

all XM-L´s should be a T6, but i´m not know, which tint, or if the leds really a T6.

whatever, i have ordered some XM-L U2´s Smile

 

...tailcap is impossible, because for measure i remove the tailcap Wink

"like everyone else - I’m looking for my next “last” flashlight" -  ohnonothimagain

Andi
Andi's picture
Offline
Last seen: 9 months 2 weeks ago
Joined: 01/22/2011 - 08:08
Posts: 333
Location: Germany

Now i have a XM-L U2 in my Brinyte and same measurement results, like in the C8.

So the LED was the reason Wink

 

Budgeteer
Budgeteer's picture
Offline
Last seen: 8 years 2 months ago
Joined: 08/24/2010 - 02:19
Posts: 3087
Location: Slovenia (EU)

okwchin wrote:

I think its fundamental torch design, the weight is almost irrelevant enough to be ignored. Its more likely the contact quality, LED variation, driver variation?

Are you changing the driver only, or is the emitter and the driver combination the same in each different torch.

+1

Also the contacts of the driver to pill also are worth a mention!

My opinion mass has nothing to do. For long runtime similar mass bodies can be distinguished also by the total square area surface. The ability for a host to transfer heat is surely more affected by surface area than mass (within reason). Look at CPU heatsinks. Check the surface area and mass. Stick a led on it and wonder why your 3 times more heavy flashlight barely cope with the emitter of choice and a skinny passive cpu heatsink works a treat.

A Intel i7 stock heatsink (nothing special there, not even with heatpipes) can run a XM-L decently driven indefinitely in passive mode if there is at least some miserable air moving around.

kragmutt wrote:

They're gonna send you a green redcat with a black LED.

Budgeteer
Budgeteer's picture
Offline
Last seen: 8 years 2 months ago
Joined: 08/24/2010 - 02:19
Posts: 3087
Location: Slovenia (EU)

Andi wrote:

Now i have a XM-L U2 in my Brinyte and same measurement results, like in the C8.

So the LED was the reason Wink

Let me guess... lower Vf?

kragmutt wrote:

They're gonna send you a green redcat with a black LED.

Oldienea
Oldienea's picture
Offline
Last seen: 6 years 7 months ago
Joined: 08/30/2010 - 23:18
Posts: 613
Location: France

Budgeteer wrote:

Andi wrote:

Now i have a XM-L U2 in my Brinyte and same measurement results, like in the C8.

So the LED was the reason Wink

Let me guess... lower Vf?

Couldn't it have something to do with the diameter of the leads. I have a C9 drawing only 2,2 A from a 2,8 A driver. I suspect the leads are to thin there. The original driver it came with was only 1,5 A before I replaced it, but I didn't change the leads.