Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Electronics, Lighting, & Gadgets HRM, GPS, MP3, HID. Whether it's got an acronym or not, here's where you'll find discussions on all sorts of tools, toys and gadgets.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 02-19-09, 11:46 PM   #26
Unknown Cyclist
Senior Member
 
Join Date: Jul 2008
Location: UK
Bikes:
Posts: 1,757
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
If it's got 5 modes it's almost certainly regulated.

How long does it run for ?

Does it dim or stay bright to the bitter end ?
Unknown Cyclist is offline   Reply With Quote
Old 02-21-09, 10:10 PM   #27
Wiggle
Senior Member
Thread Starter
 
Join Date: May 2008
Location: Halifax, NS
Bikes: 2013 Jamis Ventura Sport, 2008 Trek 7100
Posts: 279
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
The light just slowly drops down, it seems like direct drive to me. The 5-modes are just created by PWM I think. I don't even know if it's possible to easily make an 18650 P7 light regulated since a fully charged 18650 will push over 2.8 amps briefly and then less as it drops so a simple boost or buck setup wouldn't work.
Wiggle is offline   Reply With Quote
Old 02-22-09, 06:22 AM   #28
Unknown Cyclist
Senior Member
 
Join Date: Jul 2008
Location: UK
Bikes:
Posts: 1,757
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Wiggle View Post
I don't even know if it's possible to easily make an 18650 P7 light regulated since a fully charged 18650 will push over 2.8 amps briefly and then less as it drops so a simple boost or buck setup wouldn't work.
2.8A is the most a 18650 can supply ?
Unknown Cyclist is offline   Reply With Quote
Old 02-22-09, 11:25 AM   #29
Wiggle
Senior Member
Thread Starter
 
Join Date: May 2008
Location: Halifax, NS
Bikes: 2013 Jamis Ventura Sport, 2008 Trek 7100
Posts: 279
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Unknown Cyclist View Post
2.8A is the most a 18650 can supply ?
No it can supply more, but the Vf needed to push over 2.8A is too high for an 18650 except when fully charged.
Wiggle is offline   Reply With Quote
Old 02-22-09, 12:15 PM   #30
Unknown Cyclist
Senior Member
 
Join Date: Jul 2008
Location: UK
Bikes:
Posts: 1,757
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Wiggle View Post
No it can supply more, but the Vf needed to push over 2.8A is too high for an 18650 except when fully charged.
Wouldn't that only apply to direct drive ?

If you had a 2800 mAh driver it would pull more amps as the voltage decreased ?
Unknown Cyclist is offline   Reply With Quote
Old 02-22-09, 01:37 PM   #31
Wiggle
Senior Member
Thread Starter
 
Join Date: May 2008
Location: Halifax, NS
Bikes: 2013 Jamis Ventura Sport, 2008 Trek 7100
Posts: 279
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Unknown Cyclist View Post
Wouldn't that only apply to direct drive ?

If you had a 2800 mAh driver it would pull more amps as the voltage decreased ?
2800mA you mean but yes it should. When I get home I'll measure Vf across the LED as the battery drops down and see if it changes. If Vf holds steady, it is indeed regulated. But I suspect it isn't because when I experimented with some thinner gauge wire, the minor voltage drop across that wire had a visible effect on the brightness of the light which shouldn't happen.
Wiggle is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 12:16 AM.