What battery to use with XM-L led hedlamp

surferman

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Jun 14, 2014
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I want to modify a headlamp and fit to a bicycle
been thinking of something like the ones on ebay with XM-L led

If i want to upgrade the battery pack just wondering if a
LIPO 3.7V 5000mah 50C pack would be ok?
thanks
 

RetroTechie

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Oct 11, 2013
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Hengelo, NL
Welcome to CPF, surferman! :)

Why not get a LED lamp that is meant as a bicycle light? The 'bay is filled with those... (and cheap too) ;)

If i want to upgrade the battery pack just wondering if a LIPO 3.7V 5000mah 50C pack would be ok?
Depends on what the light takes as input voltage. Many bicycle LED lights use battery packs based on 4x 18650 cells, in 2S2P or 2P2S configuration. Meaning the LED light is designed to take ~7V as input voltage, and thus may not work with just 3-4V.
 

surferman

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Jun 14, 2014
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Most of battery packs on eBay with the headlamps run with one or 2 18650 batteries so I'm guessing when its 2 they are in parallel and the ones with 4 are parallel as well.........
If anybody actually knows please tell
Also the brackets for bikes are pretty dodgy and my friend attached a similar headlamp to a aluminum flat bar and works great so I'm thinking of doing as well
 

teoman

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Jun 15, 2014
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I have one of these
*link removed... please try to find a way to post without constantly linking to ebay - thank you.

good light output. But most definitely not 9600 lumens...


I just measured the voltage for you. And the battery pack outputs 8.2V. It has 4 18650 cells shrink-wrapped. So they are 2 Series and 2 parallel.


I agree with the previous poster that they usually do like to be 2 in series to get the voltage right and then more are added in parallel to extend the run-time.


Teoman
 
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teoman

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Jun 15, 2014
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*link removed... please try to find a way to post without constantly linking to ebay - thank you.

Teoman


Sorry about that. I noticed that it was a no-no when my first post got deleted. Absolute noob here :(

I did see a lot of links to DX on other places on the site and I assumed that it was ok to post links to vending sites.

I did take pictures to post on here after my first link got deleted, but then i noticed that you can only post linked pictures, and unfortunately i currently do not have a site to host them.

Anyhow let me not dilute the thread with my incompetence.
 

surferman

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Jun 14, 2014
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thanks for replies guys
I think im starting to understand how they work now
Seems like most of the battery packs available are running middle of the road cells
Id like to get some 26650 cells in a pack of 7.2v with 4 or 6 cells
Anybody know a site to recommend please message me
 
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