Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers



Laser Pointer Store

What kind of current can 10440 safely supply?

Helios

New member
Joined
Jan 7, 2011
Messages
1,341
Likes
58
Points
0
I know it varies from battery to battery but in general how much current can a single 10440 supply?

Im making a pen kit and I would like to know what kind of current range to suggest to buyers. For simplicity lets assume its running a micro flexdrive.

Thanks all!
 

BShanahan14rulz

Well-known member
Joined
Dec 29, 2009
Messages
3,175
Likes
151
Points
63
You will need to find the efficiency of the flexdrive at a given output with input from Li-Ion being 2.8V. This is when the boost part of the circuit will be drawing the most current from the cell.

Rule of thumb is usually 2C, based on actual capacity. Most 10440 are 350-400mAh, IIRC. So, 0.7 to 0.8A would be the 2C value.

Some protection circuits will cut out not only when there is an over- or under-voltage condition, but when there is an over-current condition too. Perhaps you should advise to find protected cells.
 

LarryDFW

New member
Joined
Dec 6, 2008
Messages
1,577
Likes
108
Points
0
Helios;

A 10440 only has a capacity of 350mah.

I have never seen a 10440 lithium-ion by a brand-name manufacturer.

As noted the output current max is ~600ma.

A boost driver like the flexdrive will require ~ 150% of the laser diode current.

That would indicate a max current of ~233ma for the diode.

I would try to move up to a #14500 size at least (750mah).

Larry
 
Last edited:

Helios

New member
Joined
Jan 7, 2011
Messages
1,341
Likes
58
Points
0
im more experienced in machining than electronics so bare with me here. Would two batteries in series boost the current capabilities? I know it would double the voltage
 

532 with Envy

Well-known member
Joined
Jun 19, 2010
Messages
1,491
Likes
104
Points
63
I have one running around 550mA, a-140 diode..judging by the output being around 500mW with a good charge.
 

BShanahan14rulz

Well-known member
Joined
Dec 29, 2009
Messages
3,175
Likes
151
Points
63
I never said that the 10440 lithium cobalt cell "couldn't" supply more current. But please read the title of the thread.
 

LarryDFW

New member
Joined
Dec 6, 2008
Messages
1,577
Likes
108
Points
0
Safely . . .

is the key word.

The cells are very small and unable to dissipate resistive heating quickly.

I would not push them beyond 400ma (1C) delivered from the cell.

That would be 266ma to the laser diode.

LarryDFW
 
Last edited:

rhd

New member
Joined
Dec 7, 2010
Messages
8,492
Likes
567
Points
0
Hey,

Would someone be willing to explain the math/technique behind determining what various (lithium ion) cells can supply in terms of current? I understand the capacity ratings in XYZ mah, but I'd love to understand how to use this data to determine maximum current. I've seen ratings like "2C" for lithium ions, and even "30C" for lipos.

Instead of an explanation, I'm quite happy to just be pointed in the direction of decent reading material :)
 

LarryDFW

New member
Joined
Dec 6, 2008
Messages
1,577
Likes
108
Points
0
rhd;

The term "C" refers to the cell capacity.

My Sanyo cells have a capacity of 2600mah.

Discharge current for them is 2xC or 5200ma.

LarryDFW
 

elite ares

New member
Joined
Oct 20, 2010
Messages
301
Likes
19
Points
0
Instead of an explanation, I'm quite happy to just be pointed in the direction of decent reading material :)
Batteries in a Portable World: A Handbook on Rechargeable Batteries for Non-Engineers is a good book. The link is to the second edition that I have which is a little dated as it was published in about 2000, but there is a third edition out now. It would be more expensive and you would probably have to get it from the Cadex website.

Update: The Third Edition will be available this month here.
You could read a lot of it here.
 
Last edited:




Top