High Power LED Driver, 9 amps

[stub]

 

[fppf]

Boards have been ordered.
Bad news, they need to run on a different line, wont be here until Tuesday or Wednesday of next week.

As long as all the calculations and modeling turn out reasonably correct we should be on target for a January release.

 

[paetzi]

Hi the 100k Pot that i bought has max 84k Ohm.
Is it a problem? How many A will i get out the driver?
Should i solder a 16k Ohm resistor to it?

 

[fppf]

Hi the 100k Pot that i bought has max 84k Ohm.
Is it a problem? How many A will i get out the driver?
Should i solder a 16k Ohm resistor to it?

You will want to add a resistor or I can adjust the trim resistor on the board for 84K. Having a lower value pot will just cause a lower drive current. You don't want to high of value, then it could over drive.

 

[Linger]

fppf,
can you put an edit line in the first post that reads something like

9amp driver fits M@g D
​

**(last revision as of Dec. 18) - design updates**
Input range x - xx volts
-(you must provide battery information on ordering so components may be adjusted to set maximum and minimum voltage cut-off)

Output options: with x holes for x or x
-may attach pwm controller for ...
-can use x for x modes
-may attach a 100k potentiometer for ......

Target shipping:late January 2010
Target cost: $65 + shipping, beer optional


////
Some of the discussion is a bit above your readers, even those following the thread may appreciate the synopsis

 

[fppf]

All Set

 

[Linger]

Looks great

 

[AaronM]

With the new parts you have, is my light still doable? If so, what performance can I expect?
6 x 17670 = 25.2V battery pack hot off the charger

12~14V vf LED looking to drive at 2.5~3A.

 

[fppf]

With the new parts you have, is my light still doable? If so, what performance can I expect?
6 x 17670 = 25.2V battery pack hot off the charger

12~14V vf LED looking to drive at 2.5~3A.

The driver will be able to do this just fine. However in this case I may need to change some other components out because of the lower drive current.
Let me get the first few built and then I will adjust the circuit for your needs. It may cost a few more bucks because I need to order some other parts. But it will drive just fine, the efficiency will be higher than the 9 amp 3.6 volt version as well.

 

[AaronM]

That's great news!
I was mostly worried about my high battery input voltage: 25.2V

I'd like to re-wire the stock switch to change modes between 1Amp and 3Amps. Is that possble?
Another switch will go in the tail cap for actuall on-off duty.

 

[fppf]

We will figure it out for you

 

[heffay]

In for one these!

 

[Nos]

When you get this working ill take one too

 

[fppf]

Good news folks
Even with the holiday rush UPS delivered a day early!
Everything is here, just need to build up the first board. Stay tuned!

 

[FlaCracker]

You may want to add an 8-9v cut-off to your standard offering for anyone running 3 l-ion cells.

Jimmy

 

[fppf]

You may want to add an 8-9v cut-off to your standard offering for anyone running 3 l-ion cells.

Jimmy

No problem, if anyone wants any other ranges as "standard" let me know now. Once I stock up on parts it will be special.

 

[Packhorse]

No problem, if anyone wants any other ranges as "standard" let me know now. Once I stock up on parts it will be special.

I was thinking of using a 7.4v Li Ion pack.

 

[fppf]

I was thinking of using a 7.4v Li Ion pack.

I think for that pack you want the lowest cut off, 6V which is already in the standard list.

 

[paetzi]

I want to use 3 x 32650 which cut off voltage will there be needed?

 

[fppf]

I want to use 3 x 32650 which cut off voltage will there be needed?

7.5 volts

Folks, the cut off voltage you use is based on your battery packs. If you look up the specs for your cells they will tell you what the minimum discharge voltage is. For Li Ion its typically 2.5 volts, for NiMH its typically 1 volt. Then just multiply that number by the number of cells you have. That will give you the lowest operating voltage of the pack without possible damage to the cells.