Ok, I got some info about calculating the A from the LD29 mod thread
So I will just enter my own values, and see if it makes any sense.
Quoted from the mentioned thread.
The ouput amps to the LED is 3A, so therefor the sensing voltage is V = I x R = 3 x 0.06 = 0.18V. The sensing voltage will stay constant, so if you want 5A output to the LED, your sensing resistor should be: R = V/I = 0.18/5 = 0.036Ω. So your best bet would be to Remove the 4 SMD resitors, and put a R036???? resistor. Unfortunately, it is not always possible to get the exact resistor in small quantities. Thus we stack resistors to get to the desired overall resistance.
I can`t follow the following numbers yet..I tried, and think its correct... but please let me know if I do something wrong.
- 2 x 0.1Ω in parallel = 0.05Ω, put that in parallel to the original 0.06Ω = 0.0273Ω = 6.5A?? correct? (0.18/0.273) - 3 x 0.1Ω in parallel = 0.03333Ω, put that in parallel to the original 0.06Ω = 0.0349Ω = 5.15A?? (0.18/0.0349) - 4 x 0.1Ω in parallel = 0.02500Ω, put that in parallel to the original 0.06Ω = 0.0484Ω = 3.71A?? (0.18/0.0484)
Forget all the math, there's no way to know if it's correct from one light to another until after you change the resistors and see how much difference it makes. Just stack one resistor at a time, something reasonable that won't whack it too hard in one go, like 1/2 ohm (R500). The higher your added resistors are, the less increase each one will give. Adding a really low one like a R020 could be too much, using a bunch of higher value ones gives you a lot more control and won't suddenly do something bad on you.
Bookmark this page, it'll decode anything: http://www.hobby-hour.com/electronics/smdcalc.php
someone mentioned this to me, and I just bought it... left it somewhere in my closest, took it out a few hours ago.. and now realized its not any better than the spoon I just used.
Doesn't matter for this, with multiple resistors the current is divided between them, and more of the current will go through the lowest value resistors. If it were some other application, or if you were replacing the bank of original resistors with a single resistor, then it might.
Tolerance also really doesn't matter since you're just adding pieces until you reach some arbitrary current. Doesn't matter if one resistor is .52 ohm and another is .45 ohm.