Modify NiteCore D11 to Reduce Idle Current from 2.5mA to 50uA
Last Updated on Tuesday, 02 November 2010 12:05 Written by Administrator Monday, 01 November 2010 13:22
Hi.. FlashAholics, This is first time modification NiteCore D11 to remove annoying idle current 2.5mA which drain battery empty every 20 days with brightness memory not corrupted.
หวัดดีครับชาวพี่น้องบ้าไฟฉายทุกท่าน นี่คือการโมดิฟายแรกในโลก ที่แก้ปัญหากระแสกินเปล่าใน NiteCore D11 จาก 2.5 mA ให้เหลือแค่ 50uA ไร้ปัญหาแบตหมดแม้ไม่ได้ใช้ ทุก 20 วัน แล้ว !!!
ปล. Brightness Memory ไม่หายด้วย
No waste the time. Let's do it..!
First disassembly head by use flat screwdriver to pull brass ring out and turn the module counterclockwise.
Soldering out red and black LED wires.
To remove PCB, use small screwdriver on the groove beside module to take it out.
This is circuit in the board and additional component to modify.
A yellow capacitor is C1, 100uF. It is converter's Cout. Very bad ESR, we will modify this to 10uF X7R or X5R.
The 100uF use for modify in next stage.
DIP resisters here, I use only it's lead.
Component List..
10uF X7R or X5R.. 2 Pcs.
10k 0603.. 1 Pcs.
1k 0603.. 2 Pcs
General purpose PNP Transistor SOT23 package. I use MMBT2907.. 1 Pcs
Enameled wire for jumper.
U1 pin 3 is Converter-Enable pin, it Pulled up with R2 (82k). We will use this to disable converter when not in used.
R9 and C3 was skipped. It intended to use as battery voltage sensing but not used.
ADC pin of U2 left Hi-Z, This great! We will use as a channel through PCB here.
Then.. move R2 to C3 (C3 connect U2 pin 6 to Gnd).
Q2 is the brightness control Mosfet which operate in PWM mode.
Check out the circuit in my notepad here. It was many ways to do (i was change it many ways as you see in my draft circuit) .
The PD switch connecting Gnd to U2 pin 2 to do the operations. We need it as starting signal to U1 to startup converter.
But U1 use logic 1 to enable it, so we need to invert it with a transistor.
Who will hold this signal to continue enable converter?
There are two way to do. U2 pin5 or Q2-drain.
It's easier to use Q2-drain with a series resistor and feed to base of MMBT2907.
Q2-drain use as converter enable holder signal.
But.. What will happen in flash or PWM pulse ?
Yes, It will stop operation !!
So, 100uF and 82k do it as time delay for converter enable signal.
Minimum is 2.5 second (SOS mode) but R2 82k and C1 100uF together make time delay around 15 second. It's OK !!
Jump wire U1 pin3 to U2 pin6 (at C3). This is converter enable and delay.
It look like this.
Check it has no any short circuitry.
Wash out red synthetic rubber coating here and remove U2 (PIC12F683) C1 (100uF) to access V+Batt pad.
You need a small tip soldering iron to wire V+Batt from a very small space here
You can see a V+batt under inductor, Connect it to 10uF and Gnd as input capacitor.
Put another 10uF on location C1 as output capacitor.
Look iike this..
MMBT2907-emitter wired to V+LED.
Add MMBT2907-base with 10k to emitter. Control signal connect base via 1k to U2 pin 2 (PD switch).
Another control signal from Q2-drain via 1k to base.
MMBT2907-collector connect directly to U2 pin 6. And at collector put a 100uF to Gnd.
100 uF together with 82k on another side form a time constant to continue enable U1 on flash or SOS mode.
Wash out flux with flux remover fluid or solvent and let dry.
Then coat it with synthetic rubber or some glue to fix circuit in place.
Battery side PCB.
Coat it too. This fixing wire to place and prevent moisture.
The operation is same almost nothing change.
When turn it on first time, you must press and hold PD button 1 second or it only flash up.
You can turn it on at second time as normally. After turn off by 15 second, you must turn it on by press and hold 1 second again.
I have notice that press and hold for 1 second cause enter dimming mode and intensity changed.
If you don't want to change setting, you must click it two time with interval 1 second between click. If you double click, it will go to SOS mode.
Button lock feature is cannot use now, but it is not problem. If it is accidentally pressed while carrying, it is only flashing up.
This time I think about new feature in flashlight such as 3 level memory step, more flash mode, battery leak prevention etc..
Ummm.. or I will written whole new code of the 12F683 !!!!
One more D11 please .....
That is all...
Enjoy.....
To NiteCore manufacturer.
This method not restricted. It's free to use my modification to your product.
It will better if use EEPROM in PIC12F683 instead of RAM to store intensity setting (store it 5 second later).
Battery voltage sensing is one feature that prevent Alkaline battery leak and increase lifetime of NiMH battery by not too deeply discharge.
My idea is sense the battery voltage and continuously check it's voltage. When voltage down to 0.9V then limiting current by reduce duty cycle until voltage is reach 1.0V(hysteresis range 0.1V). If battery too low and cannot reach 1.0V at minimum duty cycle then turn light off until voltage come up and turn on again. It will flash with frequency depend on last drop of battery power. If off voltage cannot reach 1.0V in few second then turn to shutdown mode. This no power to light it up.
This flashing will notice user it is the time to recharge or change battery before it leak.