Hi,
First I tried it on my regular 6x Tail boards with conventional 6 Balance resistors and a 1kOhm Bleeder
Main Problem was that with low battery voltage the higher voltage LEds (Blue, White, pink, ice blue) get dimmer tan the low voltage ones (red, yellow, green)
I came up to enhance this idea with a voltage regulator, but had to do some steps to make it work
first get the voltage and resistor value for each LED at the same brightness
Then I made some calculation to get fixed current draw versions
It is also possible to use this with side switch lights like Convoy L6, as I can get the parasitic drain for the 18kOhm bleeder down to 0.4mA when the tail board has 0.15mA for the LEDs
Now the first 4 Prototypes
I did quite some measurements and tests to even out the brighteness of them
Firt L6/L2 prototypes are build and successfully tested on my bench, modding the lights will follow
One tme i skipped the very current hungry Emerald green for a warm white
The tail board itself uses a voltage regulator so the brightness is constant down to 3V cell voltage and can be fitted with 1S or 2S voltage regulator
The 2S Voltage regulator has a 0.1mA higher drain
I haver also ordered fitting 3x3mm trimmers so that the brightness of the board can be adjusted for 2V and 2.5V LEds in 2 groups
On the other hand I can also build em with a current draw from 0.15-1mA with the balance resistors without trimmers
The rainbow LED boards have one drawback which are the inefficient Emerald green and yellow LEDs,
so their brightness is lower than green or white LEDs at the same current
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