Power Supply for Car Lighting Question

Projects General Guidance
1

Hi all,

i have a control box custom made for my application and it worked until the led neopixel power supply on the board failed. I replaced this led 5v power supply with a 12vdc to 5vdc transformer which i have wired from the car ignition to the led strip.

here is a photo of my wiring

the connector blocks are for testing purposes, in the car these are bullet crimped. anyhow the photo shows coloured boxes these represent different parts of the interface.

From the right is the wiring from the control box interface. the wiring from the left is from the car.

The Highlighted connector blocks are grouped

Black is LED Strip
Red is Car Power Supply 12V
Blue is all the Car Inputs for various things +12V

in the Black group
we have the Brown wire which also has a Black wire attached to it. This is the LED Neopixel Strips Earth (-)
we also have a Green wire along with a red wire which is the LED Strip 5V Supply (+)
the white wire is the data signal to the LED Strip

Moving down we have in the Red Box,
Red Wire is 12V supply from car ignition (+)
Black Wire is for the chassis (-)

These are also doubled up to the 12v > 5v transformer which powers the LED Strip

moving down into the blue box we have 6 wires which are 12v inputs.
These do a variety of things. these are Left and right indicators, brake light, tail light, fog light and reverse.

all this worked as it should. Indicators would 'scroll' either way on the set amount of LED's i programmed it to. brake light covers most of the led strip (except indicators) Reverse overrides section of the brake light and so on and so on.

anyhow i have a problem that when the board receives a 12v supply to lets say the indicators they will scroll but when 12v has been removed they stay lit at the sequence they were at. I also get a faint BLUE led part of the RGB chip (LED address #20 to be precise)

now because the power supply for the led strip has failed in the control box and im using a external 5v supply does the earth (-) from the LED Strip need to be LINKED to the earth of the vehicles 12v supply? or do i remove the LED Strip Power Supply COMPLETELY from the control box?

Many thanks for your time

wiring car led strip.jpg
wiring car led strip.jpg1242×1978 565 KB

2

so you can understand what i mean it used to do this

Video When First Installed and Programmed

whereas now it does this

Video Today

3

Do you have a schematic of the board? How do you know that only the power supply failed? Following your wiring without schematics is pretty useless.

"I replaced this led 5v power supply with a 12vdc to 5vdc transformer"...
Do you mean a buck voltage converter? Is it rated for enough current to operate that many LEDs?

When I see one LED in a string that doesn't work right, it usually means that that LED is toast.

4

Ive managed to get the unit to work again properly. My LED Strip which was new was faulty.

Thanks Steve anyway.

in answer to my own question i dont need to connect the LED strip - to the cars negative earth cable just to the 12v>5v3a converter

5

andy_s87:
in answer to my own question i dont need to connect the LED strip - to the cars negative earth cable just to the 12v>5v3a converter

Don't the automotive power systems generate massive spikes? Especially when the starter motor disengages.
I have read many times about the need for much conditioning for this.