Hello all,

I am going to use these LED strips to light up my HO coaches. Each coach will need 18 LEDs:


The input is 12V DC. Every 3 LEDs are connected in series:


What capacitors are small enough to fit into an HO coach but powerful enough to provide backup power for these 18 LEDs? Would a 1F gold cap powerful enough?

Thanks in advance
Chris

Hello,

1 Farad is certainly enough. But be aware that this big capacitor has to be charged. If you run your layout DCC, the central unit will assume to find a short. So charge the Gold Cup via a resistor plus a parallel diode (which shortens the resistor when discharging).

Martin

Hello Martin

Thanks for your reply. Yes I use DCC, so my connection will be like:

Track power > bridge rectifier > resistor > capacitor (5,5V/1F) > LED strip

Is this connection OK?

Thanks again
Chris

Hi Chris!
Be aware that the goldcap is built for 5,5V and the LED-strip for 12V.
Or do you want to operate the LED-strip with less then 5,5V aswell?

And if you run on DCC and you have a constant power supply, i think a "common" 100µF to 200µF 35V capacitor is enough. I use very similar LED-strips with 100µF 35V and a 4k7 resistor like this:



But here I charge the capacitors directly from the track, so if you have to many cars on your layout and turn on the track voltage the DCC-central can detect a short because of the high current flow.

Hi Chris,

as far as I know must be the capacitor connected behind the resistor. This will limiting the charge current.

You will find some informations to similar ledstrips on my homepage in German language. I use 25V 470uF capacitors for H0 cabs.

http://www.ingomoegling.de

Regards,

Ingo