12V power hub - circuit help please

[troypiggo (Troy)]

G'day guys. I've bought some bits and pieces to put together a bit of a 12V power supply hub for my gear. Just need some advice to confirm how I'm attacking this little project.

12V power will come into this hub from a 12V power supply. On this hub I'll have 4 RCA sockets, into which I'll plug in power for mount (EQ6), imaging camera (QSI583ws), dew controller (Kendrick Digifire 10), and have one spare for future additions if it arises. The dew controller coming off this will power all dew heaters, and has 2 constant 12V ports that I'll use for primary fan and lightbox power as needed. So I don't need variable power supply from this hub itself.

Based on peter_4059's prototype that I'm cheating this off, I want an LED to display if power is running through that RCA, and a fuse to protect the gear. Fuse blows, LED goes out so I know where the problem is. Plus it makes it look more hi-tech

The dew controller requires an 8A fuse if you want to run all the supplies off it. The others I'll use, say, 2A fuses or whatever is appropriate but I think that's about it IIRC.

Refer to the attached sketch I just knocked up. Please excuse me if I've gone against any and all electronic circuitry diagram conventions, I don't know what they are. But I used pretty colours instead Hoping it makes sense what my intentions are. That's the background, now for some questions.

1. Guess I'd better ask if the wiring all looks correct for the above?

2a. Wire thicknesses. I understand that the cable leading into the box will have to be pretty thick. Refer (1) in green on sketch. I bought some heavy duty speaker cable WS1708 from Jaycar for this. Will that suffice do you think?

2b. If I were to put the 8A dew controller first in the series there, and split the heavy duty cable (2) into that first RCA socket and fuse, could I drop the wire thicknesses after that one? I have some hookup wire for that. Or should I keep the thick wire all the way through. Just that it's more difficult for me, inexperienced, to solder to sockets etc.

[Bassnut (Fred)]

Well that won't work. You need to have the LEDs across the fuses, with resistor (light up when a fuse blows) or across the outputs (light up with output) not in series with the outputs

[troypiggo (Troy)]

Hmm, back to the drawing board. Looks like I need to do some more reading. Thanks for the feedback, Fred.

[peter_4059 (Peter)]

Troy - the 12V LED's we discussed have resistors built in to the wiring under the heat shrink.

You want the LED in parallel over each RCA socket. When the fuse blows no current flows to that RCA so the LED goes out.

[troypiggo (Troy)]

Got it. Thanks all.

[midnight (Darrin)]

Originally Posted by peter_4059

Troy - the 12V LED's we discussed have resistors built in to the wiring under the heat shrink.

You want the LED in parallel over each RCA socket. When the fuse blows no current flows to that RCA so the LED goes out.

Yes, the LEDs need to be across the socket or it may be easier to wire from the fuse output to the LED (+) and the other end of the LED to your 12V negative (-).

LEDs need a current limiting resistor but sounds like your ones already have this.

BTW, I ended up putting in some fairly high resistance (4.7k Ohm & in some cases 10k Ohms) in series with my LED as at night (99% of the time I use it), I didn't want a blazzing red beacon. It's suprising how bright a "conventionally" design LED cct is at night. Keep this in mind if your LEDs end up too bright. Just wire in a resitor in series with the LED if you do go down that track. Jaycar etc sell them.

Darrin...