Power from clock

[landoman]

In my 110 I have tapped into my clock wiring to hook up my UHF radio so that I have radio power even when the ignition is switched off .

I now want to tap into the same source to wire up a spare USB port and similarly have it live when the ignition is turned off so I can charge my iPhone in a convienient location

Question .....is there any danger of over load .....ie running the clock, the UHF and a USB with my iPhone charging from the same circuit going back to the main battery ?

[Toxic_Avenger]

Fuse F29 for the clock is fused at 10A.
So if the total load exceeds that, you'll blow that fuse.
Overloading is a possibility.

[Toxic_Avenger]

To further the above...
Unsure what clock and UHF amp draw is, but the USB would be approx 2A.

[landoman]

To further the above...
Unsure what clock and UHF amp draw is, but the USB would be approx 2A.

Ok that's great .....the UHF radio has an inline 2 amp fuse .....so I guess we can assume that the draw is less than 2 amps .....plus 2.1 amps for the USB port ........which leaves the clock ....so hopefully the 10 amps on the clock circuit fuse should not be exceeded ?

.......or can you add amps for the 3 things running off that circuit like that ??

[Tins]

.......or can you add amps for the 3 things running off that circuit like that ??

Yes. Total load is a matter of arithmetic. 2+2+2=6. 6<10, so no prob. Question is, why is that fuse 10a? Is there something else on there?

[Toxic_Avenger]

Fuse 29 also supplies the radio.

[MarkM]

Also, from memory only, doesn't it also supply the live 12V in the driver's rear wheel well that people usually pick up for a rear socket to run a fridge?

[landoman]

Fuse 29 also supplies the radio.
Ok thanks .....so 2 for the USB ,2 for the UHF And say 2 for the clock ......any idea what standard radios run at ...2.....? ..........if so I should be ok on that 10 amp fuse

[Toxic_Avenger]

Just suck it and see.
As long as you have a suitable fuse installed, the worst that can happen is it blows- it's its job after all.

Turn radio on and up loud (I'd suggest some Metallica for best effect)
Turn CB on, turn the squelch off so it is making noise (oh, that soothing white noise!)
Plug in device to charge.
Collect underpants
???
Profit.

If it goes pop, reassess!

[LR V8]

What is the rating of the clock pos wire ? It may be less than 10amp if F29 powers other things....

You could compare the clock wire thickness to a known 10amp wire to be sure(ish).

[Toxic_Avenger]

Purple/brown wire to clock is 0.5mm CSA, whereas the supply to fuse 29P is 2.5mm CSA, based on the drawings.

[LR V8]

That'll only handle 1 or 2 amps. A sparky on here should be able to confirm...

Good luck.

[Toxic_Avenger]

Borderline.
Wire Gauges - Current Ratings (http://www.engineeringtoolbox.com/wire-gauges-d_419.html)

[landoman]

Borderline.
Wire Gauges - Current Ratings (http://www.engineeringtoolbox.com/wire-gauges-d_419.html)

Ok .....great chaps ..........looks like that 10 amp fuse will be ok ....worst is it blows
.......my real concern is that some thing overheats and catches fire .....as I sleep in my truck I'm a bit wary of the potential for fire ....

speaking of which i have have been looking for a COMPACT smoke alarm .....any suggestions ?
....most are household clumpy versions

[LR V8]

The fuse is fine, but the clock wire is not.

[landoman]

The fuse is fine, but the clock wire is not.
im now a bit lost .........so guess I should get a fresh power source form the battery

[Toxic_Avenger]

Darn tootin!

[LR V8]

Don't forget to use an inline fuse....