Auxillary lighting

[KiwiCol]

It's all maths Celtic,  it depends on how much current you want to draw through the fuse.  It works like this:


12V x 5amps (fuse) = 60 watts draw / running as max, after that the fuse will blow.


The equation can be expressed several ways; W=VxA   A=W/V    V=W/A  using any 2 known values, you can work out the third.


You don't want your fuse to be at the max draw rate (5amp as above), you'd want say 7.5amp for that.  You wouldn't go & bung a 30 or 40 amp fuse in as it would never blow, unless there was a dead short, so something this big is too big to be of any use. Go for 10 - 25% higher rated fuse than normal use & you'd be fine.

[Celtic32]

Thanks Kiwi.

So there is no harm running both lights through the same fuse provided it is sized appropriately for both lights in use together?

According to the included info, the lights have a 10W consumption and require approx. 0.66A per light at 14.2vDC. So...

Using W/V = A

10/12 = 0.84 A per light at 12vDC.

0.84A x 2 allowing for both lights = 1.68A.
So a 2A fuse would be OK?

When checking the included info, I noticed that it says "if splicing direct into existing lighting an extra fuse is not critical, however for extra protection you could add a 3-5Amp inline fuse". So not the 5A as I initially posted.

[KiwiCol]

Yep, sounds good.

[Celtic32]

Thanks for that Kiwi, much appreciated!

[gsxbarmy]

One fuse is fine Andrew as Kiwi says, just put it inline on the Power wire. It will then protect the original circuit better as well, as if the lights fuse blows, it won't blow the standard fuse.