Head and work light revisited

for instance.. (3) 55w 12v lamps is 165w... thats 13.75 amps... I would use a 20 amp automotive relay (SPST).. they are cheap and can be found on the shelf at nearly all auto parts stores for adding foglamps.. etc...

Fuse with a 15A SB or a 20A FA fuse... might get away with a 15A FA, just depends on the surge current.. and if you turn on all 3 lights at the same time.. or the 2 first then the rear.

Pull in current for the relay will be low..I'm guessing less than half amp.. more like 300ma I would guess. That's the nice things about the relay... small wire and switch to control the realy.. and install the relay close to the load/power source.. less money in big wires.

now if this is a 6v system.. and you are using say (3) 35w lamps.. that is 17.5 amps...
Again.. use a 20A FA if you can get away with it.. or if not a 20A SB.. and as a last choice.. a 25 FA. For a relay.. ( SPST ) you might have to get somehting for a volkswagon?.. etc.. just make sure its contacts are rated at 20A.

If you have other light or load combinations.. just figure out as above.. formula for ohm's law is :

E x I = P
P / I = E
P / E = I
I x R = E
E / I = R

Where E is voltage, P is power (watts), I is current ( amps ), and R is (DC ) resitance ( ohms )..

Soundguy

steve

That said.. I don't seen any need to amend my previous message.

Soundguy

Kinda interesting, my N-Ford MPC will list bolts with thread specs and lengths along with the p/n's, but won't list electrical stuff specs; Like battery is p/n 2N-10655-C, 13 plate, domestic. (NLA) Who wooda gussted its a 6 volter, size 1A? 'course meybe never figgered on 12 volt batterys nether..... ...Dell

Soundguy