running 2 sets of spotties on 1 relay

Post by **83-mud-lux** » Mon Jul 13, 2009 5:31 pm

i got a set of rectangle spotties on the headboard of the lux and just got another set of round ones but they didnt come with a relay.
im going to put them on the same switch but im not sure if i can run them through the same relay..also less wiring to do..help would be much appreciated thanks..smiley..

Post by **ausoops** » Mon Jul 13, 2009 5:43 pm

a 12v30A relay costs about $10, do it right, you will destroy your wiring and existing relay if you try to double up on the one circuit.

Post by **bru21** » Mon Jul 13, 2009 6:28 pm

Watts = volts x amps.

assume 1 light is 100 watts
2 lights is 200 watts
4 lights are 400 watts

now divide the energy needed in watts (400) by the voltage supplied - (use the lower voltage to be safe ie 12v not 13.6 running voltage)

400 / 12

=33.33 Amps

Therefore assuming the relay is the limiting factor

a 30A relay (at 12v) would be too small.
a 40A relay would be adequate.

You need to see also if the wiring can handle it etc..

V = IR etc or Narva site etc

http://en.wikipedia.org/wiki/Ohm%27s_law

http://www.howstuffworks.com/question501.htm

Post by **83-mud-lux** » Mon Jul 13, 2009 7:17 pm

thanks bru21.
all to technical for me but i got eventually haha.
i will get a 40amp relay tomorrow.yea its pretty good wiring set-up i got..

Post by **bru21** » Mon Jul 13, 2009 8:54 pm

make sure the relay holder is rated to 40 also, it will die if its not. Also I always choose a s/h ford relay over a narva etc as you cannot match oem quality

Post by **DamTriton** » Mon Jul 13, 2009 9:10 pm

Globes can draw about 50% more amps on startup (1-2 secs). Two 30 amp relays would be better as you will only have 2 lights out if you blow fuses or a relay sh*ts itself. Cheaper in the longrun and easier to purchase and replace out in the sticks.

Post by **chimpboy** » Mon Jul 13, 2009 9:22 pm

DAMKIA wrote:Globes can draw about 50% more amps on startup (1-2 secs). Two 30 amp relays would be better as you will only have 2 lights out if you blow fuses or a relay sh*ts itself. Cheaper in the longrun and easier to purchase and replace out in the sticks.

I agree, I would rather run two 30A relays than one 40A relay.

It is hardly any more work to install.

Post by **T_Diesel** » Mon Jul 13, 2009 9:24 pm

I woud wire each set on a 30A relay and fuse each relay individually. Better off doing it properly first up to avoid any hassles down the track.

Outer Limits 4x4 Board

running 2 sets of spotties on 1 relay

running 2 sets of spotties on 1 relay

Who is online