LEDs for floorboard lights

Hey guys, I got 8 orange 5mm leds that draw 2v at 20ma. I am hooking them up to a dpdt 3 position switch for off, on with key turned to acc and on position, and on with door open. I have tapped into the phone charger for power with key in acc and on postion. I read on here you can tap into a wire in the A-pillar for the dome light.

Will 18 ga wire be good enough for 2 legs of 4 leds?

Here is the wiring diagram some website made me.
Solution 2: 4 x 2 array uses 8 LEDs exactly
+13.4VR = 270 ohmsR = 270 ohmsThe wizard says: In solution 2:

• each 270 ohm resistor dissipates 108 mW
• the wizard thinks 1/4W resistors are fine for your application
• together, all resistors dissipate 216 mW
• together, the diodes dissipate 320 mW
• total power dissipated by the array is 536 mW
• the array draws current of 40 mA from the source.

Is this right?

And if I do a series then the hot wire will be soldered to all the leds and the ground will only be hooked to the last led correct?

Can I just hook a resistor inline to each leg of leds instead of a resistor per led?

 

that diagram is correct. you only need 1 resistor per 4 leds wired in series.

 

the hot wire will be soldered to the first led. the last led will be soldered to the resistor and then connected to a ground wire.

 

you also going to need a relay to convert the door trigger from negitive to positive to turn on the leds.
http://www.the12volt.com/relays/relaydiagram8.html

 

Thank you.

 

hope that diagram helps

 

final diagram up

 

So what size relay would be good?

 

the standard 30/40 amp relay.

 

Thank you for your help.