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Incentive:   Our RV uses 4 x 1141 lights for interior lighting.  At ~ 18w / 1.5A each, I wanted to upgrade to energy efficient LED equivalent to prolong battery life.   Here's how to make 5 for the price of 1

DATA: 
- Each Assembly of 27 SMDs at 12v produces about 189-270 Lumen at 2.16w and .18amps.   50,000hr life
- Each 1141 bulb at 12v produces about 240 lumen at 18W and 1.5 amps.  1000hr life

Materials Needed:
1 - Roll 3528 SMD White LED "Ribbon" Light (~$15 USD for 16feet)
1 - 6"x8" pre punched Perfboard
20AWG solid copper wire
5 - 1141 or 1156 Automotive bulbs
Double sided Foam mounting tape
Liquid Tape (Optional but Highly recommended))

Tools needed:
15w Solder Iron & Solder
Hot Glue Gun or non-conductive epoxy
X-acto  or razor Knife.
Scissors
Wire stripper

Note: A 6" x 8" Perfboard is enough to make 5 light assemblies and provides a rugged surface to attach the light strips.

Step 1: Preparing the Light Strips

a.  Using a scissors cut 9 segments from the ribbon light - you will see cut points approximately every 2 inches (copper contacts).  Each 2 inch strip will have 3 SMD lights and a voltage limiting resistor.

b.  Using your X-acto knife carefully press down evenly to cut (do not slice) through the gel water proof coating til your blade rests just behind the copper contacts.  Slowly move your blade across the contacts in a sweeping or scraping motion (not slicing motion) the clear gel coating will peel off revealing to copper contacts. NOTE: Only expose one end.

Step 2: Assembling the Boards

a.  Cut 6 - 4 inch lengths of 20AWG wire and strip off insulation.  Tin one end of each wire with solder.
b.  Solder 1 piece of wire to the each copper contact you exposed (in step 1b).  NOTE: Be careful DO NOT melt the flexible board and DO NOT lift the copper contacts off.
c.  Measure approximately 3.25 inches from the edge of the perfboard.   (This is where you will install the first light strip.)
d.  Insert the wires from assembly you just made into the adjacent edge of the perfboard.  Stagger the wires so that Negative (-) goes in column A and positive (+) goes in column B
e.  Remove protective paper from adhesive back of light and stick to board, carefully apply pressure on the wire leads to conform to the board.
f.  On the back side of the board, bend the wires perpendicular to the light strip you just attached and run to the edge of the board along column A & B.  (These will be the power leads for the remainder light strips you attach to the board.)
g. Insert the wire back through the perfboard and pull tight.  (This will be the 12v connection point.)
h.  Repeat step 2d  & 2e however this time solder the wire to the leads of the first light strip and snip off excess with snips (I like to use a toenail clipper for this step as it cuts the wire flush with the leads)  Reuse the excess you just cut off, (re-tin if necessary)

Step 3: Adapting to the 1141/1156 Automotive/RV

a.  Place bulb (preferably a burnt out one) under a rag and strike lightly with a hammer using care not to strike socket.   Carefully remove glass from bulb.
b.  Clean off original solder and wires from socket.
c.  Cut 2 sections of 20AWG wire, strip each end and tin.
d.  Solder 1 wire to the center positive (+) connector of the socket and one to the rim negative (-)
e.  Soldier Positive (+) and Negative (-) wires (respectively) to your assembly from step 2.
f.   Use hot glue gun or non-conductive epoxy as filler in socket.

Step 4: Test and Finish the Assembly

a.  Preferred method,  if skilled, test continuity with an ohm meter.   Rework solder points as necessary.  Check for shorts and proper polarity of connections. 

b.  Connect to a 12v power source verify all light strips work. ( I used a low amp, 12v AC/DC wall adapter )

c.  Optional (but Highly recommended)  - coat all bare wire on light assembly with liquid tape following instructions on bottle.

Congratulations you just completed your 1141/1156 replacement bulb.

DATA:
- Each Assembly of 27 SMDs at 12v produces about 189-270 Lumen at 2.16w and .18amps.
- Each 1141 bulb at 12v produces about 240 degrading to Lumen at 18W and 1.5 amps

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More by rkoch3:Replace your 1141/1156 12v Automotive/RV lights with these easy to build LED Lights at a fraction of the cost. 
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