Can I use aluminum tape or naked two paralleled striped cables to connect parallel LED strips?

Question

I need to parallel connected couple dozen cut LED strips. The total current reaching them won't exceed around 2 amps.

My constraint:

• I can not order any more components for the job.

My tools:

• Lots of cable, soldering wire, solder, aluminum tape.

My question:

• Instead of soldering wires for each strip piece and later connecting them together, can I get hard plastic, put on two parallel lines of aluminum tape and solder cables directly from strip there?

• Or: Can I glue stripped cable on plastic and solder cables coming from strips on it?

That way I have the parallel aluminum or just one set of cables at the end.

Answer 1

Aluminum forms a layer of aluminum oxide as soon as it is exposed to air. This is good because aluminum oxide is sapphire or corundum and is very tough. This is bad because it is in insulator. Electrical connections to aluminum chassis use pointy lock washers or press-fit terminals to cut through the oxide. Silver is OK. Silver oxide is a conductor.

Stripped solid copper sounds easy. Or cut away rings of insulation at the needed intervals. If you look inside mass produced low voltage lights you will see lots of the bare copper method.

Here is a way to use solid copper wire with vinyl (or similar) insulation. Using wire that is not too big - say #22 - tie one end to something solid. I use a door knob. Unroll about 6 feet and tie to a screw driver or dowel. Apply strain and try to stretch. Increase the pressure slowly until you feel the copper "yield". You have exceeded the elastic limit and it will stay completely straight. If someone can help, clip it at each end and carry to a table and cut to convenient lengths with an Xacto or razor blade.

Not only are the pieces straight and great for bread-boarding, but the copper has stretched and reduced in diameter so that the insulation will slide freely. You can make little rings of open copper by rolling the wire under the blade to cut the insulation then making a lengthwise cut and peel out the piece. I have been doing my bread-board wire this way since the solderless breadboard was invented, or maybe before? On the bread-board thing, I always had a pair of hemostats to bend the wire and hold it to insert in a hole and make bends so every thing is nice. Neat but not gaudy. If you want to do it with heavy wire, add a little leverage with a broom handle or a jack. You can add that nice science fair or Hack-a-Day look.

Answer 2

Aluminium is probably a bad idea, for two reasons:

Firstly, aluminium oxidizes on contact with air. This is good because it forms a protective patina preventing further oxidization of the metal (unlike iron, which just keeps rusting), but it's bad because aluminium oxide is an excellent insulator. It's not impossible to make a good electrical connection to aluminium, but it takes some care. Ordinary electrical solder is not designed for bonding aluminium.

Secondly, aluminium in contact with copper is subject to significant galvanic corrosion, probably causing your connections to fail prematurely.

In the 60s, copper was very expensive and some people had the great idea of using aluminium for home electrical wiring instead of copper. You can read about all the problems that caused.

You can use copper just fine, though. As long as your wire is thick enough to have low enough resistance that running 2A through it won't waste too much energy (or worse, catch fire), then the particular geometry of the wire doesn't matter much as long as everything is touching the same piece of copper. Take a look at a wire gauge chart: anything less than 18 AWG is probably not a great idea for 2A.

Of course, if the wire is bare you should be confident that nothing will come in contact with it and do bad things. It would be bad, for example, if a metal object touched both at once, since this would short the power supply. At the voltages you are probably using for LEDs (I'm guessing 12V), it's unlikely to present any severe safety hazard, but there's easily the potential for some everyday occurrence to break your device.

If you don't have heavy enough wire, you can always run multiple wires in parallel and the current will split between them, just as current splits between parallel resistors. Remember, wire is just a very small valued resistor.