jfangohr

I’m in the process of assembling my own 5 cell, 6 volt battery pack to power the receiver and servos of my new jet. I bought some 20 gauge wire to make the harness exiting the pack. In looking at the wire I discovered it only has 7 copper strands. I’m not sure where the battery will ultimately be located so the harness between the battery and switch harness may be up to two foot long. Will a 20 gauge 7 strand wire supply the amperage to keep everything happy or should I hunt up some multi-stranded wire?

Thanks,

John

rcu guest-delete

John, with all due respect, I must tell you there is no straight answer to this ? as it is. There are too many variables that you do not mention. Seriously, if you are building this pack for a Jet, ( $,$,$,$,$ ), a mistake in the battery room and you`ll have "fire in the house". We could tell you what to use, but a cold-solder or a burnt-cell will be the sad end to your beautifull project. Leave that part to a pro, like an R/C battery company, you`ll be glad you did. Johnny ( Avionics Tech )

Lynx

Number of strands is irrelevent, more technically offeres slightly better vibration resistance, but 7 strands is just fine. This is how higher gage wire is made, they just include more strands. Every time they double the number of strands (cross sectional area) the gage goes up by three. The higher the gage, the lower the voltage drop and power loss across that piece of copper. 20 gage wire can take about 11 amps. Honestly, from the pack the the receiver's power buss, you can't use too thick a gage of wire (as long as it fits) Everyone wants to use thiner wire, but as you half the weight you (cross sectional area) you quarter the power carrying capacity. You truly get what you pay for in weight.

JohnW

My Feedback: (6)

Ditto...

If you need to ask the question, you are probably better off purchasing a premade pack from a quality source. Your not saving any money by making your own pack if it crashes your plane. For low voltage, high DC current apps, I'd say you'd be much better off with more strands at the same guage. But like motocros mentioned, there is really no way to know exactly what is needed until we know total current draws, dropout voltages on serovs, RX, loss due to connectors, cable lenghts, etc. If you insist on making your own pack, please error on the side of caution... Find some high quality high strand count cable designed for power bus or high current low volt application.

jfangohr

Thanks for all the info. You've given me some something to think about. The pack that I'm using is not completely home made. I get them from a local battey supplier who builds the pack, gluing the cells together, welding on the tabs, etc. He hands me the pack with tabs on the outboard cells along with a length of shrink tubing. I take it home, solder on the wires to a custom length and I'm done. The only problem with pre-assembled packs is that they all have about a 4" pigtail and I always have to lengthen them.......I'm not about to use a cheap servo extension. I asked this question because servo wire is always multi-stranded and I wasn't sure why. If vibration resistance is the ONLY reason then I need to take that into consideration. The ultimate goal is not to save money but to get a custom length pigtail lead coming out of the battery.

John

Lynx

More strands makes the wire more flexible that's about it. I believe a solid core wire of the same gage as stranded wire will actually handle a little more current because it can disipate heat faster (it's one piece of metal not multiple strands laying against each other) but that's virtually irrelevent and solid core copper tends to break fairly easily.