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Discussion Starter · #1 ·
Just finished up a new batch of busbars made from hammered copper pipe for my new pack configuration, so thought I'd share my method.

Why: A typical 2/0 connector costs around $8 (lugs $2.50 x 2, 2/0 $3/ft). A DIY busbar is just $1-$2/ft, and not much more work than using a hammer crimp with 2/0. Also, dissipates any heat quickly.

Why not: Hammered copper pipe is not as flexible as 2/0. I only use the bars to connect batteries in the same frame, where I expect little to no flexing.


Steps:
  1. Buy copper pipe. I use type L as it's a little thicker than M.
  2. Use pipe cutter to cute pipe to desired lengths. I do them to length between posts + 3.5" (3/4"x2 past posts + 2" for bending)
  3. Hammer peices flat. I don't have an anvil so I use a 20lb dumbbell and do an initial pass with the end of another 20lber, then finish with 5lb mini sledge.
  4. Drill and deburr terminal holes (Mine are 5/16")
  5. Bend peices into U shape using pipe bender I broke mine (it's not meant to bend hammered pipe) after a few, but repaired (and upgraded) easily with a bolt and nut. The bend makes the bar more flexible, allowing for potential thermal expansion as well as mismeasurements or reconfigurations (give or take 2"). The bend can also go over well covers if necessary.
  6. Cut, fit, and heat heatshrink, leaving ends exposed.
  7. Bend ends to ~90 degrees, test fit and adjust as necessary. I use 2 chunks of angle iron clamped together with a couple scraps of pipe sandwiched in to auto measure and make it quick and easy to bend.
 

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looks like a pretty good DIY solution, although a bit time intensive, probably not much more than crimping lugs on custom cables. Only technical downside is that the copper pipe *probably* has significantly higher resistance than more pure copper in welding cable, and may heat more and waste a little energy under high-amp loads. Probably not a huge issue given the minimal length and that not many of us pull high amps for extended periods of time.
 

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Discussion Starter · #4 ·
looks like a pretty good DIY solution, although a bit time intensive, probably not much more than crimping lugs on custom cables. Only technical downside is that the copper pipe *probably* has significantly higher resistance than more pure copper in welding cable, and may heat more and waste a little energy under high-amp loads. Probably not a huge issue given the minimal length and that not many of us pull high amps for extended periods of time.
Yeah, not sure the relative resistance, but the pipe is specced at 99.9% copper and silver, and after a heavy run the bars are cool while 2/0 is warm.

When I made the first batch 20 months ago they were just flat bars, but were much more work. Having an easy way to bend it eliminates the need to redrill for a bad fit, and drilling was always the hardest part.
 
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