The first iteration of my system used all 2/0 cabling between the big components such as between the battery and the shunt and fuse. I'm in the process of rearranging my system to make way for an inverter/charger upgrade. In doing so, I decided to ditch the 2/0 cable where I could and use copper flat bar as bus bars. This is a learning process for me since I've never worked with copper bar.
I started by ordering copper flat bar from MidWestSteelSupply.com in 1/8"x3/4"x72" and 1/4"x3/4"x72". I've ordered aluminum square tubing from them in the past with good results and good prices. In another thread I compared prices between Midwest and another online source and a local source. The local source for this order - which didn't have it in stock (two weeks minimum) - quoted more than $400 while Midwest was $146 including shipping.
Here is the box my copper from Midwest arrived in. It was taped very well with nothing sticking out. An order from a different online vendor arrived with aluminum flat bar sticking out and all banged up.
Here's where I was surprised. They didn't just stick the copper in a box and ship it. They attached the copper to wood slats with plastic wrap with tape outside the plastic wrap. The flat bar came out of the box unbent. It was still nice and flat and not banged up. When the plastic wrap was removed there was no adhesive residue like there might have been if they had used tape directly on the copper.
I drilled a test hole using my Cobalt drill bits in a drill press with the copper held by a drill press vise. I punched a dot on the copper for the drill to follow, but it still wandered, causing the hole to be a bit off center.
Drilling copper isn't as straight forward as I thought it would be. The drilling process produced a significant burr crown around the hole. I had to file and sand that down, which took a lot more time than drilling the hole did. I used Tap Magic cutting fluid. That helped quite a bit and I'll use more of it next time.
In the picture below, the area around the drilled hole has been sanded with progressive grits of sandpaper starting with 150 and ending with 400. There's still a nick at the top of the hole that I'm not going to address. The other side looks better with no nicks. The right side was not sanded at all.
I'm looking at different drill bits to use for this project. They should help with the burrs (different type and drill bit angle) as well as the wandering (different tip). The recommendation for those drill bits came from a friend that does fabrication. I found the drill bit set for much less at NationalToolWarehouse.com. It's still a lot of money though. Twice as much as my Cobalt drill bits.
I cut the bus bar to length using my Dewalt chop saw that has a Freud Diablo Non-Ferrous blade. This was the easiest part of the project. The blade went through the copper like a hot knife through butter. The bus bar pictured above has not been dressed on the cut end (right side). You can see minimal burring on the edge. A quick swipe of 320 grit sand paper took care of that.
I'm a bit uncomfortable with the ampacity of the 1/4"x3/4" flat bar. It may be at the margin of how many amps my inverter could pull so I put in new order for 1/4"x1" and 3/8"x1" bar. I'll stack the narrower flat bar for now and use it for lower amp connection later.
I started by ordering copper flat bar from MidWestSteelSupply.com in 1/8"x3/4"x72" and 1/4"x3/4"x72". I've ordered aluminum square tubing from them in the past with good results and good prices. In another thread I compared prices between Midwest and another online source and a local source. The local source for this order - which didn't have it in stock (two weeks minimum) - quoted more than $400 while Midwest was $146 including shipping.
Here is the box my copper from Midwest arrived in. It was taped very well with nothing sticking out. An order from a different online vendor arrived with aluminum flat bar sticking out and all banged up.
Here's where I was surprised. They didn't just stick the copper in a box and ship it. They attached the copper to wood slats with plastic wrap with tape outside the plastic wrap. The flat bar came out of the box unbent. It was still nice and flat and not banged up. When the plastic wrap was removed there was no adhesive residue like there might have been if they had used tape directly on the copper.
I drilled a test hole using my Cobalt drill bits in a drill press with the copper held by a drill press vise. I punched a dot on the copper for the drill to follow, but it still wandered, causing the hole to be a bit off center.
Drilling copper isn't as straight forward as I thought it would be. The drilling process produced a significant burr crown around the hole. I had to file and sand that down, which took a lot more time than drilling the hole did. I used Tap Magic cutting fluid. That helped quite a bit and I'll use more of it next time.
In the picture below, the area around the drilled hole has been sanded with progressive grits of sandpaper starting with 150 and ending with 400. There's still a nick at the top of the hole that I'm not going to address. The other side looks better with no nicks. The right side was not sanded at all.
I'm looking at different drill bits to use for this project. They should help with the burrs (different type and drill bit angle) as well as the wandering (different tip). The recommendation for those drill bits came from a friend that does fabrication. I found the drill bit set for much less at NationalToolWarehouse.com. It's still a lot of money though. Twice as much as my Cobalt drill bits.
I cut the bus bar to length using my Dewalt chop saw that has a Freud Diablo Non-Ferrous blade. This was the easiest part of the project. The blade went through the copper like a hot knife through butter. The bus bar pictured above has not been dressed on the cut end (right side). You can see minimal burring on the edge. A quick swipe of 320 grit sand paper took care of that.
I'm a bit uncomfortable with the ampacity of the 1/4"x3/4" flat bar. It may be at the margin of how many amps my inverter could pull so I put in new order for 1/4"x1" and 3/8"x1" bar. I'll stack the narrower flat bar for now and use it for lower amp connection later.