I was watching Madi on Digital Mermaid assemble some flexible buss (jumpers), four #8AWG I believe and noticed how low the resistance readings were. This had me confused because I had bigger a cable and my reading were higher. Could tinned cable make the difference? YES!!!!!!
My test conditions: 54 volts at 100 amps.
Lugs: Newly purchased Selterm 2/0 1/4 stud
Cables: Ancor 2/0 tinned copper marine rated, fine strand.
Windy Nation 2/0 copper not tinned
Welding cable, fine strand.
All cable was 4-3/8 cut length (OAL)
Reference item: standard plated copper battery buss.
First 3” of cable was discarded. No oxidation noted on either cable.
Jacket stripped back no further than 3/4” so strands can’t bottom in lug and disorganize.
(Scraped) means outer wire strand surface was scraped with a utility knife while a twist tie held strands in place at end of strands. The lug was started and tie was removed.
Tinned cable was used as is, not scraped.
(Random) means strands were not straight and some were across others strands, disorderly, but 100% of the strands were crimped.
(Polished) means the inside bore of the lug had a few rotations of Scotch Bright to remove surface oxides.
Crimp: hydraulic- hex. Single crimp, single positioning. Hex impression reduce to die travel limit. Hex had crisp, complete non-rounded corners, no split line extrusion. Lug did not extrude in longitudinal dimension.
The cable was held into an arc shape with a wooden fixture while crimping to “lock in” the shape. A test piece (same length) was also done with a tighter bend using a buss it fixture it. The lugs were mount on the buss over/under to perfectly counter the twist when the lug was released.
……Ohms. ……Millivolts…… Watts
Buss……….. .07 … .004 …. .4
Ancor
(Polished)…… .07 ….. .004 …. .4
Windy …..… .11 …. .008 …. .8
(Polished/scraped)
Windy. …. .23…. .018 ….1.8(warm)
Windy. … .32 ….. .025. …. 2.5 (hot)
(Random)
My take away is a tinned 2/0 cable/prepped lug as a diagonal cell connect has the same resistance as a much shorter buss bar. Cell balancing should also be just as good an low heat buildup. Contact surface with the Lug on a small welded stud terminal should be superior to that of a solid buss due to the omission of a slot. The tinned-tinned connection may prove useful in many other locations.
There’s a possibility that a copper lug on copper wire may render an improvement but I don’t want the potential for corrosion so no test was done. Lastly, a battery internal resistance meter is an excellent predictor of cable quality.
My test conditions: 54 volts at 100 amps.
Lugs: Newly purchased Selterm 2/0 1/4 stud
Cables: Ancor 2/0 tinned copper marine rated, fine strand.
Windy Nation 2/0 copper not tinned
Welding cable, fine strand.
All cable was 4-3/8 cut length (OAL)
Reference item: standard plated copper battery buss.
First 3” of cable was discarded. No oxidation noted on either cable.
Jacket stripped back no further than 3/4” so strands can’t bottom in lug and disorganize.
(Scraped) means outer wire strand surface was scraped with a utility knife while a twist tie held strands in place at end of strands. The lug was started and tie was removed.
Tinned cable was used as is, not scraped.
(Random) means strands were not straight and some were across others strands, disorderly, but 100% of the strands were crimped.
(Polished) means the inside bore of the lug had a few rotations of Scotch Bright to remove surface oxides.
Crimp: hydraulic- hex. Single crimp, single positioning. Hex impression reduce to die travel limit. Hex had crisp, complete non-rounded corners, no split line extrusion. Lug did not extrude in longitudinal dimension.
The cable was held into an arc shape with a wooden fixture while crimping to “lock in” the shape. A test piece (same length) was also done with a tighter bend using a buss it fixture it. The lugs were mount on the buss over/under to perfectly counter the twist when the lug was released.
……Ohms. ……Millivolts…… Watts
Buss……….. .07 … .004 …. .4
Ancor
(Polished)…… .07 ….. .004 …. .4
Windy …..… .11 …. .008 …. .8
(Polished/scraped)
Windy. …. .23…. .018 ….1.8(warm)
Windy. … .32 ….. .025. …. 2.5 (hot)
(Random)
My take away is a tinned 2/0 cable/prepped lug as a diagonal cell connect has the same resistance as a much shorter buss bar. Cell balancing should also be just as good an low heat buildup. Contact surface with the Lug on a small welded stud terminal should be superior to that of a solid buss due to the omission of a slot. The tinned-tinned connection may prove useful in many other locations.
There’s a possibility that a copper lug on copper wire may render an improvement but I don’t want the potential for corrosion so no test was done. Lastly, a battery internal resistance meter is an excellent predictor of cable quality.
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