Can't fix this electrical issue.

I don't think 0.045 milli ohms is going to make that much difference. He mentions the nuts making "grooves" in the bus bars, the OEM ones do as well, because there were circular grooves cut into the bus bars when I took the pack apart for the very first time.

Also he didn't use a torque wrench, just a nut driver, so there is no "control" in his little experiment, if he tightened the bus bars down not as tight with the new nuts, it would increase resistance.

Should have repeated the experiment 3 times with each bus bar and nuts, to account for discrepancies.

I can't even find the nuts Toyota uses. I'm not sure if originally they used some kind of securing adhesive, because all flange nuts I can find either have a nylon insert, or serrated. I'm sure as hell not paying $1.20 each for these nuts when 56 are needed.

It's also interesting..that the Toyota Parts site lists 2 different part numbers for the nuts, with each requiring 28, so it looks like one side of the modules takes a different nut than the other?

 

Wait..the oem nut is ZINC?!!? That would explain a lot too. You are going to have galvanic corrosion when you have zinc plated nuts and copper bars in presence of moisture/electrolyte.
What the actual...did the electrical engineers sleep that day?
No wonder why those original nuts were so grody when I took them off..

 

Not my pic, but similar to how the nuts originally looked.


Really a stupid system if you ask me..toyota should of used metals that would not of reacted so poorly.

Also..see that red coloring around the nuts? Do you think they originally used some kind of liquid to secure the nuts in place? I can't imagine non-locking nuts staying tight over 14 years of cold winters, hot summers, 190k miles of bumps, etc.

 

So they use nothing to keep the nuts locked in place?

 

I got fed up with strange measurements and bought an new fluke meter. Glad I did...look how much off in voltage it was when hooked to a module.

 

Originally wanted an 87V, but they are like $400 new, this was $140 at Lowe's.

 

I have a friend who is an electrical engineer, he said a lot of electrical meters like voltmeters will go out of calibration after so many years. But honestly for hobby stuff it's not a huge deal, but when you are working on mil-spec stuff where you have to be within 0.01 volts I'm sure it pays to have them calibrated every so often.

They use fluke meters as well.