Mark Hanson wrote:
... I found a few other battery terminal bolts not tight after 20k miles (even with sealing paint on terminal bolts CALB 130). So it's best to tighten terminal bolts on lithiums every 10k miles it seems. I used to tighten terminal bolts on old lead GC batteries every 500 miles but didn't think it was necessary with lithiums but apparently they need it as well just less often.
Soft metals like lead, aluminum, and copper can "cold flow" due to pressure. Temperature cycling and vibration also play a part.
Unfortunately, these factors are common in electrical connections. These soft metals are used for their high electrical conductivity. High currents make the temperature extremes worse due to self-heating.
Dis-similar metals are another factor. These create corrosion couples, that corrode if the joint isn't absolutely air tight. They expand at different rates with temperature, leading to large pressure changes in the joint. Inexperienced or cheapskate designers seem to have a total disregard for the metals used in their electrical contacts. They ignore 100 years of experience and use whatever metals are handy.
My guess is that if (for example) you bolt a copper strip to an aluminum stud with a stainless steel screw, it's hopeless to expect a reliable connection.
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