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War story: the hardest bug I ever debugged

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462 points jakevoytko | 1 comments | 24 Mar 25 14:37 UTC | HN request time: 0.222s | source
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TrackerFF ◴[27 Mar 25 17:14 UTC] No.43495694[source]▶
My hardest debug was actually not software related, it was my first car - late 80s VW Passat. The problem was that the battery would simply not charge, and I had to jump-start it every time I used it, or park at the top of a hill/street and start it rolling down.

Bought a brand new battery, but the problem persisted. Started looking at all the various parts in the car, that were connected to the electrical system. Took them out, troubleshooting the parts to my best ability, even ended up buying a new alternator AND solenoid just out of sheer desperation.

3 months went by, countless hours in the garage, and I thought to myself...could it be...could it be the new battery I bought? Bought yet another battery, and everything worked. Just like that.

Turns out the battery I had in my car originally had degraded, and couldn't store enough charge. And the second (brand new) I bought turned out to also be defect, having the very same fault.

Those faulty batteries would charge up to measure the correct voltage, but didn't get the correct charge capacity - and thus the car couldn't draw enough current to start the engine.

And don't get me started on the weird wacky world of electronics...but the car debugging was by far the longest I've spent, at one point I had almost every component out of the car, going over the wiring.

replies(1): >>43496723 #
1. Suppafly ◴[27 Mar 25 18:44 UTC] No.43496723[source]▶
That's the worst when you buy a new part and it still doesn't fix it, you rarely think that the new part could be bad, especially something like a battery that generally wouldn't have problems fresh from the store.