Battery not charging

[MillerCobra]

Hi everyone, I have 1400 miles on my build. Yesterday car was running great, stopped at a friends house and when I started up again the battery almost could not crank the engine over. After a couple to times it started. Looking at electrical gauge it read below 12 and dropped to 11 if I turned the lights on. Checked my main ground and tightened it a bit. Threw on a charger for an hour and went for a drive. Again slowly dropped to 12 (usually gauge sits at 13-14). Noticed that when I put on my turn signal I could see the gauge drop with each pulse. So my battery was not being recharged.

This is what I found this morning on inspection.

5292852929

I have no idea when this happened. You would think I could smell melted plastic. You will notice this is the same setup that Edwardb used in his second build. Any ideas on what next to do?

[MillerCobra]

I cleaned up the contacts and put it back together. Now everything looks fine solid 14 volts on the gauge. Put my hand on the wire and it is just slightly warm. Only thing I can think of is that the nut had worked it self lose and there was arcing which would have heated up the post.

[videodude]

No lock washer?

Video

[MillerCobra]

The fuse comes with a nut that is flared and scored on one side. Should have stayed. The fuse was not blown so that is why I think it was just arcing and heated up both posts. Just glad it did not start the plastic cover on fire, hot dripping plastic on the left leg would not have been any fun.

[videodude]

Seen those nuts. Crap. Use an internal tooth lock washer with it, it will never loosen again. Those "scores" aren't going to hold that nut tight in a high vibration environment.

Video

[JC Of NM]

How old is the battery?

[MillerCobra]

Hey JC, my thought also but the battery is new. Checked all connections. In addition I have a main cut-off switch which I closed when charging. So I really think that the nut loosened up a turn and that it arced as the car shook. Cleaned everything up and holding 14V on the gauge and the wire is not hot ( I can reach under the dash and touch it) . My engine is a 351W but displacement is 430, dyno was 546HP . The car at idle really shakes. I could have just missed tightening this one enough. Thanks for your thought!

[CraigS]

Does the number 100 on there mean it is rated for 100 amps? What is the output of your alternator? Just double checking w/ you.