It sounds like you had a loose connection. If the bolt was free spinning then you didn't have a tight connection This means you weren't properly charging the battery when running the car, or even with your battery tender hooked up.
I would keep check on the tightness of your connection. If the bolt was stripped, then even though you replaced it, the post could be stripped as well.
In my opinion there's not much strength in a side post battery connection, which is why I don't like them. You have to be very careful not to over tighten them.
Just keep an eye on it. Check your voltage both running and not running, to confirm you're charging as well.
Check your alternator connections.
Hope this helps.
95 DGGM 396 Stroker, Eagle crank & rods, LT4 heads, LT4 intake, LT4 hot cam, Finish Line long tube headers, 2 1/2" exhaust, Big Baer brakes, 3.73 rear, Hotchkis lowering springs, Front and rear Hotchkis Sway bars, aluminum driveshaft, Metco aluminum boxed trailing arms, K&N, Gary's Cables, 42# Green Giants, T84's,T56 Magnum