Question about a old mad bypass repair

If this periodically happens every couple days you could be having something like voltage spikes, which could be from your voltage regulator. Make sure you are running a quality voltage regulator. Another thing you may want to do, as was suggested to me by slantsixdan, is to run a ground wire from your alternator case, to your voltage regulator to the negative post of your battery. This now puts your charging circuit all on one plane and should help with voltage spikes.