I don't think you're going to get hydrogen sulfide from a diesel's catalytic converter, I really don't think there's enough sulphur in the fuel anymore. Gassers, oh yeah, they stink...
I will triple the check batteries comment. Might also want to check your system voltage, if you're very high, you could be cooking the batteries. Might have a bad voltage regulator. If you do add water to your batteries (if it's possible) make sure you only used distilled water, tap or well water with other minerals in it aren't good for the life of the battery.