Originally Posted by Hit Man X

This killed my Die Hard in my SD just recently... well the fully working HVAC system did. The puny alt was just not able to charge the car at idle/my city driving with the lights on, blower on max, HVAC relays on, clutch engaged, etc

Bought a 150A, problem solved. I never encountered this issue on my other stuff as I have upgraded the alts in all of those already... did not dawn upon me to be proactive and swap it. Oh well.

I was told the big issue with the small alts and these batteries is that they are almost all not Maintenance-Free which does not allow them to charge well.