What kind of issues alarms would a Low battery do? Or a possible electrical iss

That is something I thought of along with starter and idler pulley. I feel like some is draining the power like a bad ground which is causing not enough voltage to certain components. Anywho car is being fixed by my Buddie blown head gasket do to water pump failed. Not due of plastic blades broke or shaft did but i guess will find out when he pulls old one out. Wondering what other damage I could have caused now. Didn't over heat to bad caught out quick and shut down. I'm looking asst blue driver scanner for future to help monitor car. Any suggestions? 2005 audi A4 Quattro 1.8l turbo? Thx I'll check alternate asap