POSSIBILITY #1.
Some of the aftermarket components have developed a short, or the wiring connections for such normenclature...

POSSIBILITY #2.
The battery has developed a bad cell or two, possibly from theory one...

POSSIBILITY #3.
The altenator may not be putting out enough amperes as a result of theories one and/or two...

Probably going to have to have a good mechanic check this one out, especially one who is familiar with electricity/electronics shorts, opens et cetera...

Seems to me the battery needs to be replaced... but the other stuff needs checked also...