I have a 2011 XFR.

If I want to have the audio blasting in the garage is it ok to attach a 13.8v 20amp switch-mode power supply to the battery (as in +post and -chassis)

Reason I ask is that when I attach my 16amp charger the battery warning will appear after awhile and the system will shut down.

Is it ok to have a power supply rather than a charger hooked up for short term use. I see guys at car shows with power supplies hooked up with there audio systems running all day.

 

Go buy another radio for your garage.

/thread

 

Power supply works good. Provides stable voltage and no shutdown warning after 40 mins. Will use for Nav updates and scan tool etc as well.

 

I wonder if that warning is a time based thing vs an actual voltage issue?

 

Not sure? I think its more of the car seeing a constant 13.5 - 13.8 (?) volts. I remember speaking to a Tech when I had my Audi and he said they use expensive power supply/chargers that maintain a specific voltage when they do updates and ECU work.