My 2010 XFR has a big battery drain. I have no service engine lights and nothing on history report. When battery gets low my screen goes blank, A/C goes off and on etc. until car won’t start. Any input with like problems would be appreciated.

EEH

 

Are you certain it's a drain ? Have you checked your battery ?

 

I have two new batteries keep one always at full charge to swap out. There is a rather big spark when I attach the positive line when changing out batteries. Yes I have replaced negative battery cable.
Thanks for the input,
EZED

 

Do you keep anything plugged in the obd port? Like a Wi-Fi/Bluetooth obd device?

 

Nothing.
Thanks,
EZED

 

Have you been able to check your voltage being produced by the alternator as well as have the batteries load tested?

 

@EZED, what is the battery voltage across the terminals with the ignition in the OFF position when checked with a voltmeter?

 

12.38
EZED

 

Alternator putting out 15 plus volts. 2 new batteries same result on both.
Thanks,
EZED

 

For the CAN and modules to correctly function, there should be a minimum of 12.6 volts present with the ignition off.

If you charge the battery currently in the vehicle for five hours at 2 to 5 amps and retest it again, there should be at least 12.6 volts available. If not, the battery is suspect and should be replaced.

Did you previously check the vehicle for a parasitic draw?