JeromeSolberg wrote:
I thought your car was 6v?

I used a benchtop power supply like this. They are handy to have around anyhow:

On Amazon for $50:
DC Power Supply Variable,0-30 V / 0-10 A LW-K3010D Adjustable Switching Regulated Power Supply Digital,with Alligator Leads US Power Cord Used for Spectrophotometer and lab Equipment Repair