a used the Black&Decker jump pack which is meant to to jump start the battery from the cigarette lighter. But rather than actually attempting a jump start this way it will provide just enough juice to light up the dash and unlock the latches.
This was back in the mid 2000's when batteries for portables were HUGE. Now the jump packs are small. I carry a Cobra JumpPack (QVC or HSN) to jump start the battery once the hood is open.
According to the
Amazon reviews it will jump start an SUV with no issue. It's about the size of small 1" book. Handy to have in the car if you ever get stuck in the middle of winter late at night.
I tried the method of trying to find trunk release cable which was a PITA.