with these clones, you will want to plug it into AC power to keep it running if you need to have it stay on while starting the vehicle, the power module used in these clones does not keep it running when the voltage drops. you can buy a module that fixes that but it takes some work to get it installed and then it still might not fix the issue or you risk screwing it up not have a working tech2
I found that if I use the cigarette lighter cord, but connect that to a lithium jump pack I can restart the engine without a reboot of the Tech 2.