So I'm thinking about installing a 2nd car battery (in the trunk) because I don't drive long distances daily and my 2-channel car cam seems to stop recording some days due to low voltage (it has automatic shutdown when it detects the car battery is getting low to not drain it and leave enough power for startup). I'm hoping that a 2nd car battery will allow me to run things like car cams and maybe some LED lights while car is off and parked. I've never done this before, don't know much about batteries, so it would be helpful if anyone can mention what some pros and cons about doing this are. I'm only looking for about a 45 AH battery or so as the 2nd battery. Not sure if I'm accurate on the pros and cons but here are some that I think may be relevant: Cons: extra weight (30-40 pounds?), maybe more stress on the alternator? Pros: having more power to run equipment off of while car is parked and off, so as to not kill the main battery.