Here's something I noticed. I can use the cigarette lighter battery eliminator cable with my 5 watt Baofengs but the 8 watt Baofeng will come on and receive but even though it tries to transmit, it wont work. No, I didn't try using the Medium or Low power setting. I put the battery pack on it and it transmits perfectly. I checked the battery eliminator and sure enough, I put 13.8 volts in and it registered 8.1 volts out, just like it is supposed to do. I suspect that there is a current limiting circuit in the battery eliminator that shuts it down if you try to draw too much current through it. I also noticed that the Battery eliminator got warm even in the receive mode. My advice is don't try to use the battery eliminator in the car. Just carry spare batteries or buy one of the 3800 ma hour battery packs. I have a bunch of extra battery packs, so its no big deal for me.