It would probably be best to try it in the driveway, close to a battery charger and electric outlet before getting out in the middle of nowhere and finding yourself stranded with dead battery. However, I stick to lower transmit power on HF in the mobile, (just the amount of power required to make contact, like in the rules) in most situations, just for this reason. Looking for a hill is always a good idea and allows more contacts at lower power.
