On an iPhone 3GS with iOS 4, running only Waze, my battery will go from 100% charge to 90% change in 7 minutes. I don't have issues with the battery under my normal usage
On an 8 hour drive yesterday, with my phone attached to a car charger whenever I was driving, Waze was running, I ended the day with 17% charge remaining. Either that charger is weak, or Waze uses power faster than my phone can recharge.
Is this normal with Waze? Later I'm going to charge to 100% with a wall charger, then run Waze and see if the battery charge drops.