Waze forum

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.

Plugged into wall power, calculating routes for about 15-20 minutes did not drop the charge at all, so I suspect the car charger is weak. I've returned that one and an trying a different brand. I'll report back after some testing.

Ok, different power adapter - DLO brand. On a short test (about 10 minutes) driving home from work it went from 86% charge to 93% charge, while waze was navigating and re-routing (waze wants me to take a bloody crazy way home).

So, different adapters put out different amounts of power. Lesson learned.

yes, it does drain the iphone battery pretty quickly, so I leave it plugged in to the car charger all the time. I have found that not all chargers are equal - some will not be able to keep up and some will charge faster than Waze can drain.

I run Waze and WunderRadio and the same time with the phone plugged into the car charger. After 20 minutes of driving, I'm down to 60% battery and my phone is almost too hot to touch.

Sometimes it's a warm issue... Any app that uses much CPU/ram warms the iPhone, and over a certain temperature, the battery icon remains "charged", while the percentage goes down.
I partially solved putting the iPhone cradle in front of an air vent...

I don't think Waze is the root problem in the power consumption, though. Waze has an almost constant connection with their servers, sending data up and down the whole time, and it has the GPS functionality always on, both these require extra power.