I just had one of those motion sensors/extended battery packs put on my phone.
Let me tell you, this is a MUST HAVE product if you really want to do some serious tracking.
I was so sick and tired of the charge running out before the day was done, or the vehicle was back. Then trying to recharge it every day was becoming a real pain.
If you think the simple GPS trakcing is cool, this extension pack is sooooo much cooler.
I received my i415 enhanced phone back on Friday. Today is already Tuesday, and I haven't had to recharge yet. In fact the battery still shows full charge, and it has tracked the normal times as always. And with the motion sensor, the phone goes idle, in fact shuts off, while there's no movement in the vehicle, which with a normal battery will just slowly drain out until it's dead, and you can no longer track. Upon movement, the phone fires up immediately and begins tracking without missing a beat.
I was now able to change my interval to 1 minute, rather than 4 minutes to try to save battery life.
I got my from the Spyoutlet (http://www.spyoutlet.com). Sent it overnight on Wednesday, and had it back Friday morning. Watched it travel all day from NY to MPLS, and haven't had to charge it since.
This was fast and great service for an excellent price. Go check it out, or post any questions here.
You won't be disappointed.