I was a beta tester for the app and would suggest it for people that don't already have a way to monitor the battery. I picked up an ELM327 module off Amazon and it worked great.
My complaints with it are really related to how iOS on the iPhone/iPad handles the Wi-Fi connection presented by the ELM327 in the car.
- When I had joined the Wi-Fi network in the car, I lost access to the Internet. The iPhone would use the local Wi-Fi for all traffic instead of just to talk to the Leaf. This meant any data application (Mail, Pandora, iTunes Radio, etc...) died when I got in the car. Apparently, you can resolve this by manually configuring your IP settings on the iPhone/iPad instead of using the DHCP server. The trick is to not configure the default router. If there isn't a default route configured on the Wi-Fi network, the iPhone will continue to use the cellular network for data transmission. Theoretically, this could be fixed by a firmware update to the OBDII reader, but since you can't really tell who made it, that's unlikely.
- Related to the above, my iPhone would frequently login in the car's Wi-Fi network when I was at home and the Leaf was parked in the garage. Even when the Leaf is turned off, power is supplied to the OBDII port, which meant the Wi-Fi network was up and running. My iPhone would randomly switch to that network from my home's Wi-FI network, which was really connected to the Internet.
I already had a LeafDD (standalone OBDII reader) on hand before getting Leaf Stat. With the two issues above, while I used Leaf Stat at times, I never used it a whole lot. The first issue is easily addressed (as mentioned) and I think with a little tweaking, you could get the iPhone to give priority to your home Wi-Fi network to avoid the other hassles I mentioned.
At $10 for the app and about $25 for the OBDII reader, it's an inexpensive way to the get the battery data if you have an iOS device instead of an Android device.
