I'm looking for something different than the usual battery monitoring apps. A while back when one of my USB cables for my phone went bad, the dealer had to plug his phone into a charger with my cable to verify it was bad for the warranty exchange. The charging indicator was coming on, even on my phone, but it would still loose charge on the battery. Usually when a dealer sees the charging icon, they call it good right away and don't bother waiting to see that the phone is really charging.
Only this particular sales rep had an app on his phone that showed him how much current was being drawn through the cable, or something to that effect. He was able to tell within a few seconds that the cable was bad despite seeing the charge indicator and I got my exchange. I didn't think to ask him what app it was before he got busy with another customer and I was in a hurry. I did ask the other rep that processed my exchange and he didn't know what the app name was, only that it required root and wasn't a Verizon company app.
I wasn't rooted at the time, but I am now and I've tried looking through the various monitoring apps but nothing reporting anything that could even hint at the condition of the cable, like showing input amperage or voltage at the USB port. They all seem to just monitor battery percentage, which I already have and can't give a quick indication of how well it's charging or if a full charge is being held during use while plugged in. I do know the phone sometimes makes a difference for these kinds of odd requests, and I'm on a Droid Bionic running stock JB with root. My current battery monitoring app of choice is AccuBat because it was specifically designed to give battery percentage to the nearest 1% on Motorola phones (most other apps only go to 10% increments because of some quirk with phones like the Bionic and Razrs).
I think the only method to get the amperage in the cable is measure it in the cable, never heard of an app that can do this ... battery apps only can show you the amperage flow of the battery while charging and discharging.
I use 'Battery Monitor Widget', the app shows and logs the amperage, even in a graph by time.
BTW, for a rough calculation which amperage flows in the cable I look at the actual charging amperage, then disconnect the cable and look at the discharging ("-" ) amperage.
The sum of both values (without mind the "-" ) is roughly the amperage in the cable when the battery get charged and the phone get its processing power.
A defective cable could be detected because Battery Monitor Widget wouldn't show any charging amperage, just discharging ("-" ) amperage :)
Re: Charging meter
I downloaded it and looks like my phone doesn't report actual amperages and the app has to estimate, which is fine. I'll see how it works out, thanks.
Re: Charging meter
Note when you connnect/disconnect the cable you might have to wait a few minutes until the shown mode switches between charging/discharging or vice versa.