This morning, my phone connected to the wall charger showed
4358mV at 97% charge. Temp was
31.6C.
I'm wondering if HTC is doing some funky implementation of SBC. For those who don't know, SBC (which stands for superior battery charging) was a feature of some custom kernels for the Evo 4G and other Android phones, where the battery was charged above 4200mV.
The trick to SBC was to charge at high voltages for short bursts rather than maintaining the voltage. It would be similar to bump charging. Because the voltage is delivered in bursts, temperatures never rise to favor the plating reaction (which is what ultimately could lead to thermal runaway and an exploded battery). But it meant that in order to take advantage of SBC, you needed to leave the phone on the charger for a long time to allow sufficient time for the battery to get bump charged.
I tried an SBC kernel for a week, saw its advantages (battery would get charged way beyond the indicator's limit, causing it to read 100% charge despite prolonged usage).
It was a controversial technique. There was no consensus over the safety of SBC. Out on the field, people claimed it gave them great battery life with no signs of long-term capacity issues. Others claim it screwed up their battery after a few months. Didn't hear any reports of thermal runaway though.
Back to the Evo 3D. Here, I have multiple apps/widgets reading the same voltage, temp, and charge. So they are likely pulling that data from the same source. On my phone, I have a discrepancy between voltage and temperature. If my phone is indeed charging at 4358mV, the battery should be way higher than 31.6C (I encourage everyone to stick with metric here, since we're dealing with an engineering problem
). So I can only conclude that the battery's not charging, or the voltage reading is wrong.
So now I've got the phone on the USB charger, and the voltage reads
4348mV at 99% charge. LED is red. And temperature is 31.0C.
While the voltage number is worrisome, I'm reassured by the temperature of the phone. Ultimately it's the temp that's going to tell you if you have plating issues, or worse, you're about to get into a thermal runaway situation.
I cannot conclude, without better measuring instruments, that the high voltage readings are causing the high temps for some people, since the same high voltage numbers are doing nothing to my battery's temp. However, if you are experiencing a very hot phone (anything above 40C), and you've ruled out heavy CPU usage, something could be messed up with the charging mechanism, and your phone needs to be serviced/examined/exchanged.