(Mod notes in posts 16 and 17.) I just thought I'd post this as an "FYI", not really looking for feedback or anything. I received my first Evo 3D through the mail from Sprint on June 23rd, and immediately noticed how warm it got while charging. I AM aware phones get warm when Wi-Fi, GPS, etc. are on, but it was getting VERY warm. Eventually I looked into the voltage the phone was charging at, and it was at 4.385 Volts! The MAX voltage a LiIon (1 cell) battery can charge at is 4.1/4.2 Volts (depending on quality of cell and if nominal voltage is 3.6 or 3.7). The Evo 3D battery is a 3.7 Volt (Nominal) LiIon battery, as is the battery in the Evo Shift, Evo 4G, and majority of other phones on the market. This means the MAX voltage the battery can take without danger of leakage, bursting, explosion, over-heating and DRASTIC/FAST life span reduction is 4.2 Volts.... not 4.21, 4.3, 4.385. The size of the battery doesn't matter... it can be 1500, 1750, 5000 mah... the max voltage per cell is 4.2 Volts. And this is exactly what my prior phone, the Evo 4G, used to reach and stay at until completely charged. After playing with the phones settings, switching chargers, and going to lower amp-hour charging rates with no change, I contacted Sprint. I spoke with several representatives, including an "Advanced Technician", who agreed the phone should not be getting as warm as it was (105+ in a 68 degree room) OR charge beyond 4.2 Volts... the phone was obviously broken and a new replacement Evo 3D was Next Day aired to me. It arrived Friday, July 1st. I plugged the new phone in and several hours later checked it's charge... it was at 97% and hovering in that area (as the 1st Evo 3D had done) and the Voltage was reading 4.350.... not as high as the previous phone, but way too high. It does not dropped below 4.2 Volts until the phone is unplugged and lost 15-20% of it's charge. This is a huge problem, because I did notice a LARGE reduction in battery life with the previous Evo 3D in only a period of ONE WEEK, because the battery was literally getting cooked. I live in a area with good coverage (3 to 4 bars) and past phones have never had to "work" to get signal. Both Evo 3D's have. Time to call Sprint again, and I did several hours ago. After describing the issue, I was transferred to another "Advanced Technical" agent. We spoke for awhile, and he did some basic trouble shooting, etc. Eventually what he said was pretty shocking... coming from the mouth of a Sprint Employee... he said he can't believe there hasn't been any "accidents" yet with the Evo 3D's battery heating and charging issues. He said there IS an issue with the Evo 3D over-heating, although no "official" releases or acknowledgements have come from Sprint or HTC because of the limited time the phone has been out, and complaints just starting to come in. He did not know if it was all of the Evo 3D phones or just a certain percentage of them, but over the past week he spoke to seven other Evo 3D customers, all of them having major issues with the phone getting very hot, some complaining about the battery life getting shorter in addition to the heat. The technician felt it was hardware issue with the phone, and not a software issue. He also commented on a customer who had called in with an Evo 3D, and while the phone was charging in his car, it started power-cycling repeatedly, even when unplugged. He was not able to stop it until pulling the battery, which was almost to hot to handle. The Technician wasn't able to tell me if there would be a fix or if an Over-The-Air fix is even possible (being that this is not an officially recognized problem AS OF YET, and that it is likely a hardware issue)... but strongly suggested I not let my 30 day return period elapse. This is no accusation, and I have nothing against Sprint... I've been a customer with them for 9 years, and I think the Evo 3D is a great phone (I really could care less about it's 3D capability... but the rest of the phone is great). I will happily keep the phone if this issue can be resolved... otherwise, I'll have to pull the 4G out of the drawer. So, that is just my experience. My apologies if I sound defensive in the comments at all.... I just ran into a few other people's comments on the forum who were commenting on the excess heat and the battery life of the phone dropping fast, and many responses they got blamed the OWNER of the phone for the problem (too many apps running, GPS, Wi-Fi and/or 4G running with other combos, etc.) I don't want to hear negative responses.... I'm just putting this out there so the problem with the phone can be addressed. Good luck... and if you have any doubts, check your phones voltage, and then check out the chemistry of LiIon/LiPo cells. I've worked and played with these battery cells for years, and believe you'll be experiencing the same problems if your BATTERY is getting more than 4.2 Volts (The chargers put out 5 or more volts to the PHONE.... the phone should only allow 4.2 of those volts to reach the phone). And one last thing... this occurs with the supplied HTC charger, as well as previous HTC chargers, and aftermarket chargers with lower amperage that I've tried. I took the battery out of the phone and charged it on a digital charger at 4.2 Volts..... it stayed cool and took a full charge.