Also I like to share my experience by charging the device, so it could be taken as an advice.
Never left the GPD XD charging more than the necesary, until it reaches the 100%. If you leave the device connected for a long period of time after it gets full battery, it will still warming up. Usually with the phones, the system automatically cut off the energy when the charge is complete, and that's for avoid overcharging, hence overheating too. When I forget to disconnect my phone after few hours it gets full, when I disconnect it, it's cold, no trace of heat.
But it seems that that feature isn't that good on the GPD, so if you leave the gpd connected 3 hours after the battery gets full, those are 3 hours that the battery will be getting warm, not as hot when its charging, but the enough to note that it's not normal.
Yeah, I guess the XD is a bit crappy on that part (but not surprising). However, I do take issues with that because, in a lot of cases, people leave them to charge overnight and what-have-you.
Thanks for adding to the topic. It's always good to let fellow XD'ers know about this.
Never had a problem leaving my XD on the charger for a longer period of time, it never gets warm. I had it on the charger for days, because I plugged it in and forgot to unplug it.
Do you turn power your XD down before charging or do you have it in standby? I always charge in standby and it definitely doesn't get warm.
If your XD is deformed after charging, the chances are good, that it is because of a defective battery. Until your sure it's not the battery DON'T CHARGE THE DEVICE. I am serious, it can catch fire. Bring the device to somebody who is able to tell if it is the battery or not. Do yourself a favor and DON'T CHARGE THE DEVICE!