[XPERIA X1 General] ianl8888:
Although there are a few threads on the X1 battery, none have addressed the real issue, in my view.

The 3.7v, 1500mAH battery specified and supplied with the X1 is underpowered for the processor (Qualcomm MSM7200A 528Mhz)

The defining symptoms for this are overheating when:

a) using wifi for over 60 minutes whilst on charge

b) using GPS for over 60 minutes whilst on charge

This 60 minute limit is somewhat arbitrary - it may be as low as 30 minutes, but within 60 minutes the overheating will definitely manifest itself. At the very least, this causes the device to behave erratically and if left unchecked may eventually cause the battery to explode.

I've tried 3 completely new batteries now - all carefully charged overnight before turning on the device in accordance with SE instruction manual. All chargers (both wall and car) have Sony Ericsson stamped all over them, as do the batteries.

I've owned these devices previously, none of which showed this problem:

HP HW6515

HP HW6910

Eten X500

HTC P3600i

HTC Polaris (still used as a totally reliable backup)

Useless to say "don't use wifi, use AS". This comment tacitly admits that my comment is accurate - ie. don't use the wifi for more than say 15 minutes, else the battery overheats

Useless to say "don't use the GPS for more than an hour" - again a tacit admission that the battery/charge system is unfit for its purpose. It has no value when I'm field mapping for 8-10 hours at a time.

My best guess is that the battery is underpowered for the system, so that when a large, constant drain on the battery such as using wifi or GPS is executed whilst charging, the balance of power within the battery is erratic. It certainly charges, but at the expense of heating the battery to unacceptable levels.

It's of interest to note that the original wall charger supplied in the box has a stamped output of 700mAH at 5V, while an SE-stamped spare wall charger I purchased has an output of 300mAH at 5V. It takes longer for the overheating to show on the lower charge rate than the higher, but eventually it does show.

Of course, some will reply "My device doesn't do that, your phone must be faulty" ... to which I ask: "What happens when you leave the device on wall or car charging and use wifi or GPS for an hour or two ?" This is a very specific question and requires a very specific and accurate answer ... not an evasive piece of generalised rhubarb.

I'm looking at two ways to resolve this serious issue, because the X1 as currently constituted is unfit for its purpose:

1) eBaying this and replacing it with an Acer DX900/X960/F900 as my experience with Eten devices have been positive (again, slagging these devices does not address the battery issue with the X1)

2) waiting in the hope that within 6 months or so, MugenBatteries or some other reliable manufacturer will produce a more powerful replacement battery that will tend to overcome the problem

I welcome constructive comments, especially those that read the post before replying. The X1 has some good points of course (eg. abundant Storage/RAM, high WVGA resolution), but the battery issue is a serious, fundamental flaw that makes the device unfit to rely on when in the field.