Firmware may have fixed Simplo battery issues, but now LG batteries have problems.
Some models of Surface Pro 3 were struck with severe battery issues, reducing their time away from the power outlet to a few minutes or less. Microsoft issued a firmware fix in late August that appeared to work, but new complaints are growing about another battery problem, as reported by InfoWorld.

Microsoft has two sources of batteries for the Surface Pro 3: Simplo and LG. The first issue, the one that's now fixed, applied to systems with Simplo batteries: affected systems saw the battery's charge capacity drop steadily, becoming unable to store any significant charge. The firmware fix reset the reported capacity.

The new problem appears to have struck systems with the LG batteries. Affected systems don't charge when plugged into the wall and, even though they're showing that the battery has charge, are turning off immediately when unplugged.

While vague complaints about LG battery issues have circulated for months now, they've become much more widespread since the release of the Simplo fix. There are suggestions that the update is causing, or at least exacerbating, trouble for owners of LG batteries. Users on Microsoft's forums are getting increasingly aggravated, with the company saying little in response. Microsoft MVP Barb Bowman was told by the firm that this is definitely a different issue from the Simplo problem, but that appears to be the extent of the communication on the issue.