For some reason, whenever I plug my iPhone into my work laptop (Lambda Tensorbook), the phone charges very slowly. The laptop only has USB 3.1 ports, so it should be charging the device with around 900 mA of current. I tested the actual output of this USB port, and it was only at 500 mA of current, which is usually what USB 2.0 ports can provide. I have tested the ports with other devices and have seen it provide up to 900 mA of current for other devices, but I'm not sure why it won't provide this level of current for my phone. I've never had any problems using the USB 3.0 ports on my MacBook, as I always get faster charging speeds on that compared to my work computer. Has anyone else had issues with slow charging speeds with non-apple computers? Is there any way to improve the charging speeds?