I had the same problems on my laptop when I was not plugged in. I recommend trying this fix that worked for me.
Click StartStart button, type Power Options in the Start Search box, and then click Power Options in the Programs list.
User Account Control permission If you are prompted for an administrator password or confirmation, type your password or click Continue.
Click Change plan settings under the power plan that is selected. For example, if the Balanced option is selected, click Change plan settings under Balanced.
Click Change advanced power settings.
In the Power Options dialog box, expand Wireless Adapter Settings, and then expand Power Saving Mode.
In the list that appears next to On battery, click Maximum Performance, and then click OK.