I have had the Sierra hotspot for about a year. I have a couple of issues with it. First, it overheats and ruins the batteries. The last battery (that I bought) only made it 1 hour! I took the unit to the store, and they told me to just remove the battery and run it off of the A/C adapter.
The other issue is connectivity. Sometimes it will work absolutely perfect, and then it will hit a 2 to 3 month stretch when I can barely get online. I have been to our local store, called Sprint customer service, and even talked to someone from Sierra. No one seems to know why I have problems with connectivity, or constant switching from 3G to 4G lte to 3G to 4G lte.. At one time the store set the unit to 3G only, but when the 4G came out (last winter?) they had me switch it back because 4G lte seems to work great, if the 4G lte signal wouldn't fade in and out.. Every time it switches I get dropped. Twice already while typing this message. I'm upset by the fact that I can see that the Sierra Hotspot has been having issues since at least 2010 and it is still being sold! Help!
It doesn't look as if we carry batteries on Sprint.com, ACCTony, but I was able to locate several different ones on Amazon. Prices varied a bit, so you might check for specifics. If you've done all the updates and the device is still dropping signal, it might be a good idea to have it checked in a service and repair facility. If you have TEP, your first visit should be free. - Christy
Sprint Social Care