AirCard 770s no battery error

I have been having the same problem for a few months. Sometimes after I take out the battery and reset it, it will last for hours. Sometimes only a few minutes. It usually does it also when my computer is inactive for 10 minutes. I have done a factory reset, verified that the software was up to date, replaced the battery, cleaned the battery contacts, added a small piece of business card to the battery to make sure that it was snug and still having the problem. It seems like most of us started having the problem at about the same time frame. That is interesting. It is really too bad. This is the best hotspot that I have used and I have been using them for years. (high speed internet is not available in the rural area that I live and work on the computer from home everyday)