Aircard 785 Battery Will Not Charge, Cannot Find Spare Battery

I am one of many who have had the same NO BATTERY and 0% charge errors on another unit, the 770s.  Someone on my thread said they were able to use it with the battery out and plugged into an outlet.  That works intermittently but you still get the same error after a while.  I've ordered (2) batteries on Amazon that fit perfectly and with the same specs.  After a day or two the errors returned, so it's not the battery.  I've done a factory re-set.  After 3 more days the errors returned.  Someone suggested removing both the battery and SIM card, letting it sit for 10 minutes.  Put it all back together and see if it works.  Not going to try it right now because I'm in the middle of something but I will in the morning.

Sure is strange how so many of these Aircards are showing these errors 6mos to a year into a 2 year contract.  And we are all getting the same advice from CS.  Frustrating.  Hope one of these workarounds works for you.