AirCard 770s no battery error

I just bought an at&t unite 770s on ebay (new - other) and didn't know about the battery problem people have been having until after I saw all of the complaints and suggested solutions about it on this site going back years... I wanted to prevent it from happening to mine so I left it plugged in to the 10 ft charging cable I had hooked up to it and took the battery out. Hotspot kept trying to boot, shutting off, trying to boot, shutting off, etc. and just kept doing that. I had almost given up when I decided to try a shorter cable. I plugged a 3 ft cable into it and then took the battery out while it was still on (I don't know if you're supposed to take the battery out while it's on but I did) and it stayed on, did say "no battery" in top right-hand corner but hotspot signal is staying on and has been working like that for hours.  I have backlight set to turn off after 30 seconds to try to keep it from sucking too much juice at once. The longer cable DOES work and it charges everything I plug it into. I used the same adapter plug on both to plug into the wall. Does the cord being shorter make a difference? Should the people who are having trouble getting theirs to turn on or stay on with no battery try a shorter cord? It seems to be working for me but a lot of the suggestions people have on here work for them but not for everyone. I have no idea if this will work on a long-term basis or extend the life of my hotspot in any way and also not exactly sure why shorter cord seems to work and it continuously tries to reboot when plugged into longer cord unless electrical current is somehow stronger in a shorter cord. Anyone know why shorter cord would work so much better other than "there might be something wrong with the longer one?"