I have a 2007 X5 ... one of the key fobs no longer charges so it is only good as a physical key (one can pull that out). The other key fob I think isn't far behind as it results in the X5 reporting it needs recharging about everytime I use it. So what is wrong? Bad built in battery? Soldier in a new battery? what is the likely fix?

Ah use a thin knife pry off battery door replace Cr2032 .... let us see. Guess the e70 remote actually has a battery one can replace hooray!