I suppose one solution may be to develop a range of self contained, portable, charging stations that one could deploy to the battlefield and allow the Challenger 2 - E. to break-off engaging the enemy and come in for it's 8 hour charge. The only problems would be the pollution caused by the diesel engine or gas turbine engine used to power the charging station and one may need to request a local ceasefire if all or most of one's armoured vehicles need charging at the same time.