fordystar

Hi there, heres hoping someone can help, i have an e class coupe 2013 pre facelift, car was bumped and unfortunatlt i have had to get car repaired myself not through insurance, anyhow car is fully repaired now i just need to have crash data removed airbags resetting, we had to replace the cable that runs from battery to starter and car starts as it did and runs perfect BUT problem is that the battery will die when left running, the alternator isnt charging the battery, i could do with a diagram of relays as i have checked all fuses front and back and are all ok, any help would be massively appreciated, thanks.