Ctek 56 959 silver mus 4 3 test charge 12 volt fully automatic charger and tester. Well worth the miniscule additional cost. To combat power drainage porsche created the porsche battery maintainer aka the charge o mat pro.
Porsche Tequipment Ctek Charge O Mat Battery Charger And Maintainer 95504490054 Battery Charger
Ctek 40 206 Mxs 5 0 12 Volt Battery Charger And Maintainer With Accessories Ideal For Start Stop Systems C Battery Charger Charger Recondition Batteries