How often should I replace my car battery? Car batteries can last for five years or a little more when properly cared for depending on how you use your car and look after the batteries. Article Four useful tips: Use a battery conditioner. More Use a battery & alternator tester to make regular checks on the battery condition and the alternator is a wise routine. Fit a high output alternator as a replacement. More battery capacity with a twin 12v batteries in parallel upgrade. Posted: 250505 Car batteries can last for five years or a little more when properly cared for depending on how you use your car and look after the batteries. With modern cars, often used on a daily basis, other than starting the engine, the battery also powers various electrical systems in the vehicle including lights, radio and infotainment screens, entertainment systems, heated rear windows, windscreen wipers, air conditioning, power windows, satnav, electrical power steering, and anything else that needs an electrical source. With a classic car like an MGBGTV8 the systems that need electrical support are less sophisticated but can include a heated rear window, heater blower motor, windscreen wipers, radio and radiator cooling fans plus any added modern devices used in the car like a satnav and a mobile phone charging lead. Some MGV8s have electric power steering fitted as a retrofit upgrade, often on RV8s. Four useful tips are highlighted. Article