While your vehicle’s alternator can keep a healthy battery charged, it was never designed to completely recharge a dead car battery. … With a seriously depleted battery, your best option is to connect it to a jump starter or a dedicated battery charger either before or immediately after a jump-start
On average, power banks last 4 to 5 years and can hold a charge for 4-6 months without losing much power. For example, a 5000mAh portable charger that’s powered up once every two days, it will need 1,000 days to reach the 500 charge-discharge cycles and drop to 80% capacity
