For actual examples, check out our roundup of the bestportable laptop battery chargersandportable solar chargers.
To do that, youll need to know the energy capacity of the gadget youll be charging.
A small 3,000 mAh charger, for example, would be more than enough to fully charge most smartphones.
This makes it harder to hold in your hand or put in your pocket.
Some USB chargers even double as flashlights or panic alarms.
Some drug stores, like Walgreens or Rite Aid, may also carry portable USB chargers.
Not all car USB ports are designed to charge phones.
If your vehicle doesn’t have a USB port, buy an adapter for the lighter port.
