This is a persistent myth, possibly due to cell phone manuals that tell you to store batteries in the fridge if you won’t be using your phone for weeks or months. The logic here is that batteries lose their charge slower in cold temps, thus prolonging the battery’s overall lifespan. This doesn’t work for Power Wheels batteries, however, which should never be exposed to extreme heat or cold. Doing so will damage the battery or dramatically slow down its ability to charge. That’s why Power Wheels recommends storing the vehicles indoors under a protective cover during snow or rain.
Here are some other helpful tips for extending battery life: 1) Don’t take the battery off the charger until it’s fully charged; 2) Unplug the charger when it’s not in use; and 3) Charge the battery to full capacity and put it away in a dry, room-temperature location before storing the vehicle for long periods of time.