spare battery

Some people take a fully charged spare battery along with them just in case!

Q. Is it true that spare batteries last longer if they are kept in the refrigerator?

Even if all is well, having a spare battery is good insurance.

You don't have long between dives, so take spare batteries.

Did they by chance load any spare batteries on board?

By the way, there's spare batteries in the bag down there.

The device will also store a charge from wall current, serving in effect as a spare battery.

"Has it got a spare battery and all the attachments for external power?"

Make sure you have a supply of spare batteries too.

Too bad he didn't have the spare batteries also.