My recent battery column elicited a few sparks, but I cannot confirm the veracity of the two emails I received concerning exploding lithium batteries. These emails won't be printed until I can be sure of their honesty and objectivity.
One referred to events almost a decade old from the first generation of lithium-ion batteries that no longer exist. They were recalled after some disastrous episodes and are long gone from the market.
Charging toward batteries from a slightly different angle, any and all batteries, from the lowliest carbon-zinc of yesteryear, to alkaline, to lead-acid to the most advanced lithium can leak and/or explode under certain, usually rare, conditions. Normally these conditions involve high temperatures, improper usage or the failure of the equipment they power.
A short circuit within a device can overheat and destroy a battery. Lead-acid automobile batteries generate hydrogen when charged, and when improperly jump-started they can explode. Yet they've been under the hood (or under the back seat or in the trunk) of automobiles for about a century.
Certainly a manufacturing defect or freak occurrence can cause any battery to overheat and possibly explode, just as you can be hurt from fragments of a meteorite falling from the sky.
I probably use more battery-powered devices, powered by more different kinds of batteries, than the average household. Considering laptop computers, iPads and various other rechargeable lithium-ion battery-powered devices, I put my safety where my mouth is. I also drive a car with a trunk full of nickel metal hydride batteries.
Nonrechargeable lithium batteries power my computer mice, keyboards, flashlights and remote controls. Uninterruptible power supplies using sealed lead-acid batteries back up desktop computers and recording devices.
My insurance company did not inquire about any of this when rating my home. If batteries posed a significant threat, insurance companies would consider it in their ratings probably before any action from the Consumer Product Safety Commission. Rocketing insurance rates because of battery usage, or battery companies unable to obtain liability insurance, would cause the batteries to disappear from the market.
I'm not in the insurance business, but my guess would be vastly greater numbers of people sustain injuries from bad AC electrical wiring or contact with it than from batteries.
Another reader asked: "You (say) not to leave lithium batteries charging for an extended period when you're not using the product. But in the owner's manual for my Black & Decker 20V Max Lithium cordless chain saw it says, 'the charger and battery pack can be left connected with the green indicator light glowing indefinitely. The charger will keep the battery pack fresh and fully charged.' "
A properly designed "smart" charger can keep batteries charged without significant damage to the batteries. It monitors the batteries and stops charging at the appropriate charge. However, I would still recommend disconnecting it once the batteries are charged. Disconnecting at the outlet also saves electricity.
On a more sanguine topic, the same reader asked for clarification of online streaming versus DVDs by mail movie market.
"You seemed to say that it was the cheapest way to go to get streaming from Netflix rather than getting DVDs in the mail. But what you failed to mention was that you don't get any of the big new releases on streaming, and sometimes they never show up there at all. Most people want to see the movies whose trailers are advertised on TV as soon as they become available, and this is only possible by getting them in the mail."
The reader is correct. I alluded to that in the column. None of the online streaming sources (Netflix, Amazon, iTunes, Blockbuster, et. al.) has contracts with all of the movie studios. Even if you subscribe to two or three services, you still would not have access to all the movies available by the Netflix mail service.
Rich Warren, who lives in the Champaign area, is a longtime reviewer of consumer electronics. He can be emailed at email@example.com.