Consumer watch: Batteries not included, so get a charger

You’ll be giving or receiving battery-powered gifts this season, maybe a pile of them. With “batteries included” rare, you’ll face what can be an alarming expense.

Luckily, the days of the cheap 25-cent carbon-acid batteries are gone. They lost a charge rapidly and leaked acid into our gear, often destroying it. Modern batteries are more “green,” and the greenest of all are rechargeable.

If you buy batteries more than once a month, rechargeables will save you money. You will need a charger (about $25).

Instruction manuals will tell you what size battery to buy, but you will be confronted with up to seven types at the store. Here’s a look (comparison prices are for AA size):

NiCad: Nickel cadmium, old-fashioned rechargeable, toxic (requires special disposal), eventually will fail to charge completely, about $2.50 each.

NiMH:  Nickel metal hydride rechargeable, replaces NiCads, longer lasting, always charges fully, best all-around rechargeable, good for digital devices. Note:  they self-discharge (lose power when not used), so do not use in flashlights,  smoke detectors and other emergency gear, about $3 each.

Alkaline: Wears out quicker than NiMH, OK for non-digital toys and clocks, non-toxic (may be thrown out in household trash). More voltage than NiMH but should not be used in high-drain devices, about $1.50 each, rechargeables about $2.50 each.

Oxyride: Updated alkaline, more powerful, lasts longer but non-rechargeable, good in high-drain gear including digital, toys, toothbrushes, personal digital assistants. Might be hard to find in stores, about $2 each.

Lithium: Lasts seven times longer than alkaline with a good amount of power, performs in extreme temperatures. Good for digital gear, especially media players and cameras. Cannot be recharged. Never mix with other battery types, about $2.50 each.

Heavy duty: Zinc chloride and carbon zinc, the name disguises an obsolete battery once the standard. They wear out quicker than any other battery and will leak acid, about 50 cents each.