Dear Co-op America, Please settle an argument between my wife and me. Which rechargeable batteries are better for the environment: NiCads (my pick) or NiMHs?
— Joe and Jessica, Milwaukee,Wisc.
LOOKS LIKE your wife wins this time. Both nickel cadmium (NiCad) and nickel-metal hydride (NiMH) rechargeables can be recharged over 500 times, but the toxic cadmium in NiCads makes their disposal problematic. Instead of cadmium, NiMHs use metal hydrides, which are less harmful to the environment. (Both are, of course, much more eco-friendly than single-use alkalines, as they last a lot longer. They also outperform rechargeable alkalines, which can only be recharged 50 times.)
Performance-wise, NiMHs have an edge over NiCads, too, with their lower discharge rate. Over 60 days, NiMHs on a shelf will experience 15 percent energy loss, compared to NiCads, which will lose 60 percent.
Because of their long life, less-toxic innards, and solid performance, NiMHs are your best bet for most uses.
When it’s time to dispose of dead batteries, be sure to recycle them. If your local recycler doesn’t accept batteries, Battery Solutions (800-852-8127, batteryrecycling.com) will recycle your used alkalines and rechargeables. You do have to pay a small fee, with discounts for large quantities.