Rechargeable batteries can save you money. Check out the price of regular batteries and you’ll see they aren’t cheap. You can recharge an AA or AAA battery many times. You can only use a regular battery once!
The Frugal Way to batteries is to purchase some rechargeables. But I wouldn’t suggest you buy batteries using the old chemistry. Nickel Cadmium batteries have been replaced with metal halides and Lithium ion.
Also, you don’t want to purchase a brand name battery. They cost much more then generic ones and work just as well.
More on Rechargeable Batteries.
It’s better to recharge them slowly. The fast one-hour chargers make the battery too hot. Heat destroys the battery chemistry. I use a 16-bank slow charger and always have batteries ready to be used.
The Tenergy charger is very good at charging the batteries and I can charge AA and AAA batteries.
9 Volt Battery
Now 9-volt batteries are tricky. There are two kinds of 9-volt battery. One battery only puts out 7.2V while the other has an output of 9.2Volts. When possible, I try to use a higher voltage battery. But for many uses the 7.2Volts battery will work fine. NIMH battery voltage is range between 7.2-8.4V. While Li-ion battery range is between 6V-8.4V and alkaline voltage range is 6V-9.6V. You have to do your homework.
Some Quick Links.
Tenergy chargers on Amazon; Click Here Ebay Click Here
Rechargeable Batteries; Click Here