CHAPTER 7 ■ NINE-VOLT BATTERIES
The disadvantages of lithium-polymer batteries are that they are more expensive and that you must use
a charger specifically designed for lithium-polymer batteries.
Alkaline
Alkaline batteries (see Figure 7-11) are the most common and are readily available. These batteries retain
their charge for years (when not in use), have a high starting voltage, and tend to keep a reasonable voltage
during use. For medium or high-current electrical draw, alkalines are the longest-lasting non-rechargeable
consumer batteries.
Figure 7-11. Some popular brands of alkaline 9 V batteries
Figure 7-10. Lithium-polymer rechareable 9 V batteries
Unfortunately, 9 V alkaline batteries aren’t rechargeable. After they’re used up, they must be discarded
into the recycling bin. This practice can get very expensive.
Specialized Use
Lithium
Lithium batteries (see Figure 7-12) have a couple of nice benefits: they’re lightweight, they operate even at
cold temperatures, and they stay fresh for many, many years. So, these batteries might be good for a
high-altitude balloon robot or a multi-year test project.