Table 3.

Characteristics of rechargeable batteries.

Technology	Lead Acid	Nickel–Cadmium	Nickel–Metal Hydride	Lithium-Ion
Energy density (Wh/kg)	35–50	30–60	60–80	80–180
Self-discharge/month	2–8%	5–15%	15–25%	2–10%
Fast-charge time (hour)	8–16	1	2–4	1–4
Charge/discharge cycles	250–1000	1000–50,000	300–600	3000