Explaining the LiPo battery (attempt)

Battery Technologies Overview

Types of Battery Technologies

• Li-Ion
• Lithium Iron Phosphate (LiFePo4)
• Lithium Polymer (LiPo)
• Alkaline
• Lithium Rechargeable
• Mercury Cell
• Zinc Air
• Nickel Cadmium (NiCd)
• Nickel Metal Hydride (Ni-MH)

LiPo Battery Technology

Advantages

• High voltage
• High energy density
• Long cycle life
• Light weight
• Smaller size
• No memory effect
• Environmentally friendly
• Good high current discharge performance
• Flexible shapes
• Great high and low temperature endurance

Usage in Drones

• Long run times and high power
• Voltage ratings:

- 2s = 7.4 volts - 3s = 11.1 volts - 4s = 14.8 volts - 6s = 22 volts

• Nominal voltage of a LiPo cell is 3.7v, fully charged voltage is 4.2v
• Example: 4s LiPo nominal voltage is 14.8v, fully charged voltage is 16.8v

Disadvantages

• Supports less recharge life (300 to 400 cycles)
• Chemistry leads to fire when punctured
• Requires special care during charging, discharging, and storage
• Expensive, almost double the cost of Li-Ion battery

Maintenance

• Fully charged at 4.2v/cell
• Minimum safe charge is 3.0v/cell
• Use a LiPo compatible charger
• Voltage is the primary measure of battery charge level

LiFePo4 Batteries

• Twice the power, half the weight, and lasts 4 times longer than a sealed lead acid battery
• Common in fishing electronics and outdoor use
• Single cell is 3.7 volts
• Stacked together to achieve desired voltage levels
• Example: 20v Dewalt tool likely has 6 cells

Optimal Maintenance

• Light use, shallow discharge and shallow charge
• Avoid deep discharge
• Avoid frequent full charge and discharge

NiMH Battery Technology

Advantages

• High capacity compared to other rechargeable batteries
• Resists over-charging and over-discharging
• Lightweight
• Environmentally friendly (no hazardous chemicals)

Drawbacks

• More expensive than other rechargeable models
• Self-discharge rapidly while in storage
• Cut power suddenly rather than a slow trickle down
• Some only work with manufacturer’s charger

NiCd Battery Technology

Advantages

• Relatively inexpensive
• Charge very quickly, simple to charge
• Easy to store and ship
• Take a high number of charges
• Functional in low temperatures

Drawbacks

• Not as powerful as some other rechargeable batteries
• Self-discharge while in storage
• Contain toxic metals that are harmful to the environment