A battery is a device that uses chemistry to provide a DC current.

A battery is made up of one or more electrochemical cells.

Some devices require alternating current (AC).

Some devices require direct current (DC).

Some devices can use either AC or DC.

The municipal power grid delivers AC. AC can travel long distances with little loss of power. DC is used for short distances within a radio or within a vehicle, for example.

AC is generated by a rotating device like a generator, alternator, magneto, or dynamo.

AC can be converted to DC via a rectifier, inverter, or commutator.

DC can also be created from sunlight using photovoltaics, and from chemicals stored in a battery.

Supplies a DC current at a constant voltage.

Can be a battery.

Is more likely plugged into the grid, and includes a AC to DC rectifier.

Input current at one voltage, output current at some other voltage.

Includes a power supply plus charge control.

Charge control maximum voltage maximum current max temperature

Variable voltage and current at different state of charge (SOC). Fast, slow, trickle charging.

Fast charging New technologies used in smartphones. The battery can take a very high input current. The phone communicates with the charger telling it to send more current.

USB 5 volt charger is actually a power supply at a fixed 5 volts.

• Lead Acid
• alkaline
• carbon zinc
• Nickle Metal Hydride (NiMH)
• Nickle Cadmium (NiCad)
• Lithium Ion (Li-Ion)
• Lithium Polymer (LiPo)
• Lithium Iron Polymer (LiFePo)
• Lithium Iron Polymer ($LiFeS_2$)

see Acid, Base, Salt

per battery size per volts

battery size ranges

• quad copter
• laptop computer
• smartphone
• kick scooter
• 125 scooter
• car Tesla
• house

internal protection circuit may be longer 65 to 68 mm

charging voltage for 21700, 4.2 to 5V, 5V max

continuous discharge current

carge discharge cycle 500 to 2000 ?

specs

• 18mm diameter
• 65mm length
• 0 - round cylinder
• 3.7V
• 1100 to 5000 mAh

Volts

Amps

USB power spec

Fast Charging Phones

Voltage regulator

Charge control

The battery has an open circuit voltage range, controlled by the BMS:

• lower voltage limit, aka discharging cut off voltage
• upper voltage limit, at which the battery charging is stopped

The battery/BMS also has a

• maximum continuous discharge current in amps

Your USB Smart Phone Charger is actually a Power Supply! As it designed to give a constant output, your Phone actually does all the charge control. This is designed to offer flexibility so your phone can be plugged into any USB port, on your PC for example. https://www.haredataelectronics.co.uk/differences-between-a-power-supply-and-a-charger

“charge control”

inverter

voltage regulator

resistor can be used as voltage regulator or current regulator?

Series and Parallel

Balanced Charging

Battery Management System

Weld lithium battery cells into a lithium battery pack. https://youtu.be/b3eRv_FZjBc

1. There are some dodgy 18650 products available for sale.
   1. Some batteries claim very high amp ratings and very high amp hour ratings. These are too good to be true.
   2. Avoid the name ultra in any battery product. These are seconds and retreads and are not safe.
2. There are YouTubes showing how to revive a dead 18650 battery. But there are also YouTubes advising to never do that. When a battery goes to zero volts and will no longer hold a charge, it's for a reason. Something has failed.
3. Faulty batteries tend to overheat, ending in fire or explosion.

As of 8 Jun 2022, Telsa Model S uses 7180 18650 batteries.
The new plant in Nevada makes the 21700. Cheaper to mfg and more efficient.

3.7V1200mAh 30mΩ LiFePo4

12V 20Ah 3S6P

3.7v 3400mAh 18650 stores about 2 aH to max of 3.5 aH.

It can store about 10 to 13 watt hours. A small air conditioning unit that can cool about 9000 BTU uses about 1100 watts per hour. So it would take more than 110 of the 18650 batteries to run the air conditioner for 1 hour.

In comparison you would need three 12v 40 amp car batteries. But 110 18650s are smaller than three car batteries

If you apply a lower voltage than the motor is rated for, it compensates by drawing more current from the source. This scenario leads to heat damage and other issues.

Higher volts, less amps, thinner wires, less weight.

For example, the 100kWh battery on the Model S is 400 volts. This battery includes 16 modules with 6 groups of 86 cells, which makes 516 cells per module. Each of the 16 models produces 25 volts, giving you a final total of 400 volts.

86*6=512 cells per module 6S86P 6*3.7V=22.2V ~=25V 16S 16*25V=400V

26S 26cells@3.7V=96V Amps?

Fire Hazard! Not for Vape! Never install, carry or handle! INR18650-30Q Samsung SDI 6 150 LM1T

INR18650-30Q Samsung SDI 6 150 LM1T

A 3000W motor for a motorcycle can run at 48, 72, or 96 volts.

V * A = W, therefore:

• 3000W / 48V = 62A
• 3000W / 72V = 42A
• 3000W / 96V = 32A

In general, choose the highest possible voltage.

A 18650 battery pack.

• 48V / 3.7V = 13S (cells in series)
• 72V / 3.7V = 20S
• 96V / 3.7V = 26S

If each cell is 3500 mAh battery rating

• 1000 mAh = 1 Ah = 1 amp delivered for 1 hour
• 3500 mAh = 3.5 Ah = 3.5 amps delivered for 1 hour

to get 32A

• 26S32P =
• 32 / 3.5 = 10 P : 26S10P

26S10P battery pack (260 cells) can power a 96V 3000W motor for 1 hour.

3 such battery packs, wired in parallel, can power the same motor for 3 hours. (780 cells)

240km = 150 miles

series vs parallel

• wire in series to multiply the voltage
• wire in parallel to multiply the amp hours

26S = 3.7V * 26 = 96V
10P = 3500mAh * 10 = 35,000mAh = 35Ah

size of one 26S10P battery pack 18mm*26S x 18*10P = 470mm x 180mm = 47cm x 18cm x 6.5cm

260 cells @ $2 = $520

The BMS controls:

• upper voltage limit - stops charging
• lower voltage limit - stops discharging (shutting down the equipment)

time to charge

Match BMS to Battery.

Match speed controller to motor.

Match battery to motor, ie. BMS to controller.

battery, bms, controller, motor, charger.

The battery has an open circuit voltage range, controlled by the BMS:

• lower voltage limit, aka discharging cut off voltage
• upper voltage limit, at which the battery charging is stopped

The battery/BMS also has a

• maximum continuous discharge current in amps

The controller also has a maximum current rating.

The controller has an under voltage protection circuit, which enforces a low voltage cut off level.

So both the BMS and the motor controller have a lower voltage limit. The BMS stops discharging. The controller cuts off current to the motor. Either shuts down the equipment. We should give the BMS priority over the controller in enforcing the lower limit. Make sure the controller has a lower limit than the battery. If the controller has a higher limit, then the system will shutdown prematurely, while the battery still has capacity left.

https://www.electricscooterparts.com/matching-a-speed-controller-to-a-lithium-battery.html

Match controller to motor

Match battery to controller

Match BMS to battery

YouTube: Beginners guide to building safe 18650 batteries https://youtu.be/tKg-jIrr_JE

PDF: Wiring batteries in series and parallel https://www.batterytender.com/site/batterytender/pdf/Connecting_Batteries_and_Chargers_in_Series_and_Parallel.pdf