Electrical Fundamentals

Understanding the basics of electricity is essential before diving into energy storage systems. This section covers the core concepts you'll need.

Voltage, Current, and Power

Voltage (V) is the electrical pressure that pushes electrons through a circuit. Think of it like water pressure in a pipe.

Current (A) is the flow rate of electrons. It's like the volume of water flowing through that pipe.

Power (W) is the product of voltage and current: P = V × I. It tells you how much work is being done at any instant.

kW vs kWh

This is one of the most commonly confused concepts in energy storage:

• kW (kilowatt) measures power — the rate of energy transfer at a given moment
• kWh (kilowatt-hour) measures energy — the total amount of energy transferred over time

Example: A 5kW solar array running for 4 hours produces 20kWh of energy. A 10kWh battery discharged at 2kW will last 5 hours.

AC vs DC

• DC (Direct Current) flows in one direction. Batteries store and discharge DC power.
• AC (Alternating Current) reverses direction periodically (50Hz or 60Hz). Grid power and most appliances use AC.

An inverter converts DC to AC, allowing battery-stored energy to power standard appliances and feed into the grid.

Why This Matters for Energy Storage

Every energy storage system specification includes:

• Capacity in kWh (how much energy it can store)
• Power rating in kW (how fast it can charge/discharge)
• Voltage (determines compatibility with inverters and loads)

Understanding these relationships helps you size systems correctly and evaluate vendor specifications.