Battery To Inverter Cable Size Calculator

Cable Diameter Formula:

\[ \text{Cable Diameter (mm)} = \sqrt{\frac{\text{Power (W)} \times \text{Resistivity (Ω·m)} \times \text{Length (m)}}{\text{Voltage (V)} \times \frac{\text{Drop \%}}{100}}} \]

Power (watts):

Resistivity (ohm-meters):

Ω·m

Length (meters):

Voltage (volts):

Voltage Drop (%):

Calculated Cable Diameter:

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1. What is the Cable Size Calculator?

The Battery to Inverter Cable Size Calculator determines the appropriate cable diameter needed to connect a battery to an inverter based on power requirements, cable length, and acceptable voltage drop. Proper cable sizing is essential for safety and efficiency.

2. How Does the Calculator Work?

The calculator uses the following formula:

\[ \text{Cable Diameter (mm)} = \sqrt{\frac{\text{Power (W)} \times \text{Resistivity (Ω·m)} \times \text{Length (m)}}{\text{Voltage (V)} \times \frac{\text{Drop \%}}{100}}} \]

Where:

Power — The power consumption of your inverter in watts
Resistivity — The resistivity of the cable material (copper = 1.68×10⁻⁸ Ω·m)
Length — Total length of the cable run in meters
Voltage — System voltage (typically 12V, 24V, or 48V for battery systems)
Drop % — Acceptable voltage drop percentage (typically 3% or less)

Explanation: The formula calculates the minimum cable diameter needed to maintain voltage drop within acceptable limits for a given power level and cable length.

3. Importance of Proper Cable Sizing

Details: Undersized cables can cause excessive voltage drop, power loss, heat buildup, and potential fire hazards. Oversized cables are unnecessarily expensive and difficult to work with.

4. Using the Calculator

Tips: Enter power in watts, resistivity in ohm-meters (default is copper), length in meters, system voltage, and acceptable voltage drop percentage. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the typical resistivity value for copper cable?
A: The resistivity of copper at 20°C is approximately 1.68×10⁻⁸ Ω·m (0.0000000168 Ω·m).

Q2: What voltage drop percentage should I use?
A: For most applications, 3% voltage drop is acceptable. For sensitive equipment, consider 1-2%.

Q3: Does this calculator account for temperature effects?
A: No, this uses resistivity at standard temperature. For high-temperature environments, use adjusted resistivity values.

Q4: Should I round up the calculated cable size?
A: Yes, always round up to the next available standard cable size for safety.

Q5: How does cable length affect the calculation?
A: Longer cable runs require larger diameters to maintain the same voltage drop percentage.