What cable gauge avoids voltage drop?
The right cable gauge for your solar or 12 V setup, and what an undersized cable really costs you.
⚡ Your circuit
A cable that's too thin over a long run drops the voltage before it even reaches the battery: less charging current, and sometimes a controller that cuts out. Pick a panel from our catalogue or enter your own values.
Voltage drop
1.2 %
ideal
Voltage drop
-0.60 V
Voltage at the far end
47.40 V
Recommended minimum cross-section
1.7 mm²
Direct-current calculation, cable there-and-back, copper resistivity at operating temperature (0.0225 Ω·mm²/m, the standard value used at 70 °C by European wiring guides). By default, picking a panel sets the current to its Isc (short-circuit current), the most conservative sizing value.
Voltage drop by cross-section, for this current and length
| Cross-section | Drop | Voltage at end | Verdict |
|---|---|---|---|
| 2 mm² | 3.3 % | 46.40 V | acceptable |
| 3 mm² | 2.0 % | 47.04 V | ideal |
| 4 mm² | 1.2 % | 47.40 V | ideal |
| 6 mm² | 0.8 % | 47.60 V | ideal |
| 10 mm² | 0.5 % | 47.76 V | ideal |
| 16 mm² | 0.3 % | 47.85 V | ideal |
| 25 mm² | 0.2 % | 47.90 V | ideal |
| 35 mm² | 0.1 % | 47.93 V | ideal |
| 50 mm² | 0.1 % | 47.95 V | ideal |