🎛️
Charge Controller Size
MPPT / PWM controller current rating.
BatteryCore inputs only — quick sizing with engineering defaults.
Inputs (SI units)
Results
Save & Load Project
Designs are stored privately in this browser — nothing is uploaded.
Engineering Formula
- I_controller = I_sc × 1.25 (irradiance) × 1.25 (continuous)
- ≈ I_sc × 1.56 per NEC 690.8
NEC 690.8 requires a 125% irradiance factor and a further 125% for continuous duty on PV source circuits.
Step-by-step Calculation
- 1.Multiplier
1.25 × SF1.563 - 2.Required
Isc × 1.25 × SF21.88 A
Design Assumptions
- • MPPT controller.
- • Battery voltage compatible with array Voc range.
Engineering Tips
- ◆Pick the next standard: 20, 30, 40, 60, 80, 100 A.
- ◆Verify max PV Voc < controller limit at coldest ambient.
Warnings
- ▲Undersizing burns MOSFETs. Always fuse PV+ separately.
Standards & References
NEC 690.8IEC 62509 (Charge controllers)