Solar Wiring & Sizing

Solar panel wiring and system sizing

Wiring solar panels in series versus parallel changes your voltage and current, and getting it wrong can under-deliver power or overload a charge controller. This tool shows what each wiring method does and helps you rough out the size of an off-grid system.

Series vs. parallel

Wiring panels in series adds their voltages while current stays the same — good for pushing power over longer runs and for MPPT controllers. Wiring in parallel adds their current while voltage stays the same. Batteries follow the same rules: series for higher voltage, parallel for more capacity at the same voltage.

Sizing an off-grid system

Start from your daily energy use in watt-hours, then work back to the panel wattage, battery capacity, and controller rating you need, allowing for sun hours and real-world losses. The sizer walks through those numbers so you can spec a system before you buy anything.

Common question

Series or parallel — which should I use?

It depends on your charge controller and wire run. Series raises voltage, which cuts current and lets you use thinner wire over distance, and it suits MPPT controllers; parallel keeps voltage low, which can be safer and works with basic PWM controllers. Many larger arrays combine both.