Sizing guides
How the sizing decisions in an off-grid build actually work. The guides explain the concepts; the builder computes the numbers for your exact components, math shown.
- What size fuse between battery and inverter?
How battery-to-inverter fuse sizing works: continuous current, safety factor, and wire coordination - with the math shown for your exact build.
- What gauge wire from battery to inverter?
Battery-to-inverter wire sizing explained: ampacity, voltage drop, and run length - with the worked math for your build's exact components.
- How many batteries do I need for my inverter?
Matching a battery bank to an inverter: continuous BMS current, surge headroom, and runtime - and how the compatibility checks verify your pairing.
- What size charge controller for my solar array?
MPPT sizing against a real array: cold-weather string voltage, current limits, and battery charge rate - checked with the formulas visible.
- Solar panel series vs parallel wiring
Series raises voltage, parallel raises current - how string design interacts with controller limits, wire runs, and shade.
- Cold weather Voc: why string voltage matters in winter
Panel voltage rises as temperature falls. How cold-morning Voc is computed against your controller's input limit, with the formula shown.
- What size inverter do I need for an off-grid cabin?
Inverter sizing for a cabin: simultaneous loads, motor-start surge, idle draw, and what the compatibility checks verify against your battery bank.
- Busbar and battery interconnect sizing basics
Why interconnects and busbars must carry full system current, how symmetric wiring keeps parallel batteries balanced, and what the guidance computes.
- Can you mix different solar panels?
Mixing panel brands, wattages, and ages: what works in series, what works in parallel, and what quietly costs you power - checked against your parts.
- 12V vs 24V vs 48V: choosing your system voltage
How to pick between 12V, 24V, and 48V for an off-grid build: current, wire cost, inverter class, native DC loads, and why changing later is expensive.
- MPPT vs PWM charge controllers: which one and why
What MPPT and PWM controllers actually do differently, when the cheaper PWM is genuinely fine, and when MPPT pays for itself - explained without the marketing.
- All-in-one inverter vs separate components
One box or four? How all-in-one solar inverters compare with separate charge controller, inverter, and charger builds - wiring, failure modes, and growth.
- How much solar do you need to recharge your batteries?
Why 'how many panels for my battery' has no fixed answer: daily energy, sun hours, charge current limits, and what actually determines recharge time.