Is DIY Off-Grid Advisor free to use?

Yes. The Scout plan is completely free — no credit card required. You can create builds, run the load calculator, use all the standalone tools, and join the community at no cost.

What off-grid systems does it support?

DIY Off-Grid Advisor supports vans, caravans, RVs, 4WDs, boats, cabins, sheds, and remote properties. It handles 12V, 24V, and 48V systems.

How does the Component Wizard work?

You enter your loads (appliances and usage hours), your location (for real sun hours), and your system type. The wizard then recommends the right battery bank, solar panels, MPPT controller, inverter, and DC-DC charger — all sized for your exact setup. It also generates a wiring diagram and PDF report.

Do I need electrical experience to use it?

No. The platform includes a full beginner-friendly knowledge base — Electrical 101, How-To guides, Troubleshooting, and a Glossary — so you can learn as you build. The tools are designed to guide you step by step.

DIY Off-Grid Advisor

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Size My System

How to use this page

Component Sizing

How the wizard sizes every component from your real data

This page is your launchpad for the 10-step Component Wizard — it shows your derating factors, build mode, and existing equipment before you dive in.

How to use it

Choose your build type

Select New Build if you're starting from scratch, or Upgrading if you already have some equipment. In upgrade mode, enter what you own — the wizard sizes around it.

Review your derating factors

The derating card shows how your location, mount type, shade risk, and season affect solar output. These factors feed directly into every component recommendation — expand it to see the breakdown.

Launch the Component Wizard

The 10-step wizard walks you through inverter, battery, solar panels, MPPT controller, DC-DC charger, and monitoring — in the right order. Each step is pre-filtered to products compatible with your voltage and setup.

Inverter sizing (Step 1)

The wizard uses smart conflict detection — it finds the largest group of AC loads that can run simultaneously, so you don't over-size for a theoretical worst case that never happens.

Battery sizing (Step 2)

Battery bank is sized from your daily Wh × autonomy days ÷ depth of discharge. LiFePO4 uses 80% DoD; AGM uses 50%. The wizard checks that your selected battery can sustain your inverter's full load draw.

Solar, MPPT & DC-DC (Steps 3–5)

Panels are sized for your location's sun hours with real derating applied per installation zone. MPPT is auto-sized from your panel array. DC-DC is capped at 50% of your alternator output to protect it.

Tips & things to know

Complete your Setup profile first — voltage, location, sun hours, and alternator data all change which products are recommended.

In upgrade mode, locking a component (e.g. keeping your existing battery) tells the wizard to size everything else around it.

The derating card is not just informational — it directly changes the panel count and battery size the wizard recommends. Check it before launching.

Once all steps are complete, the wizard generates a full system summary with cable sizes, fuse ratings, and a printable load plan.

DIY Off-Grid Advisor

Step 4 of 4

Component Sizing

Unlike generic calculators, this wizard works from your actual data — your vehicle type, real load entries, location, sun hours, and setup configuration. Every component recommendation is filtered and sized for your specific system, not a one-size-fits-all estimate. The more complete your setup profile, the more accurate the sizing.

Recommendations drawn from 286 products across 26 brands

63Batteries

73Inverters

43Panels

39MPPT

29DC-DC

live

My Systems

Locations

Loads

Components

Complete Your Setup First

The Component Wizard needs your setup data — system voltage, vehicle type, location, and derating factors — before it can recommend any components. Without it, every recommendation would be a guess.

Step 1 takes about 3 minutes. Once saved, you'll add loads in Step 2, then come here.

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Ask Watt anything

Watt knows your build. Ask about wiring, sizing, troubleshooting — from any page. Press Cmd /

Ask Watt anything

Press Cmd+/ or click here to ask Watt about your build, wiring, sizing, or troubleshooting.