How Many Solar Panels for a 100Ah Battery?
The mathematical breakdown for charging a 100Ah LiFePO4 vs AGM battery within a single 4-hour peak sun window.
Read Guide →Off-Grid Solar System Calculators & Sizing Guides
Published: • Curated by Marcus Vance (NABCEP PV Associate)
Whether you are wiring a campervan, refitting a sailboat, or powering a remote cabin, in short, our calculators run the exact formulas professionals use to size lithium battery banks, solar arrays, wire gauges, and inverters.
Solar Calculators Quick Reference Matrix
| Calculator | Primary Inputs | Standards Followed | Key Output Metric |
|---|---|---|---|
| Solar Panel Sizer | Daily appliances, sun hours | NREL insolation tables | Recommended solar watts (W) |
| Battery Bank Sizer | Daily Wh, autonomy days, chemistry | 80% DoD LiFePO4, 50% AGM | Battery bank capacity (Ah) |
| Wire Gauge & Drop | Amps, one-way distance, voltage | NEC 310.15 & ABYC E-11 | Safe AWG gauge & fuse size |
| Inverter Capacity | Simultaneous continuous & surge watts | Pure sine wave surge handling | Continuous & peak inverter rating |
| MPPT Charge Controller | Panel Voc, Isc, array watts | Cold-weather Voc coefficient | Minimum controller amps (A) & Voc (V) |
Interactive Solar Calculators
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Solar Panel Sizing Calculator ⭐ (Flagship)
Audit your daily watt-hours with pre-filled appliances. Instantly calculates total solar watts, LiFePO4 battery capacity, and MPPT requirements based on your peak sun hours.
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Battery Bank Capacity & Autonomy Sizer
Compare LiFePO4 vs AGM usable capacities, configure days of autonomy, and view recommended series/parallel wiring arrangements for 12V, 24V, and 48V banks.
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Wire Gauge & Voltage Drop Calculator
Complies with NEC 310.15 and ABYC E-11. Enter DC current, run length, and target voltage drop (1%–5%) to get recommended AWG wire size and inline fuse rating.
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Inverter Continuous & Surge Sizer
Calculate simultaneous AC appliance loads, compressor motor startup surge wattages, and minimum DC battery feed cables with proper Class-T fusing.
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MPPT Charge Controller Sizing Calculator
Calculate maximum open-circuit voltage (Voc) under sub-zero winter temperatures, compare MPPT vs PWM efficiencies, and determine exact amp ratings.
Solar Engineering & Installation Guides
12V vs 24V Solar Systems: Which Should You Choose?
Why large 12V systems suffer severe wire thickness penalties and when stepping up to 24V or 48V cuts copper costs in half.
Read Guide →LiFePO4 vs AGM Batteries: The Real Cost Per Cycle
Don't get tricked by upfront sticker prices. We calculate actual cost per usable kilowatt-hour over a 5,000-cycle lifespan.
Read Guide →What Size Inverter Do You Need for an RV?
From 1,000W laptops to 3,000W induction cooktops and air conditioners: continuous rating vs surge margins explained.
Read Guide →Solar Panel Wiring: Series vs Parallel Explained
How series strings increase voltage to trigger early MPPT charging, and when parallel strings are essential to combat shading.
Read Guide →MPPT vs PWM Charge Controllers: The True Comparison
See the exact conditions where PWM throws away 35% of your solar panel capacity versus when a cheap PWM is totally fine.
Read Guide →Frequently Asked Questions
How accurate are these engineering numbers?
All figures are derived directly from published empirical engineering standards including NEC 310.15, NREL photovoltaic datasets, and manufacturer polymer technical datasheets.
Are calculations processed on a remote server?
No. Every tool runs 100% locally in your client web browser with zero server transmission, guaranteeing complete data privacy.