Four practical calculators for DIY solar, RV, golf cart and off-grid users — convert Ah to Wh, estimate run-time, work out charge time, and compare lead-acid vs LiFePO4 upgrades.
Convert battery capacity between amp-hours (Ah) and watt-hours (Wh).
How long will your battery power a given load?
Estimate how long it takes to fully charge a battery.
Compare weight and lifetime savings when switching to lithium.
Multiply the battery voltage by its capacity in amp-hours: Wh = V × Ah. A 12V 100Ah battery stores 12 × 100 = 1200 Wh (1.2 kWh). This works for LiFePO4 and lead-acid alike.
Run time = (V × Ah × usable ratio) ÷ load power. For LiFePO4, usable capacity is roughly 85-95% (versus ~50% for lead-acid without damaging it). The calculator uses 85% by default to stay conservative.
Charging is not 100% efficient — roughly 15-25% of energy is lost as heat, and LiFePO4 absorption/balancing adds time. The calculator applies a 20% buffer: time = Ah ÷ current × 1.2.
Usually yes. Dajiu Energy's drop-in replacement batteries are designed as 1:1 lead-acid replacements — same voltage, plug-and-play, with 6000+ cycles and about one-third the weight. Confirm your charger supports LiFePO4 charging profiles (14.4V absorption for 12V systems) or use a lithium-compatible charger.
Because you can safely use ~85-95% of a lithium battery's capacity (vs ~50% for lead-acid), a 50-100Ah LiFePO4 battery typically matches or exceeds a 100Ah lead-acid bank — with much longer service life.
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