Battery Storage & Chemistry Calculators
Precision tools for sizing energy storage banks, calculating discharge duration under load, modeling recharge recovery time, and wiring series/parallel configurations.
Capacity Sizing
Unified Battery Bank Sizing (LiFePO4 & AGM)
Calculates required Amp-hours and Watt-hours for daily energy demand and autonomy, comparing depth-of-discharge and weight between lithium and lead-acid.
Discharge Curve
Battery Runtime & Discharge Estimator
Estimates how many hours and minutes a battery bank will run under specific AC or DC loads with Peukert's law capacity correction for lead-acid.
Recovery Time
Battery Charge Time Estimator
Calculates bulk and absorption charging durations based on charger current output, battery chemistry, and Coulombic efficiency.
Wiring Topology
Battery Series/Parallel Configurator
Determines series string counts and parallel connections to achieve 12V, 24V, 36V, or 48V banks with diagonal wiring to prevent cell imbalance.
Monitoring
DC Shunt Sizing & Wiring Tool
Calculates shunt continuous current ratings, millivolt drop, and proper wiring placement for accurate state-of-charge monitoring.
Electrochemical Storage Dynamics & Chemistry Trade-Offs
Lithium Iron Phosphate (LiFePO4) and Lead-Acid (AGM, Gel, Flooded) chemistries exhibit radically different physical properties under mobile and off-grid operating conditions:
- Usable Depth of Discharge (DoD): LiFePO4 cells safely deliver 80% to 90% of their nameplate capacity across 3,000–5,000 cycles. Traditional lead-acid batteries suffer severe plate sulfation and accelerated cycle degradation if discharged beyond 50% DoD. A 200Ah LiFePO4 bank delivers 160–180Ah of usable energy, equivalent to a 320–360Ah AGM bank weighing over three times as much.
- Peukert's Law & High-Current Discharge: Under heavy inverter loads (such as running a microwave or induction cooktop), lead-acid battery capacity collapses due to electrolyte diffusion limits (Peukert exponent $k = 1.15 ext{ to }1.28$). LiFePO4 possesses extremely low internal resistance, maintaining a nearly linear discharge relationship ($k pprox 1.03$) with negligible capacity loss under heavy loads.
- Multi-Stage Charge Acceptance: LiFePO4 accepts continuous maximum charging current (0.5C or higher) until approximately 95% State of Charge (SoC). Lead-acid batteries transition into a diffusion-limited absorption stage around 80% SoC, requiring 2 to 4 hours of tapered current to reach full charge, which significantly reduces the effective charging efficiency of solar and alternator runs.
- Low-Temperature Charging Hazards: LiFePO4 cells must never be charged at ambient temperatures below freezing (0°C / 32°F). Forcing charge current into sub-zero lithium cells causes permanent lithium metal plating on the graphite anode, inducing internal short circuits and fire risk. Cold-weather installations require integrated heating pads or low-temp charge cutoff protection.