Battery Voltage Calculator 🔋

Battery Type

Current Voltage

-- V

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Max Cell Voltage

Nominal Cell Voltage

Min Cell Voltage

Controller Cutoff (V) Voltage when scooter stops (for accurate % calculation)

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Quick Reference

Battery & Scooter Tips Guide

Overcharge scenarios

Slightly overcharged (≤ about +0.05V per cell, or ≤ ~2% above pack full): often surface charge right after charging; let the pack rest 15–30 min and it should settle. Calibrate/verify charger if this happens often.
Over full charge (~+2–10% over expected full, or ~+0.05–0.10V per cell): unplug immediately; let rest; avoid hard riding until it settles. Check charger output and BMS balancing.
Dangerously overcharged (> ~+0.10V per cell, typically > 4.30V/cell): stop using; DO NOT charge; move to a non-flammable area; inspect wiring/charger and seek service.

Tip: Use only the manufacturer-approved charger. Lithium-ion uses CC/CV charging and should not be pushed above the rated max (typically 4.20V/cell).

Undercharge / discharge scenarios

Healthy low (~40–60%): fine for storage; normal for day-to-day use.
Low (~20–40%): rideable with reduced performance; plan to charge soon.
Very low (~10–20%): voltage sag increases under load; avoid steep hills; charge soon.
Near cutoff (0–10%): scooter may shut off suddenly under load; charge now.
Deeply discharged (roughly < ~3.0V/cell equivalent; severe < ~2.5V/cell): cells may be damaged. Do not continue riding. Charging could be unsafe if cells are severely depleted—seek professional advice.

Set Controller Cutoff in Advanced if your scooter shuts off early. It does not change the actual voltage—only the 0% baseline for more accurate %.

Temperature and charging

Best charging temp: about 10–30°C. Avoid charging below 0°C (risk of lithium plating) or above ~45°C (accelerated degradation).
Riding in cold: expect less range and more voltage sag. Warm the pack indoors before charging.
Heat: avoid leaving the scooter in hot cars or direct sun; high heat shortens lifespan.

Storage

State of charge: store around 40–60% and in a cool, dry place (~10–25°C).
Periodic checks: top up every 1–2 months if it drifts low; never store long-term at 0% or 100%.

Measuring and interpreting voltage

Measure at rest: after charging/riding, let the pack rest 15–30 min to reduce surface charge or rebound effects.
Voltage sag: under load, voltage dips; this is normal. The % here assumes resting voltage.

Charger and BMS tips

Use the correct charger and verify its output voltage matches your pack.
Occasionally charge to 100% and let rest so the BMS can balance cells. For longevity, daily charging to ~80–90% is common.
Do not leave on the charger for days; unplug after it reaches full.

Safety and damage checks

Stop using the battery if you notice swelling, hissing, strong odor, smoke, or unusual heat. Isolate in a non-flammable area and seek service.
If the scooter or battery gets wet, do not charge until fully dry. Water can corrode connectors and cause shorts.
Transport and store away from flammable materials. Never puncture or crush cells.