⚡ Wheelchair Battery Charger Cheat Sheet

System Voltage: 24V Standard

CRITICAL WARNING

This guide applies to AGM, GEL, and Sealed Lead Acid batteries only.

DO NOT use these parameters for Lithium-Ion batteries. Lithium batteries require specific chargers to prevent fire hazards.

Charger-to-Battery Match

The "Sweet Spot": Charger Amperage should be roughly 10–15% of the> Battery Ah.

Charger OutputBattery Capacity RangeCommon Applications
24V - 2.0A7Ah – 12AhSmall Travel Scooters / Portables
24V - 3.5A12Ah – 18AhMid-size Travel Scooters
24V - 5.0A20Ah – 45AhStandard Group 2 Power Chairs (Most Common)
24V - 8.0A50Ah – 79AhGroup 3 Chairs / Heavy Duty
24V - 10A60Ah – 110AhBariatric / High-Performance Outdoor

🔌 Connector Reference

Standard: 3-Pin XLR (Round)

Most power chairs use the Neutrik XLR standard.

  • Pin 1: Positive (+)

  • Pin 2: Negative (-)

  • Pin 3: Inhibit (Prevents chair from driving while plugged in)

Non-Standard:

  • Coaxial (Barrel): Usually found on very small, older travel scooters.

  • Clips/Square Plugs: Specific to older proprietary brands (e.g., older Invacare or Everest & Jennings).


🛠️ Quick Diagnostics

  1. Charging Logic:

    • Charger too small? Will take 12+ hours to charge; may not fully desulfate plates (shortens life).

    • Charger too big? Will overheat the battery, causing swelling or “gassing” (ruins battery).

  2. Troubleshooting:

    • Chair won’t drive? Unplug the charger. The “Inhibit” pin is doing its job.

    • Charger light flashes immediately? Usually indicates battery voltage is too low to detect (dead cells) or a loose connection.

    • Charger gets hot? Normal operating temperature can reach 140°F (60°C). If you can’t touch it, it’s too hot.


🧠 The “10% Rule”

If you encounter a battery size not listed above, use this formula:

(Example: A 35Ah battery 0.10 = 3.5A. You can safely round up to a 4A or 5A charger.)