How do i charge a dead wheelchair battery？

Step 1: Identify the Battery Type

Most powered wheelchairs use:

• Sealed Lead-Acid (SLA): AGM or Gel

• Lithium-ion (Li-ion)

Look at the battery label or manual to confirm.

Step 2: Use the Correct Charger

Use the original charger provided with the wheelchair. Using the wrong charger can damage the battery or pose a fire risk.

• SLA batteries need a smart charger with float mode.

• Lithium batteries require a Li-ion-compatible charger with BMS support.

Step 3: Check If the Battery Is Truly Dead

Use a multimeter to test voltage:

• SLA: Below 10V on a 12V battery is considered deeply discharged.

• Li-ion: Below 2.5–3.0V per cell is dangerously low.

If it's too low, the charger may not detect the battery.

Step 4: If the Charger Doesn’t Start Charging

Try these:

Option A: Jump Start with Another Battery (for SLA only)

1. Connect a good battery of the same voltage in parallel with the dead one.

2. Connect the charger and let it start.

3. After a few minutes, remove the good battery, and continue charging the dead one.

Option B: Use a Manual Power Supply

Advanced users can use a bench power supply to slowly bring voltage back up, but this can be risky and should be done cautiously.

Option C: Replace the Battery

If it's old, sulfated (for SLA), or the BMS (for Li-ion) has shut it down permanently, replacement may be the safest option.

Step 5: Monitor the Charging

• For SLA: Charge fully (can take 8–14 hours).

• For Li-ion: Should auto-stop when full (usually in 4–8 hours).

• Monitor temperature and stop charging if battery gets hot or swells.

Warning Signs to Replace the Battery

• Battery won’t hold charge

• Swelling, leaking, or heating

• Voltage drops too fast after charging

• Over 2–3 years old (for SLA)