EGO ST1521S PowerLoad Trimmer 15 in 56V Cordless String Trimmer with Automatic Line Feed CHG-ALT-FLASH Error Fix: Charger Alternating Red-Green Flash

Error code CHG-ALT-FLASH on the EGO ST1521S PowerLoad Trimmer 15 in 56V Cordless String Trimmer with Automatic Line Feed means: Charger Alternating Red-Green Flash. The charger LED alternates between red and green, indicating the charger is attempting to recover a deeply discharged battery or is performing cell balancing — this process can take several hours; do not remove the battery during this process; if it continues for more than 8 hours, the battery may be too deeply discharged to recover

The most successful fix is "Replace Battery or Charger Components" (hard difficulty, ~45 minutes). Estimated DIY cost: $20-$40. HomeMD has 2 community-ranked fixes for this error.

This error is rated medium severity. It should be addressed soon, but your appliance may still function in a limited capacity.

Yes — the top-ranked community fix ("Replace Battery or Charger Components") is rated hard difficulty and takes about 45 minutes. Tools needed: Multimeter, T20 Torx screwdriver, Electrical contact cleaner.

DIY cost: $20-$40. Professional repair typically costs $150-$220. Many homeowners save money by trying the top-ranked community fix first.

The EGO ST1521S PowerLoad Trimmer 15 in 56V Cordless String Trimmer with Automatic Line Feed has 8 other known error codes, including: BAT-1-FLASH (Battery Single LED Flashing), BAT-COLD (Battery Too Cold to Operate), BAT-HOT (Battery Overtemperature Protection), BAT-LEDS-OFF (Battery LEDs Not Lighting Up), BAT-NOT-RECOGNIZED (Battery Not Recognized by Tool), and 3 more.

Error code CHG-ALT-FLASH also appears on 11 other EGO models: CS1401 14 in 56V Brushless Motor Cordless Chainsaw with Rapid Reload Chain Tensioning, EGO POWER+ CS1804 18-Inch 56V Cordless Chainsaw with Chain Tensioning, EGO POWER+ EA0800 56V 8-Inch Cordless Edger, EGO POWER+ HT2411 24-Inch 56V Cordless Hedge Trimmer, EGO POWER+ LB6000 56V 615 CFM Cordless Leaf Blower, EGO POWER+ LB6504 56V 650 CFM Cordless Leaf Blower, and 5 more. The fix may vary by model, so check each model's specific page for tailored repair steps.