58V ECHO Cordless Chain Saw Replacement Battery 5.0Ah Li-ion

My ECHO chainsaw cuts fine for the first few branches then bogs down and loses power mid-cut — new battery, same problem

This is thermal throttling, not a weak battery. The 58V brushless motor on this saw pulls hard current through dense wood, and if the battery's internal temperature sensor trips, the BMS steps down output before a full cutoff to protect the cells. Let the battery rest for 10 minutes off the tool, then check whether the charger shows a solid green or a fault blink when you seat it — a fault blink after a hot session means the pack is cycling in and out of protection mode. Keep cuts moving rather than pinching the bar, which is the fastest way to spike draw and trigger the limiter. If it happens consistently even on light wood, check resting voltage with a multimeter: a fully charged 58V pack should read between 60V and 63V at rest.

Chainsaw chain stopped moving but the motor is still running — could this be a battery issue or is it the brake?

The chain brake is the first thing to rule out — if it's engaged, the motor runs but the sprocket won't turn, and that's not a battery fault at all. Reset the brake, then make one cut: if the chain moves but the motor sounds strained and then cuts out, the battery's overcurrent protection is tripping under the sprocket load. We've seen this on 58V packs that have been partially discharged and then asked to restart under load — the cells can't sustain the inrush current. Charge the pack fully and try a cold start with no wood contact first; if it drives the chain freely at idle, the pack is functional and the original stall was a load-start overcurrent event.

Replaced the battery on my ECHO and now the charger just blinks red and won't charge it — sat in the garage all winter

A battery stored discharged through a cold winter will often drop below the minimum voltage threshold the charger needs to begin a standard charge cycle — typically under 42V on a 58V lithium pack. Measure the pack voltage across the terminals; if it reads below roughly 40V, the charger is seeing it as a deeply discharged or faulted pack and refusing to engage for safety. Some 58V ECHO chargers have a recovery or "wake" mode — disconnect the pack, wait 30 seconds, reseat it firmly, and watch whether the LED pattern changes in the first 90 seconds. If the charger continues to blink red without transitioning to amber or green, the cells have self-discharged past recoverable threshold and the pack will need replacement.