56V EGO CS1400 Chainsaw Replacement Battery 6Ah Li-ion

My EGO chainsaw cuts fine for a few seconds then bogs down and loses power mid-cut — new battery, same problem

This is almost always voltage sag under load — the chainsaw is drawing peak current through a dense cut and the battery management system is throttling output to protect the cells. Check that the chain tension and lubrication are correct first, because a dragging chain multiplies the draw and triggers sag faster than a properly tuned setup. On the bench, we saw this most often when chain oil was low — the motor works harder, pulls more amps, and the BMS steps in. Oil the bar, reset tension, then try the same cut and watch whether the bogging point moves.

EGO battery clicks into the chainsaw but the tool won't turn on — no lights, nothing

The most overlooked cause here is the battery's key switch or the safety lockout on the saw itself — both have to be active simultaneously, and one stuck or misaligned interlock kills all power with zero feedback. Before assuming a dead battery, press the battery's charge-check button to confirm it holds a charge, then hold the chainsaw's front guard in the correct position while pressing the trigger. If the battery shows charge but the saw still won't respond, the problem is usually the interlock contacts on the battery port getting dirty or slightly bent from repeated removal — inspect and clean those contacts with a dry cloth. Reseat the battery firmly with the saw pointed down and try again.

Charged my EGO battery to full overnight and it was almost dead by morning — did I get a bad one

A 56V Li-ion pack at this capacity class should lose very little charge sitting overnight — if it's dropping significantly, the battery's self-discharge rate is abnormal and points to one of two things: a cell group with elevated internal resistance, or the BMS drawing parasitic current because it never fully exited active mode after charging. Let the battery cool completely, charge it again until the indicator shows full, then physically disconnect it from everything and check the level again after 24 hours. If it drops more than one indicator LED in that window with no load attached, the pack has a cell-level fault and the overnight drain will not improve with use.