Mid-2012 Mac Book Pro battery sudden death

I seem to have done some damage to my usually-reliable mid-2012 MacBook Pro. Yesterday I removed the power cable when a thunderstorm roared in. It died immediately instead of continuing on battery, as it has always done before. The battery was at about 88% when I disconnected the power. Now it is at 40% even though it’s plugged in…down to 36% now.

It won’t start up or run on battery now and I’m concerned it won’t function at all when the battery dies completely.

Does anyone have any suggestions as to what caused the sudden death of the battery. Could there be some damage to the interface between the battery and the CPU?

I obviously don’t know what I’m talking about. Would appreciate some insight, please.

It’s working fine while it’s plugged in.

Thank you.

Batteries can certainly die completely at any time without warning. However, if this was the case, I would expect it to show 0% charge. I would try resetting the System Management Controller before anything else:

Reset SMC

Thank you Richard. Tried that. Now it isn’t showing the green or orange light on the magsafe.

Just changed the charger over and the orange light is on and it’s gone from 9% battery to 12% so it’s charging!!

Do you know if unplugging it without shutting down can cause damage? I’ve done that for years without consequence but this time it seems to have wrecked the charger and immediately killed the battery.

At 15% now so charger must be communicating with the battery.

Thanks for the input, Richard.

Unplugging without shutting down shouldn’t cause a problem. Maybe the charger just died. It happens. You’re lucky you had another one to try. I would let the battery fully charge & see what happens. Maybe see if you can get the other charger tested somewhere.

Thanks, Richard. I won’t throw the charger out and will see if I can get it checked. Laptop is at 90% now and I’m leaving it get to 100% before I shut down, unplug and restart on battery.

The cable had started to bend a few months ago just behind the magsafe connector so it was bound to a toothpick to keep it straight. There may have been a frayed wire in there just waiting to be bumped and disconnected.

Let us know what happens…

Very happy! Charged right up and runs without a hitch on battery or connected to mains power.

I still don’t know why the battery was 0% charged after the disconnect as it still had about 88%. I’d looked before I disconnected to see if I could finish what I was doing. I’d never experienced that instant battery drain before.

I would think that the battery charge amount just hadn’t updated for some reason.

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