Really strange battery problems (C2D 17" MBP) - Help!

[danielbriggs]

Hi!

Well I was in IT class today, and we had to give a short presentation ~10mins. I got out my mac that was around 70% charged and plugged it into the projectors. (during the presentation it was not plugged in) Fine... at the end of the presentation, I noticed my battery was on 16%!!!!

So I plugged it in quick and fired up coconut battery and the battery health had gone from 100% - 6367mAh to a shocking 49% - 2717mAh.

I want to know why?

I did "power cycle" my mac a few days ago, as I do with it every month as per apples directions on their site.

After leaving it charging, it's been fully charged for hours, and the health has stuck around 79% - 4395mAh.


Am I right in thinking the battery has just got muddled up with it's capacity and the percentages have scaled accordingly or is there something up? This has never happened before...very strange.

Anyone think that another complete discharge and charge would solve this?



Dan

 

[Chansey]

I think you just have to give it some time, a few charges, no full discharge, and it will return itself to good health.

 

[danielbriggs]

I think you just have to give it some time, a few charges, no full discharge, and it will return itself to good health.

OK, I'll try that, but do you know why it halfed it battery health and lost 60% in the space of 10 mins????

 

[Chansey]

maybe the projector drained a lot of power from the computer and the battery sensor is not used to that so it doesnt really know what is happening?

 

[danielbriggs]

maybe the projector drained a lot of power from the computer and the battery sensor is not used to that so it doesnt really know what is happening?

Could be, but I doubt it...

I don't think it would have drained that much, if I had tried to run a car off it for that length of time...

hmm...now there's an idea

BTW: I tried charging it fully to 100% and then let it drain to 95%, then charge (repeat x3) and it's back to virtually full health, like you said.

Cheers!


Dan