General Question

auhsojsa's avatar

When I plug my MacBookPro into a wall socket does it run power through the wall into my battery? Or is it a separate function?

Asked by auhsojsa (2516points) January 23rd, 2012
4 responses
“Great Question” (2points)

I have the MacBookPro that was installed with 2.7ghz intel i7. So does it run the electricity from the outlet into my battery and then the computer? Or is it directly from the wall to computer, passing up the battery? The reason I ask is because I like to plug it in the wall, but I feel like it might drain the battery faster in that manner? What do you know of the situation? Thanks!

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digitalimpression's avatar

Batteries these days are good for about 1000 charges before they start to really weaken or die altogether.

I’m interested to see other explanations on this topic. Personally, I’ve had my laptop for 5 years now (almost always plugged into the wall outlet) and it is still going strong.

It really depends on the layout of the laptop too. I.E. Apple does not recommend leaving your laptop plugged in. Some people report that they remove their battery altogether and run straight from the wall, eliminating this problem. I’m not really sure.

I’d love to hear an electronics tech explain this.

robmandu's avatar

Power flows from the wall to your laptop’s battery… and the battery runs the thing. That way, when power is interrupted, your laptop doesn’t even blink… keeps on running a-ok.

Once the battery is fully charged, sophisticated electronics ensure that it’s not overcharged even as your laptop runs off it at the same time.

I had my wife’s MBP battery replaced under warranty at the Apple Store recently. Their suggestion to ensure the longest battery life is to run the laptop unplugged a couple of times a month so that the battery can go through a complete charging cycle. Else it might reach end of life sooner than expected (which was why I was in the store).

DrBill's avatar

the power come from the wall and into a reduction coil and a Wheatstone bridge to lower the voltage, and to convert it from AC to DC. that goes into the battery. The computer pulls power from the battery to run. If the battery is removed, he computer will run off of the battery charger.

If you look at the power ratings on your battery, you will see it is very low voltage compared to the 110Volts from the outlet, also the outlet has only Alternating current (AC) and the battery and computer run on direct current (DC)

EdMayhew's avatar

The battery is charged, then discharges a little, then is charged again, causing the charge cycles to repeat more often, wearing your battery out quicker. Also, because your charger lead has a transformer, it means that your charger is wasting power even when it’s not plugged into your laptop or your battery is fully charged.

The best way make sure your battery lasts as long as possible before you have to replace it, and to be as economical with expensive electricity – not to mention kind to the planet – is to charge your battery until it is full, then unplug it and run it from the battery. Once the battery is running low, charge it up to full again. Repeat. REMEMBER, when you unplug the laptop, also unplug the charger as the charger cable really does use up electricity even when it’s not plugged into the laptop. Hope this helps.


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