Late 2013 Retina Macbook Pro power brick extremely hot to the touch! This affected my computer (It was hot as well) - I could smell something burning! I am unsure the issue!

I noticed this while migrating, the brick cooled to what I can best describe as normal when compared to my 2011 MBP. MY 15" did not get hot and has been running fine and fully charged.

To start, my MBP has not been below 20%, and rarely sees less than 40%. Less than 20% I call "dead" because LithiumIon batteries are injured by low charge levels.

You can leave it plugged in. It will stop charging at 100% and slwoly discharge to 95% before recharging automaically to 100%.

Read this for more information: http://www.apple.com/batteries/notebooks.html

AppleSupportNow

Please help! I started the charge at 3%

Really bad idea, I hope you have not been doing that often.

You NEVER want to do a full /very low discharge, EVER. period. 😊

The only quantified abuse seen to LiPo cells is instances when often the cells are repeatedly drained very low.

Never let your Macbook die from power, you can corrupt files that way, and the Lithium Polymer batteries absolutely do not like it.

*Also new evidence suggests that sudden loss of power can adversely affect data on a SSD (solid state drive).....again, dont let it ever shut down from total power loss

LiPo batteries do NOT like to be dropped down to 15% or so often,....key word being "often"

A lot of battery experts call the use of LiPo cells the "80% Rule" ....meaning use 80% of the charge or so,.. then recharge them for longer overall life.

AppleSupportNow

I always thought that keeping it plugged in nearly 24/7 can damage the battery too?

No, not at all, the only damage from being plugged in all the time are IF:

A: its not turned off and in sleep mode ALL the time while plugged in

B: you dont unplug it ever couple weeks or so and drain the battery down to about 30 to 40%

*Also, if youre going to store your macbook away for a few weeks or more,... make sure it has at least a 50% or so charge.

*Cycle count / use/ lifespan is one thing that cant be countered.

Proper treatment is another thing. Just because LiPo batteries dont need conditioning in general,.. does NOT mean they dont have an ideal use / recharge environment. Anything can be abused even if it doesnt need conditioning.

Just use and enjoy your new macbook,

From Apple on batteries:

http://www.apple.com/batteries/notebooks.html

http://support.apple.com/kb/HT1446

but really all you would keep in mind is --"consider 15-20% is the same as 0% and recharge it"

Important useful info on your Lithium cells as compiled from battery experts:

Heat increases battery performance but shortens life by a factor of two for every 10°C increase above 25–30°C (18°F above 77–86°F). This is yet another important reason for the cooling of any notebook, not just keeping the processor and GPU cool. Mavericks lower power tasking (app nap) and combined with the cool running Haswell processor both greatly protect battery life on your Macbook now more than ever before.

Good news: *Mavericks not only increases a single charge cycle for longer battery use off a full charge,… but also prolongs the overall long term life of the LiPo battery in a Macbook by reducing the load conditions the battery experiences from heavy peak-use.

Counting cycles is not conclusive because a discharge may vary in depth and there are no clearly defined standards of what constitutes a charge cycle on a Lithium Ion battery empirically. Similar to a mechanical device that wears out faster with heavy use, so also does the depth of discharge (DoD) determine the cycle count.

The shorter the discharge (low DoD), the longer the battery will last. If at all possible, avoid full discharges and charge the battery more often between uses. Partial discharge on Li-ion is fine.

Frequent HIGH depth of discharge rates (draining the battery very low) on a Lithium battery will hasten the lowering of maximum battery capacity.

Although better performing when warm, lithium polymer batteries live longer when kept cool.

Lithium cells prefer draining conditions at a steady pace rather than fast pulsed or quick discharges, …this fact is idealized now with the Haswell and Mavericks app-nap low power tasking for battery use.

App nap:

http://www.apple.com/osx/advanced-technologies/

Many keep it plugged in to save charging cycles. I use mine down to 40% at least once a month to exercise the battery, but I do not intentionally add cycles (2 charges from 50% to 100% is 1 cycle).

Too many posts come from people who "drain it once a week" and the battery is dead at 200 cycles.

AppleSupportNow

I always thought on a brand new device, you let it drop to nearly 0% prior to charging it........////.........What do you mean by it affecting data on SSD? Does it make my Read/Write Speeds slower?

Whoever gave you that 0% "advice" shouldnt be listened to.

meaning sudden power loss has been recently proven in instances to cause data corruption on SSD...... Speeds? NO,....meaning data corruption.

Your charger could have a dying capacitor or short if it is extremely hot. Dont risk your macbook, have it investigated.

We are not trying to make you feel "uninformed". We volunteer our time to help, and gladly answer questions. Please ask before you try something because I am saddened when I must tell a university student that his/her never-backed-up PHD thesis dies when then HD died.

My brick is still in the sa,me location since I started the migration and both are cool to the touch ter hours of operation. I'm going to assume the temp increased during charge. Once migration has been completed I'll run a few ststo see if I can identify a pattern.