Macbook Pro retina Battery health

Don't overthink the issue. Your battery will stay healthy if you do two simple things:

1) Use the computer on battery power at least a couple of times a week.

2) Avoid running the battery to zero charge. Sometimes this cannot be helped and the occasional "run-down" will not do perceptible harm. However, routinely running to zero charge will damage the battery. I recharge at 15-25 percent charge remaining.

You have a "smart" battery system. It will not allow itself to overcharge. Once it reaches 100 percent you can ignore it, as long as you remember item 1 above.

insotman wrote:

So when the battery is full, the MBP will actually start getting the energy from the charger and ignore the battery ?

Yes, until the battery charge drops to about the 95% level and then it will again provide power to the MBP and charge the battery. This cycle will be repeated as long as the charger is connected.

Here are Apple support articles regarding batteries and their usade:

https://www.apple.com/support/macbookpro/batteries_power/

Ciao.