Running rMBP off External Battery | 16V or 19V?

[MRxROBOT]

I have an Anker Astro Pro2 20,000 mAh multi voltage external battery that I have connected via the DC output to a MagSafe 2 lead.

The MagSafe 2 Charger that came with my MacBook is rated 20V.

The Anker has 2 settings (16V and 19V) that charge my rMBP 15". It appears 19V charges the laptop quicker. Is it as simple as that, 19V charges quicker so use that or is the 16V more efficient in some way?

Am I overthinking things here?

 

[Mcmeowmers]

I would use the source that is closest to but not over the rating capacity of the device.

Is there much of a time difference between 16v charging and 19v?

I would use the 19v as long as the current is within the rating of the device.

 

[MRxROBOT]

I would use the source that is closest to but not over the rating capacity of the device.

Is there much of a time difference between 16v charging and 19v?

I would use the 19v as long as the current is within the rating of the device.

I don't know nearly enough about batteries and charging. I've been using it as you suggested because as you said its the closest rating without going over.

The time difference is minimal. Maybe around 55 mins charge time instead of 45 mins. I think the best thing would be to take note of percentage increase via both voltages, but that's hard to remember to do when your your working.

I was just hoping someone with a better understanding of batteries/charging could spell it out for me.

On another note, I love this battery pack. Does everything the HyperJuice or HyperMac or whatever they call it nowadays does for a fraction of the cost all from a brand we can trust. I can't recommend it enough! (wow that sounded like a sales pitch).

 

[Mcmeowmers]

The battery pack simply swaps charge from itself to your other device. However, there will be some loss due to the energy transport and conversions. The two voltages should provide the same quality of conversion. From theory I would expect the higher voltage to be better(in the sense that it is more efficient but I would also expect this to be nearly imperceivable). The faster charge would be better than a small boost in charge (less than 2% maybe - I'm just guessing here!)

The number of charge cycles would have a greater effect than the charge voltage choice. This is assuming the device is not in use during charging.
I'm pretty confident but It's been awhile since I've studied this material so any corrections or additions by others are welcome