Do external battery packs hurt macbook batteries?

[pjny]

Do external powerbanks damage the macbook 12 battery? I had a service battery warning on my old battery and premature battery wear(38% or so after 2.5 years).

After getting the new battery I plugged in my old Anker 26800 using usb-a to usb-c and the next time I had bootup issues and had to bootup using ac adaptor.

I also had to reset smc and pram as the clock showed the wrong time. I'm not sure if it was the Anker but the RAV works great with USB-C cable and 30W charge compared to the way lower Anker charge

Perhaps the USB-A to USB-c cable on the anker was causing issues.

Just wondering if anyone has had issues with external battery chargers.

 

[velocityg4]

The only issue would be if the external battery is putting out the wrong voltage or insufficient current. If it provides power within the same tolerances as an AC adapter. It shouldn't make a difference to the computer. As far as it is concerned. It is getting power from an external source.

 

[Mike Boreham]

I use RavPower and Anker 26,800 batteries with my 2016 12" MacBook regularly. An important factor is that the batteries comply with the USB-PD spec. Very few battery packs do. They connect USB-C to USB-C. USB-PD will charge the MacBook at the same 30W rate as the supplied power adapter. The voltage may be 15V (RavPower) or 20V (Anker), but doesnt matter as both operate at 30W.

Anything connecting by USB-A will be 5V and while it won't do any harm, will be a lot slower and will barely keep up with usage if the MacBook is being used while charged.

Long thread on the subject here: https://forums.macrumors.com/threads/charging-macbook-with-battery-packs.2035431/

PS Dont be misled by the big number "26800 mAh". These batteries will charge a flat MacBook about 1.5 to 2 x before becoming depleted. "26800 mAh" is not a measure of battery capacity, which should be expressed as Watt-hours. These RavPower and Anker batteries are about 100Wh capacity and the 12" MacBook is about 40Wh, which, with the transfer efficiency loss, means you get about 1.5-2x. I get slightly more from the Anker, even though it is the same rating, but the Anker is a bit bigger and heavier.