MBP 16 with 87W USB-C Power Adapter

Hardware
1

In a pinch, for short periods of time, under light workloads (no music or video editing) can you safely use a 87 watt power adapter in place of the supplied 96 watt adapter?

Thanks

Mark

2

according to Apple If you use a power adapter that is lower in wattage than the adapter that came with your Mac, it won’t provide enough power to your computer.. They don’t explain why or what happens tho.

It should cause no harm, and in case of a difference of 9w it should only charge a little slower o don’t charge at all if in use.

3

So this is actually one of the best things about USB-C. USB-C chargers are about to communicate between the device and the changer, meaning that you can use just about any charger on any device. They will always try to charge at the fastest rate they both support.

Meaning that you can charge your laptop with a phone charger if you wanted too. The only issue you have is that your laptop can drain power from the battery faster then you can charge it. So you can end up with a Mac that says it is charging while the battery goes down.

4

My 16" MacBook Pro is getting it’s power from the LG UltraFine, which was designed to power the earlier MacBooks. No issues…as @memex states…just a little slower charging. Like charging your iPad with an iPhone charger…slower rate than the native charger.

5

A better way to think of it is that it will discharge slower than with no charger. Some people use a much smaller charger for travel even though it won’t provide full power. Charge overnight, use the charger during the day when possible, and you never run out of power.

1 Like
6

I’ve got a 15" MBP (so 87w charger) but also have an Anker battery pack & USB-C charger both of which only deliver 30w… I’ve used both successfully on a few occasions to charge the MBP, so far without issue.

While doing general web browsing etc. 30w will charge the MBP albeit slowly. If I fire up Lightroom and start flipping through images quickly or anything else that pushes the performance then it will start drawing power out the battery faster than it’s going in. As @glenthompson points out, that’s still a slower rate of discharge than if it wasn’t plugged in at all though.

7

Thank you all for your feedback and guidance!

Cheers,

Mark

8

I’m late to this, but: Someone (Appleinsider, I think) tested the MBP16 under full load (CPU+GPU) with an older 87W power adaptor and they found it discharged the battery at a rate of about 4% per hour, which is kind of in line with expectations. Unless you’re really pushing your MBP to near 100% of its CPU and GPU capability nearly all the time, I think the older chargers will serve you well.

I’ll find out myself in a couple of weeks when mine delivers :slight_smile: (I have 85W Thunderbolt docs at home and work; those are pretty much the only chargers that I use for my current MBP and I expect to use the new one in exactly the same way)