A question about mbp 16 and thunderbolt 3 dock power usage.

[dapa0s]

I am going to buy the CalDigit TS3 Plus t3 dock (link), and it provides 85w of power. I have a macbook pro 16 that uses 96w for charging, so I'm wondering what if I keep my mbp16 plugged in to my charger, while it's simultaneously plugged in into the external t3 dock, what will happen, charging-wise? Is the mbp16 "smart" enough to just use the Apple charger with it's 100w of power?

 

[chrfr]

I am going to buy the CalDigit TS3 Plus t3 dock (link), and it provides 85w of power. I have a macbook pro 16 that uses 96w for charging, so I'm wondering what if I keep my mbp16 plugged in to my charger, while it's simultaneously plugged in into the external t3 dock, what will happen, charging-wise? Is the mbp16 "smart" enough to just use the Apple charger with it's 100w of power?

It'll use the higher power charger, but you most likely won't need it at all unless your computer is fully using the CPU and GPU, and even then you still may not need supplemental power.

 

[dapa0s]

Well that's great news, thanks! I guess I won't need it. I mean, I do heavily use my CPU in logic pro daily, but both the gpu and cpu? Maybe only when I game, but that's very rare. Guess I'll just plug it in the dock.

 

[chrfr]

Well that's great news, thanks! I guess I won't need it. I mean, I do heavily use my CPU in logic pro daily, but both the gpu and cpu? Maybe only when I game, but that's very rare. Guess I'll just plug it in the dock.

You might occasionally see the battery not charge or discharge some, but this can even happen using the 96W adapter, and no, the computer will not power itself from both sources simultaneously.

 

[dapa0s]

I was hoping if I plugged in both it would do something like this.

 

[carestudio]

MBP will be smart enough to take whatever is higher wattage for its charging. so you will be fine. by the way, caldigit has 87w firmware upgrade available, not necessary but nice to have. Been using caldigit one for years, absolutely love it.
I just hope Apple can stabilize their macOS for all the thunderbolt support including external monitor's bugs and sleep problem that happened across the thunderbolt devices.

 

[njvm]

The above is what is supposed to happen but in practice it seems not to. My MBP 16" takes a 85W charge from a CalDigit TS3 Plus dock, even though my MBP is also plugged into a 2nd gen LG 5K monitor which delivers 94W of power (refer Power Source).

 

[dapa0s]

The above is what is supposed to happen but in practice it seems not to. My MBP 16" takes a 85W charge from a CalDigit TS3 Plus dock, even though my MBP is also plugged into a 2nd gen LG 5K monitor which delivers 94W of power (refer Power Source).

Well, that sucks

 

[carestudio]

Not sure about LG monitor though, but I just checked with my MBP 16" with caldigit's TS3 plus dock and apple charger. My MBP 16" actually took Apple's 96W charger while TS3 plus is connected. I believe Apple design their laptop correctly on this feature

 

[David58117]

The above is what is supposed to happen but in practice it seems not to. My MBP 16" takes a 85W charge from a CalDigit TS3 Plus dock, even though my MBP is also plugged into a 2nd gen LG 5K monitor which delivers 94W of power (refer Power Source).

Did you download the firmware update for the dock? I believe they released an update that increases it to 87W.

 

[njvm]

Thanks - yes I did - it increased to 87W but my MBP still seems to ignore the 95Ws from the LG 5K monitor.

 

[CYB3RBYTE]

I do the exact same setup, except with a OWC dock and not the cal-digit.

If I'm gaming in windows, and its a heavier game, it will start to drain the battery while plugged into JUST the dock. If I have both my 96w charger and the dock plugged in, the charger becomes primary power and the dock secondary, from my understanding it will draw from the primary until the load decreases (CPU, GPU) and then shift it 50/50 to the dock and charger.

 

[chrfr]

I do the exact same setup, except with a OWC dock and not the cal-digit.

If I'm gaming in windows, and its a heavier game, it will start to drain the battery while plugged into JUST the dock. If I have both my 96w charger and the dock plugged in, the charger becomes primary power and the dock secondary, from my understanding it will draw from the primary until the load decreases (CPU, GPU) and then shift it 50/50 to the dock and charger.

The computer will never charge from 2 sources at once.

 

[CYB3RBYTE]

Correct, from my understand it will take 50% of the battery charge at one time from one source (The more powerful wattage), wait for that to finish, and then move to the secondary (the lower wattage) to finish charging. Similar to the iPhones new charging mode in that it fast charges for a portion then slows down the charging rate.

It will do this regardless of 1 or 2 sources plugged in, to help reduce stress on the battery. This is straight from a genius a few months back before stuff hit the fan.

 

[chrfr]

Correct, from my understand it will take 50% of the battery charge at one time from one source (The more powerful wattage), wait for that to finish, and then move to the secondary (the lower wattage) to finish charging. Similar to the iPhones new charging mode in that it fast charges for a portion then slows down the charging rate.

It will do this regardless of 1 or 2 sources plugged in, to help reduce stress on the battery. This is straight from a genius a few months back before stuff hit the fan.

It's unlikely this is the case, but I haven't checked personally. As the battery charges, the computer will draw less power from the charger even if there's only one charger available, so it would be unnecessary to switch sources to accomplish this.

 

[carestudio]

According to Apple's support article, Mac will automatically select the single best-suited power source and charge from it. https://support.apple.com/en-us/HT207097

Not sure about LG5K though, but with Apple's 96W charger and CalDigit TS3 Plus together, I could see my Mac is drawing power from Apple's , if I unplug charger, it then will switch to TS3 Plus.

I can't see the performance or even charging speed difference when using apple charger vs TS3 Plus only. 87W from TS3 Plus so far is holding up pretty well.

 

[dapa0s]

Well, after buying the caldigit ts3 plus and using it right now together with Apple's charger, I can confirm that my Macbook is using "Power Adapter" as it's power source while both are plugged in. Mystery solved!

 

[njvm]

Does where the cable is plugged make any difference? Normally I have the white TB3 cable from the TS3 Plus plugged into the rear most TB3 port on the left hand side of my MBP. Today I have the black cable from the LG5K monitor plugged into this port and System Information shows 94 watts!

 

[chrfr]

Well, after buying the caldigit ts3 plus and using it right now together with Apple's charger, I can confirm that my Macbook is using "Power Adapter" as it's power source while both are plugged in. Mystery solved!

You should just try using the computer with the dock alone. It'll be fine for the vast majority of use.