3 ms·

I love this and have considered doing it myself. However, what worries me is whether using a single power adapter will shorten the life of devices which require

I love this and have considered doing it myself. However, what worries me is whether using a single power adapter will shorten the life of devices which require different levels of wattage. Sure you can use the same USB-C cable, but the benefit is largely diminished if you have to carry a bunch of different power adapters for each device's unique wattage. Or am I worrying about this unnecessarily?

zenexer 6y ago
Just carry around a first-party Apple charger that matches the highest draw among your devices. Using a higher-rated charger won’t hurt anything.
- ChrisMarshallNY 6y ago
  I used to carry around a 60W adapter, even though I had a device that required an 80W adapter. The reason was airplane seats. They have a breaker that flips at 75W. I wouldn't get fast charging with the 60W adapter, but I wouldn't run out of juice on a 14-hour flight.
davidrm 6y ago
It’s not a concern, the more powerful the charger, the better. The devices that are being powered are the ones controlling the charging, the charging brick will derate itself if devices demand more than it can handle. It might hurt the brick, it will get hot or perhaps noisy if it’s a cheaper one. It’s like openning every single faucet at your house, as long as the pressure and flow at the source are ok, the faucets will output the same as in any other case, otherwise each faucet will “slow down”.
- BlackVanilla 6y ago
  Thanks for this. Would that "slowing down" harm the device though? Obviously, I should err on the side of higher wattage, but if the power adapter provides lower wattage than is required, would that harm the device?
  - avianlyric 6y ago
    No. That really isn’t how electronics works. Basic charging works on the principle of deciding a charging voltage (which is either 5v or negotiate to be higher via Power Delivery) plus as many amps as the charger can provided. As a receiving device the only thing you really care about it voltage. If it’s to high, then stuff gets fried, two low and stuff just doesn’t turn on. The amps are determined by how much the receiving device can consume. And of course decreases as the device charges (if you’ve got a full battery, then you don’t need more power). If the receiving device pulls to many amps, then the voltage will start to drop, this then causes the receiving device to reduce its power consumption. Ultimately power electronics are extremely robust today, you would have to try very hard to fry modern electronics. This is a result of how modern electronics converts power, which naturally makes them very robust to fluctuating inputs. (I’m simplifying a lot, want to learn more then look up DC-DC converters, and see how they’re implemented in silicon) In short, just don’t worry.
rfoo 6y ago
You are worrying unnecessarily. These devices use USB-PD to negotiate how much power it wants with the power adapter, and a well-behaving power adapter would refuse to output anything above the minimal current without the negotiation happening.
allending 6y ago
Worrying unnecessarily. The USB PD spec requires negotiation of delivered power - https://en.wikipedia.org/wiki/USB_hardware#USB_Power_Delivery_(USB_PD) https://en.wikipedia.org/wiki/USB_hardware#USB_Power_Deliver....
1996 6y ago
> Or am I worrying about this unnecessarily? You are. Provide a lot of amps. Each device will take just as much as it needs. So err on the side of more watts - it will even help your batteries charge faster. The only thing that can be diminished with fast charging is the number of battery cycles (the battery lifetime) so set a low charging engage (only charge if <= 50%) and a high ceiling (stop charge if >90%) in your bios: this will increase your battery life. Source: all my devices use USB-C. They all share the same AC adapter with power delivery, and a Lenovo Dock also USB-C with PD. No USB-C charging = I don't buy.
- ahartmetz 6y ago
  The rule to maximize life of Li-Ion batteries is to keep them between 20% and 80%. Total charge and discharge current cause wear, especially in extreme states of charge. The number of cycles only matters when you assume a given amount of charge in each cycle. The batteries of my 7 years old previous laptop, which was used mostly stationarily and mostly kept at 75-80% state of charge, are still at above 90% capacity. I don't fully trust the >90% reported, but the batteries are quite obviously still good.
- atonse 6y ago
  I got excited at the idea that I could set those thresholds on my MacBook (like on a Tesla) but then realized when you said BIOS that you’re talking about a PC.
rzzzt 6y ago
USB-C is probably smarter and more unified in this regard, but back in USB 2.0 land the devices negotiated how much power they need/can accept, and compliant adapters wound themselves down as appropriate: https://www.maximintegrated.com/en/design/technical-documents/tutorials/4/4803.html https://www.maximintegrated.com/en/design/technical-document...

zenexer 6y ago

Just carry around a first-party Apple charger that matches the highest draw among your devices. Using a higher-rated charger won’t hurt anything.

ChrisMarshallNY 6y ago
I used to carry around a 60W adapter, even though I had a device that required an 80W adapter. The reason was airplane seats. They have a breaker that flips at 75W. I wouldn't get fast charging with the 60W adapter, but I wouldn't run out of juice on a 14-hour flight.

davidrm 6y ago

It’s not a concern, the more powerful the charger, the better. The devices that are being powered are the ones controlling the charging, the charging brick will derate itself if devices demand more than it can handle. It might hurt the brick, it will get hot or perhaps noisy if it’s a cheaper one. It’s like openning every single faucet at your house, as long as the pressure and flow at the source are ok, the faucets will output the same as in any other case, otherwise each faucet will “slow down”.

BlackVanilla 6y ago
Thanks for this. Would that "slowing down" harm the device though? Obviously, I should err on the side of higher wattage, but if the power adapter provides lower wattage than is required, would that harm the device?
- avianlyric 6y ago
  No. That really isn’t how electronics works. Basic charging works on the principle of deciding a charging voltage (which is either 5v or negotiate to be higher via Power Delivery) plus as many amps as the charger can provided. As a receiving device the only thing you really care about it voltage. If it’s to high, then stuff gets fried, two low and stuff just doesn’t turn on. The amps are determined by how much the receiving device can consume. And of course decreases as the device charges (if you’ve got a full battery, then you don’t need more power). If the receiving device pulls to many amps, then the voltage will start to drop, this then causes the receiving device to reduce its power consumption. Ultimately power electronics are extremely robust today, you would have to try very hard to fry modern electronics. This is a result of how modern electronics converts power, which naturally makes them very robust to fluctuating inputs. (I’m simplifying a lot, want to learn more then look up DC-DC converters, and see how they’re implemented in silicon) In short, just don’t worry.

rfoo 6y ago

You are worrying unnecessarily. These devices use USB-PD to negotiate how much power it wants with the power adapter, and a well-behaving power adapter would refuse to output anything above the minimal current without the negotiation happening.

allending 6y ago

Worrying unnecessarily. The USB PD spec requires negotiation of delivered power - https://en.wikipedia.org/wiki/USB_hardware#USB_Power_Delivery_(USB_PD) https://en.wikipedia.org/wiki/USB_hardware#USB_Power_Deliver....

1996 6y ago

> Or am I worrying about this unnecessarily? You are. Provide a lot of amps. Each device will take just as much as it needs. So err on the side of more watts - it will even help your batteries charge faster. The only thing that can be diminished with fast charging is the number of battery cycles (the battery lifetime) so set a low charging engage (only charge if <= 50%) and a high ceiling (stop charge if >90%) in your bios: this will increase your battery life. Source: all my devices use USB-C. They all share the same AC adapter with power delivery, and a Lenovo Dock also USB-C with PD. No USB-C charging = I don't buy.

ahartmetz 6y ago
The rule to maximize life of Li-Ion batteries is to keep them between 20% and 80%. Total charge and discharge current cause wear, especially in extreme states of charge. The number of cycles only matters when you assume a given amount of charge in each cycle. The batteries of my 7 years old previous laptop, which was used mostly stationarily and mostly kept at 75-80% state of charge, are still at above 90% capacity. I don't fully trust the >90% reported, but the batteries are quite obviously still good.
atonse 6y ago
I got excited at the idea that I could set those thresholds on my MacBook (like on a Tesla) but then realized when you said BIOS that you’re talking about a PC.

rzzzt 6y ago

USB-C is probably smarter and more unified in this regard, but back in USB 2.0 land the devices negotiated how much power they need/can accept, and compliant adapters wound themselves down as appropriate: https://www.maximintegrated.com/en/design/technical-documents/tutorials/4/4803.html https://www.maximintegrated.com/en/design/technical-document...