Re: USB-C chargers
Paul Wayper via linux-aus <[email protected]>
| Newsgroups | gmane.linux.australia |
|---|---|
| Message-ID | <[email protected]> |
On 28/11/22 6:53 pm, Adam Nielsen via linux-aus wrote: > As for the charger itself, if you look at the specs they list the > voltages and currents supported for USB PD. I think the Thinkpad wants > 20 volts (although it may accept less, I don't know), and both chargers > you have linked to claim to output 20 volts in their specs, so in theory > they would work. > > However without knowing the specs on the 30 W charger you have, it's > hard to say whether this is the problem. If the 30 W charger can't > output above 17 V then I'd suspect that could be why it doesn't work, > given a known good USB-C cable. The other problem here is that the USB 3 PD spec has the charger and the device talk to eachother to find out what power modes each supports. At 20V there is one mode for 45-60W and another for 60-100W; a device capable of delivering 30W may well be in the 15V range (27-45W). If the battery charging hardware requires greater than 18V (the usual reason AFAIK for laptops to need 20V), then it's just not going to turn on for a 15V charger. https://en.wikipedia.org/wiki/USB_hardware#USB_Power_Delivery If the new 30W charger does actually deliver 20V, then it's under-spec - the minimum should be 45W. Caveat: I am not a USB 3 expert :-) > As more devices start to use USB PD, you may want to consider getting a > USB power monitor that supports PD, so you can plug it in between the > device and charger and actually see what's going on. These devices > will show the actual voltage and current on a small screen, so you can > see exactly what's going on and more easily compare different devices > and chargers. Here is an example I picked randomly from Aliexpress: +1 for these devices, very handy. Make sure you also get one that's bidirectional - I mistakenly got one that only shows charging stats if it's plugged into the charger (i.e. the charger has to have a socket, not a plug). Very annoying. So why were we trying to get a low power charger? I don't find the Thinkpad one very bulky... is it? Have fun, Paul _______________________________________________ linux-aus mailing list [email protected] http://lists.linux.org.au/mailman/listinfo/linux-aus To unsubscribe from this list, send a blank email to linux-aus-unsubscribe-cunTk1MwBs8iFSDQTTA3OBCuuivNXqWP@public.gmane.org