I live in a world where I can trivially supply 12V at up to 100A but a wall outlet is difficult to efficiently provide. I would like to be able to use this existing power as the basis for running a laptop. From what I can tell Framework doesn’t support direct usage of 12V input in this manner, but I wanted to be more specific and ask on the module side not just generically supported PD profiles.
From what I can tell, there are basically two options here:
A) Upregulate that 12V into a higher voltage PD spec and then route it to a conventional USB-C port.
B) Do something fancy that involves custom EE internally.
I don’t know of an obvious way to learn about B or I would have just looked up the documentation myself. Where can I find out about the internal voltage situation inside the laptop?
I will also note that I don’t specifically need to charge the laptop like this. As long as I can operate indefinitely on 12V while plugged in, that would be a huge victory.
There are very use-able 100W stepup/down USB-C PD boards on ali. Very affordable as well All you need is put it into an enclosure and a plug you are golden.
Ham radio power supply actually, but yes in general RV-esque environment. Reasonably clean yes, but I can make it as clean as I need to if that’s what it takes. What I’m hoping to avoid is carrying an entire inverter setup with me since that’s not friendly for a hiking go kit. If I’m back at my car, I have solar+100Ah@12V.
I have a Baseus 65W car adapter that has (so far) worked great, but you are probably not the only person who has had trouble with it considering that the Amazon seller pulled the old “listing switch trick” and the product listing is now for a handheld vacuum cleaner.
Interestingly, many Amazon listings for USB-PD car devices say “must plug in to a 24v truck system for full 20v/65W power, 12v car systems will only provide 12v/30W” but then they actually work just fine on 12v and provide the full 20v/65W. I assume this is because the people who write the listings have no clue how the technology actually works.
24V/3A is a lot easier and more forgiving on the cabling and electronic components than 12V/6A. Some EV automakers are going with 400V and even 800V internal wiring for this reason. Sure, that Baseus 65+20 might work on a 12VDC outlet, however the wiring and other stuff need to be designed specifically to handle such high sustained current loads - 10A of heat needs to go somewhere. If all that heat ends up at a critical system component, you’re pretty much screwed.
They built the circuit to be able to raise the voltage. If they really didn’t want it to work that way, they would have had to change the circuit so it can only lower the voltage, not raise it. From the way the text is written, it seems clear (to me at least) that the content writers who make the description just don’t know the features of the product.
It’s not about the voltage. Aftermarket USB car chargers are commonly designed to handle 12V-24V by default because 24V is commonly used in trucks and other heavy equipment. The current a.k.a. Amperage is what matters here. An USB-C 5A cable is thicker than a 3A one because it needs thicker wiring (as well as contacts and other electrical components) to handle the higher heat output that comes with driving the circuit at up to 5 Amps.
Baseus says 24V is required in order to use that 65+20 to its full potential, and they’re not entirely wrong. Even accounting for power losses, that charger would only require 24V/4.0A tops to fully power both ports. On the other hand, if all you have is a 12VDC outlet and you run that same car charger to full power, you’re looking at some 7.5A-8.0A coming from the 12V input. 8 Amps peak/surge is tolerable on a product designed to handle 4 Amps sustained. However, when it’s doing 8 Amps continuous/sustained, that’s a lot of heat generated, way more than that of 4A on a 24V circuit - and such car chargers are not designed to dissipate 8 Amps of heat well.
If you try to use that 65+20 at full power on a 12V circuit, you can buy ten thousand units of the same product - and they will all burn out.
Maybe this point is where we are seeing things differently. In 20 years of collecting a large number of devices that use a car lighter-style plug (including phone chargers, incandescent and LED amber construction lights, dashcams, and others), I have only two that support 24v systems - this Baseus one, and one for a dashcam. All my others explicitly say they are 12v only. To me (and a handful of auto mechanics I’ve asked for confirmation), this implies the following:
They made the decision to support both 12v and 24v systems.
They made the decision to include components that raise the voltage when a 12v system is used. If they had wanted to, they could have only allowed lowering the voltage, not raising it.
Either they designed the rest of the circuit knowing both of the points above, and therefore designed it to actually support that 7-8Amp current, OR they deliberately designed the rest of the circuit knowing that it would by design deliver more power than it could handle.
If the former is true, then I’m right that it’s a marketing problem. If the latter is true, then I’m wrong and they have deliberately designed the device to fail when used with a 12v system, since there is no way to tell it to only deliver 30W at 12v or less. I wanted to assume that they didn’t deliberately make the device defective, but maybe you’re right that they did. I have emailed them asking for clarification.
