Full Power Magnetic Charging Card

I’m still confused what that has to do with a magnetic charging cable. Or why in this case you’d need an extender at all. Just use the USB-C cards to bring the full USB-C port out, and plug into one of the USB4 ones. Sounds like I’m completely missing something though.

Oh, gotcha, the purpose would be to recess the charger and magnetic connector inside the card, so nothing to snag on when taking it in and out of a bag. Similar to the first post in this thread.

Oh, I see. Hm. Why not just get a PCB with appropriate signal traces, except not quite as deep as the current USB-C expansion card, and 3D print up an appropriate case for it. Unless doing full pinout traces is harder than just getting some printed on a PCB, I can see that being possible since it’s got to support such high frequency, and you want to be sure the signaling arrives at the exact same time on each pin from one connector to the next.

I don’t have the know how to do that or where to order it, in one of my earlier posts on this thread I invited others to.

So for 10 bucks and printing a card this is the better option for me. Although I was hoping others might be interested as I could use help getting the stl file perfected.

As discussed previously in this thread, I’d strongly advise against using something like this, the high speed data lines are super sensitive against electromagnetic discharge and having them exposed on a magnetic connector will kill them sooner or later. Especially in climates with a lot of dry air.

2 Likes

I understand the risk, but am not quite sure it’s as inevitable as everyone is making it out to be. The physical pins, in at least the wide frame of the magnetic adapter, are physically further apart than in the actual cable.

Are you saying that static electricity would be the culprit here? I’ve been using the magnetic connector for 9 months now with no issues, and with this card the pins would be further recessed and protected.

Arcing is a potential issue even with just one pin. The process of connecting / disconnecting even a single pin on its own by definition means there will be a tiny air gap for a short period of time, and the electricity will arc across across that.

You can see in this video 48V arcing across a 0.25 in / 6 mm air gap, and the higher the voltage the bigger the gap across which it will jump. Here’s another video of arcing across a single connection, much higher voltage but I like it as it shows connecting/disconnecting.

Metal is worn away by arcing, and every time the magnetic connection jiggles will cause a bit of arcing and wear. Far more jiggle with a magnetic connection results in far more wear than with a regular connection.

On first contact there is a 5v negotiation to see if PD can be used, so that reduces the risk.

Connecting is a very minor risk here due to 5V, yes.

But disconnecting happens while it’s already at the full 48V. Here’s a video showing constant arcing in a loose house power connection. The pins aren’t too close to each other, the issue is the tiny air gap in each jiggly connection.

1 Like

I know for an arc to travel across the air one inch, it requires 1000 volts.
voltage - Easiest way to produce electric arcs from battery - Electrical Engineering Stack Exchange

That’s approx 40v for 1mm or if charging at 20v and disconnecting 0.5mm would be on the edge

The video wasn’t clear if that was AC or DC anyway 40V at .25 inch, and the 96V for .5 inch leaves 240v at 1" which is unrealistic.

Video maybe but I’ve been a radio electrician in the Royal navy way back in the 60’s and that is not something I encountered, nor would expect. Of course humidity is a huge issue but I will disregard that video.

And don’t forget the 48V is now an option for the USB C connector, officially and there’s no 6mm gap anywhere, or is there ?

Of course as any power connector is unplugged when powered on there is going to be an infinitely small gap that any infinite low voltage could spark across. However then the current has to be considered to see what overall power there is to create a possibility of a damaging em or static effect.

You need to be careful extrapolating that to an arc in a magnetic connector. The USB connection is limited to 5A and the power supply will have fault cutput protection - but a house connection has the closest thing to a constant voltage source that you will find anywhere, i.e. if you start an arc the current will possibly go to hundreds on amps (which is why such connections should have an appropriate fuse upstream).

Every time the magnetic connection jiggles will cause a bit of arcing and wear. Far more jiggle with a magnetic connection results in far more wear than with a typical mechanically secured connection.

At 240W, that must be 240W÷48V=5A of current going though the cable. Looks like USB-C has four VBUS and four GND pins, so you could argue 5A÷4=1.25A though each pin. And in USB-C, those are some very tiny pins.

I’m not saying it can’t be done, just pointing out why it’s caused so many issues for people so far. It’s not a trivial problem that can be easily resolved in the USB-C form factor. Of course if you change the connector by using fatter pins that are spread out more, and no data pins, then it’s much easier to solve.

i don’t know as much about magsafe 3, apple’s current incarnation, but as i believe i mentioned some time back in one of these threads magsafe 2 had a bad habit of cooking the charging circuit. it was functioning as a consumable component, even though it wasn’t designed that way (and it sometimes didn’t stop with that circuit).

the expansion card CAN potentially act as a sacrificial intermediary, but i know i wouldn’t want to bet on it

A house connection is also ac, so the arc is self extinguishing, dc doesn’t have that luxury.

But the arcing concerns aren’t really about loose connections but regular unexpected disconnects, inductance resists changes in current and will raise the voltage until it’s magnetic field is depleted. Best case it’ll damage the contacts, much worse case it sends spikes of way too high voltage to to data pins which may blow up either the expensive re-drivers on the usb4 ports, the cpu or the internal hub after the esd protection is overwhelmed.

If I really wanted magnetic charging I would make damn sure only the power and cc pins are connected and put the beefiest esd protection I can find on the cc pins.

1 Like

I haven’t seen a lot of evidence that this theoretical safety issue is actually a general problem with magnetic charging cables.

There’s no charging cable or brick in existence, for example, that does not have knockoff brands that have fried things and/or started fires.

We’ve all probably heard the stories of cheap Alibaba etc chargers that explode when people use them etc, that doesn’t make OEM chargers inherently unsafe to use because other brands are.

I have had my Volta XL chargers now since the start of 2019 (I had one of their earlier versions before that but can’t find when I started using those) and have never had any funkiness. I use it for my FW16 every day (it’s currently plugged into one).

You see a lot of “Because it works for you it doesn’t mean it’s not an issue” arguments, but I would counter with “Have you or anyone else managed to get a volta charger (or other specific brand) to spark in the mentioned manner?” for example which has destroyed equipment.
If a brand has fried something, you stop buying stuff from that brand and move on to something more trustworthy.

I am at least not finding any signs that people have managed to do so for Volta chargers specifically so I’m not really concerned.

There are countless reports of magnetic cables killing devices or causing the ports to malfunction.

Volta isn’t “OEM”. Framework would be OEM for a Framework laptop. Lenovo OEM for a Lenovo laptop, etc.

But I take it you just mean high-priced magnetic cables.

For Volta? You need to look no further than right here in this forum. No, actually, right here in this thread.

If you look at Volta’s site, they make zero claims of any ESD protection. And I’ve seen someone do a Volta teardown, nothing there. Which is expected, as there is no room at all in the device end, where you want protection. You could tear one open yourself to see. Volta is not USB-IF certified. No 3rd-party add-on USB magnetic plugs are.

One needs to be careful of Choice-supportive bias. When one makes a purchase, uses it and likes it, well enough, at least, there is a strong tendency to want to feel that they made the right choice, this influences one’s judgement of information to the contrary.

Use them if you want. But you shouldn’t post as if they are safe, and as if there is no evidence that they aren’t. It encourages others to think it might be ok to start using them.

reddit.com/r/UsbCHardware/comments/motlhn/magnetic_usbc_cables_are_not_recommended

1 Like

Maybe this conversation is useful to others, but to me it comes across as a bunch of internet nannying.

How about we agree that that is a risk, put aside how much risk as there are differing opinions and we’re not going to settle it here, and go from there.

Some of us are interested in using these connectors even knowing the risks. Thanks for the warnings, but at this point you’re at the base of skydiving school yelling to the people going in that it might be dangerous.

I’m happy to hear about ways to mitigate risk, but at this point the thread has plenty of post about the fact that there is a risk, and personally it’s getting annoying and feels like it’s more of a hamper to any progress.

I’m fine with people using them. I do take some issue with someone acting like there is just no risk at all and no evidence. As it can cause others to kill their devices without understanding that it was an actual risk. I apologize if I came off as too harsh.

People have posted about mitigating the risk. I myself have detailed the minimum you could do to reduce the risk. Unfortunately, since the whole idea is to have a plug not stick out much, it would require a custom-made expansion card. But https://jlcpcb.com/ does offer assembly service.

If you don’t care about it being as minimum profile as possible, using a USB “condom” type device, which disconnects the data lines, will reduce the risk in a plug-and-play off-the-self way. Only the CC lines, which are needed to negotiate USB PD, should be connected.

Here is the first one I found with a little googling which seems to claim PD support. amazon.com/JSAUX-Blocker-Transparent-Protect-Charging/dp/B0CCS3D2H1

PD 3.0/2.0 fast charging technology, supports 100W fast charging (20V/5A), and is also compatible with charging power of 240W/140W/60W/45W/36W/27W/15W, etc

And this review also claims it supports USB PD 3.0

That has been mentioned here - using something like this. While I would like to use that as well, personally, I would also like to try the magnetic full data in an internal card. If someone could design a print for the adapter above, I’d love to try to out, but it won’t stop me from trying to move the magnetic connector I currently use to an internal card.

Something that I will admit I do not understand, is why the danger is so much larger in a magnetic connector vs the arc that could be created by a standard usb C insertion. Is it just the “wobble” potential of pins becoming disconnected? With the pins being so much closer together on a standard USB C I guess I’m skeptical about risk claims as no one seems to have issues with “hot unplugging”, where is seems like the risk would be just as high. Not trying to say that the risk might not be there any greater, but it’s hard for me to see why it would be so much larger. I’ve had two phones that have essentially be scrapped by someone tripping over the wire and destroying the USB port so at this point is seems like it might be the smaller or the two risks, and I get the cool factor.

The off alignment / wobble that is possible with magnetic connectors might be a factor. But I think the much bigger issue is that during a hot unplug, normal USB-C plugs are able to disconnect power before actual physical contact is lost, to prevent arcing. The power contacts are longer. The outer long pins are gnd, the 2 long pins closer to the center are vcc. And duplicates of them are on the flip side. You can see them here

On disconnect, the CC pins will disconnect first, upon detection of this, the power will safely be cut before physical contact is lost on the power pins and arcing can occur.

I get the cool factor. Definitely.
It made be buy some. Couldn’t resist just, at least, seeing how they snap in-hand. I didn’t ever use them on a device, tho. I really couldn’t once I saw how unprotected they are in my hand, and how wobbly they felt. I’ve brought several different designs.

1 Like