Once you have multiple USB adapters (not sure you can parallel these), stepping down and converting the AC-mains voltage, and a big boost-converter to step everything back up again are you gaining anything over just using a standard AC-mains to pack-voltage charger box?
The few percent loss of power through the USB adapters and again through the boost-converter can add up. Though I guess it’s not a real issue when using the AC-mains. If you were using a pack as a type of powerbank then it could be a problem.
1: ability to charge slowly using whatever usb C PD charger, if you built step-up into the board. Even if you do not have one they are universal if you borrowed one.
2: ability for that PD charger to be battery powered if you so desired, and easily using that same PD battery for all you other devices.
I think most of the time that you’re using multiple PD sources they’ll likely be different models, and that could cause some problems. Even good designs are often mains referenced to a small extent, like loosely coupled through a feedback resistor or capacitively coupled through parasitics. This could be an issue if you have 2 sources that are referenced to mains, but not at the same potential relative to mains. If they are connected in parallel you’re effectively shorting together the difference in the common reference.
It could probably be done with some more thoughtful input protection, and maybe it’s not really an issue at all, but it doesn’t seem completely plug and play
sorry I made that giant blob response where I almost wanted to make a thread dedicated to the PD sources. So I was really looking for a solid one to get to try all this with, paralleling and stuff.
I am looking mostly at this as it is the cheapest and I found a nice video showing it off:
That would be using a battery or maybe 24V server psu so they would have identical V DC input.
does not seem to need contact with the case for cooling so I was thinking the easy way to make a compact dual PD would be to stack two of these in a case with some airflow.
Are their numbers on the (two?) bigger chips?
If you can read them we can look up some info on whether their outputs can be paralleled. I’m hopeful but, TBH, doubtful this can be done.
I was confused by the AliExpress page for that module as one image seems to say that you can only get the 20V/5A 100W PD output by using a >87W PD input. But if you already have a 100W PD adapter to power this module’s input then why would this module be needed?
But, another image shows the barrel jack being used for the input and a USB tester showing the PD output of the module being 20V/5A.
I’m definitely confused about what that module can do but I’m very interested in seeing what can be done.
That is prob some bad translation. It seems to me as long as you give it like 21+V then it can put 5A at 20V out. I am curious about when we will see these buck USB C PD modules with faster shipping on ebay/amazon, does not seem to be a large amount of people using them but when they are only in china it would be that way.
Why not just use an AC-mains powered 100W PD adapter connected to a USB pass-through tester that can force the adapter to 20V/5A? Then send that to the boost charger.
No need to have an intermediate stage to convert voltages.
they are the layer of intercompatibility that makes the battery bank for your phone also for the board.
It’s possible that confusion has occurred.
It is true that if you have a battery bank powering a USB C PD system that the battery powering the PD buck could instead direct output be connected to the boost inputting to the boards battery. wow mouth full there
It would really depend on the design of the battery bank PD system and your boards buck input.
I see your point.
I would hope that the tester module would handle compatibility issues but having that additional USB stage definitely takes care of it. Thank for your patience in dealing with my questions.
huh now I am kinda thinking about how it would be a fun challenge to make a booster pack/USB PD powerbank that supercharges.
A 8S2P with A123 cells and charge the sucker over 50A or something. Then it can more slowly keep the big pack charged. 130Wh is not much, maybe 3P but getting too chunky then.
Has anyone else just permanently put the charger in the enclosure and used an AC adapter on the enclosure? Then you just need a 2m 3 prong cord and still get 100W
And it’s naturally water resistant like phase leads