Diy DC USB pd for laptop and highspeed charging for tablet

[Jeremiah]

I have a few related issues ...
1-I would like to make a DC USB PD charger for a laptop which needs 100w.
House voltage is 48v. Most of our things run on DC, fans, lights, USB charging etc. Is there any special circuitry required or is this as simple as sending 5v over a 20v USB line? I understand it would need to be protected from voltage spikes. I'm just wondering if there is special circuitry involved like the highspeed quick chargers have or not?

2- if i want to make an ultrafast charger dc-dc for phones and tablets does anyone know of a part that has the right chip on it? Currently i have DC DC devices that support QC 3 but not the ultrafast option some devices support. I realize it's not great for batteries to ultrafast charge, this is only for some occasions.

3-does anyone know where to source highly reliable DC DC buck converters or how to modify them to make them very reliable (i live in humid Asia). I don't mind soldering and such to make things reliable. Thanks in advance

 

[Don B. Cilly]

I made a 24-18V thingy for my laptop (which uses <10W idle, goes to ~20 on full load).
Very simple, an LM7818 (about €1) and a small transistor.
It worked, but the laptop complained that it wasn't an "approved adapter" and started doing all sort of silly things. I gave up.
-

 

[Jeremiah]

Thanks Don but i know how to just do a step down. For that I'd prefer a buck converter as it's less wasteful

 

[maxx-v0]

It looks like you need module like this - https://www.aliexpress.com/item/1005004383983407.html but most of them requite 24_35v, so you need add dc 48->24 converter

 

[Jeremiah]

Exactly what I need. Thank you!

 

[pekka8]

I'm also lookin to connect USB PD plugs to12V system. USB PD seems to have 5A max current, so for example for 100W voltage is 20V.
I guess these cheap adapters don't have step up converter 12V -> 20V?

https://www.amazon.com/65W-12V-USB-Outlet-Laptop/dp/B09YTWNCM2

So you would need a additional step up converter for voltage?

 

[sirslayer]

I would use this adapter…. and I would recommend good usb c 3.1 cable of your likings.

I'm also lookin to connect USB PD plugs to12V system. USB PD seems to have 5A max current, so for example for 100W voltage is 20V.
I guess these cheap adapters don't have step up converter 12V -> 20V?

https://www.amazon.com/65W-12V-USB-Outlet-Laptop/dp/B09YTWNCM2

So you would need a additional step up converter for voltage?

Baseus 100W USB C Car Charger, PPS PD3.0 QC4.0 Super Fast Charging Type C Car Charger with LED Display Adapter Compatible with MacBook Pro Laptop iPad iPhone 14/13 Pro Max Samsung S22 S21 Ultra/Tab S8 https://a.co/d/iwV9U9Y

 

[MarcoWasRight]

It looks like you need module like this - https://www.aliexpress.com/item/1005004383983407.html but most of them requite 24_35v, so you need add dc 48->24 converter

I have had terrible luck with anything that has the SW2303
The SW3518S is the buck option I prefer but I don't think it'll work on a 48V system. Pretty sure anything on the market right now would require you step down the voltage.
I bought the 4 channel version just because it looked cool but I can't even fully test it because I can't find a way to sink 400W PD. If I were you I would take a look around Feb 22 Store on Aliexpress.

https://www.aliexpress.us/item/3256803122247067.html?spm=a2g0o.detail.1000014.3.2ba86ff5q5u1nR&gps-id=pcDetailBottomMoreOtherSeller&scm=1007.40000.333918.0&scm_id=1007.40000.333918.0&scm-url=1007.40000.333918.0&pvid=ed03c307-b8fd-4655-93a2-7de32fa2c91a&_t=gps-id:pcDetailBottomMoreOtherSeller,scm-url:1007.40000.333918.0,pvid:ed03c307-b8fd-4655-93a2-7de32fa2c91a,tpp_buckets:668%232846%238113%23613&pdp_npi=3%40dis%21USD%2110.12%218.7%21%21%21%21%21%402103252b16839540573703013eefd1%2112000025127933696%21rec%21US%213589144974

 

[jezohare]

I am also looking for better DC charge adapter for my laptop. I have 3 "AUKEY" brand 12v dc car charger (lighter socket) USB-C & USB adapter to charge mobile phones, headlamps, cameras, powerbanks etc in the car, bike & from solar batteries at home but it don't work well with my macbook air - It works most of the time, but with 'gaps in the charge', sometimes quite frequent & therefore I get an annoying sound from macbook every time it starts charging again, not sure if it could also damage something. So back to my 220v USB-C adapter on the inverter.

I saw the links above and nothing seems like a robust battery to USB-C charging solution, they all seem similar to what I have.

I read there seems to be a 3-5% chance we could have a solar storm in 2024 / 2025 that could disrupt AC power (& inverters) for a while, I think its a good idea to have some good DC (& analog/manual) life solutions for basic things like water pumps, lights, charging devices, cooking etc.. trying not to become a doomsday prepper but I keep looking for DC things now just in case

 

[pekka8]

I would use this adapter…. and I would recommend good usb c 3.1 cable of your likings.



Baseus 100W USB C Car Charger, PPS PD3.0 QC4.0 Super Fast Charging Type C Car Charger with LED Display Adapter Compatible with MacBook Pro Laptop iPad iPhone 14/13 Pro Max Samsung S22 S21 Ultra/Tab S8 https://a.co/d/iwV9U9Y

Missed your reply. This one is only 65W per port but Baseus has also 160W model with 100W per port. Problem there is it charges at full power only for about 15 mins then thermal throttles to lower power. So something similar to this but a bigger with better cooling would be perfect. Maybe with a barrel connector.