USB C charging (60watts) without an inverter

YamInaBox

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So I see all these "solar generators" with these high power usb c ports that you can use without turning on the inverter. I'm curious how they pull this off? Does anyone have any idea how to do this? Is it possible to make a plug like this and connect it to the battery bank without having to use an inverter and deal with the power loss involved?
 

chrisski

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Not sure about 60 amps, but this charger I’m working on is suppposed to be capable of 32 watts:


I’ve measured it at 24 volts and .3 amps, so a little less than 8 watts.
 

Tecnodave

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most USB is 5 volts, no need for an inverter for that. There are chip boards that will generate USB voltages from a battery, Best to use one chip board for each USB port. A buck or two each 5 volt regulator board in small currents.
 

JMc

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The max theoretical power for USB C is 100W, or about 20A. I’ve never seen a USB cable that I would trust to carry 20A. :)
 

chrisski

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That voltage goes higher for these protocols, so amps go down. I’m unsure of the exact US-C protocol you’re asking about, but it would likely be 24 volts at 4 amps, not 5 volts at 20 amps.

They start out at 5 volts and as the device and charger shake hands voltage and amps got up.
 

rmaddy

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Most likely the title of this thread should have stated 60 watts, not 60 amps.
 

YamInaBox

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Most likely the title of this thread should have stated 60 watts, not 60 amps.
You're right, my mistake, I went ahead and fixed it. I'm basically asking about the laptop charging ports on the solar generators like bluetti and the like. Is it possible to make a circuit like that and how would you go about it? So one could possibly charge a laptop without an inverter.
 

YamInaBox

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most USB is 5 volts, no need for an inverter for that. There are chip boards that will generate USB voltages from a battery, Best to use one chip board for each USB port. A buck or two each 5 volt regulator board in small currents.
So basically, use a buck converter to drop the voltage down to 5v and it should just pull the power it wants? Or would you have to find a specific usb-c boad that will allow that much power to pass. Sorry, I'm a little clueless when it comes to the usb suff. I've seen ports that only have 2amps some that have 3amps and some that have more. Is that the usb board or a current limiter in the circuit or what?
 

YamInaBox

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Not sure about 60 amps, but this charger I’m working on is suppposed to be capable of 32 watts:


I’ve measured it at 24 volts and .3 amps, so a little less than 8 watts.
So if I have a 24v system then I could simply install that and get 64 watts out of the usb c port? Seeing you bucked your voltage up from 18 to 24 I assume you could do the same on a 12v system and get it to work? Would there be any draw backs to using a buck up converter on the 12v system? Like would the current wind up being super low and taking forever to charge? Or would it just pull more to get what it needs from the battery?
 

A.Justice

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So if I have a 24v system then I could simply install that and get 64 watts out of the usb c port? Seeing you bucked your voltage up from 18 to 24 I assume you could do the same on a 12v system and get it to work? Would there be any draw backs to using a buck up converter on the 12v system? Like would the current wind up being super low and taking forever to charge? Or would it just pull more to get what it needs from the battery?
Like stated above, there are quite a few different "USB C" charging protocols (QC, PD, etc). If you just want a simple QC 2.0 charger for a 12 volt system, you could get something like this.


Just fuse it and hook it to the battery, no need for AC inversion. There is some debate on how much power you can actually pull from a 12 volt source, so it may not technically be "fast charging" but my phone registers it as a fast charge, and it takes a little over an hour to charge my phone from dead.

If you have a 12 volt system, I would suggest getting a 12 volt automotive socket.


Hook it up, and you could use any car charging accessory with ease.
 

Tecnodave

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What they dont say......when these buck converters get overloaded they short out the control chip and output the full input voltage.....have you ever seen an iPad or android phone charged from a shorted buck converter, I have and its terminal.......I will not use some hack to charge my electronics.....at overvoltage they short out in a few milliseconds

You just might want to check out the crowbar overvoltage preventer, a fast blow fuse just ahead of a Zener diode that is rated at a voltage just above the proper charge voltage and below the maximum input voltage for your device .

At over-voltage the zener diode shorts the supply and blows the fuse thus protecting your device.
 

chrisski

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I'd use something like this: https://www.amazon.com/Charger-Qidoe-Voltmeter-Adapter-Motorcycle/dp/B0915CCH5N or similar ready to use 12V -> USB C auto charger.
That's basically what I used. The panel outputs at between 18 and 22 depending on the temperature and load. I also put a DC to DC converter between the panel and the charger.

I used it the other weekend camping and it did just what I expected by keeping two devices charged and I'll put it in a project box with a second charger.

The bad thing about the DC to DC converter I chose is its 12 to 24 volts with an input range of 10-18 volts. Because most of the time the panel puts out more than 18 volts, the output is the same as the input. If its hot outside panel voltage will drop and the converter will then kick the voltage up to 24 volts. Without the USB charger actually reaching 24 volts, the charger never goes to quick charge mode.
 
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