Homemade USB Quick Charge 3.0 with no battery

chrisski

Solar Addict
I am have built and am testing a homemade USB Quick Charger 3.0. I'm using a charge socket, a solar panel and a converter. Want to do this without the battery, so I'm hoping the converter will work. Long story short, not sure this project works for a bunch of reasons. I know I'm not the first one to try this, but I don't see results in the search feature or Google.

I bought a 64 watt USB Quick Charge 3.0 Socket that also comes with USB-C. This can draw up to 64 watts when it has greater than 24 volts of power and goes into quick charge mode.
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I also used one of my Lion Energy Portable 100 watt panels, which is unstickered, but the performance specs from my multimeter and battery charger make the open circuit voltage of 21 volts and open circuit amps of 6. When it is performing, the max my charge controller saw was 18 volts and 5.6 amps.
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I did not use my Solar Charge Controller for this, because I want some ease of setup and portability. I used a up down buck converter to get the voltage from the panel up to 24 volts.
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The buck converter took the power from the 100 watt panel, and converter it to 24 volts, and when plugged in the phone did charge. The picture did not come out good, but the charger is saying 24 volt.
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This does look like a success, so the only way I have to measure this is a amp meter. This is the first time I used this thing. So, appears there are .381 DC amps at 24 volts going into the USB Quick Charge. So at a 24 volt profile, it should charge at a max of 33 watts. The Amp Meter puts the charging watts at 9.1 watts. When I see my phone plugged into the 12 volt side of my RV, it can pull 1 amp, so that would be 12 watts.
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So by going to 24 volts for quick charge, appears my phone is charging a little slower. Whole intent of this thing is to be able to sit in my chair somewhere outside with the 100 watt panel and plug this in to charge my phone. Not pretty, but as I tweak this, I'll put it in a project box,
 

chrisski

Solar Addict
After an hour and a half of charging my iPad while not in use, went from 76% to 94%. I don't think this quick charged and I think the charging was negligible at the end.

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When first hooked up, this is what I saw 24 volts and .316 amps.
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When I returned, it was still at 24 volts, but had dropped to a negligible .002 DC amps. When the iPad was opened, the charge indicator still showed and the amps jumped up to .3+.
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Substrate

Solar Addict
Interesting stuff but just some .02c comments ...

Watch out for the grass with that little ground mount. Elevate the bottom off the grass with something nearby, a stick, whatever. You know it's just begging to cast a little shadow across the bottom as time passes when you aren't looking. :)

Direct device charging with no stable source is sometimes an issue on how a device reacts to that. Ie, if a shadow passes, large bird flies over with a shadow, whatever, some devices when seeing what they think is a brownout, will be protective enough to stay at that level with their smart-charge circuitry even if the full output returns.

You can see how the device reacts / resets if you put yourself or some other covering in front of the panel, and then remove the shadow and see how the device's own charger circuitry responds. Sometimes you have to do a full powerdown / reset to get full current charging again. Total pain but depends on the device, and sometimes how the cabling is wired internally.

Other than that, maybe think of using a smart-iq battery pack to charge instead. I know the Anker brand recovers well from weird power doing direct stuff like this. But yeah, that's another thing to have around and an intermediary step you may be trying to avoid.
 

chrisski

Solar Addict
You can see how the device reacts / resets if you put yourself or some other covering in front of the panel, and then remove the shadow and see how the device's own charger circuitry responds.
Thanks. I had not thought of doing that today. This recovery is actually a concern for me. I am wondering how steady the converter power is. Reviews say there’s a 300 ma ripple. I can’t measure that, but there is .1 amp AC power. When that panel is putting out 6 charging amps, I put my hand across it and power out drops to 1 amp. I am trying to come up with some device to test how the converter works putting out a couple of amps. I may pick up a 24 volt incandescent or LED bulb and see what happens.

Maybe that this project is not practical without a battery. I am somewhat reluctant to hook my expensive USB devices to this now. A battery would normalize that voltage. The converter has potential to draw 10 amps at 12 volts, and to I have a 92 ah lead acid battery that would match that charging voltage wise, but now I’m lugging around a full sized car battery. This may turn into a 20 ah lithium battery build.
 

Substrate

Solar Addict
There are other issues too which may not apply in your situation ...

Heat. Directly charging the device means you'll probably have it in the shade, but in summer devices can still get toasty while charging which isn't the best for the battery. Depends on environment, time of year etc.

Theft - you can't leave your device if you are camping whatever, run around to check on something, and when you return, the device is gone. Better to have a battery-pack stolen.

In the long run I have done the same - but I just got a honking big Anker li-on bank that has TWO charging inputs, and a larger film panel that has two regulated 2.5a outputs. That hit's the Anker pack pretty quickly and overall is a smaller and more practical "just throw it out there" measure.

No worry about shadows with the thin-film panel. Already regulated with it's own multiple 5v outputs. Large capacity Anker batt with it's own smart-iq inputs figures out all the reset issues, or weird usb power cabling (they are different). No experience with USB-C myself, but the idea is the same.

Just turned out to be more practical to do it this way with an intermediary charging step for me. Weird just picking it off the shelf and having nothing really to setup.
 
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