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USB Buck Converter, DROK 4pcs DC-DC Step Down Module 6-32V 12V 24V to 5V QC 3.0 Charging Module Power Supply Voltage Regulator Volt Transformer Board?
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9 reviews of this product found across Reddit:
So you dont want to use that module, you can find a usb PD or QC module that has a wider input voltage, like this: https://www.amazon.com/Converter-DROK-Charging-Regulator-Transformer/dp/B087RHWTJW/ref=mp_s_a_1_3?dchild=1&keywords=qc+buck+converter+usb&qid=1621459544&sr=8-3
Much wider input range
Thanks for the response!
Yeah, looking back at, maybe using RMS to calculate the wHr needed to sustain 7-8 hours battery life wasn't a good metric because this thing is humungous.
You thinking a couple of these bad boys might make the battery size more justifiable haha.
u/myself248 I'd love to hear your thoughts as well!
Thank you both again, I really appreciate it!
I use one of these USB buck convertors to power my Raspberry Pi. It's wired to the printer's power supply, so when the printer is switched off, the Pi loses power too.
I don't always remember to shut the Pi down safely before cutting power, but I've never corrupted an SD card. I think maybe because OctoPi doesn't write to the SD card very much, the chance of catching it during a write when you shut down is pretty unlikely as long as you aren't in the process of uploading a file or processing a lapse. Or maybe just corrupting SD cards is an overstated. Or maybe because I use decent SD cards.
He's actually got QC3.0 compatible buck converters in there, Amazon.com: USB Buck Converter, DROK 4pcs DC-DC Step Down Module 6-32V 12V 24V to 5V QC 3.0 Charging Module Power Supply Voltage Regulator Volt Transformer Board: Home Audio & Theater
These will work for converting 24v to 5v USB: https://www.amazon.com/Converter-DROK-Charging-Regulator-Transformer/dp/B087RHWTJW/ref=mp_s_a_1_3
> I had no idea the amp could take more than 24v.
Well, the completed amp module doesn't say so, it claims a max of 24v. But look up the datasheet for the amp chip. Then tear apart the amp and look at the voltage ratings on every component in the power path. Combine all this info and use your own engineering judgment to determine if you can push it to 25 or 26.
> However, this could be entirely explained by PSU B's low current output right?
Bingo. And you'll run into exactly the same situation (albeit at a higher point) with the DC-DC converter, unless said converter is incredibly beefy, or backed by a capacitor adequate to buffer the largest bass hit. (Either of which is a silly waste of space, weight, and cost, imho.)
> Also, quick question about current draw. If each individual cell is rated to discharge 15A at a given point in time. Because this is a 5s pack, does the discharge rate increase by 5x? Is my new discharge rate 75A
Not because it's 5s, but because it's 5p. (Or on the 6s4p pack topology, not because it's 6s but because it's 4p, your new max current is 60A.) Series increases the voltage. Parallel increases the current. Anyway, assuming your inter-cell wiring is up to snuff, yes. That's a big assumption though. Your lab has a good fire extinguisher near the exit?
Also to be super clear, all the cells in a given parallel group have to be in parallel first before the groups are wired in series. That's the middle vertical wire in this illustration. So the BMS's balancing function can touch all the cells. I like how this writeup explains it, drawing each group as "1s4p" and then putting all those in series (his ebike pack ends up being 12s4p!).
> You thinking a couple of these bad boys might make the battery size more justifiable haha.
Oh for sure. No sense carrying around that much power if you can't use it for other stuff. Consider one of these instead/also, because PD is the future. Run the laptop and soldering iron off the boombox? Don't mind if I do!
But in both cases, put hard power switches upstream of them, so their idle draw doesn't leach the battery down in storage.
I've got these daisy chained.
I'm not great with electrical stuff so please let me know if I'm doing something wrong.
Tip from a South African where rolling blacouts ( aka loadshedding) happens almost on a permanent basis. Be prepared!
You get one of these solder some leads and clips onto it and throw it in the cupboard or your car.
These step down converters are also very handy. One of them hooked up to an LED light strips and a 12V 7Ah battery and you will have decent light for a few hours.
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