power bank w/ 12Vdc at 3A output, for running a CD player

lumen aeternum

Enlightened
Joined
Sep 29, 2012
Messages
907
I have a retro boom box with a built in lithium polymer battery that it says takes 5 hours to charge, but after a few years, it only runs a cd for about 30 minutes. I might take it apart to see if I can replace it with a larger capacity, but probably would need to solder, which I avoid.

The wall wart charger puts out 12Vdc 1.5A. I don't know how much power the CD draws. EDIT: the speakers are each 5W rms, so figure 10W plus the CD motor...

I plugged in a COAL 8Ah power bank that has different voltage outputs, and says 3 "QC" voltages including 12Vdc at 1.5A. The CD ran for a little while, but the COAL may not have been fully charged. Have to try it again & time it.

What does "QC" mean & indicate?

How many Amp hours might I need to make the CD run for 4 or 8 hours? Is there a reliable brand that will give me the stated Ah capacity? And I guess I need some circuit protection to keep it from being completely drained, which I would think the COAL would have but... Do I need a $100 thing the size of a car battery? Would a car battery work at its nominal 14V or blow something from overvoltage?

I see ads for cables that have Type C USB to a "12v" barrel plug. How many sizes of 12V barrel plug are there? The wall wart plug is about 1/2" long and 3/16" dia, but the ads are all gone metric, and I see 6mm x 4mm as a size?

What is a "PD" device? This has the wrong size barrel plug though:

"【USB C to DC 12V】Built-in a smart PD chip,it can convert the PD Charger into DC 12V. It supports 12V 3A Max. output for devices with 5.5*2.1mm DC interface."

"This Cable is just a conversion device,you should provide correct PD power Adapter or PD Power Bank which support 12V output.

Please note that Type-C PD charger power must be over than the output end power. If the usb charger supports 5V/9V/15V/20V without 12V, the cable will output the closest lower voltage 9V. "


Or this?

" INIU Portable Charger, 22.5W 20000mAh USB C in & Out Power Bank Fast Charging, PD 3.0+QC 4.0
LED Display Phone Battery Pack Compatible with iPhone 15 14 13 12 Pro Samsung S21 Google iPad Tablet, etc. "
"With one USB-C port and two USB ports"


But it does not state the output voltages, and I don't know if both of the two types of port will output 12v. I have a cable with a standard size USB to the correct barrel connector. So this power bank would have to output 12v on the "big" USB jack.

Q: Is the DC barrel jack for input, output or both? What is the voltage and current for it?
A: To my knowledge it can be used for both. The USB-C port is rated for 5V at 3A 9V at 2.22A and 12V at 1.5A
Props to the manufacturer for this "All the power banks could only supply 60%-70% battery to other devices, since around 30-40% of the capacity is lost in circuit heat and voltage conversions
 
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lumen aeternum

Enlightened
Joined
Sep 29, 2012
Messages
907
This COAL power bank is not working. I deduce that the QC circuit cannot decide what voltage to give to a "dumb" device, and the device needs a QC circuit to ASK for 12Vdc ???

Solar power panels usually output 12Vdc. But need to recharge it from 120vAC...
 
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