Is there a device that makes my multiple USB powebanks work together?
Is there a device that makes my multiple USB powebanks work together?
My current means of powering things is USB rechargable batteries. I have a about five of them that range between small 3000-5000mah ones to a big 20000mah interstate battery jump starter pack. Is there a device that lets me add all their power together into a centeral power source so I don't have to keep swapping them out?
I'm assuming you mean USB powerbanks.
I'd be surprised if there was such a device. It would require somewhat sophisticated electronics to work well, and the market for it would be small. A design that didn't result in power cutting off during the switchover would need to keep at least two powerbanks active at a time, and that could negatively impact efficiency since the electronics in the powerbank consume power when active even under light loads.
Or, I mean, it could just wire all the positives together and all the negatives together and hook that right into your target device.
It'd be the same output voltage regardless. A little less internal resistance, and lower step down in the later phases, but neither should make a difference in what you're powering.
Kinda like how there were those converters for the GameBoy back in the day that let you put C batteries into it. Same principle.
It's probably not possible to do that safely because USB power supplies aren't just dumb batteries. They actively communicate with the device receiving power about how much current the device wants, and should only supply 500mA if they fail to do so.
USB-A ports aren't supposed to receive input power, which is effectively what would happen in that arrangement after a powerbank shuts off to prevent over-discharge of its batteries. The resulting behavior is, as I recall unspecified and might result in damage to the powerbank. Worse, it could interfere with the over-discharge protection and damage the batteries. Charging damaged Li-ion batteries is bad, where bad may include fire, explosion, and/or emission of toxic gas.
What you need is a communist dictatorship. That ought to make them work together.
Plug the charging port of one into the next one?
That can work, but since the batteries are at roughly 3.0-4.2V depending on state of charge and standard USB power is 5V, that's a whole lot of steps up and down. Each one takes an efficiency hit. The last one in a series of five would likely waste the majority of its energy.
They typically won't provide power while taking in power.
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Just get a few big ones and put aside the small ones for portable/mobile use.