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[-] ilinamorato@lemmy.world 1 points 1 hour ago

I recognize why power banks can't charge and discharge simultaneously. But surely, with as cheap as integrated circuits and voltage regulators are, we can have a power bank that can be charged while it redirects some power around its cells to a device on the other side?

Sure, both would charge at half the speed. But if you only have one brick, it's better because you don't have to swap the cables halfway through. Plus, if your phone charges faster than the power bank (which it almost certainly will), you can unplug it at full charge before the power bank is done and let the bank finish- or unplug both and have a fully charged phone and a partially charged power bank.

Made even better, what if we integrated a power bank into a GaN charging brick? Plug it into the wall, use it to charge your devices every night, the smarts inside it regulate the battery with charge/discharge cycles; but then when you're ready to go somewhere you just unplug it from the wall, flip the prongs back inside, and go. Maybe you could even push a button to tell it to charge to full. It would also be a UPS of sorts, since it wouldn't know the difference between a power outage and you taking it on tour. Yeah, it would need to be kinda big and bulky when it's on the wall, but the convenience of not needing to track it down and plug it in before you go on vacation would be worth the hassle of needing to plug it into the bottom outlet on a power strip. Something about the size of a MacBook charger, but with all the high-wattage stuff swapped out for battery cells.

[-] Duamerthrax@lemmy.world 1 points 1 hour ago

That's called Pass Through. Some battery banks do have that.

[-] Boozilla@sh.itjust.works 2 points 2 hours ago

Last time I attempted this, I threw my back out for a week.

7/10 will try again.

[-] Mauryamj@programming.dev 9 points 10 hours ago

All u did was decrease the life span of power bank

[-] RampantParanoia2365@lemmy.world 2 points 11 hours ago

I nearly did this by accident a few nights ago. I was worried I almost killed it.

[-] filcuk@lemmy.zip 5 points 11 hours ago

Most banks can't charge and discharge at the same time.
If they did, worst case it heats up as it moves the energy around until it runs out due to losses or blows up.
Nothing that can go wrong really.

[-] Comment105@lemm.ee 9 points 11 hours ago

...or blows up.

Nothing that can go wrong really.

hmmm

[-] RampantParanoia2365@lemmy.world 2 points 10 hours ago

Yeah, that's actually worse than I thought it might be, lol

[-] OsrsNeedsF2P@lemmy.ml 46 points 1 day ago

No you shorted your battery

[-] FiskFisk33@startrek.website 3 points 10 hours ago

I'm pretty sure both directions are regulated, and the only reason it went up is some slight change in the voltage reading due to temperature or somesuch. All that I believe will happen here is that the battery, due to generating a bit of heat, will discharge itself at a safe rate.

[-] qjkxbmwvz@startrek.website 39 points 1 day ago

I'm not sure though


the power output and the charging input are both regulated and (almost certainly) current limited. So I think (not positive...) that you're basically dissipating your power in the inefficiency the charging and output circuits, with this power coming from the battery.

The inefficiency should (I think...) just be the round-trip inefficiency of the charging/discharging of your power bank


this should be way, way less than the short-circuit power dissipation.

The simplest toy model is to take a battery and try to charge itself. So you put jumpers on the + terminal and you connect those to the + terminal, and same for - (charging is + to +, NOT + to -). But this is silly because you've just attached a loop of wire to your terminals, which is equivalent to doing nothing. With charging circuits in between things get much more complicated, but I'm not sure if it goes full catastrophic short...

[-] OsrsNeedsF2P@lemmy.ml 13 points 1 day ago

I think you're right and I was just memeing, but I'm curious how the battery percentage went up

[-] myplacedk@lemmy.world 2 points 13 hours ago

I guess that running power in a circle like that as fast as possible might heat up the battery, which reduces internal resistance, which increases battery voltage during load, which tricks the sensor that uses voltage to estimate charge.

It similar to when a fully charged but very cold car battery cannot start a car, as if the battery was discharged. Then you turn on the cars lights for a while, which to the cold batter is a significant load. The battery heats up, and then you can start the car.

[-] michael_palmer@lemmy.sdf.org 14 points 1 day ago

I think the charge controller counts the amount of energy that has passed through it.

[-] BarbecueCowboy@lemmy.world 10 points 1 day ago* (last edited 1 day ago)

You're probably mostly correct. Some of them do literally count that, but (to my knowledge) most measure voltage as a battery with lower charge usually outputs less and vice versa.

[-] Sterile_Technique@lemmy.world 6 points 1 day ago

My guess is it didn't, and the numbers were pulled out the OP's ass.

Otherwise, idk how power banks monitor their percentage of charge, but being that it's a percentage, if you fuck up the capacity, the same amount of energy will take up a higher percentage of that capacity. /shrug

[-] qjkxbmwvz@startrek.website 6 points 1 day ago

I'm curious how the battery percentage went up

Physicists hate this one weird trick...

[-] Grandwolf319@sh.itjust.works 67 points 1 day ago

In this house we obey the laws of thermodynamics!!

[-] Sibbo@sopuli.xyz 76 points 1 day ago

Does burning down your own house count as science? Give this guy a medal!

[-] TachyonTele@lemm.ee 25 points 1 day ago* (last edited 1 day ago)

Only if you blast Talking Heads while doing it.

[-] marcos@lemmy.world 3 points 1 day ago

No anymore, but if you destroy it in some more interesting way...

[-] qjkxbmwvz@startrek.website 2 points 1 day ago

Is that true though? As in, is it really that dangerous? It seems that you'll dissipate power equal to the inefficiency times the nominal charging power, so something like 5V x 2A x inefficiency (inefficiency being 1-efficiency), which will probably be of order a watt.

I can use my car battery to charge itself without any issues


I just plug the red terminal to itself, and same with the black, which is to say, a battery is always connected in a way that "charges itself."

I think the key is that the battery probably isn't really playing a big role in OOP's setup


electricity doesn't "go through the battery," it just goes from the charging input to the power output circuits, with the additional power (due to inefficiency) being provided by the battery.

[-] Entropywins@lemmy.world 7 points 1 day ago

Battery pack loopback test successful...

[-] random_character_a@lemmy.world 34 points 1 day ago

Just informed to the Nobel comittee.

Yea just gotta bring it on a plane and strap a coundown timer to it that makes loud beeping sounds

[-] DragonsInARoom@lemmy.world 8 points 1 day ago
[-] TachyonTele@lemm.ee 3 points 1 day ago

My heart can't take it anymore

this post was submitted on 10 Jan 2025
327 points (94.1% liked)

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