I learned a bit about electricity. I know about voltage and amperage and stuff. I learned that a too high voltage can blow your equipment (or if you’re lucky just the fuse) but amperage is something that the device just takes as needed. You should just make sure that there enough available.
How does this work when charging batteries? I read something about a guy almost blowing up his battery because he charged it with a too high amperage… So I kinda had a short-circuit myself because I really don’t get how that works. This just doesn’t match with what I learned.
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When we say a device pulls x amps, that assumes normal voltage. When you said “damaged the equipment by putting too much voltage” that also means too much current. The current is actually what destroys the equipment
For pretty much everything you can think of, it’s a voltage source. This means a constant voltage is supplied by the source, and the load dictates the amps. Sometimes by ohms law for heating elements, so the current = voltage/resistance. For things like motor or battery charging, a little bit more complex or relation, but still, more voltage usually means more current.
Current sources do exist, but you probably aren’t familiar with any. Certain electronics like amps use them, current is held constant while voltage varies with load.
For a battery, yes, charging it too fast with too high of current will cause overheating and damage, and potentially an explosion. But how do you get high current? Simple. High voltage. Applying high voltage to a battery causes high current.
> I learned that a too high voltage can blow your equipment (or if you’re lucky just the fuse) but amperage is something that the device just takes as needed.
Actually, fuses blow on high current. Not high voltage.
This sometimes can be achieved by high voltage (say lightning), causing high current. But more than likely it’s caused by high loading, with the voltage being normal. Locking a motor from spinning will cause high current. Insulation failing and shorting out cause high current. Voltage is normal in both those cases, but fuses (or other protection) open.
You can blow thing on high voltage alone, even without it causing high current or any current for that matter. This causes insulation to fail. This is basically like lightning and static shock. Build up enough voltage, and even an insulator, like air, will conduct. And if that insulation is within electronic or the rubber around wires, it is promptly destroyed so it won’t work in the future as soon as it does this.
It’s more complex for “smart” device, where digital communications are exchanged between the source and load, and they can vary things. Your phone and fast phone charger do this. That’s why fast charging only works with chargers meant for it, and a simple setting on the phone can turn it on and off even without changing the charger. Phone just says “please give me this voltage and I will draw this current, this is what may battery can take”, and then charger goes “sure, I can do that. Here you go, as requested”
If you plug your phone into a regular dumb USB port, the port just gives 5V, the phone realizes it’s dumb so adjusts it’s charging circuits to draw 0.5A at that 5V. If something tries to take more than 0.5A, the port blows it’s fuse, although in a more metaphorical sense where no physical fuse is actually melting. If it’s on a computer, windows just starts yelling at you and cuts the device off.
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