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This question already has an answer here:

I am told that I must use 5V, 1A charger to charge power bank. If I will use 5V, 2A charger then will it burn power bank?

Is that possible?

\$I = V / R\$

Charger give constant voltage and current depends on resistance. That is why I think only Voltage is important and charger must be able to give enough current.

But battery bank may have some smart impulse chip like charger have. It may play with its resistance and voltage may jump.

Also I do not understand if I can plug battery bank in PC's USB to charge power bank.

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marked as duplicate by RedGrittyBrick, Dave Tweed, PeterJ, Stephen Collings, Anindo Ghosh Oct 1 '13 at 12:18

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • \$\begingroup\$ See: electronics.stackexchange.com/q/34745/2028, \$\endgroup\$ – JYelton Sep 30 '13 at 20:13
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    \$\begingroup\$ batteryuniversity.com Read the part of the site, which deals with charging for your particular chemistry. \$\endgroup\$ – Nick Alexeev Sep 30 '13 at 20:17
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    \$\begingroup\$ This question cannot be meaningfully answered without detailed knowledge of your "power bank". If it has an internal charge controlling circuit, then an external power supply is required (the specs of which may, or may not, be flexible depending on the sophistication of the charge circuit). But if it's just a battery, then an external charge controller is required. \$\endgroup\$ – Chris Stratton Sep 30 '13 at 20:52
  • \$\begingroup\$ Power bank has 6 18630 cells and some electronics. I have not disassembled it to see what is inside. It has 3 USB connectors. IN 1A, OUT 1A, OUT 2.1A \$\endgroup\$ – Max Sep 30 '13 at 21:53
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This is a very common question here.

Current is pulled depending on the load, not pushed by the charger.

If the load needs or pulls 1A, then the power supply must be able to supply 1A. If it is capable of supplying more, then that's fine; the load will not pull more just because it's connected to a supply with greater capacity.

Think of it this way: A mains power outlet can operate a small space heater which may require 1500 watts. But it also can charge your phone. Your phone does not suddenly burn up or consume more power, even though it is plugged into a supply that is obviously capable of much more current.

Edit:

Your computer's USB ports are only rated for 500mA (or 0.5A). If your battery pack requires 1A, then the USB port will be unable to supply the current. At best your computer will shut off the USB hub because of an over-current condition. At worst you will permanently damage your USB port(s).

Warning!

I was treating this as a power supply and device rather than specifically as a battery bank and charger. In the latter case, the charger may necessarily limit current to a value that is acceptable for the battery bank composition. In such case, it is not recommended to use a different charger or power supply than what the manufacturer specifies.

Without knowing how your device operates, it is not possible to tell if current is limited at some other point, such as the battery bank itself, which would allow the use of a different power supply.

That being the case, I must recommend you adhere to the 5V 1A rating recommended by the manufacturer.

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  • \$\begingroup\$ Thank You. Yes. Exactly. I also think I can use more powerful charger. But few ebay sellers in red printed that I can't use 5V 2A to charge it. I wished I have 1A charger. But all my charges are less or more. And I debate if there any risk to use more powerful one. \$\endgroup\$ – Max Sep 30 '13 at 20:16
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    \$\begingroup\$ They prohibit specifically a 2A charger? (Instead of prohibiting use of anything over 1A?) That seems unusual. Your power bank may need to be current-limited to 1A, which the designer may have done with charger that is specific to it; but we would need more information about it to make any such determination. \$\endgroup\$ – JYelton Sep 30 '13 at 20:22
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    \$\begingroup\$ @JYelton You are dangerously oversimplifying this. Some battery chemistries during some stages of the charge cycle are charged at constant current (CC charging). The charger is in fact pushing current. It will raise voltage to push the current that it's intended to deliver. If too small a battery is presented with too large a current, the battery's live will be diminished, and even more exciting things may happen. \$\endgroup\$ – Nick Alexeev Sep 30 '13 at 20:29
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    \$\begingroup\$ Indeed, this post presumes that the word "charger" is actually intended to mean "Voltage Regulated DC Power Supply" - a common if incorrect usage. Given that we don't know the actual situation of the questions, it is entirely possible that the device being sought will actually be responsible for controlling the battery charge, in which case using a high current voltage-regulated power supply would be quite inappropriate. "5v" does suggest the power supply role, though not strongly enough to rely on. \$\endgroup\$ – Chris Stratton Sep 30 '13 at 20:49
  • \$\begingroup\$ Can't find exactly same listing on eBay. But it seems 1A and 2A charger a most common and seller was telling 1A not 2A. \$\endgroup\$ – Max Sep 30 '13 at 21:45

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