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If you need to buy the USB charger for your devices, what to look for in terms of determining the quality?

Ivan Kolmychek
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  • your question is off topic here as it's not about computers. Depending on your device you may ask it on android / windows phone / ask different (apple) stackexchange sites. – Máté Juhász May 26 '16 at 09:20
  • @MátéJuhász ok, thanks for the feedback. I'm not sure where to ask if you want the universal charger. Also there are some questions about USB chargers around here, that are not marked as offtopic, like https://superuser.com/q/412337/326474. Is that a moderation miss and it's really offtopic or is it somehow different? – Ivan Kolmychek May 26 '16 at 09:26
  • @MátéJuhász Another similar question: https://superuser.com/q/372819/326474 – Ivan Kolmychek May 26 '16 at 09:28
  • They're really old questions. Since than scope has changed. Also buying a charger really depends on the device you want to charge. Your current question - if not off topic - then would be considered as too broad. – Máté Juhász May 26 '16 at 09:48
  • @MátéJuhász ok, flag then it as off-topic and let it be there so others can see that this is an offtopic question. – Ivan Kolmychek May 26 '16 at 09:50

1 Answers1

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It's a rather complex answer overall, but I will try to cover the important aspects. Things to note:

  • Most of the current mobile devices use Li-Ion batteries or cells to power up. All Li-Ion batteries are compatible with each other (except for power tools - those require higher current, but not the case here). They are also compatible with direct USB charging (will talk about this below).

  • Li-Ion batteries are compatible no matter the capacity. So yes, you can use a 1000mAh battery with a phone that has an 800mAh one or 2000mAh one. The only difference will be how much it will last.

  • Li-Ion batteries charge up to 4.2V or even 4.35 (for high capacity smartphone versions). That means a power supply of 5V will charge them just fine (but should not provide unlimited current, no more than 2A for standard Li-Ion).

  • An important aspect of a charger is the maximum charge current. The higher that current, the faster the battery/cell will charge, but this must not exceed the recommended charge current limitation of the specific battery...and this can vary a little depending on the manufacturer. Most classic phone chargers use a charge current between 400 and 800mA.

  • Another thing to note for chargers is how complex they are. While some have only the basic charge circuit, most of the ones today will auto-stop the charge when the battery voltage reaches the level that is considered 100% charged (usually 4.2V for Li-ion) and have a signaling LED (single color or dual color) to indicate when the charge is complete.

  • The most complex ones charge discontinuously in order to prevent battery overhear and have advanced charge level detection capabilities and will no longer try to charge to full a defective (reduced capacity) battery. That means that they will charge the battery for something like 10s then stop for 2 seconds and repeat. In the halt interval, they also read the parameters (mainly charge level)of the battery.

  • While that, the most simple thing one can do to charge a Li-Ion battery is to cut an USB cord (from mouse/kb), use the red and black wires from it to + and - of the battery and plug it into a USB. The battery will certainly charge, but you will have no indication of when it is fully charged.

So basically it comes to your preference between the very basic (geek wire mode) and very 'smart' chargers.

For notebooks, you can't USB-charge anymore, because they use series (of pairs) of Li-Ion cells and will require higher voltage, how much being dependent on how many cells are in series.

Overmind
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