I have gone through various materials online to understand the concept of trickle charging and other types of charging. I have a few queries which were not clarified.

From what I understand, trickle charging helps the battery to reach 100% by providing very low current upon reaching 90-95% of the battery level. So, it always provides some amount of current despite the charge level of the battery, right?

My query :

  1. Is trickle charging property of the charger that I plug into the wall socket and connect to the phone? Or is the property of the phone to support trickle charging? Is the charger an intelligent device to provide trickle charging? From what I observed, chargers only have power components and circuitry to deliver the required amps at the mentioned voltage, say 5V.

  2. Can someone also help me to understand what is Float charging? From what I understand from the Wikipedia section on float charging, it charges to the required battery voltage continuously at the mentioned voltage and the current and then stops upon reaching 100%. After the battery drops to some threshold (which is set by the phone or the charger ? please tell this ), say 95%, the charger wakes up and provides charge to increase the battery to 100%? Am I right?

  3. How is fast charging different from the above two types of charging? Are there any other types of charging apart from this?

Please help me understand my queries.


1 Answer 1


Is trickle charging property of the charger that I plug into the wall socket and connect to the phone?

The phone chargers which we connect to the wall socket are AC to DC converters which provide 5 V. The trickle charging and other features are from the charger IC or section which will be put inside the mobile phones.

After the battery drops to some threshold (which is set by the phone or the charger?

It is set by the phone. Think of using chargers from softener supports to different phones with different types of batteries.

Float charging is also a property of battery management system inside the mobile phones, if they are implemented. This is not property of the charger.

  1. Trickle charging charges the battery with a short amount of charge ( for example C/40) regardless of the battery voltage.

  2. Float charging charges the battery for a while and waits until a preset voltage is reached. It charges the battery to full again

  3. Fast charging needs to be supported by chargers as ell. The phone can ask the charger to provide fast charging over the USB cable. Charging happens at high voltage later.

  • \$\begingroup\$ "Trickle charging charges the battery for a very short amount of time regardless if the voltage" - I'm not able to understand when you say regardless of the voltage. Please explain that too. If a mobile battery reaches 100%, what are its values in voltage or current? Like please provide some example with metrics? percent is the ratio of input to output right? What are those input and output in the case of mobile battery showing 100% ? \$\endgroup\$
    – user220456
    Mar 7, 2020 at 9:43
  • \$\begingroup\$ I have updated the voltage. It is battery voltage. Charging the battery with very very small percentage of the battery capacity will enable to compensate for the self discharge of the battery so that the battery will be kept at full charge all the time. \$\endgroup\$
    – User323693
    Mar 7, 2020 at 10:07
  • \$\begingroup\$ Ok. Thank you. But you missed you telling me this : "When the battery in my mobile phone reaches 100%, what does it mean? Like does it mean like it has charged upto full voltage? or... "? \$\endgroup\$
    – user220456
    Mar 8, 2020 at 4:09

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