I was looking at the following question: How to Calculate the time of Charging and Discharging of battery?
And I was wondering if the voltage takes part in the calculation somehow?
For example, I have the following items:
- 5v 1000mAh battery
- 6v 1000mA charger
- 12v 500mA second charger
both chargers have a power of 6 watts

Which one of these will charge the battery faster and how fast?

On one hand my logic says that because both chargers have the same power, they deliver the same charge to the battery,
but on the other hand it seems that battery charging is calculated according to the current only.

  • 1
    \$\begingroup\$ There is no such thing as a 5V battery. Do you mean a USB power bank? \$\endgroup\$
    – winny
    Commented Apr 11, 2018 at 12:59
  • \$\begingroup\$ @winny Maybe it's a 4-cell NiMH. \$\endgroup\$
    – DKNguyen
    Commented Jun 24, 2019 at 5:07
  • \$\begingroup\$ @DKNguyen It’s a stretch but yes. \$\endgroup\$
    – winny
    Commented Mar 30, 2020 at 11:04

2 Answers 2


The answers (mine and others) to the question you cite adequately cover your query.

A battery or battery charging system USUALLY specify voltages in a limited range. In such cases, mA input is an indication of charge rate if the system will accept the offered current.

In a small percentage of cases a system will tolerate a wide range of input voltages, with voltage being converted internally to meet requirements. In such cases supplies with the largest I x V product will charge fastest. When supplies have different V specs BUT the same power spec then both are nominally equal but the system is liable tom operate optimally at a voltage which makes one or other slightly faster.

Generally, for systems not designed to accept a wide range of input voltages. applying a voltage much greater than specified may result in destruction.


In practical, if you put 12 V across 5 V then the battery will be damaged. Theoretically it van charge the battery faster but the battery will be so hot to be stable. If you insert 6V the battery will charge. It will take about 1 hour to charge the battery fully.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.