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Li Ion Charging

  1. Nov 16, 2016 #1
    I made powerbank for my bicycle to charge my phone while I ride it.
    I am using one 4400 mah Li Ion battery. I was wandering If it is possible to charge the battery with less than 1 amp and not constant current? Because, generator I have on my bike produces 3W and it varies as I change pedaling speed.
    Thank you in advance !
  2. jcsd
  3. Nov 16, 2016 #2


    Staff: Mentor

    In a previous post here on PF, I read that cell phone charging protocols are complex. They must prevent damage because of improper charging.

    Hopefully someone else can provide details, but they will need to know the make and model of your phone.
  4. Nov 16, 2016 #3
    I think the model of the phone does not matter as long as 1amp 5 V is provided. But in my case, I have 5 V constant but variable current.
  5. Nov 17, 2016 #4
    I have been looking at these really cheap modules on ebay, search on "LI-ion charger module" or battery charger board or similar terms. Many of these regulators are for 5V input but I found one with this title "LiPo Charger Step Down 5A 5V-32V to 0.8V-30V Power Supply Buck Module" that would cope with a wider range of input voltage typical of a human powered generator, you just need to ensure that the generator output is at least 5V after rectification most of the time.

    A deeper search of more sites may find an even better suited module with lower min input voltage, this can't be a new problem, someone must have solved it previously, keep digging. Expand the search to buck and boost voltage regulators. These are generally inexpensive component modules. You don't need really pure power for charging.
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