Solar power bank for e-bike

StephanieLynStephanieLyn Posts: 1Registered Users
Hi, I am trying to figure out if I can charge an ebike with a solar power bank. I'm hoping someone here can help me figure this out. the e bike that I would like to get has is 36V and 500Wh. Is this possible to charge using a portable solar bank? If so which one is the best one I should get that would charge it in the least amount of time? Thanks!

Comments

  • BB.BB. Posts: 27,931Super Moderators, Administrators admin
    It can be done... But charging Li Ion batteries incorrectly can cause the batteries to fail or catch fire.

    Many Li Ion battery banks have BMS (battery management system) to help ensure the the cells are properly charged/not over discharged. And BMS systems may directly communicate with the charger, or at least are designed to work with a specific charger output profile (i.e., not too high of charging current, not too high of voltage, etc.).

    An alternative is to create a Solar->12 VDC battery bank->AC inverter->AC bike charger (or skip the AC charger+inverter if you have a portable DC charger for the ebike).

    For example, 2x 6 volts @ 200 AH "golf cart" batteries store (12 volts * 200 AH=) ~2,400 Watt*Hours. Or realistically:
    • 2,400 WH of storage * 0.50 max discharge (for longer GC battery life) * 0.85 AC inverter eff * 0.80 bike charger eff = 816 Watt*Hours of "over night" charging into your "dead" ebike battery
    Whether a system like this would make sense to you ($200 for batteries, $100-$200 for solar charger, $150-$250 AC inverter, $200-$400 for solarpanels--Just really rough numbers)--You have to decide.

    Many times, having a battery based charging station allows for over night and "stormy/cloudy" weather charging. Something that a pure solar panel+charger is sometimes not good at (i.e., you charge ebike over night at "home", and ride during the day).

    Sometimes, AC chargers can be hacked with high voltage DC input (like 170 to 380 VDC or so). May work, or may not (many AC devices do not like the variable nature of solar panel supplied DC power input).

    Another alternative is to power a 12 volt AC inverter directly with a solar panel--But you may have to make a "reset" circuit for when the sun power drops (or shadow falls on panel). Many DC to AC inverter will "shut down" and need a manual reset (cut DC power and reconnect) to start up after a shade event (or during sun rise, etc.).

    Li Ion batteries are not something to play with--They can be very exacting in their charging requirements. I would highly suggest not hacking a DC charger for your ebike unless you know, in detail, what you are doing.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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