Solar Charging -- A Basic System

Discussion in 'Parts and Accessories' started by George S., Jun 9, 2015.

  1. George S.

    George S. Well-Known Member



    Someone asked me how to charge off solar. This system is designed for parts that are off the shelf. It is not very efficient. If you have an RV battery, or a trolling battery, it's easier. The solar panels are cheaper. What you save makes it hard to build the system from scratch.

    With the Hobby King type batteries, LiPo, it's much simpler. The chargers are 12v so you can recharge a small battery with the sun.

    There's a woman going cross country with solar. Not sure what here charge system or battery system looks like:

    http://electricbikereport.com/cross-country-solar-electric-bike-tour-video/

    She is using the light and flexible panels in a design discussed on EBR a time or two. Good luck to her!
     
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  3. katie6963

    katie6963 New Member

    My phone won't play the video. I wish it would. Last night I purchased a second hand trailer. I intend to put four 50w panels on it. The folks at Energie assure me that I won't harm anything by using the charger that came with the bike while riding the bike. I need a battery to put between the photovoltaics and the inverter. A small gel cell will get cooked whenever it is the only load on the panels. I wonder if there is a small capacitor type battery available and if they can handle a higher charge rate?
    I have spent the last fifteen years living on a sailboat with electric motors for alternative power and lots of big heavy deep cycle batteries make good ballast. This is my fifth Soler powered boat so I thought I knew enough. I don't. What I intend will be very inefficient but sufficient for unlimited range away from the power grid. I will be grateful for any input. Thanks, Katie
     
  4. George S.

    George S. Well-Known Member

    Hi,

    Not sure if this is a bike trailer or a standard trailer for a car or truck. The basic system is 1) solar panel 2) solar controller 3) battery 4) inverter 5) charger for ebike. The battery for the ebike is at the end, plugged into charger. Both the charge controller and inverter go to the battery. That's all the video says.

    It's good to know you can use the charger while riding.

    The 4 x 50 watts, 200 watts, is a lot of power for any small battery. The solar panel charge controller is what keeps the battery from charging too much. But 200 watts (15 amps) is about what I would use with two golf car batteries in a travel trailer. Is this a bike trailer with panels, or some kind of RV? Not sure...
     
    katie6963 likes this.
  5. katie6963

    katie6963 New Member

    Thanks George, for your input. The trailer is the kind you pull behind a bike. I haven't driven an automobile in years so I didn't think to be specific. What you describe is what I have used on my electric boats. Where I ran into a difference is that my sailboat doesn't mind carrying a few hundred pounds of lead so a high charge rate hasn't been an issue. My charge controller limits the voltage by pulsing the charge. Maybe that is enough to protect a 20ah gell cell. I don't know. I can install a switch that would open the circuit from the panels. I'm sure I'd forget to use it sometimes. I can almost remember a way to limit the current. It's been right there at the tip of my brain for days but my electronic skills are rusty and moldy.
    Thanks and if you have any stray thoughts about this then please pass them on to me.
     
  6. George S.

    George S. Well-Known Member

    I would like to know what Marissa Muller is doing.

    http://www.marissamuller.com/rig

    She has basically the same setup. There is no mention of a battery, other than the bike battery. She is using two MPPT controllers, where you can set the voltage. There is no mention of how to make the panel output power the bike and charge the bike battery.

    Ravi (@Ravi Kempaiah) is supposed to talk to her when she gets to DC ( I think). There is an email link at the bottom of that link. I'd really like to know if she knows a simple way to just feed the output from the panel to the ebike battery, without much else.

    I looked around a little more and found these solar charge controllers for lithium batteries. These might be the people to talk to. Let us know. Fascinating stuff.

    http://genasun.com/products-store/mppt-solar-charge-controllers/mppt-for-lithium-batteries/
     
    Ravi Kempaiah and katie6963 like this.
  7. Ravi Kempaiah

    Ravi Kempaiah Well-Known Member

    @George S. , I will get more details once she reaches DC in August.
    Yes, two MPPT controllers directly feeding panel Amps to the bike battery. There is no need for auxiliary battery.
     
    katie6963 likes this.
  8. katie6963

    katie6963 New Member

    I suppose that using three panels to deliver 36 volts directly to the bike battery from the voltage controller would be much more efficient and save wear on what is probably an expensive battery charger. That would still leave me one panel for charging a 12 volt battery for powering music, lights, phones and stuff at night. I will put together something with the parts I have on hand and upgrade it as I pedal and learn. Because (I think) my Energie Excursion was designed for folding and stowing it is a very clean bike and I have no idea how to access the battery except through the charging jack. I will quite likely replace my bicycle with something more suitable soon but summer is half over and I'm wanting to be gone now. Thanks for the help, katie
     
  9. Solarman08

    Solarman08 New Member

    I came here to read about Solar Charging and followed to Marissa Muller's fascinating adventure, wondering why I didn't hear about it sooner...
    Anyway, I am very much intrigued with the idea of opportunity charging my eBike battery with a portable light solar setup without using an intermediate battery. If anyone has any tips on what is possible, and what hardware will work, please share. I just ordered the Rad Power Rover bike with the 48v 11.6Ah battery (Panasonic 18650 cells) and I wonder if it can be charged with DC...