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Energy Wind PV system for a self propelled bicycle trailer

Discussion in 'Off Grid Living' started by Minihound, Apr 1, 2016.

  1. Minihound

    Minihound Monkey

    I've built a mini camper. Although I have some limited knowledge of renewable energy and electric motorized bike parts I have been finding new ways to confuse myself. I currently have a mid drive PAS bicycle running a 48v 20ah lipo4 pack, this gets me about 80miles. I also have a hub motor mounted to a large trailer it has two, 36v 15ah lipo4 packs in series 72v maxout, this is basically an aux throttle power for hills or just a boost.
    I believe I have ample room to install two 120watt semi flexible panels and a 400 watt wind turbine on said trailer. From here I'm very unsure about exactly how to replenish my battery bank without carrying any additional battery storage. My thought is I could run the two 36v packs in parallel as my system battery bank. This might work since the trailer hub motor is only drawing load intermittently. I have read you can charge a system like this using 3 phase parameters and still safely apply load. This method would, I think, allow me to charge the other 48v system via the inverter after I stop for the day.

    Other components I think I need: hybrid MPPT controller, power inverter, load dump

    With so many options on the market I'm hoping some guidance will allow me to come up with a viable systems. I'm planning to travel the country with this set up in the coming year. Obviously that makes overall weight a major focus. Thanks for reading.
    Ganado, UncleMorgan and Dunerunner like this.
  2. Dunerunner

    Dunerunner Monkey

    Your wind turbine will add drag, remember the conservation of energy theorem.

    The solar is a good idea though.
    chelloveck, Ganado and UncleMorgan like this.
  3. Minihound

    Minihound Monkey

  4. UncleMorgan

    UncleMorgan I eat vegetables. My friends are not vegetables.

    Nice design...
    Ganado likes this.
  5. hitchcock4

    hitchcock4 Monkey

    I agree with Dunerunner -- either lose the wind turbine or make sure that it can be taken down while traveling. Most autos and campers are made with aerodynamics in mind -- you could end up more than paying for the energy generated by wind in gasoline prices.
    chelloveck likes this.
  6. kellory

    kellory An unemployed Jester, is nobody's fool. Banned

    Yes, you want as little drag as possible. You might consider an adjustable sleeve to skin your cargo with to reduce drag further. Solar is good, and regenerative brakes would help, but anything that catches wind would work against you.

    I will leave the wiring to the experts, but my first though is to use a split feed off the solar panels, and run each leg through a separate buck transformer for the right charging voltage for each battery bank. (If you have to have two banks).
    I would suggest, one bank that exceeds both requirements, and buck transformers for feeds to the drive motors. That way you have a single voltage system, until the last leg.
    Solar panels and grid power to charge bank through charge controller. (Self standing wind generators only when stationary, and also through the charge controller.)
  7. Tevin

    Tevin Monkey+

    I like this idea. But there are a few things to consider...

    1. Two 120 watt solar panels are going to take up approximately 5'x5' of space. The two panels can be aligned in various configurations, but either way that's a lot of surface area to stuff into a pedal-able package. Are you sure you can find a way to make this work?

    2. An MPPT controller will convert the solar panel output into either 48 or 72 volts to charge the batteries, but not both unless you want to drag two charge controllers around. Having two different voltage requirements is a huge drawback in your application. Also, MPPT controllers are expensive and do not lend themselves well to being bounced around on bike.

    3. The wind turbine...oh my. A decent one will run you over $1000 and will not likely put out much power. I agree with the others. Skip this idea.

    You could probably set something up with solar and an MPPT controller to extend the range of one set of batteries but I don't see a way to make anything small enough to fit in a pedal-able package and powerful enough to be primary propulsion in a dual voltage system.

    On my blog, Off Grid Ham, I have an article explaining solar charge controllers. I think it might be helpful:

    What You Need To Know: PWM and MPPT Solar Charge Controller. - Off Grid Ham

    Good luck...please keep us updated on your project.
  8. Minihound

    Minihound Monkey

    This all very helpful!
    Newest plan:
    2 120v panels. Genesun. MPPT boost controller for lithium batteries. Or a flex controller? I'll use my 2 36v 15ah batteries as my bank. These seem safer than my other battery pack which is an at home 6v series. Each pack is outfitted with an Anderson 50 power connector and xlr plug for charging. Any thoughts on how to wire the hub motor and an inverter to this bank with the PV charging continuously? To attach the panels I'm making a slidable fiberglass pole system which will allow me to maximize aerodynamics during high wind but then allow me to open the panels up to maximize PV collection. I do appreciate the help so far! As soon. As I'm confident about what to get I'm moving on this project. Shipping off last weekend in July
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