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Solar power?

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  • Mark Garvey
    OK, here is a sub set of discussion! Has anyone tinkered with Solar panels on an electric bike other than ME? I have worked out a couple of solutions that
    Message 1 of 3 , Apr 6, 2008
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      OK, here is a sub set of discussion!  Has anyone tinkered with Solar panels on an electric bike other than ME?  I have worked out a couple of solutions that work well with an e-bike, and in my case, I have a couple of solar panels that work pretty well.  a bit FRAGILE of course, but the whole idea will work.

      I have a small utility trailer that I plan to set up as my solar power station and power system.  I don't mind my frame mount battery but it does make the bike a little awkward. nothing terrible, but I can more easily mount the battery pack in a trailer that incorporates BOTH the power pack AND the solar array which means that the ONLY thing left on the bike is the electric motor and controller.  The Xtracycle is a PERFECT electric assist platform.  The Currie USPD that I have gives me an average speed of about 12 mph.  I don't really add power above 10 mph or so generally and use teh boost to kick my speed up as I ride and when I have a load.

      I am wondering if any of you "Electronic experts" out there may have a soltion to this question.  WOULD IT BE BETTER, to a) place BOTH batteries in the trailer and charge BOTH as I ride, using both battery packs as power packs at one time (parallel system) or to use ONE pack on the bike and have the solar panels and second pack in the trailer as an adjunct that can be swapped out when Pack #1 goes flat? 

      I am thinking about complexity and all that.  I am leaning toward the self contained system with the solar panel charging the secondary pack for both simplicity and the fact that the second pack will be a "back up" and when the time comes, I can swap packs, giving me a frresh pack and putting the first one on a charger immediately.

      Pros, cons, all that is welcome.  Yeah yeah, I know a trailer is a hassle, but this is not a bad idea. I have used the trailer as a battery carrier in the past!

      mark

      --
      Give a man a fish and feed him for a day. Teach a man to fish and feed him for a lifetime. Teach a man to cycle and he will realize fishing is stupid and boring. –Desmond Tutu
    • kwikfile08
      Huh?
      Message 2 of 3 , Apr 6, 2008
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        Huh?





        --- In rootsradicals@yahoogroups.com, "Mark Garvey" <lazybee45@...> wrote:
        >
        > OK, here is a sub set of discussion! Has anyone tinkered with Solar panels
        > on an electric bike other than ME? I have worked out a couple of solutions
        > that work well with an e-bike, and in my case, I have a couple of solar
        > panels that work pretty well. a bit FRAGILE of course, but the whole idea
        > will work.
        >
        > I have a small utility trailer that I plan to set up as my solar power
        > station and power system. I don't mind my frame mount battery but it does
        > make the bike a little awkward. nothing terrible, but I can more easily
        > mount the battery pack in a trailer that incorporates BOTH the power pack
        > AND the solar array which means that the ONLY thing left on the bike is the
        > electric motor and controller. The Xtracycle is a PERFECT electric assist
        > platform. The Currie USPD that I have gives me an average speed of about 12
        > mph. I don't really add power above 10 mph or so generally and use teh
        > boost to kick my speed up as I ride and when I have a load.
        >
        > I am wondering if any of you "Electronic experts" out there may have a
        > soltion to this question. WOULD IT BE BETTER, to a) place BOTH batteries in
        > the trailer and charge BOTH as I ride, using both battery packs as power
        > packs at one time (parallel system) or to use ONE pack on the bike and have
        > the solar panels and second pack in the trailer as an adjunct that can be
        > swapped out when Pack #1 goes flat?
        >
        > I am thinking about complexity and all that. I am leaning toward the self
        > contained system with the solar panel charging the secondary pack for both
        > simplicity and the fact that the second pack will be a "back up" and when
        > the time comes, I can swap packs, giving me a frresh pack and putting the
        > first one on a charger immediately.
        >
        > Pros, cons, all that is welcome. Yeah yeah, I know a trailer is a hassle,
        > but this is not a bad idea. I have used the trailer as a battery carrier in
        > the past!
        >
        > mark
        >
        > --
        > Give a man a fish and feed him for a day. Teach a man to fish and feed him
        > for a lifetime. Teach a man to cycle and he will realize fishing is stupid
        > and boring. –Desmond Tutu
        >
      • Morgan Giddings
        Hi Mark, I d respond directly, but one or two others here might be interested. Regarding solar power for an electric assist bike, I do not believe current
        Message 3 of 3 , Apr 7, 2008
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          Hi Mark,
          I'd respond directly, but one or two others here might be interested.

          Regarding solar power for an electric assist bike, I do not believe
          current solar panels are of reasonable efficiency to make it worth
          carrying them with your bike. To achieve sufficient power to recharge
          your batteries, you need to be able to gather 250 watt hours or more
          of power. That means a 50 watt solar panel for 5 hours of direct sun,
          or a 10 watt panel for 25 hours of direct sun. A 50 watt panel is
          getting awfully large to carry on a bike (and is a theft magnet, since
          it is worth at least $200). A 10 watt panel just isn't going to give
          enough power to make it worthwhile.

          However, I do frequently use solar to power my electric assist bike.
          I do this using rooftop-mounted solar and a secondary battery storage
          system. It goes like this:
          Sunlight -> 12 Volt 60W solar array -> 12V charge controller -> 12V
          60AH lead acid battery storage & Xantrex Xpower powerpack inverter ->
          120 VAC -> 36V battery charger -> 36V 7 amp hour LiFEPO4 batteries.

          Now, this is not very efficient, since several of these steps are lossy.

          One alternative I have considered is setting up the system as follows:
          48 Volt 60W solar array -> Programmable charge controller (Outback MX
          60) -> 36V LiFePO4 batteries.

          In this scenario, I would need two LiFEPO4 battery packs, rotating
          them out each day. They're kind of expensive. Plus, the charge
          controller would need to be dedicated to charging bike batteries, but
          I like to use the system to power other small things.

          So, another possibility I have considered is:
          48 Volt 60W solar -> Programmable charge controller (Outback MX 60) ->
          48V lead acid batteries for storage -> secondary charge controller ->
          LiFEPO4 battery pack. This will involve a second charge controller
          (they're not cheap), and getting a 48V battery bank set up.

          In any case, that's my approach - collect the solar at home, rather
          than on the bike.

          Regarding your question about batteries, since you are using SLA, for
          long life, you definitely should connect the two in parallel, both
          being charged and used simultaneously. The reason I say this is it
          kills SLA batteries quickly to discharge them too deeply. Further,
          you won't get as much power out of them if you discharge them
          rapidly. If you configure the two batteries in parallel, it will
          address both of these issues, because you won't be discharging either
          battery as completely, nor will either one have as much current load
          at any given time.

          Given your interest in this kind of stuff, you should consider getting
          a CycleAnalyst - it will tell you all about your power usage on the
          bike, so you know exactly how much power you have used, how much is
          left in your batteries, how much you get back from the solar panels,
          your bike's efficiency, and etc. We have one available (cycle9.com),
          or you can get one from the guys at Renaissance if you prefer
          (ebikes.ca).

          Regards,
          Morgan
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