alternator connector too recharge while riding . is it possible

Discussion in 'Electrical' started by fredie, Jun 7, 2008.

  1. fredie

    fredie Member

    we have some ideas . i have been told there is a electric bike from asia. that recharges itself while riding. plus we might be able too use an alternator with a few mods too work from the front or rear wheel . any ideas out there:p

  2. HoughMade

    HoughMade Guest

    Can a setup be made that recharges while riding? Yes- while you pedal, that is. You lose more energy by trying to use electricity to make electricty than just conserving the energy in the batteries to propel you forward.

    A practical system that can recharge discharged batteries rapidly when you pedal? That's another mattler- not yet, really. But you can put energy back in the batteries when you pedal.

    Hybrid cars have several technologies to use as little energy as possible- what they do not do is attempt to recharge the batteries when running on electricity- except for regenerative braking.

    No matter what anyone on the internet says about any technology- you can never get more energy out of system than is put in at some point (over time by nature as in fossil fuels, or by recharging in electricity)
  3. crabdance

    crabdance Member

    Hi HoughMade, Thanks for the info... I've been keeping my ears and eyes open about recharging batteries while you ride. Why is it that we can't do it on bikes? Remember I'm not a mechanic at all so my understanding is very limited. But I intend to learn all I can about the subject. I get tired of dead ends where someone tells me something can't be done (my next door neighbor just did this over building a 2 stroke muffler). So I want to know all I can about it.

    Like I said, I'm dumb about this stuff, but why is it that a motorcycle can have lights with no problems but we have problems doing it with a mb? I hope this does not sound like I'm romping on you because I don't mean it to come out that way at all. Sorry if it sounds that way. I have just been reading and reading about a way to have good lights and recharge the battery at the same time. Why is that such a hard thing? (remember I'm dumb about this lol)
    Last edited: Jun 7, 2008
  4. HoughMade

    HoughMade Guest

    You can easily have enough energy to charge batteries for lights.

    I took his original post to be referring to powering the bike itself with electricity- that is another matter altogether.
  5. crabdance

    crabdance Member

    Oh.... now I feel like a dummy lol... Thanks for clearing it up though. I have a question now. Can you explain what I need to do (in plain English) to make a light system that has a headlight and tail light where the battery is a 12v and is recharged (somehow). What do I need to do? Hope you don't mind me asking, but I would appreciate it. I'm really a dummy about it. What is it that charges the battery? I know:

    battery works the headlight and tail light(s)
    battery gets charged (somehow)

    And thats the extent of my knowledge. You don't need to go into any great detail, just a basic idea of what I need to know.

    I really appreciate it. Thanks!
  6. BoltsMissing

    BoltsMissing Active Member

    A basic concept design, understandable to all and be able to build is what is needed. There is a diagram somewhere under a topic of bicycle lighting, but when I myself look at the diagram, it DOES make sense when you join the dots, but try geting the right terminology from tech speak to sale counter rep speak to purchase the parts is another matter.

    But, im layman's term this would be my idea of a bicycle rechargable light system, after having tried a few myself may I add.

    Dynamo would have to be the Sturmey Archer hub type.
    But I would modify that dynamo if I was on the SA "think tank team".
    ( more on that later)

    Basic Light Set
    For this set up to keep it simple, for now a front and rear light set.

    Rechargable Battery and compartment.

    Wire, odds and ends, diodes, regulators and all those bits and pieces we know that work but cant "see" it work like a piston in a cylinder.

    The idea is this.
    Develop some patience and follow some easy to do DIY diagram and parts list that explains the EXACT part number and and where to connect the wires
    from the Dynamo to the regulator,to the battery and from the battery to the light switches and from the light switches to the lights.
    I personaly don't have a problem with connecting wires, it's what are the correct regulators, rechargable batteries, diodes and all those other menaingless but relatively important gizmos that are required to match the max. output of the dynamo at varying speeds.

    All this stuff can be easily worked out by those who understand these minute details, while others undertsand engines the same as they that don't.
    A bit of give and take and really cool bicycle lights system can be established.
    Last edited: Jun 7, 2008
  7. eljefino

    eljefino Member

    One needs an understanding of electric theory, volts and amps.

    This correlates to water plumbing rather well.

    Volts is pressure and amps is volume. When you demand a lot of volume pressure might drop.

    The HT motor and most little motorbike motors cannot supply enough volts and/or amps to run high powered lights.

    Batteries in vehicles generally get a "float" charge which is a subconscious operation, when the vehicle has power to spare. A "float" charge is generally 120% of the battery rating, so 7 volts would charge a 6v battery. Bumping up to 12v requires a relatively complex transformer, and when that bump happens half the amps are gone-- you can't make something from nothing!

    The happy time motor dynamo makes "around" 6 volts at 1/2 amp. To run a 55 watt "bright enough" headlight bulb one needs, typically, 12 volts at 4.5 amps. (v x a = watts.)

    So the end all run of this discussion is the HT motor doesn't make enough on its own, so one needs to look at external generators. There's a nice long thread somewhere where someone did find a nice 12 volt generator that runs off the chain.

    A properly sized (in amps) generator would need a very small or none at all battery for storage. For occasional night riding one could use a smaller amp rated generator (as long as volts were the right amount) to charge a battery but then run at a deficit when the lights were on.

    The simplest battery design would be around a 6 volt system, the problem there is finding bulbs that run on 6 volts. Stopped using them in cars in the mid 1950s. Maybe longer on bikes? But the bonus is you can find cool retro stuff on ebay etc.
    Last edited: Jun 7, 2008
  8. crabdance

    crabdance Member

    Thanks BoltsMissing... That helped a lot. I will have to do more digging on the subject. Like I don't know what a dynamo does. Is that the part that is responsible for the recharging? Sorry if this seems dumb... can't help it. I'm going to spend some time looking around for some of the keywords in your explanation. I REALLY appreciate your help on this... a little picture is starting to form in my head. Thanks!
  9. eljefino

    eljefino Member

    Thomas edison popularized the term "dynamo", it is a generator. IDK if it is slightly different internally in design from a generator (brushes etc) but as bicycles were popular in the 1890s the term stuck. :)
  10. crabdance

    crabdance Member

    Hi eljefino, Thank you for your help. I think this might be the thread that you were talking about:
    I'm going to go back over and read it again. There are a lot of good thoughts there. it's just that a lot of it was over my head. I think the more I read the better I will get though, so I will keep on trying.

    Thank you for your help... I sometimes think I don't know enough to be asking questions lol... but I do appreciate your answer a lot. I'm going to read that thread again and then come back and read your post and see if things make more sense.

    thanks a lot!
  11. crabdance

    crabdance Member

    I found a battery that might be good to use it's a: Rechargeable 12volt 7.0AH Sealed Lead Acid Battery. Is that good to use with a lighting setup?
  12. BoltsMissing

    BoltsMissing Active Member

    Just try it and see how it goes, then tweak as required from there.
    At least you'll have 95% of the work done with wiring, clips etc.
    If THAT battery don't suit the application, just try another battery to the work/wiring that's already been established.
  13. crabdance

    crabdance Member

    Thanks man... I think I'm going to try it and see how it works out. Have to find a light now. Been looking but haven't come up with anything yet.
  14. eljefino

    eljefino Member

    12 v 7 ah is what I run!

    I expect an hour of power with 55 watts, with some in reserve. Have heard of a H3, 35 watt bulb which I may persue. 35 watts= low beam headlight.

    It's bad to repeatedly drain a battery to less than half its capacity, with a 50 minute ride I am just making it to this point.

    One will have to charge said battery on shore power until they figure out the on-bike charging, but my electric rates are still reasonable compared to the cost of gasoline, (even more reasonable if I charge at work) and even a coal fired plant is way greener than my 2-stroke. :)
  15. crabdance

    crabdance Member

    Hey eljefino, cool about the 12v 7ah. An hour of power seems not very much. I was expecting more, I guess. Do you get more time on the 35 watts? If so how much more. What about 20 watts.... any idea of how long that would last? Sorry to question you to death lol. The reason I ask is because I was thinking about trying to use my lights all the time and that would not be practical if you only get an hour or so use out of the light.

    Yea, charging it while you ride is the best thing if you can do it. Saves taking stuff off of your bike when you get back from a ride. Once I get deeper into this I will (hopefully) post more answers than questions. I'm going to find a way to charge the battery while riding one way or another. It might take me a while cause of money but I will get it eventually. In case anyone is looking for a 12v 7ah sla battery; here's a good one for a good price:
    To me it's a good price.

    Well, better go for now. Talk to you in a bit.
  16. eljefino

    eljefino Member

    Watts are just volts times amps so a 20 watt would draw 1.666 amps, a 7 ah battery would last 4.2 hours at 100% load so your ride time should stay under ~2.5 at the most.
  17. eljefino

    eljefino Member

    Watts are just volts times amps so a 20 watt would draw 1.666 amps, a 7 ah battery would last 4.2 hours at 100% capacity so your ride time should stay under ~2.5 at the most.
  18. crabdance

    crabdance Member

    Thanks man for the numbers... at least I have an idea of running time now. Now if I can only recharge the battery while the bike is running I would be all set. I'm still reading the thread about that one.
  19. Timmylikesthing

    Timmylikesthing New Member

    AH stands for amp-hours.

    Amp-Hours = Amps x On-Time in Hours

    If you have a 35W light and a 12V supply you can find the amps by using the equation P=VI (or Power equals voltage times current). A little algebra later, I= P/V so our 35w light at 12v pulls 2.9 amps.

    Now if you want to figure out how long your battery would last, say a 7AH, you would use the above equation AH=Amps * Hours with a touch of algebra and its AH / Amps = hours. So, 7AH / 2.9 amps = 2.4 hrs. If you want more, you'll need more amp hours.

    Say 4 hours is acceptable, so you would need a battery of at least 2.9 amps x 4 hours = 11.6 AH...

    Then, you have to consider the fact that for optimal battery life you should never drop a battery below 50% capacity... So you should double any number you calculate to allow for battery life.

    Now, on most automobile alternators, the alternator actually handles every electrical power requirement (under normal operation) except for starting the engine because, well the alternator isn't turning then. The battery is only there for starting and emergency situations where you lose the alternator.

    So essentially, there are not TOO many good ways to charge a battery while simultaneously draining it, however you may be able to have it switch between battery and alternator/generator when the bike isn't rolling or when travelling at or below optimal speeds...

    Hmm... a conundrum. If there were a way to route the drive of the generator such that it was independent of the clutch, like in a car, that could be an option, but that'd take a slightly longer engine shaft or a short jackshaft to drive the generator and clutch. Not impossible. Just not easy.

    You just wouldn't want it on your main drive chain.

    Last edited: Jun 9, 2008
  20. crabdance

    crabdance Member

    Thanks Tim... most of it a little over my head. Algebra was a LONG time ago for me. I think I've forgotten more than I knew, lol. Thanks for working out the numbers for me (I just looked at your age and I see you still have brain cells). I'm going to work out a way to charge the battery while riding. I don't understand how yet, but I am going to get some people to put their heads together and figure out a way. I bet the boys at the bike or motorcycle shop could give me some ideas. Will have to check that out when I get the chance. I don't know about the shaft for the generator... I will have to let greater minds than mine help me think about that, lol. Thanks for the ideas!