[bigwilly312]

I'm getting ready to build a light weight trike and need some good advice on what's already going to be an unconvential project. I've got 2 deep cycle 12v Optimas coming. I plan to use them in parallel with a pedal powered generator that will generate more than 48V pretty easily. Yes, I know It's definately outside the box, but I'm going for it. Ideally, I hope to set it up so that the generator charges the batteries and any excess voltage is automatically dumped to the brushed Etek style motor I'm using. Would it be possible to have battery A only engage when charging voltage is reached and battery B only engage when charging voltage is reached for it? Can I do this without a charging system? Am I just dreaming? I know that a slider throttle could do part of this but, I'm hoping to make it all work together seemlessly. Any advice would be grealy appreciated.

 

[bigwilly312]

Well, I guess it would be more of a series parallel set up then. The two batteries would be in series and the generator would be in parallel to either add power or to charge the batteries. I'm not sure which way is best. Coleman Air makes the perfect charger for this I believe. It handles up to 160 amps dumps excess voltage to what it calls a "dummy load". Would this work? I just can't rap my head around the wiring. As far as just pedalling to turn the rear wheel....the Etek motor can reach close to 50 mph with just 48v applied to it. I think a shared load approach between me, the generator, and the mohonkin batteries should produce a perfect symphony of singular synchronisity. If I just had a wiring diagram perhaps. The idea would to have up to four gears: pp-pedal power only,1-for battery A, 2-for A and B together, overdrive-both batteries working with generator. You can pedal when you want or just use battery power at slower speeds. So a charger is a definite?

 

[bigwilly312]

Hi big,

Don't know if this is good advice, but WTH. Take a discharged Optima and connect it to an automotive alternator. Then belt drive the alternator from a stationary bicycle with the wheel driving the belt. See how long it takes to charge that one battery. Multiply that by 2.

My bet is that it would take you 20 hours to charge those 2 Optimas peddling full time as hard as you can.

Now add in the discharge efficiency of a PbAcid battery and lose 10 to 20% of that energy you just worked so hard to store. Now add in the propulsion motor efficiency and lose another 20 to 30% of that energy you worked so hard to store. See where I'm goin' here?

So, the electric/human hybrid bicycle is a good machine. But use it wisely. Put the human power to the wheel and let the utility company generate the electric energy which you use to charge the battery. Or get a solar cell to charge it for you.

Back to your question about wiring. You cannot discharge 2 batteries in series while charging them in parallel from the same generator. So you will need to use two isolated generators, one for each battery. But these generators can be half size then.

Regards,

major

That's the point of trying to keep them fully charged as I go. The Coleman Air is a charge controller that specifically works off of windmill turbines. That's what I'm using. It dumps the extra voltage to whatever you want so as not to overcharge the batteries. I accept criticism but not impossibility. I'm talking extended range. Not perpetual motion. I'm fully aware of everyone's opinion on that.

 

[bigwilly312]

Well I agree totally with what Major says on the efficiency of it. But if you are going to do it anyway then here goes.

You dont necessarily need a charge controller. I really wouldnt worry about overcharging your batteries. Simply pass the AC output of the generator through a bridge rectifier, then the output of this straight to your batteries. The faster you pedal, the more current will go into the batteries. You may need to experiment with gearing to get a comfortable pedal speed and torque to your liking.

Then connect your motor controller straight to your batteries, and control the motor speed/current via a handlebar mounted throttle.

With this setup, depending on how much effort you put into peddling and the demand on your motor, any excess current you generate will charge the batteries, likewise if you dont generate enough current, then the batteries will supply the rest.

Is this how you see your setup working?

Thanks. Yes except the generator is already putting out DC. So generating say 48v to the batteries would send approximately 20V straight to the motor? Sounds good to me. Only problem is I had no idea motorcycle wheels cost so daggon much! Can a person run a car wheel on a motorcycle chain? I don't really want to go that big though. Any suggestions?

 

[bigwilly312]

Ok thanks. I'll map it all as soon as I get all my facts straight. Thanks again for all of your help.

 

[bigwilly312]

OK guys here's what I got for ya. www.hydrogenappliances.com/manta.html has an example of a battery controller I hope to somehow construct. I'll be using a Mars Etek style motor that produces 8hp at 48v. It is rated up to 72v. I believe for only short periods of time though or it may overheat. The generator is a windmill style and produces 12v per every 150 rpms. I'll have 2 12v deep cycle Optimas. I want to modify the battery controller to use the generator obviously. The ideal setup would be as follows: Slider 1 position would just connect the generator to the batteries so as to charge them while in park. Slider 2 would be generator only to the motor for just pulling out or hopefully reverse if pedalling backwards. slider 3 would engage 1 battery for extra power. Slider 4 would engage battery 2 for full power. I will be running accessories as well in an effort to make this street legal. Such as headlights, turn signals, etc. The weight is looking to come in around 300 to 350 lbs. Which is good because I'm a pretty big fellow. I come in around 275 lbs. The battery controller diagram mentions regen braking but I'm not fully sure how it would work. If a charge controller is necesarry, please google the Coleman Air 160 amp rated charge controller/voltage diversion device. Looks like it could make this work if necessary.

 

[bigwilly312]

I guess I should have mentioned that I will be pedalling at a 10 to 1 ratio. I don't know if you took that into consideration or not. I just assumed you would expect some ratio gain. As far as the controller, it clearly points out that contact should be fully disengaged before the next contact is made. I should achieve 48v to the motor at what amounts to a leisurely pedalling frequency. Granted it will very well feel like I'm pedalling uphill with the load placed on it. I'm just puzzled as to why that would barely get me anywhere when 48v to the motor achieves around 50 mph. Oh well, where there's Will there's a way and my name is Will. The Coleman Air has no baring on your critique I suppose. Thanks for your time. God bless and power to the people.

 

[bigwilly312]

So if everyone is in agreement that a pedal powered generator can produce no more than 100 watts, I guess I'm dead in the water. Even though I've seen multiple examples of them powering 1000W inverters and powering 250W light bulbs. I watched a video just last night of a kid producing 1500 watts to power a huge subwoofer. So, major, do me a favor and wash your hands of me. I'm not trying to be talked down to or stress you out. I just have ideas on how this could maybe work and was hoping for people much smarter than me to give ways it could work better. Whatever that may be. Maybe I need another battery. Maybe I have to use an expensive speed controller. I don't know. But if your argument is that this highly efficient specialized DC generator can produce no more than 100 watts and barely over 2 amps no matter how hard or fast I pedal, I find it a little hard to find your criticism constructive. So anybody with some advice on how to make this work with actual wattage numbers, please help.
I just want to figure out a generator only mode for the batteries. Then a generator only mode to the motor. Then some kind of combined mode were the generator just adds a little more power straight to the motor. If this impossible, even with the Coleman Air diverter, then I shall retire from this thread with an apology for wasting your time.

 

[bigwilly312]

Ok. I've been dreaming a bit. Sorry major. I finally come across the spec sheet for the generator. It produces 10 amps at 48v but it maxes out at barely over that no matter what after that. My apologies. I've got to rethink things a bit. Thanks for the tough love major. I salute you.