Series Hybrid with Hubmotor

[hotsauce492003]

This looks promising:

http://www.windbluepower.com/ProductDetails.asp?ProductCode=DC-512&Show=TechSpecs

I checked that website and sounds very interesting.

I personaly would opt for straight Lithium if i can afford it, but use the windmill to generate electricity to charge my batteries. That is as green as it can get, plus a windmill is many times cheaper per watt generated than a solar panel. It would be an electric bike and not an Hybrid.
The problem I see with bike-Hybrids is the extra weight and size of the engine/generator unit added to the weight of the bateries already needed.

Your whole R&D is very informative and I am impressed by your initiative.
We all are trying DIY solutions to a common transportation/recreational need. So my comment on the paragraph above is not to discourage anyone from exploring options, but just my own thoughts after learning your results.

 

[shroomer]

Low power, but may work well

http://www.econvergence.net/Merchan...D&Store_Code=econvergence&Product_Code=PAWG-1

 

[jimraysr]

Honda Gxh35 Generator

I assume the 35 cc is like the 50cc model that I have on my bike. I use the built in governor which serves to sense heaver loads and open the throttle. Ideal for you application where the generator would need more throttle as the battery voltage dropped and the current increased do to the delta increase of generator voltage.

Sounds like a workable arrangement other that the raising of the center of gravity with the generator rack mounted, assuming the frame area is taken up with the batteries?

An other thought is to saddle bag the generator on one side and batteries on the other? Should not add to your riding width.

How expensive is th generator? I assume the 35cc is well under the $210 I paid for he GXH50.

The eBay link for the generator is broken. Will look for the Bosch site. How about rotation? is the generator both CW or CCW in which case it wouldn't make any difference on the engine rotation. Give me a couple of more minutes and I will think a a few more questions. )

Good luck,

Jim

I am going to use this thread to work out some ideas for a series hybrid hubmotor system. I saw an example on this forum by Denny and I am just trying to work out the idea and maybe it will actually become a reality.

I am starting out with a Wilderness Energy brushed hubmotor:

http://wildernessenergy.com/index.php?cPath=24

I have had this kit for a few years on a Giant Sedona. I am running 36V 12aH lead acid currently.

The goal is to build a Series Hybrid.

http://en.wikipedia.org/wiki/Hybrid_Vehicle_Drivetrains#Series_Hybrid

A gas motor powers a generator which can be turned on to power motion and charge batteries. The motive force comes from an electric hubmotor which is powered by batteries or by a combination of batteries and generator.

So basically this is an electric bike with an add on gas powered generator that can be turned on to increase range.

The hubmotor is a 600W motor. The motor probably uses 600W only when starting from a stop uphill. At full battery charge (about 37.5V) the motor would draw 16 amps (600W / 37.5V) at full load. At 50% discharge (36.6V) the motor would draw 16.4 amps at full load. Note that cruising along at the normal top speed of 17mph will likely use much less than 16 amps, 16 amps is a short term, peak load.

Currently I use 3 batteries to reach 37.5V full charge voltage. I would like to increase this to 4 batteries -> 50.6V full charge voltage. I have heard good reports that the hubmotor and controller can handle up to 72V and remain reliable.

In order to choose an output voltage for the generator, I will look at the maximum recommended fast charge voltage, which is 2.45V per cell. With 4 batteries each with 6 cells, I get a fast charge voltage of 58.8V. This is my target voltage for the generator.

http://www.batteryuniversity.com/partone-13.htm

My next goal is to specify a gas motor and dc generator to provide about 58.8V and to be able to power a peak 600W, more or less, which is what the hubmotor is rated for. Note that average power use will be less. I also want to specify a lightweight generator system.

http://cgi.ebay.com/ws/eBayISAPI.dl...rkparms=algo=CRX&its=S%2BI&itu=UCI%2BSI&otn=4
If link doesn't work search on BOSCH 1/2 HP 120V DC WIND GENERATOR MOTOR MILL LATHE

This dc electric motor has the following ratings:

120V at 10,000 rpm's
640W
5.5 amps
Continuous Duty

Voltage and rpm's are roughly linear, so I would expect 58.8V output at 4900 rpm's. (12V per 1000 rpm)

The amp rating is lower than I would like, so it is possible that this motor will not provide enough power. However, in short term high load situations, the batteries will act as a buffer and will provide additional power beyond what the motor can put out, so I am hoping that the 5.5 amp value will provide more than the average current draw while riding the bike. At 58.8V, 600W of power would result in just over 10 amps peak load, so I may be OK with 5 amps for average load. If not, I might need to move to a 5 battery system at 73.5V. If 73.5V are needed, I would expect to measure 73.5V at about 6125 rpm.

So the generator is rated at 640W and it needs to run at about 4900 rpm to produce 58.8V. Now a gas motor is needed that will produce more than 640W at about 5000 rpm.

The Honda GX35 four cycle motor is rated at about 800W at 4900 rpm and about 950W at 6125 rpm. The power rating is adequate and the maximum torque for the motor is in the desired rpm range. This means the gas motor will be running efficiently.

http://www.honda-engines.com/engines/gx35.htm#per

The motor and generator would be connected with either a flexible or solid coupling. The motor throttle (idle screw) would be adjusted until the generator produced the desired voltage, which is 58.8V for a 4 battery system and 73.5V for a 5 battery system. To start the generator, a double pole double throw switch would connect the dc motor to the battery voltage and would also break the ground to the motor shut off, allowing the motor to run. The dc motor would start the gas motor by turning it. The gas motor would fire up and produce voltage to charge the batteries and power the hubmotor.

In operation, the bicycle could be used as a battery powered bike until it is noticed that there is a reduction in power due to batteries starting to discharge. Then the motor could be turned on either full time or during heavy loads such as starting from a stop or climbing hills, depending on how much additional range is needed. For long distance travel, the motor could be run full time.

The benefit of a series hybrid is that it works well for extending range and provides a guarantee that you will make it home if you travel further than your battery range. It is less suited for long distance travel but may work using full time power generation. Adding a gas powered generator turns the electric bicycle into a plug in hybrid vehicle. My current range with the 36V 12 aH battery is about 10 miles. Adding additional batteries would likely extend this range to about 14 miles. The gas generator system should at least double the range and perhaps would be powerful enough to provide as much range as the fuel tank allows.

 

[jimraysr]

Lith-Ion Batteries

I assume you are aware of the critical nature of Lithium-Ion batteries. Not the friendly Ni-Cad or NiMH that we are used to.

Temperature sensors, voltage limiters, current fuses all in a package with the cells. Remember the Sony Li-Ion plant burn 15 years ago and the after market cell batteries that burned people last year or two.

Jim

I checked that website and sounds very interesting.

I personaly would opt for straight Lithium if i can afford it, but use the windmill to generate electricity to charge my batteries. That is as green as it can get, plus a windmill is many times cheaper per watt generated than a solar panel. It would be an electric bike and not an Hybrid.
The problem I see with bike-Hybrids is the extra weight and size of the engine/generator unit added to the weight of the bateries already needed.

Your whole R&D is very informative and I am impressed by your initiative.
We all are trying DIY solutions to a common transportation/recreational need. So my comment on the paragraph above is not to discourage anyone from exploring options, but just my own thoughts after learning your results.

 

[skyl4rk]

The gas motor is from a discarded weed whacker that I picked up for free. It did not have a governor, but the idle screw served to keep the rpm's high. The generator puts a load on the motor which slows it down a bit. A gas motor with a governor would be ideal in this configuration.

The specs on the generator (electric motor) are

1. it must be a brushed motor, not brushless
2. it should have permanent magnets, if you want it to have electric starting capabilities
3. it should be rated at a high voltage, about 100V
4. it must be a DC motor
5. it should be rated higher than 1.5hp
6. it should be rated for an rpm of over 5000 rpm
7. it should output the desired V at the operating rpm, for example 70V at 5000 rpm

Rotation is not critical because you just check the leads from the generator and find which one is positive, they will work in both CW and CCW rotation.

This was the electric motor I used, but it did not put out enough amps:
http://cgi.ebay.com/110-VOLTS-700-W...5|66:2|65:12|39:1|240:1318|301:0|293:3|294:50

This one might do the job better:
http://cgi.ebay.com/2-5hp-130V-DC-m...5|66:2|65:12|39:1|240:1318|301:1|293:3|294:50

search terms to try:
dc motor
dc generator
treadmill motor

 

[jimraysr]

Dc Motor / Generator

I agree that the permanent magnet motor is to be preferred, but not necessary. Many wire wound field electric generators are "motorized" to start their driving engine. They use the battery to energize the field windings.The down side of such an arrangement is the energy required to power the field coils. In larger generators, the stator has the output windings and the rotor has the field coils. Our 6KW diesel backup generator doesn't have any brushes for the rotating field. It has an arrangement whereby the field current is inducted into the rotor. Smart.

The super magnets have done a lot to increase efficiency.

The second generator you referenced on eBay looks very reasonable. Wish I lived in an area with wind. Nice unit for home built wind generators.

Jim

 

[jimraysr]

Smaller Generator Is Ac

i just went back and looked at the listing for the smaller of the two generators. While it generates and the AC output is sent through a full wave rectifier to produce pulsing DC, I don't see how you could motorize it with a battery? I think it would take a modified signwave inverter to make it work and more weight and switching.

Jim

 

[skyl4rk]

I believe both motors are DC output, not AC.

Do you think there is a way to use this alternator to start the gas motor?

http://www.windbluepower.com/ProductDetails.asp?ProductCode=DC-512&Show=TechSpecs

What would it take, some kind of special controller?

 

[jimraysr]

Ac Generator And Pm Alternator

No an automotive alternator is a 3 phase AC " alternator" . Cannot be motorized as it has a three phase bridge rectifier board internally and there is no commutator to make it work as a motor.

A commutator is the circle of copper bars on the end of a universal AC / DC motor like a plug in drill motor and has two carbon brushes. I know you know what they are, just not sure you were familiar with the term for it.

The alternator produces three sine wave outputs per revolution, the output from each of the three sets of windings feed their output to a pair of diodes. As the wave goes up the current goes out one of the diodes, then as the wave goes down the current goes out the other diode. When the six outputs are put on a common buss you have a DC output with all of the Mickie D's arches combined, but overlapping each other so the output has 6 humps per revolution. Much more efficient than a DC generator.

As to the smaller gererator being DC, take a look at the wiring diagram. It shows the single phase output going to a black square potted unit with two lugs for the output. Inside the black block are four diodes (looks like a bar in contact with an arrow point pointing at it. Those diodes only pass current in one direction and combined produces a pulsing DC output.

The commutator of older generators and motors are used to reverse the DC voltage to either produce DC voltage or to reverse the DC volage to make the motor turn. In general any small PM DC motor can be made to generate a voltage if driven by a rotary power source. Water wheel, air turbine,engine, etc.

The commutator can be thought of as a mechanical diode pack. Look at Wikipedia and search DC motors. It does a pretty good job of explaining how they work.

I would say you are on to something that could provide a long range electric bike.

If you have any more questions, I will be glad to share my limited knowledge.

Jim