Electric X development - Petro-Electric bicycle project.

cj7hawk
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Electric X development - Petro-Electric bicycle project.

Postby cj7hawk » Sun Mar 15, 2015 3:19 pm

Hi All,

Well, I've been sitting on it for a while, but I am building a new electric bicycle project at the moment, and thought I'd share and see if anyone else is doing similar?

It's an electric system, and will be a combination pedelec/PAPC with 250w brushless direct drive system, 24v operation ( I'm using a 48v 500W rated motor running at 24v ) for power, running around 7.2AH of batteries ( 172WH ) and with a throttle and a pedal sensor... However I'm building an ElectricX system.

This means it also includes a very small form factor petrol 4-stroke based generator onboard as an APU ( non-propulsion motor - so is not regulated ) to maintain or top-up battery charge, allow off-grid charging and generally enhance both operation and range. As such, it's likely to be one of the first systems to include petrol that can be ridden in every state.

Just to be specific - it's not a hybrid - Hybrids are not easy to legally operate in any state as hybrids have two propulsion motors and both count towards limits of the 200/250w limit. This is a pure electric bicycle with a range extender, that allows the generator to reduce the load on the batteries during operation, but does not interfere or modify the bicycles status under any current Australian law.

Just to add some information -
[*]Economy - I'm aiming at 150km/litre - It's regular unleaded and 4-stroke so can be filled from petrol stations directly.
[*]Safety - No modification is made to the bicycle and the design complies with other laws regarding the generator.
[*]Fire safety - The standard systems are used, in approved designs as sold and used around Australia already, so no dangers there. Uses parts designed to be operated in very close proximity to tall, dry grass even on fire-ban days.
[*]Momentum - Total weight of the system is less than a typical schoolkid's backpack weighs, so doesn't add significantly to the momentum of a bicycle. Typical wet weight < 7Kg - about the same as a second set of extended batteries.
[*]Clip-on - This doesn't attach to the bicycle in any meaningful way - it just clips on and recharges the batteries. Removal is about as easy as unplugging a charger.
[*]Noise - Operates well below the noise level of most existing bicycles due to low-RPM function within the continuous operational range of a small engine.
[*]Exhaust - Engine is fully enclosed and so hot gases are diffused prior to expulsion, and are comfortable within a range of 12 inches or so.
[*]Smell - No significant odor - It's fourstroke so no oil to burn.
[*]Retofittable - since it's a clip-on it should work with any existing system, either through the prior charger, or via direct connection to the batteries. No skills required - just snap-on and plug in.
[*]Legal - Does not power the bicycle in any way, so is not affected by petrol-banning legislation in any state. ( has not been tested in court, but appears to comply with legislation )
[*]Safe - Addresses ALL aspects of ALL complaints made by government agencies and ministers regarding dangers of petrol-powered bicycles.
[*]Power - No power increase to existing bicycles is possible through this system - It will actually slow the bicycle slightly ( eg, A pedelec that averages 19kph will probably now do 18.something ) - Cannot me made to increase power to bicycle.

This system is still an electric bicycle in every sense - it just extends the range of the bicycle by allowing charging of the battery while in motion. The initial prototype should hopefully have about 110km range without refilling, and then allows all the best advantages of petrol and electric systems to be harnessed effectively.

Better still, it's more environmentally friendly than charging at home, and eliminates the requirement to charge on-grid as it can self-charge if desired, so allows trips to locations where chargers or grid-power are unavailable or undesirable. Cost to charge is slightly more, but emissions are slightly less than grid-charging. Generator power output is operated to "Just in time" operation, so fuel burned is minimized. So short of going solar, or living near a hydro-electric dam, this design is greener than pure-electric and far more suited to commuting.

The system can't be used without batteries, as it is an Electric-X system and uses the batteries to maintain operation - These are recognized as Battery-Electric systems worldwide even though they do use a small petrol motor.

So far, work on this project includes;

* Design on a new form of DC micro-generator suited to bicycle use, using COTS components.
* Design of an advanced power regulation system / autothrottle to control motor power output to optimum levels ( reduces noise considerably )
* Allows both direct and charger-based connection to batteries - Can charge batteries directly and responds to battery hysteresis.
* Design of a new electrical filter system to supply clean power to the batteries/electronics.
* Design of a new capacitor system using COTS components suitable for bikes that eliminate high ultra-capacitor costs
* Cannot be modified to provide more power than the bicycle is designed to operate at -
* Supports start/stop operation and can shut down when bicycle comes to a stop or slows, then start back up when pedaling again.
* Support manual start to charge batteries when too low for electric start to operate.
* Maintains low RPM even at high power output, reducing noise travel and avoiding "Mosquito" syndrome.

I have tested this already as proof-of-concept with a 180w go-cart and am now building a brushless bicycle for the prototype. I'm about halfway through the conversion and waiting on parts to arrive ( Thank you Ebay ! )

I started this project because, although I have and love using a petrol-powered PAPC, It's not really legal in other states if I travel with it, and it lacks the benefits of electric, such as torque at low speeds and silent operation when I want to remain powered, but want to be quiet ( eg, sneaking in late at night )

The final project also has the goal of a 1000km range.

With this project, it will finally be possible for disabled people and people who cannot ride distances without assistance to use bicycles for touring, and to explore places and parts of our country that are not available to those with un-extended electrical systems.

Any thoughts or questions from the forum?

Regards
David

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Re: Electric X development - Petro-Electric bicycle project.

Postby eldavo » Sun Mar 15, 2015 4:22 pm

Thought - love your problem solving and fortitude :)

cj7hawk
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Re: Electric X development - Petro-Electric bicycle project.

Postby cj7hawk » Thu Mar 26, 2015 12:34 am

Update: Have finally received all parts necessary for the base electric bicycle - including motor and new controllers - I went with the 500w 48v rear wheel hub motor and ran this from a 24v 250w controller, which, with losses, comes in well under the 200w mark - and even without losses seems to sit within the level. Top speed is about 19kph, so about that of a pedelec, and won't go faster. Downhill, power bleeds off with angle, and it's a bit slow to climb, but has enough torque to pull away from a standstill and is accurate enough on throttle to control speed pretty well, even climbing my relatively shallow driveway and parking in the garage.

Image

Yes, those are cable-ties holding the batteries in place - Very large ones. They were temporary so I could collect some use data - and it's pretty ugly and not really suited to use like that, but worked OK -

Now I can set about turning it into a dedicated E-bike so I can use it as a basis for my project. Yes, it's an old Big-W Huffy :) After all, I wouldn't go wanting people to think it's not a frankenbike ;) Current goals are to work out why it's only 19kph and work out if I need to uprate it to get the full 24 kph ( 200w ) out of it, as output power, but that may not be possible as it seems speed limited to around 19 kph in any respect... :( I may have to find another controller to get around that limitation - This one doesn't support pedal mode anyway, so I will have to upgrade it before I'm done.

I'm away for a few weeks, then back to connecting the genset to the bike so I can operate it as a full extended electric and collect data on operation.

Regards
David

p.s. Generator prototype ( four-stroke ).

Image

geebee
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Re: Electric X development - Petro-Electric bicycle project.

Postby geebee » Thu Mar 26, 2015 7:46 pm

The first 2 items maybe of interest http://www.staton-inc.com/store/index.p ... id&x=0&y=0
Image

cj7hawk
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Re: Electric X development - Petro-Electric bicycle project.

Postby cj7hawk » Thu Mar 26, 2015 10:17 pm

Those things are awesome - Hybrid petrol/Electric systems. Unfortunately, because of legal wording in the way the laws are written, they are illegal in every state in Australia :( Reason being that you have to add the combined power of the petrol and the motor, even if only one is operating at a time - all propulsion motors must be added together. Thank you for posting it though - I hadn't seen that specific type -

That's one of the reasons I'm building an BEVx system - ( = Battery Electric Vehicle Extended ) - These are usually legally recognized as an "electric" system, despite the petrol motor - and as such should be legal in every state in Australia... Even NSW and QLD.

Because the petrol system is a non-propulsion system, it's not recognized as a part of the vehicle.

In simple terms, it charges the batteries as you ride, but the power is provided by the battery system and is regulated/controlled by the battery system as well.

This means it also supports legally compliant Pedelecs as well - something that was impossible to do with a hybrid or a petrol-only system.

Aside from that, it's quieter, smaller, less polluting, safer, etc.... And should be better mileage too, even with the extra losses of the electrical charge system.

I still have to make permanent mounts for the batteries on the bike though - and finish installing the electrics and the test monitoring equipment.

Regards
David

yellagonga
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Re: Electric X development - Petro-Electric bicycle project.

Postby yellagonga » Fri Mar 27, 2015 12:59 am

Cool concept. By using a 48v 500w motor at 24V, you are getting 125watts out of it. That's why you are only getting 19kmhr. If you switch to 36v you will get 280watts. AND Because you have an onboard power plant, you dont need a big battery. 36v 2Ahr would be plenty.

cj7hawk
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Re: Electric X development - Petro-Electric bicycle project.

Postby cj7hawk » Fri Mar 27, 2015 1:50 am

yellagonga wrote:Cool concept. By using a 48v 500w motor at 24V, you are getting 125watts out of it. That's why you are only getting 19kmhr. If you switch to 36v you will get 280watts. AND Because you have an onboard power plant, you dont need a big battery. 36v 2Ahr would be plenty.


Seems about right - when I make allowance for losses through the motor at around 30%

I realize it's not possible to say with precision that if I use half the voltage I'll get half the power, but it's pretty close with a brushless - And in any event, the markings/ratings on many cheap hub brushless motors are kinda of flaky to begin with - So I'm working initially off of volts/amps and measuring it, and allowing for losses before the output.

The speed issue is definitely related to the controller though - it just doesn't push the speed - yet under load, it will easily hit/exceed 200w ( and I have seen it go to 300w which is the cutoff ) - So under load, the wattage should be at least close to linear. The torque is pretty good and it will almost spin the wheel if it can't go anywhere ( it can spin the wheel without me sitting on it, while on concrete ). It will pull away from a standing start OK.

However as the load reduces and I reduce braking, instead of speeding up, the motor hits a fixed max speed and the current drops off as back-emf starts to counter the load - And it gets to about 20w at full speed without load... :( Yet still not all that fast. If I change the load dynamically while on the test setup, the wheel maintains speed while the power varies - So based on all of that, I'm assuming there's a maximum limit in the controller that I can't change. If I could set it for 24 kph, I think it would get there OK -

Also, it's a little frustrating, because it should produce power at any speed - as PAPCs are allowed to do, but the controller cuts off all power above about 20kph and the current drops to near zero no matter how much throttle it has. I'm looking into whether I can get a programmable controller at 24v now as well. The motor setup I have will do 36v and 48v as well, but reasonably needs a boost controller to ensure good regulation above 30v, as I'm using a 24v motor/generator at present.

It's still compliant from what I can tell - Electrics seem to be allowed to have a "peak power" and a "max continuous power" and as long as it doesn't exceed 200w at the wheel, that should be OK. I'll use max speed tests to ensure I'm within the compliant range.

Once the motor is on, it should sit around 27~28v, but could reasonably sit safely up to 30v, which is mid-way between the two, and won't overload the batteries, but I'd prefer to keep the current to the batteries low and accept a lower speed. I fried a battery controller/regulator during early experiments, but have fixed that issue now with a fairly hefty power filter and capacitive array connected to the output.

The maximum continuous output from the generator should be around 300w, but I need to keep it down as I don't want it overheating while I'm still collecting data. I've located some 1kW models and will change to them later - The main problem with heat is that I'm using plastic flanges, so don't want them getting to the point that the temperature reduces their strength. Also, while I want plenty of power available for practical reasons, I'm still trying to ensure the final design is intended to be used on legal bicycles, so as long as I can continuously produce around 10A (AT) around 27~28v, that's the goal.

Regards
David

yellagonga
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Re: Electric X development - Petro-Electric bicycle project.

Postby yellagonga » Fri Mar 27, 2015 9:29 pm

Half the voltage does not mean half the power, it means a quarter of the power.

Power is volts x amps. Halving the voltage on a constant impedance(R) will result in half the amps.

Half volts x half amps = 1/4 Power.

P = V^2/R

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Re: Electric X development - Petro-Electric bicycle project.

Postby cj7hawk » Sat Mar 28, 2015 12:32 am

yellagonga wrote:Half the voltage does not mean half the power, it means a quarter of the power.

Power is volts x amps. Halving the voltage on a constant impedance(R) will result in half the amps.

Half volts x half amps = 1/4 Power.

P = V^2/R


:( You are absolutely correct :shock: - I did something very stupid :oops: because I just figured it in my head without actually calculating it - :( Then I tried to explain it away with another logic without rechecking my original assumptions...

I guess when a mistake is made early on, it's easy to ignore it completely because you accept it as correct until you go back and check it :( I was thinking amps and forgot to take into account that I had to multiply it by voltage again.

Still, I am measuring far more power at the battery, so I assume the motor isn't running as expected either - I guess this means I could potentially include a voltage booster to address that.

Though ultimately, I guess I still need to put my dyno together so I can measure the real output at the wheel and adjust things there -

OK, I'll go sit in the corner and mull over something daft I did...

Meanwhile, I'll have to work out where I need to be to hit the correct output power and hopefully I am just plain wrong about the speed limiter ( though I get the feeling I'm not wrong about that, just slightly incorrect, as the power drops off dramatically when cycling downhill at around 20kph, so there's probably some kind of limit there... )

Time for me to pay attention to the calculations again instead of making assumptions - :) :oops:

Thanks for the correction. I'll continue with the motor gen at the moment and see if around 28v helps much - I can live with it a little low in power as long as I'm sure it's legal... Then I can install a 10A booster to tweak it up to full output later. :D

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Re: Electric X development - Petro-Electric bicycle project.

Postby yellagonga » Sat Mar 28, 2015 4:28 pm

The battery appears to be drawing too much because the motor is too big. You will have 1/4 peak power which is locked rotor or during initial acceleration. After that, you are still putting the motor under the same load, regardless of voltage. So if at cruising speed the motor is under a 300watt load, it will draw 300 watts. If you drop the voltage, the motor will draw more amps.

You are noticing the power cut out down hill because a hub motor can only turn at a maximum speed. Like squeezing the trigger on a drill with the drill in the air. The chuck will only spin so fast, the gear box is its load and thats as fast as the drill can turn it. Most hub motors do about 27kmhr if you lift the wheel in the air and hit the throttle. Your top speed is less because you have dropped the voltage.

Can you get another 24V battery and series them up to power the motor but charge them in parallel? Or maybe get a 24V 250W hub motor?

cj7hawk
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Re: Electric X development - Petro-Electric bicycle project.

Postby cj7hawk » Sat Mar 28, 2015 11:36 pm

yellagonga wrote:The battery appears to be drawing too much because the motor is too big. You will have 1/4 peak power which is locked rotor or during initial acceleration. After that, you are still putting the motor under the same load, regardless of voltage. So if at cruising speed the motor is under a 300watt load, it will draw 300 watts. If you drop the voltage, the motor will draw more amps.


What you are saying makes sense, but the load here is related to wind resistance, which is only 200w at around 25kph ( plus losses ). In this case, the controller cuts out at 10A and won't exceed 300w even momentarily as it's current limited - but even then it ill only draw a little more than 7A at 19kph -


You are noticing the power cut out down hill because a hub motor can only turn at a maximum speed. Like squeezing the trigger on a drill with the drill in the air. The chuck will only spin so fast, the gear box is its load and thats as fast as the drill can turn it. Most hub motors do about 27kmhr if you lift the wheel in the air and hit the throttle. Your top speed is less because you have dropped the voltage.

Can you get another 24V battery and series them up to power the motor but charge them in parallel? Or maybe get a 24V 250W hub motor?


This particular motor should do nearly 40 kph with another 24v or two-more 12v batteries. Anyway, if I could have found a suitable motor at 250w to begin with, I wouldn't have started with another. Also, I'm mixing and matching brushless controllers as 48v controllers won't work with 24v due to the low voltage cutout.

So... I could go 36v, but that's a little high, so I will get one of these http://www.ebay.com.au/itm/New-600W-DC-DC10V-60V-to-12V-80V-Boost-Converter-Step-up-Module-car-Power-Supply-/331457056813?pt=LH_DefaultDomain_15&hash=item4d2c61502d and see if that allows me to increase the speed by upping the voltage slightly - And will also regulate the power output - and I guess I get to see if that converter really can maintain 10A... :) If it works, then I'll just dial in the optimal speed. Though I don't think the problem is entirely back-EMF related either as I would expect the load to remain the same with small speed increases, but the amps drop off very quickly once I hit 20kph. It might be trying to do something like simulated pedelec mode?.... It's difficult to buy a good brushless controller on spec - I didn't even get instructions with the one I got, and had to figure out the wiring - not that difficult though.

I tested to throttle servo upgrade today - with fairly good results. It sat quietly at idle ( or near it, since it was charging the batteries ) with a 24.3 lower limit and a 25.5 upper - this provides a hysteresis range which limits hunting and slowly zeroes in on a suitable power output, so when power isn't being heavily drawn, it doesn't make a lot of noise or use a lot of fuel. I was charging at about 50w, so with 250w drawn by the test load ( 2.5 ohm, 500 watt resistor array ) it slowly throttles up, but throttles back down very quickly - the lag is primarily due to the large capacitor array and the batteries, meaning that sudden changes in current don't cause an immediate change in voltage.

I'll include an extra 40w 12v output for headlights and taillights, since I need 12v to run the servo ( or thereabouts ) - Though since I really don't want to exceed 300w total power output, I might need to limit the throttle so it won't go past about 300w.

I didn't include a "motor not running" sensor, so the result is that the servo goes full throttle when I leave it running with the motor off. That made the motor a little harder to start, but the autothrottle kicked in before the motor could overcurrent the batteries. I can always include the autothrottle on it's own circuit so it runs whether the battery is connected or not - if the battery isn't connected, I get about 27~28 volts floating, which is fine for the batteries to be permanently connected to.

It hunted a little at start, but after about 30 seconds, settled down and gives fairly stable voltage management. Also, I only had about 1/2 a volt hysteresis there.

Regards
David

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Re: Electric X development - Petro-Electric bicycle project.

Postby yellagonga » Sun Mar 29, 2015 10:16 am

Sounds like you've got it nearly ready for a 100km+ test ride. Hope the seat is comfortable :)

You should post it on endless sphere forums, they'll love it. http://endless-sphere.com/forums/

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Re: Electric X development - Petro-Electric bicycle project.

Postby cj7hawk » Sun Mar 29, 2015 2:35 pm

Good idea - I have borrowed thoughts from there in the past, so I should at least make a first post there.

I ran a cold test this morning with the increased hysteresis, and it immediately settled into a stable configuration with no hunting. When cold the ripple can get a little high ( around 1v ) which I think adds to the hunting, so this time I tried it with the settings from yesterday and it was stable.

A pic :)

Image

From left to right ( ignoring stuff like the multimeter ) -

The autothrottle is the black-box and adjusts the engine output to maintain correct generator output - Typically accurate settings to within 1v, with subsecond response to a voltage variation, which, with the batteries, typically means voltage is maintained within about a 2v range and can respond instantly to demand.

Next is the 12v circuit - That's a $4 part that takes up to about 50v and converts it to 12v (AT) 3A with around 95% efficiency - Will be used for LED lights later ( about 20w worth ) so I can light up like a car at night.

Then there's the rectifier and the filter, that clean up the output from the generator, which delivers around 24v power at idle, with around 20v peak to peak unless it's cleaned.

This goes into the capacitor array which allows for 20A continuous ripple RMS, meaning they never get warm and should last for the lifetime of the engine - It doesn't look like much, but took about 3 weeks to engineer, and over 50 datasheets reviewed. Only certain capacitors are suitable.. It's about 10,000 uF - so pretty significant and buffers the power significantly - Makes a good crack when I bring the battery online... Gotta do something about that - Then again, maybe just a good switch. Or connect via a soft-start circuit.

Then the batteries - Just 7.6Ah 12v SLA gel cells. Very suitable for cycling - not too heavy and not insignificant for range on battery alone - Saved from cycle related damage by the generator.

Finally, the generator itself. 3D printed to mate a 300w generator with a 4stroke petrol engine, that can supply peaks of around 800w or higher, but generally I'm engineering the whole thing for around 250w.

Overall, not too many parts - Now I have to repackage them - except the bike rack I bought is twisted to about 10~20 degrees off horizontal ( ebay crap ) so just ordered another - I'll use the frame of it to dissipate heat from the rectifier. Nothing else really needs the heat addressed at this point. Also, I have to build a custom box to fit it all.

That's about it at the moment - I completed testing of the standalone circuit ( without battery ) and despite the WOT start, it re-sets the throttle to idle within a few fractions of a second on start up, so now it works just fine without the battery - that's significant, because it's going to be difficult to always match battery to generator ( though I managed this time ) so will need a charge controller in some applications, which inhibits my ability to use direct battery connection, but provides smart-charging/load-operation and also gives a separate set of inputs so it can charge ( maintain/top-up ) the batteries via solar when the engine isn't running, allowing more efficient use of the engine.

Well, it's been a couple of months of development now - the time it takes for Ebay stuff to arrive is slowing down progress - so it was a difficult decision to go with a new rack as opposed to fixing the bent one that arrived in the post. :( I know that's going to grate on me, so I might come up with a hybrid solution in the mean time so I can progress to road testing - or I might move to incorporating all the separate components into a single box, and maybe re-align the generator so I can fit stuff in a smaller space, integrating the autothrottle with the other items.

Regards
David

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Re: Electric X development - Petro-Electric bicycle project.

Postby yellagonga » Sun Mar 29, 2015 4:52 pm

Wpuld it be possible to design a bike like yours but instead of a petrol motor, the pedals drive the generator and not at all connected to the rear wheel. This way you can pedal at a constant cadence and power which would give you greater endurance than surging your legs at take off and uphill. Could even include a stand to allow you to pedal and charge while stopped. Can use a direct drive hub motor for regenerative braking.

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Re: Electric X development - Petro-Electric bicycle project.

Postby cj7hawk » Mon Mar 30, 2015 12:25 am

yellagonga wrote:Wpuld it be possible to design a bike like yours but instead of a petrol motor, the pedals drive the generator and not at all connected to the rear wheel. This way you can pedal at a constant cadence and power which would give you greater endurance than surging your legs at take off and uphill. Could even include a stand to allow you to pedal and charge while stopped. Can use a direct drive hub motor for regenerative braking.


It would be very easy to do that (just run the crank chain to the generator) but the problems occur with respect to power losses - A chain is incredibly efficient - more than belt or driveshaft/gears or any other means - and so is still widely used on cycles today. Electric only systems would be horrendous losses. So while it's technically possible and not even that difficult, it's not a good idea.

Also, it would still be a pedal/electric and would be legislated - and given a good rider can generate more than 200w, it might be technically illegal - It would be classed as a motorcycle ;)

However the hub motor I got was direct drive, so if the bike's on a stand and you were pedalling, it is possible to generate power from it ( as is, without any controller or other electrics ) and you could rectify that and use it straight into batteries for storage, or to generate spare power.

I tested that by shorting the wires while riding and the braking was pretty sudden... I managed to pedal past it at low speed, and the current was significant, warming the wires in my hands.

Regards
David

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Re: Electric X development - Petro-Electric bicycle project.

Postby cj7hawk » Tue Mar 31, 2015 3:26 pm

Battery brace system complete - Batteries now firmly fixed to bicycle frame... A combination of custom frames designed and 3D printed to guide and protect 120kg nylon straps and it's pretty solid ( no movement with a good heft ) and locks everything on. The upper middle frame section includes 4 x m3 integrated hardmounts to allow me to put a cover over the terminals and to include other parts ( charge socket, output line, key/switch etc )

Without the straps ( framework only ) - Yes, it's solid like that, but can slide around a little as it's designed to use the straps structurally.

Image

And with the straps installed - I probably just doubled the working weight range of the bicycle frame :lol:

Image

Regards
David.

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Re: Electric X development - Petro-Electric bicycle project.

Postby cj7hawk » Wed Apr 08, 2015 1:14 am

Completed E-bike conversion, then used the old parts to quickly fit the kit, and took it for a test run - though it's storms here and I was getting wet, so only quick and the photo isn't much... But it works, and it's riding.

Image

And so the prototype is now ready for testing :)

Currently getting better than 50km/l including charging the batteries while riding.

Regards
David

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Re: Electric X development - Petro-Electric bicycle project.

Postby geebee » Wed Apr 08, 2015 5:17 pm

If you tossed the generator and SLA's and replaced with a similar weight in LiPo you could have a 100 ah capacity, using my trikes range with no pedalling you should be looking at a 300 km range.
Real world it would be easier, lighter and a lot quieter to use LiPo's for any realistic distance short of long distance touring and camping away from all facilities as otherwise you could charge overnight.

A fun project but It would be far worse than grid charging polution wise, efficiency losses are massive.

On your current build you need to urgently brace the rack to the frame as seat post racks break alot with heavy loads and sometimes take out the seat post or frame as well.

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Re: Electric X development - Petro-Electric bicycle project.

Postby biker jk » Wed Apr 08, 2015 6:10 pm


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Re: Electric X development - Petro-Electric bicycle project.

Postby cj7hawk » Thu Apr 09, 2015 12:54 am

What can I say? Leo !! BAN ME NOW FOR SWEARING !! was my hero as a kid :)

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Re: Electric X development - Petro-Electric bicycle project.

Postby cj7hawk » Thu Apr 09, 2015 1:10 am

geebee wrote:If you tossed the generator and SLA's and replaced with a similar weight in LiPo you could have a 100 ah capacity, using my trikes range with no pedalling you should be looking at a 300 km range.
Real world it would be easier, lighter and a lot quieter to use LiPo's for any realistic distance short of long distance touring and camping away from all facilities as otherwise you could charge overnight.

A fun project but It would be far worse than grid charging polution wise, efficiency losses are massive.

On your current build you need to urgently brace the rack to the frame as seat post racks break alot with heavy loads and sometimes take out the seat post or frame as well.


I would have thought the energy losses would be offset by the difference in fuel - anyway, I know several people have suggested a huge lipo, but that might be a later project. But I'll need to collect more data to be able to work out the exact emissions from it.

The frame is supposed to support 10 Kg and it weighs 6, but it does leave me kind of nervous. I just got my new frame today for the rack - seems pretty strong and has two braces - And is fully clip-on ( There's reasons I can't use bolts ).

Regards
David.

geebee
Posts: 186
Joined: Sun Oct 12, 2008 4:55 pm

Re: Electric X development - Petro-Electric bicycle project.

Postby geebee » Thu Apr 09, 2015 9:01 am

A well made comercial generator is ~20% efficient, Coal based grid power at the power point is still ~30% (newer power stations are better), turning oil into petrol is very electricity intensive ( look up fully charged on you tube there is an entire episode on it).
Real world usage of a generator " I've just finished testing my Honda EU20i, it managed to drink 900ml and produce 1kWh, so $1.50 / litre for fuel, that's around $1.35/kWh!"
http://forums.whirlpool.net.au/archive/1719762

If you have braces it should be ok, if you search any ebike forum you will find numerous examples of broken racks, one had braces to the seat tube and it snapped the tube and top of the frame still!

Have fun with your project :)

cj7hawk
Posts: 1144
Joined: Sun Jan 18, 2015 9:00 pm

Re: Electric X development - Petro-Electric bicycle project.

Postby cj7hawk » Sun Apr 12, 2015 2:11 pm

geebee wrote:A well made comercial generator is ~20% efficient, Coal based grid power at the power point is still ~30% (newer power stations are better), turning oil into petrol is very electricity intensive ( look up fully charged on you tube there is an entire episode on it).
Real world usage of a generator " I've just finished testing my Honda EU20i, it managed to drink 900ml and produce 1kWh, so $1.50 / litre for fuel, that's around $1.35/kWh!"
http://forums.whirlpool.net.au/archive/1719762

If you have braces it should be ok, if you search any ebike forum you will find numerous examples of broken racks, one had braces to the seat tube and it snapped the tube and top of the frame still!

Have fun with your project :)


Hi Geebee,

Thanks for the suggestion, but I couldn't find the episode you were referring to - Can you offer any hints such as what the topic was they discussed so I can find it a little easier?

The comments I was making were around the general pollution levels of coal, and were more based around this kind of research - http://www.popularmechanics.com/cars/hy ... -17535339/ - But I haven't calculated things yet.

I was originally aiming for around 150km/l and I'm getting around 51km/l, but I'm also charging almost as much as I'm using, so the the battery charged, that might increase - if I get halfway there, I'll be happy - around 80 to 100 km/liter would be good - but a lot of additional research ( and tests, and collecting results ) is needed first.

It will take me a while to design all the flanges for the new rear-rack so hopefully the existing one will survive until then. Total weight on it is about 6kg distributed in the center of the carriage area - fingers crossed then.

Here's a pic of the 3D CAD diagrams of how the electric bike goes together too - and to that extent, I've not seen a lot of 3D printed battery housings on bicycles before?

Anyway, Red is straps, Cyan is mount parts ( 3D printed ABS ), Yellow is the terminal cover ( 3D printed ABS ) - Green is ESA's ( Electronics/ Batteries, etc ) and white is the aluminium frame.

Image

The mounts seem to confirm to the EN15194 standard so should be compliant for PAPC or Pedelec.

Regards
David

geebee
Posts: 186
Joined: Sun Oct 12, 2008 4:55 pm

Re: Electric X development - Petro-Electric bicycle project.

Postby geebee » Sun Apr 12, 2015 4:24 pm

Link to the episode of Fully charged. https://www.youtube.com/watch?v=BQpX-9O ... ubs_digest
I have seen a couple of 3d printed e-bike parts, If I can find the links I will post them.

cj7hawk
Posts: 1144
Joined: Sun Jan 18, 2015 9:00 pm

Re: Electric X development - Petro-Electric bicycle project.

Postby cj7hawk » Sun Apr 12, 2015 9:30 pm

Thanks for that, I'll watch it.

Update:

I began some serious data collection today at full load. Heading up the hills I normally tackle that leave me breathless and gasping, and I managed all of them without too much effort under power, though the motor alone wasn't enough. Then, on the way home after I'm done, and the motor starts screaming for about 20 seconds, then the safety circuits kick in and slow it, then it stalls completely. I'm close to home by this stage, having had an otherwise perfect test run, except for the low top speed.

And then I notice the smell of burning electrical circuits... Generator is too hot to touch ( after a perfect run - shouldn't be that hot ) and I can't start the motor except at full throttle, at around 1000 watts. ( Gen watts, not propulsion watts, estimate based on RPM and load ) - Check all my circuits, nope, they are all cool and working perfectly.. No abnormal heat anywhere. So I pull the gen off and apart ( whole thing unclips from the bike in seconds ) and the stink comes out. Several windows have broken from the commutator and shorted around the armature. Not so good. It was rated for 16A continuous and wasn't being pushed anywhere near that - so I guess it was faking it. I hadn't run continuous operating conditions before, and I guess it was too much, so I'll use a 1500w model in the next version.

Other than that, a very successful test run. Circuitry worked perfectly, motor ran nicely and slowly picked up as I hit harder sections, making it very quiet in operation - so far, a winner all around. Way quieter than the petrol bike even with a smaller muffler. Most of the time, it only idled, trickling in the power at low RPM even though I was sitting on 20kph at times.

Oh, and I get back and Strava tells me I'm ranked 5th on my route... First time I used it for position information, so I look further and find that the killer hill I've been using to finish my rides is a challenge. Normally, I struggle up it with the petrol at about 10kph even pedaling like crazy. I can barely make it in low gear on a normal bike, but the electric has better torque when I'm at lower speeds, so I maintained about 15-16 kph up this hill that normally beats me, with only medium effort to keep it up, which was OK. Actually, the main difference the current setup does achieve is it's great up hills. A little slow in the flats ( 19 kph max ). I suppose I should tell Strava it it's an electric, but I'm not sure how to.

So, it will be broken for a while, but then I'll rebuild it and go onto the prototype Mk II. If the idea of a petrol enhanced electric bicycle hadn't already appealed to me, after today's test runs, it really would.

David.

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