Electric X development - Petro-Electric bicycle project.

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

Postby Storm Boy » Tue Apr 14, 2015 6:09 am

Hi David,

I've just been reading your post with interest.

Out of curiosity, have you considered using a brushless motor as an alternator instead of using a brushed generator? There would be some number crunching and experimentation to be done but you should end up with a more efficient and more reliable unit, if you could physically mate it to the existing 4 stroke motor. This should increase your total system efficiency and therefore fuel efficiency. Typical peak efficiency for a "standard" small, cheap brushed motor might be around 60%, whereas peak efficiency for a fairly inexpensive brushless motor should be around 80-85%, or possibly more. This could equate to real mileage gains of around 30%.
There are a number of model aircraft/car brushless motors available quite cheaply these days, and they have a range of kV values (RPM per Volt values). You could experiment with smaller cheaper motors with regard to RPM input/Voltage output, and use a three phase rectifier as it is a three phase permanent magnet motor being used as a permanent magnet alternator. The usual capacitor smoothing would then be used but could be downsized as the output waveform from a three phase generator/rectifier will be inherently smoother.
Once the basic concept has been tried on a small (inexpensive) scale and you have an idea of the values you need, you could purchase a larger unit appropriate for the bike. Adequate air or fan cooling will need to be considered as the ratings on these units assume some airflow over them.

Regards,

Matt

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

Postby cj7hawk » Tue Apr 14, 2015 9:58 am

Storm Boy wrote:Hi David,

I've just been reading your post with interest.

Out of curiosity, have you considered using a brushless motor as an alternator instead of using a brushed generator? There would be some number crunching and experimentation to be done but you should end up with a more efficient and more reliable unit, if you could physically mate it to the existing 4 stroke motor. This should increase your total system efficiency and therefore fuel efficiency. Typical peak efficiency for a "standard" small, cheap brushed motor might be around 60%, whereas peak efficiency for a fairly inexpensive brushless motor should be around 80-85%, or possibly more. This could equate to real mileage gains of around 30%.
There are a number of model aircraft/car brushless motors available quite cheaply these days, and they have a range of kV values (RPM per Volt values). You could experiment with smaller cheaper motors with regard to RPM input/Voltage output, and use a three phase rectifier as it is a three phase permanent magnet motor being used as a permanent magnet alternator. The usual capacitor smoothing would then be used but could be downsized as the output waveform from a three phase generator/rectifier will be inherently smoother.
Once the basic concept has been tried on a small (inexpensive) scale and you have an idea of the values you need, you could purchase a larger unit appropriate for the bike. Adequate air or fan cooling will need to be considered as the ratings on these units assume some airflow over them.

Regards,

Matt


Good thinking :) I originally used a brushed motor because it was there, and so that's how I got started - I used it for the proof of concept ( building a small gen to light two lamps ) using a 2-stroke motor - it worked OK and even blew the lamps, so I knew it was producing more than enough power.

I ordered my first brushless motor over the weekend for this - hopefully it will work - one that I'm using is a 3000w aircraft brushless, 170kv that I hope will maintain the current OK. The other is a 1500w bicycle brushless - Both should be OK. The aircraft one is very light and should be matched to the voltages I want, while the bicycle one isn't quite a match and I might have to hope it's close enough when matched.

These are the basis for the MkII version, and it would only be better if I could find an even lighter GX25 motor for the aircraft one, then I might be able to get the weight under 3Kg.

Parts will take time to arrive though. Usually from order, it can be up to a month... Which reminds me, I need a three-phase bridge.

Regards
David

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

Postby Storm Boy » Tue Apr 14, 2015 10:46 am

Hi David,

It looks like you have the project well thought out, I'll be interested in watching how it develops :-)

Regards,

Matt

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

Postby Joeblake » Tue Apr 14, 2015 6:31 pm

Image

Image

One of the advantages of a trike is that the solar panels can be horizontal to gain maximum sunpower. The system has a 24 v Heinzmann 250 watt motor which is governed to 193 rpm, so the two different wheel sizes give different max speeds, 16 km/h and 27 km/h. The red one can climb a steepish hill on motor alone. The meters tell me that on a "good" day the panels are delivering 0.4 Amps at 24 volts which is 9.6 watts. I only use the motors at the lights, climbing hills and occasionally to give my legs a rest. I can use a 24 volt battery charger if needs be, but since I've got solar panels on the house it's all solar anyway, nothing at all from the grid.

The batteries are lead acid (sealed) so no maintenance problems. When LiPo or whatever comes down in price I'll change over, but the SLA do the job well.
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Re: Electric X development - Petro-Electric bicycle project.

Postby cj7hawk » Fri Apr 17, 2015 10:42 pm

Joeblake wrote:The batteries are lead acid (sealed) so no maintenance problems. When LiPo or whatever comes down in price I'll change over, but the SLA do the job well.


That's a really nice bike Joe - What sort of capacity are you getting from your SLA setup? I'd suggest that it would be great with something like my Gen on that bike, which would give you the ultimate solar/electrical/petrol system, but the size of it might be a problem with that setup - It looks great though.

Anyway, some pics of the damage from the last test -

Image
The burnt out windings of the brushed generator - Five of eight windings are destroyed.

Image
The transfer shaft got hot enough for the ABS to soften and the drive pins slipped, so I had to rip the generator free once it cooled - The retailing slots were still intact, but with enough heat, it was still able to mess it up - mind you - heat would have been well over 100 degrees transferred through the generator shaft so that the ABS would deform like that without showing any signs of stress in the plastic. Pins were suprising well held and despite power outputs from the motor at maximum while it tried to maintain the power, the end result was that the heat only increased until the windings overheated and failed.

So in this case, the maximum output of the generator wasn't close to it's rated output - :( Still, it did a pretty good job until now - and I was running it at full power.

The new parts haven't arrived, so a quiet weekend - And next weekend and the weekend after I'm likely to work overtime, so I might not get the Mk II under progress until three weeks from now :( Hopefully the electric system upgrades will arrive in the mean time and I can test those through the week -

David

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

Postby Joeblake » Sat Apr 18, 2015 9:32 am

Deep cycle AGM Battery capacity is 2X 12 volt 14 A/h.

The green machine weighs about 37 Kg, and the red one 34 Kg.
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Re: Electric X development - Petro-Electric bicycle project.

Postby trailgumby » Sat Apr 18, 2015 10:46 am

What are you doing for emissions control? The stench from those things is pretty strong - two stroke with oil in the fuel and less than perfect combustion - and makes me want to gag when they pass. You planning on fitting some kind of catalytic converter?

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

Postby Storm Boy » Sat Apr 18, 2015 12:48 pm

David's actually running a little Honda four stroke, they're very nice small motors and pretty clean running.

Regards,

SB

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

Postby trailgumby » Sat Apr 18, 2015 1:33 pm

Thumbs up for going four stroke but I still find myself gagging when stuck behind four stroke motorbikes in traffic. Petrol sniffing :roll:

While at least the motor on this project is small, I'm not too sure I'd be very keen n their widespread adoption.

I do really like the solar-augmented recumbent trike though - hits all the right notes. :D

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

Postby cj7hawk » Sat Apr 18, 2015 11:58 pm

trailgumby wrote:Thumbs up for going four stroke but I still find myself gagging when stuck behind four stroke motorbikes in traffic. Petrol sniffing :roll:

While at least the motor on this project is small, I'm not too sure I'd be very keen n their widespread adoption.

I do really like the solar-augmented recumbent trike though - hits all the right notes. :D


I like the solar panels too, but I'm not sure how I'd go about putting 200w of panels on a normal 2-wheeler - The three-wheeler is a nice implementation that really impresses me, but those panels are too small for continuous assist. Still, that configuration does allow for additional batteries.

Anyway, that particular motor is a Subaru Robin 4-stroke clone, and it's pretty clean... It hits the sort of emission standards expected from modern small engines and is much less than you're probably getting from nearby traffic on roads, unless you're following within a meter of me - something no sane cyclist would risk even if the engine was turned off.

I've sat in the same carport as it and in the exhaust path while it's running over a period of hours and even sniffed the exhaust and it is pretty clean, not to mention it's putting out an order of magnitude less than what a car would produce. I can still tell it's petrol exhaust, but in the same relatively confined area ( ventilated, but without wind often ) the two-stroke leaves me gagging after a few minutes, even though in the open and moving I can't really notice it much... Yet the four stroke is pretty clean and I can continue working in the space.

You might even be particularly sensitive to the smell of petrol, but if there's traffic nearby or you ride on PSPs alongside roads, I doubt you'd detect it at all even if you were following behind me -The emissions from that small engine would be easily lost in the background level of nearby car emissions.

The other good thing about the system is that it's quite slow to respond with a well-defined hysteresis and so it cuts in quite slowly under power and always drops to the lowest possible RPM for a given power output. Given it's a 1.2 kW motor, and it's only pushing 200w as a typical maximum, that means it runs pretty slow and it's a lot quieter than direct-drive systems, and the noise increase is slow, meaning there's no sound of revving - even under maximum power. During the final test of the MkI system, it did get a bit noisy, almost as much as my petrol bike, but even then it was in a failure mode and still wasn't that noisy.

Finally, it's foremost an electric bicycle, so that gives the rider the option to simply not-use the motor and ride on battery, which will increase the cycle wear on the batteries though all electric bicycles have that limitation. But is just as quiet as any electric - With a good range, then the petrol could be used as a pure backup system for when the batteries got too low ( eg, < 20% ) to avoid excessive wear.

This system isn't intended to replace or be used instead of electric bicycles. It's a range enhancement technology so that they can go further, with smaller battery packs and reduce the cost of battery replacement. Also, it is clip-on - at the moment, I'm running pure-electric and so I just unclipped the generator and am running on batteries and charger alone. Removing the generator is very simple - just a plug and a quick-release and it's off ( or three quick-releases with the heavy duty rack ) - so it's quite practical to keep for when longer trips are expected instead of using it all the time - Or to install it when I realize I've forgotten to charge it up and charge while I'm riding it. The rest of the time, it could stay electric only.

I'm not planning on fitting a cat to it though - they do make them but I have no idea where to get them from. I'd be pretty happy if I could get an improved exhaust, but I'd want it built in - At the moment, the engine I have is built to be operated in contact with a human, without burning them - something current P-bikes don't handle so well - but I can pick the engine up by the hot sections and as long as I'm not directly over the exhaust, can hold it - But as for a cat? Well, most small engines don't have fuel injection, which is pretty much a requirement for a cat if efficiency is important anyway. Keep in mind though that future small engines are quite likely to have all kinds of stuff in them to reduce emissions.

You can always look up the emissions data on small engines - eg, http://www.makita.biz/environment/mm4.html - but if you're fundamentally opposed to petrol ICE engines ( which some people are - I'm not going to criticize them ) then I guess the only options would be to run on ethanol or similar - It's not like power loss is a problem - And cooling levels are most likely adequate for the applied power range too, so it's mostly just that you'd need to change the carburetor system. Even without that though, it would still probably be a good thing for the environment if these took off - because it would have two effects. One is reducing car-levels of pollution - and the other is pushing people to improve electrics.

Now, Solar for good days, late-night grid charging and petrol for cloudy days or when you're low on charge or long on range? That's probably about as efficient as you can get, and removes the need to use a car on many bad days :)

Regards
David.

Edit: Found some emissions information "aka, Marketing" on that engine series.

The EH035 and EHO35V engines are engineered to minimize emissions and exceed industry regulations. Producing only 10-percent of the THC-Nox emissions found with conventional two-cycle engines, the EH035 and EH035V exceed both EPA Phase 2 and CARB Tier II emission regulations. Featuring a quiet, low-vibration design, the units meet EMC noise level standards and minimize operator stress. Additionally, the highly-efficient combustion system produces less exhaust smoke and odors than two-cycle engine alternatives.

Which doesn't say that much, but does provide some information on emissions compliance.

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

Postby Joeblake » Sun Apr 19, 2015 10:55 am

I like the solar panels too, but I'm not sure how I'd go about putting 200w of panels on a normal 2-wheeler - The three-wheeler is a nice implementation that really impresses me, but those panels are too small for continuous assist. Still, that configuration does allow for additional batteries.


200 watts of solar power? The panels on my trike(s) are 450mm x 450mm, and deliver 10 watts. 200 watts would create a dangerous traffic hazard. I really think you need to re-examine what it is you are trying to achieve. Eg how far you intend to travel and how quickly do you wish to get there.

You seem to be trying to have the worst of both worlds. I understand when you talk about ease of removing the generator, but the panels are permanently fixed, and with their frame and wiring weigh about 1kg or so. I have secure parking with ready access to sunlight for enough hours a day to keep the batteries fully charged at nearly all times. I ride out occasionally and rack up about 80-85 km. Usually when I reach the foot of the Welshpool road ascent my ammeter shows zero, which means that the batteries are fully charged, and I then begin climbing. Because I'm travelling in an easterly direction my panels are facing directly towards the sun and when I reach the flat my batteries have still got sufficient grunt to take me to top speed for the final couple of km. At this stage my average speed over the entire ride is about 18-19 km/h. At no time have I ever felt a need to have a generator running to supplement the panels.

Now, Solar for good days, late-night grid charging and petrol for cloudy days or when you're low on charge or long on range? That's probably about as efficient as you can get, and removes the need to use a car on many bad days :)


If I need to go faster that 19 km/h I have the option of my motorcycle (4 stroke 650cc) which returns about 26 km/l. I sold my car in 1981 and if I DO ever need a car, I simply hire one. A MUCH less expensive option than buying and maintaining one. It's into its 10th year and has only got 76,000 km on the clock. I bought my first trike in 1990 and motorised it in 2007, adding solar panels in 2008. I bought my second trike in 2009, and fitted solar straight away. I've replaced both sets of batteries and bought the usual tyres, tubes and chains, otherwise it costs me nothing to run.

To summarise, your system may eventually work, but it's far too complicated with too many breakable parts, and I would suggest that you look at your end goal and examine alternatives.
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Re: Electric X development - Petro-Electric bicycle project.

Postby cj7hawk » Sun Apr 19, 2015 12:27 pm

Joeblake wrote:I like the solar panels too, but I'm not sure how I'd go about putting 200w of panels on a normal 2-wheeler - The three-wheeler is a nice implementation that really impresses me, but those panels are too small for continuous assist. Still, that configuration does allow for additional batteries.


200 watts of solar power? The panels on my trike(s) are 450mm x 450mm, and deliver 10 watts. 200 watts would create a dangerous traffic hazard. I really think you need to re-examine what it is you are trying to achieve. Eg how far you intend to travel and how quickly do you wish to get there.

You seem to be trying to have the worst of both worlds. I understand when you talk about ease of removing the generator, but the panels are permanently fixed, and with their frame and wiring weigh about 1kg or so. I have secure parking with ready access to sunlight for enough hours a day to keep the batteries fully charged at nearly all times. I ride out occasionally and rack up about 80-85 km. Usually when I reach the foot of the Welshpool road ascent my ammeter shows zero, which means that the batteries are fully charged, and I then begin climbing. Because I'm travelling in an easterly direction my panels are facing directly towards the sun and when I reach the flat my batteries have still got sufficient grunt to take me to top speed for the final couple of km. At this stage my average speed over the entire ride is about 18-19 km/h. At no time have I ever felt a need to have a generator running to supplement the panels.

Now, Solar for good days, late-night grid charging and petrol for cloudy days or when you're low on charge or long on range? That's probably about as efficient as you can get, and removes the need to use a car on many bad days :)


If I need to go faster that 19 km/h I have the option of my motorcycle (4 stroke 650cc) which returns about 26 km/l. I sold my car in 1981 and if I DO ever need a car, I simply hire one. A MUCH less expensive option than buying and maintaining one. It's into its 10th year and has only got 76,000 km on the clock. I bought my first trike in 1990 and motorised it in 2007, adding solar panels in 2008. I bought my second trike in 2009, and fitted solar straight away. I've replaced both sets of batteries and bought the usual tyres, tubes and chains, otherwise it costs me nothing to run.

To summarise, your system may eventually work, but it's far too complicated with too many breakable parts, and I would suggest that you look at your end goal and examine alternatives.


Hi Joe,

In this case, my end-goal is to make it work - Having a bicycle to ride is secondary. If commuting on the bicycle was primary, I may well have gone the same way you did.

The Mk I prototype was achieving > 51km/l during road tests, with stop-start operations and a net positive charge to the batteries at the end of the ride. A motorcycle is fine, but can only be ridden on the road as a licensed vehicle. I'm trying for something that qualifies as a bicycle :) The other note is that it can continuously supply 300w, which is enough to charge the batteries, drive the bicycle and power the lights simultaneously.

I guess the intent isn't to have to pedal, but to be able to rely on the bicycle power for the entire trip. I did a trip last night with limited power, and regretted it, though mostly because of mechanical issues that forced me to abandon the ride when a new part turned out to be faulty.

So to that extent, I set my goals at power for 100km of ride and my objective at 1000km range without charging.

I guess a very large lithium pack would do it, at least the 100km goal, but I'd like to go past that - This project is just a challenge I've taken on and everything you've pointed out about things that can go wrong due to complexity are absolutely correct, so I have to find out what the problems are and engineer a solution until it's as robust as a motorcycle - or equivalent anyway.

10w for solar isn't a problem the way you're doing it - Solar would come closer to fulfilling my goals than charging alone, but I want to have the generator built in. I did consider adding a small quantity of solar to offset battery loss over time though - ( another factor is I want a bike that's ready whenever I want it - even if I haven't ridden/charged it for 6 months ). I think you could probably achieve around 100w peak with technology upgrades on your current setup if you wanted to. At least, I think it should be possible.

I've had to solve many problems so far - they include;

* Automatic throttle control on the motor.
* Automatic current regulation to the batteries - Detects battery load condition and supplies more power with effective hysteresis range.
* High power, low cost filters.
* High capacity, low-cost capacitive arrays with ripple current > 20A.
* Lightweight ( under 8kg ). Small size ( fits behind rider ).
* Easily attached/detached. Must be possible without any tools. ( that's actually a regulatory requirement ).
* Allows use of low-cost batteries ( eg, Gel cells ) with long life. - Addresses cycle-related issues in batteries.
* Qualifies under EN15194 ( This was particularly challenging ) as a Pedelec - even with the ICE engaged.
* Grass-safe - Can be used in fields and paddocks safely.
* Human-safe - Can be used safely in close proximity to the body.
* Easy to make - Uses low-cost 3D printing technology to reduce costs ( I'll likely Open Source this, so others can make it themselves ) or stuff than can be worked at home.
* Long life - > 1000hrs - OK, still working on this one. The Mk I lasted about 10 hours as the generator I first selected wasn't capable of delivering the rated amperage.
* Cost effective - Around the cost of a single battery replacement - including batteries. ( this was particularly challenging ).
* Retrofittable - Likely to support all existing bikes with little or no modification.
* Must qualify under all states legislation as an electric ( still being tested, but so far looks to be compliant, and conforming to EN15194 is a bonus here. )

So far, I've managed to overcome most of the issues and am still working on others. I just need to keep on working to find and resolve all the problems.

It's not for everyone. It's not going to revolutionize transport. It's not going to suddenly take off an be fitted to every bicycle - It really is a niche product for people requiring extended range for their e-bike :) It's also connected to some other research I'm doing, so I guess you'd call it an offshoot.

Regards
David.

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

Postby cj7hawk » Wed Apr 29, 2015 11:07 pm

Work on the Mk II has commenced. Changes -

* 1kW maximum output ( 3kW rated, 82A peak, but I'll be using about 10 to 16A continuous )
* New weight savings - now 4.6 Kg - This thing is seriously lightweight... ( about 10 lb for those over 50... )
* Lower RPM operation, so will use power-regulated boost circuits to save on RPM - However can now run up to 8000 RPM for serious off-road use... Will be developing a 1kW rated output version.
* The following modifications to deal with heat.
i) Triple fan design - One centrifigal, One axial-centrifigal hybrid, One axial. Air is forced over the outside of the magnet housing, over the coils and sucked away through the engine to improve cooling.
ii) Higher rated brushless generator.
iii) Low RPM operation, but rated at over 8000 rpm.
* Lower cost ( yeah, I was surprised by that - I had to get creative in my strategies ).

Anyway, I fired it up tonight for the first time, and quickly got it up above 24v at around 4000 RPM. So at 8000 RPM, this thing could run a 48v 1kW bicycle. I didn't have much to test it with, so wrapped some wires together around a makeshift rectifier ( two rectifiers wired together - the 3-phase rectifier hasn't arrived yet ) then connected a 10w light - light lit up beautifully, with no audible loss of RPM, so it easily pushed past the point of running basic circuitry - which is neat because the brushed generator didn't do that - This thing has about 2.5mm wires going into it and around the windings, so it's pretty heavy duty. Overall, I'm happy with it.

It will take me a few more weeks to finish the Mk II version for testing, but it should be ready soon and then I'll start with the new testing. This has a different method of transferring power, but it's a lot quieter and seems to be smoother as well. I only use 4 pins this time ( I used 11 before ) but they are threaded and have an 8mm dia size, so much better than 11 x 3mm and won't come apart even if they fail.

That's about it for the moment - More to come :)

David

p.s. Pictures -
Image

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

Postby Storm Boy » Wed Apr 29, 2015 11:25 pm

Very nice!

Is that a printed cover over the permanent magnet alternator?

Regards,

Matt

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

Postby cj7hawk » Thu Apr 30, 2015 9:12 am

Storm Boy wrote:Very nice!

Is that a printed cover over the permanent magnet alternator?

Regards,

Matt


Hi Matt,

Yes, it is - The two main structural parts of the adaption are both 3D printed in ABS - That cover also holds the generator in place and provides structural support as well as anti-rotation function. The shaft adapter to the generator is also 3D printed.

Regards
David.

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

Postby cj7hawk » Sun May 10, 2015 10:51 pm

An update - First-day testing for the Mk II generator went perfectly today - I rode around for a couple of hours on the motor, both as assist and standalone, with the Generator doing most of the work - Performance was good and operation was exactly as it should be - Then I connected in a 10W high-intensity LED light and went out tonight - and WOW! I could see stuff for the first time - The path ahead was lit up like a car headlight was on it - Good visibility out to about 30m to 40m, with light at around 90 degrees wide, with about 20 degrees very bright... This would be perfect for getting around my paddocks.

Anyway, the changes;
Image

The new generator is a lot smaller - Weight is now about 4Kg making it very suited to the back of a bicycle. Operation is quieter now, with no mechanical noise and I'm starting to hear other sounds clearly, like the chain on the pedals not being quite right, or the different road surfaces undertire. The pickup is so slow, I often had to throttle back to cause a cut-out so I could confirm the engine was working as expected. Overall, the operation was much better. I've removed the filters now, though haven't checked for spikes in the circuit. Still though, with three-phase power and a big capacitor array, I don't think it will be a problem.

Normally, the battery goes flat after about 1/2 an hour - This time it stayed at about 30% and went no lower as the generator was constantly kicking in and driving the power to the battery while it was under load. Total ride time today was around 2.5 hours. Way more than I'd expect to get even from a high capacity battery pack and probably enough for my 40km round trip if I start commuting.

Construction is perfect now - The 3D printed parts don't get warm at all, and all stress is in compression mode, so they are well and truly strong enough and should take up to around 1kW. I have to run it like this for several hours, then I'll do a teardown and see how the wear is internally. At this point though, I'm not expecting a lot, though the latest design could be made from metal plate by just drilling 6 holes in it, since I've modified the connecting mechanism completely.

I still need to dyno it externally though, as I think I can drive a little more power through it within the laws - Top speed today was around 50, down a steep hill, but if I switched off the booster, the motor was retarded by the controller and brought speed back down to something more manageable. So it seems that over 30, the motor will slow the bike in normal ( low power ) mode... Though I need to check if that's going to the batteries as regen yet.

Also, I head back from DoT last week, and they've confirmed it should be OK to ride under EN15194 or PAPC, so I can connect to either 200w or 250w systems and use on the road - A great outcome.

Regards
David.

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

Postby Storm Boy » Sun May 10, 2015 10:54 pm

Nice work David, and thanks for the update!

Regards,

Matt

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

Postby geebee » Sun May 10, 2015 11:04 pm

^^ WHat he said :)

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

Postby cj7hawk » Thu May 14, 2015 11:15 am

An update - A full set of 3D printed flanges have now been completed, meaning that the bolting of the generator to the engine is fairly straightforward. Just print, clean up and attach.

Image

Now I need to work on making the electronics assemblies look neater -

David

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

Postby cj7hawk » Sat May 16, 2015 12:46 am

* Milestone - First full tank of fuel used without incident - Engine ran over two trips - One 20k, one 7.5k, both without break. Some changes were made to the system beforehand ( Bowden cable replaced for throttle ) and the system performance was improved by this, with response close to optimal. Battery was drained to unusable levels beforehand and charged during the trip.

Over the trips, a total of 367.8 grams of 91 octane unleaded was consumed, which equates to approximately 0.487 litres of fuel. The test was to determine if I could make it to Perth on a single 500ml tank, and given about 25-30km distance, the answer seems to be "yes". Fuel economy was therefore calculated at around 56km/litre, but is more than 100% better over the best results a toyota prius has achieved - and means range exceeds 100km for 2l of fuel. That's about 133 mpg for the old measure, or about 6 to 10 times more efficient than most typical modern cars for the same sort of trip.

The current parts seem to be handling the stress well, but I'll tear down at about 10 hours and observe for measurable wear. Then I'll do it again at 20 hours, then at 100 hours, with a planned oil change every 100 hours (These engines don't use much oil - About 130ml, but do need to have their levels checked and topped up every 10 hours or so ).

Regards
David.

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

Postby eldavo » Sat May 16, 2015 10:05 am

Congrats, so the charge output was able to start with a flat battery, charge and power the motor use, how much capacity did the battery have end of trip?

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

Postby cj7hawk » Sat May 16, 2015 11:37 am

I didn't measure the battery voltage before and after, but the voltage output is limited to 25.5v maximum, with 25 average, so charge probably wouldn't have exceeded 30% or somewhere about that point. It pulls around 300w when I'm struggling uphill, it hits 25.5v ( just before it's adjusted ) and the battery is consuming around 50~60w, the motor controller and wheel around 240~250w ( that's pre-controller, so it's under 200w - and I checked current draw on the booster so it wouldn't go over 195w pre-controller - include efficiency loss in the booster, motor and controller at typical levels, and I'd still be well below 200w - estimated 150 to 160w output on boost. )

The battery was very flat as I left the lights on - they will draw about 12W by themselves. The lights are great though - especially at night and are actually usable to light up the full path at any bicycle related speeds ( up to about 60kph ) so I can stop within the limits. So at an estimate, battery voltage went from about 21~22 without load to about 24+ after charge. At full charge it's around 26.6... I'm planning on adjusting the controller for 25.5 to 27 as the hysteresis range... But later I'll use a voltage booster to allow 30v at 1A for battery charging while idling, going downhill or with a lot of wind and off-boost, or perhaps just one big one at 26.5v (AT) 10A ( 265 w ) - which should allow charge to about 80~90% - I can't go above this for the final design, as it's possible to overboost electrics which can affect there performance, and DoT did warn me about that from a compliance perspective, but under 26.5, I should be fine. The ripple in the circuit is sufficient to maintain a slighly higher level within the hysteresis range, so it's not as not as large as it seems.

Also, as a direct connect, I'd be happier with a slightly higher voltage out of the generator at around 3000rpm so the pitch is lower under power. Which reminds me, I should probably re-install the tacho on to the motor.

Anyway, one way I can tell ( now I fixed up the cable to the motor ) is that when I started it, it was constantly high-tone, but once I got running, I found that on significant downhills, I could drop the motor back to minimum idle, which meant the battery not only wasn't dropping below 24.5v at that time, but probably wasn't going below 25v either - Below 25v, it still idles. but the ripple int he system forces the point where there's some tension on the throttle, but not enough to move it far. Above this point, it drops to cutoff levels where it idles back to whatever the motor is set for. Though even at slow idle, the motor will still produce more than 20w without flinching and I need to change the design to make better use of that.

David.

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

Postby human909 » Sun May 17, 2015 9:48 pm

Wowsers. Great work. I'm reading this thread and props to you for your home engineering. I still don't like the concept of a petrol engine on a bicycle, but that doesn't change the fact that this is a cool project.

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

Postby cj7hawk » Mon May 18, 2015 9:38 am

human909 wrote:Wowsers. Great work. I'm reading this thread and props to you for your home engineering. I still don't like the concept of a petrol engine on a bicycle, but that doesn't change the fact that this is a cool project.


LoL! Thanks though. FWIW, I do use a 4-stroke and it's a lot quieter than many 2-stroke bikes. I did some tests at operational power levels yesterday and it wasn't audible past 30m. Mind you, there was a lot of wind. Also, it doesn't put out smoke like a 2-stroke either, so just smells like any other vehicle. It also can't be revved up.

So while it's not a perfect replacement for the older type of petrol bicycle, it is a big improvement. It's main benefit is range, while gaining all the other benefits of electric ( and it does run without the petrol motor operating )

Regards
David

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

Postby cj7hawk » Mon May 18, 2015 3:26 pm

geebee wrote: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.


Bingo !... I just had a look and my seat post is bent... :(

Not really sure how best to replace/fix it yet.

All-up weight is now about 5kg, which is within the specs of the rack, so I can't blame the rack. I'll need to do something about that -

David

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