Design principles for a solar/electric/pedal outback machine

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Aug 11, 2020
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In the time of Covid 19, if you live in the state of Queensland, Australia as I do, there is only one place where you are allowed to cycle and that is in the state of Queensland, Australia. Our borders, state and national are shut tight. If you leave Queensland, you can't get back without paying for hotel quarantine accommodation for 2 weeks (AUD$2800) and currently, you are not allowed to leave the country at all (with some exceptions not including to go cycle touring - we have had 2 European cycle tours cancelled this year).

Fortunately, Queensland is a big state so a few weeks ago, my wife and I set out on our conventional touring bikes for a tour of the remote parts of the state (we call it the "outback"). There are large distances between towns when you leave the coastal regions of Australia (where most of the population lives). This is because the countryside west of the Great Divide (the mountain range which runs north south the length of the country only 100km from the east coast) is arid with poor soils. It sustains only small populations in towns increasingly distant from each other as you journey west.
The consequence is that there is usually only one main sealed road between towns separated by 100km or more and these roads carry all the traffic on these routes. There are no services or sources of potable water in between. In particular these roads carry a beast which may be peculiar to Australia called the road train which consists of a prime mover and up to 4 trailers strung out behind, These vehicles can be more than 60m long and travel at 100km/hr on roads hardly designed for them. Furthermore, having cycled in many countries in Europe and in the United States, I can safely say that Australian drivers are the worst in the world for looking out for cyclists.

However, starting our from our home on the coast just north of Brisbane, through a combination of unsealed roads, bicycle trails, a few tracks and some short sections on busy roads, my wife and managed to ride to a little town called Tambo, about 1100km from home before deciding to curtail our intended cycle tour of about 2000km. Up to that point we had felt reasonably safe but the last 50km into Tambo were a taste of what lay ahead. After Tambo the only feasible route to the north of the state is the main highway and on our last day, the combination of road trains, motorhomes coming too close and the smell of dead animals every few hundred metres made the cycling so fraught and unpleasant that we decided to pull the plug on the tour. We have a small motorhome which we have collected and in which we will complete our original bicycle route.

So where does this lead?

There are alternative routes on unsealed roads between the towns but they add many kilometres and several days between services and potable water, water of any kind, to the journey. For example, the distance on the highway between Tambo and adjacent Blackall is 107km, doable on our bikes in a day and easily in 2. The alternative route is 247km over unsealed roads, a journey of 4-5 days requiring the carting of at least 25 litres of water per person well as an EPIRB - no mobile coverage and almost no traffic out there. I would really like to be able to travel these routes in a fully independent way (my wife is not so keen) so I turned again to plans purchased a while back from AZ to find a solution.

I cannot imagine cycling 60 kilometres per day (I am 67) without some sort of assistance and the only feasible assistance is an electric motor. In order to power this motor, I will need 300-400W of solar generating capacity - 3 panels each independently charging a 12V 20ah lithium battery, the batteries connected in series to power an 800W 26V electric motor, and a capacity to carry a minimum of 30 litres of water. That's quite a lot of weight.

I like the visibilty and semi-recumbent position of the delta runner and I am thinking of adapting this frame to the purpose of carrying 2 panels above the rider on a frame with a trailer behind carrying the 3rd panel and luggage (water and camping gear). I also like the larger wheels as they roll better than smaller wheels over rough surfaces but I am concerned about the lateral stability of the larger wheel when cornering.

So that is the scenario. Most of the opinions I have read discussing the tadpole versus the delta configuration, opt for tadpole so I would be grateful for an insight into the ride characteristics and experience of those who have built some of Brad's delta designs. I would also be grateful for any advice on the other aspects of the project.

Cheers

Alex
 
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Hi Alex.
On a recumbent trike it is a lot easier to ride long distances. But it depends on the underground. In loose sand I got stuck, where others could keep riding. A recumbent trike works best on hard underground.
I have a taptole but I think that a delta is better for what you want to do. You can cary easily more on the trike. A trailer makes it heavier to ride and you want yo keep that as light as possible.

I have a 250w 36v motor. All yo do with rules out here.
But it delivers enough power. With the right battery, you can easily ride long distances.
I would get 2 36v batteries. Than you can charge one and ride with the other one. With my 17,5ah I could ride easily over 100km. But with more weight and support, that range goes down a lot. I think that with max support and high weight of the trike and trailer, that 50 to 60km will be the distance. So 2 of them for 60+km is enough. Especially as you can charge one, while riding with the other one.
 
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Joined
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Messages
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Location
Lanc's, England
I cannot imagine cycling 60 kilometres per day (I am 67) without some sort of assistance and the only feasible assistance is an electric motor. In order to power this motor, I will need 300-400W of solar generating capacity - 3 panels each independently charging a 12V 20ah lithium battery, the batteries connected in series to power an 800W 26V electric motor, and a capacity to carry a minimum of 30 litres of water. That's quite a lot of weight.
If you watch the movies above, most of the participants of your age group do over 100 km/day, day after day.
To have 3 independent battery are not ideal, there is a chance of battery failure. You better have one 36 volt battery.
To charge a 36 volt battery from solar panels you need a "boost MPPT controller", you find chinese ones on ebay
or search for Genasun.
 
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Second Pegasus with his remark on batteries. I would start with 1 batterypack to test the setup, and add packs when funding and time allow.

Also, for the more demanding applications, I would go for 48V or even 52V batterypacks. (in cell count 13 or 14S LiPo)
36V 800W means you can draw 23A nominal. And a lot more if the electronics allow it. This in turn makes thicker wire needed.
For myself I use 10AWG and XT90 plugs to feed the Bafang 750W 48V midmotor.
 
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Sydney Australia
Somewhere on the internet I came across a video of a tandem tadpole tadpole which had the solar panels as a roof. I think the seats were back to back. Cant find it at the moment.
Anyway using the panels as a shade as you suggest is a good idea for the Queensland sun, might be especially relevant if your forum name skindoc refers to being a dermatologist?

Regards
Stewart
Edit ---just read your thread on learning to ride a recumbent, I am still learning to ride the the high roller i made, gets hard to balance at low speed, maybe a good reason to go with a trike of some kind.
 
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Hi Alex from a fellow Australian.

There are many interdependent problems associated with your aims. It is daunting enough for someone much younger but I wouldn't like to tackle it at your age.

1. How much power? There is a legal Australian on-road power limit of 250W. You would be able to get around it with registration with obvious requirements for engineering compliance and probably many other impediments that you wouldn't want to contemplate. Buying an electric car would probably be much easier. On that note, bicycles are bicycles and cars are cars but I see an emerging opportunity for someone to make something in between for the likes of what you are contemplating.

2. How fast do you want to ride? Requirements begin to add up: more speed, more suspension (especially for off road), more mass, more power, larger battery, more charging, larger solar panels, etc. A deliberately slow and off-road approach will mean you are between towns much more often and for longer periods, more vulnerable, and that probably also means alone which in itself is probably enough to make you want to stay at home. Reliable communication would be a necessity.

3. Not being able to make it to towns for comfort things requires the carriage of the usual accoutrements that would make life bearable - tent, cooking, food, water, tools, first aid, etc. The elements of No. 2 come into play again.

4. Shelter from the sun will be a necessity and the hotter it is, the more water that will be required.

5. One could keep on going and the idea begins to look more than a little daunting.

Covid-19 has also affected my plans - see my eLecTricks thread elsewhere on this site. Heck, being from Victoria, I'm not even allowed out of the state at the moment, so I can't keep you company. A crook back as well as a recent leg injury and my construction is currently stopped. However, that doesn't stop the dreaming and planning. I have a few rail trails that I still want to explore when freedom returns and I am forced to only set my sights on those. I'm 72 and I wouldn't contemplate an outback tour. I would have to "put my affairs in order" first.

I'm looking forward to seeing how your plans develop. Please keep us updated.
 
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250w on a high support is strong enough.
Even as you use solar, a second battery is useful. Than you have a backup.

But I am not worried about that part.
What sort of toad surface is it? Is it hardent or only loose sand?
 
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Hi Alex from a fellow Australian.

There are many interdependent problems associated with your aims. It is daunting enough for someone much younger but I wouldn't like to tackle it at your age.

1. How much power? There is a legal Australian on-road power limit of 250W. You would be able to get around it with registration with obvious requirements for engineering compliance and probably many other impediments that you wouldn't want to contemplate. Buying an electric car would probably be much easier. On that note, bicycles are bicycles and cars are cars but I see an emerging opportunity for someone to make something in between for the likes of what you are contemplating.

I know about the 250W legal limit but I rode a Bafang (750W) around Brisbane for quite a few years pulling all sorts of loads - the 7 on the side of the motor somehow morphed into a 2!. I think if you are intent at driving your machine at speeds above 25km/hr then you will inevitably attract attention but my purpose was always to make a long commute through hilly terrain (28km) at reasonable speed and without arriving at work completely exhausted.

I am actually thinking about 2 projects.

a) I own an AZUB suspended trike which I haven't used much. I am thinking of constructing a powered trailer to pair with the trike. One 200W panel would form a protective roof to the trike and another 200W panel would sit on the trailer with a 250W motor on the trailer providing the push. Thank you for the links in the other posts to this thread. Samagaga in Taiwan make a nice differential designed for pedal machines - I prefer driving both wheels rather than one. I plan to pull a few ideas from the 6 sets of Brad's plans I purchased some years ago to design and build the trailer.

The electrical system I have in mind is thus: 2 X 200W panels each individually dedicated to charging one of 2 X 20ah 12V batteries; each panel with its own dedicated MPPT regulator. The batteries would be connected in series to provide the 24V feed to the motor. I prefer a pedal-activation system to thumb throttle where I can dial up the power as I need it. With at least 8 hours of uninterrupted sunshine guaranteed west of the divide, this equates to 3200wh, let's say 1600wh usable. Usage might be 200w X 5 hours for the time I am riding each day, so perhaps 1000wh per day - should be enough to keep the batteries charged?

Can anyone with more knowledge of solar and electrical systems comment.

b) If I can make a success of this project then longer term I think I would like to have a go at constructing a tandem, probably a delta to be able to put a lot of weight over 2 wheels at the back with at least 600W of panels forming a protective roof. 250W simply won't cut it to make a beast of this size and weight move up a hill at reasonable speed so 36V 800W motor would be a minimum for this project.


2. How fast do you want to ride? Requirements begin to add up: more speed, more suspension (especially for off road), more mass, more power, larger battery, more charging, larger solar panels, etc. A deliberately slow and off-road approach will mean you are between towns much more often and for longer periods, more vulnerable, and that probably also means alone which in itself is probably enough to make you want to stay at home. Reliable communication would be a necessity.

As a cycle tourer, anything over 20km/hr is wasted energy in my opinion as self-created wind resistance goes up exponentially with increased speed and the whole idea of travelling by bicycle is to move fast enough to cover real distance, but slow enough to experience the place where you are travelling.

3. Not being able to make it to towns for comfort things requires the carriage of the usual accoutrements that would make life bearable - tent, cooking, food, water, tools, first aid, etc. The elements of No. 2 come into play again.

We currently carry about 15-20kg each which includes all of the above (including an espresso maker!), and in these parts, an EPIRB. We travel 70km per day in about 5 hours riding time on unsealed but reasonable surface roads and 80-90km on sealed surfaces, this with leg power only, less in hilly country (not much of that out here). Being able to be fully self-supported is necessary in western Queensland even when travelling the highways as the distances between services exceed our daily maximum on a regular basis. On our most recent trip on several nights, we simply pulled off the road into the bush and camped for the night - we could carry enough water on our conventional bikes for 2 days only, about 10 litres each.

The whole reason for considering solar and electric assist, is to be able to carry much more water, at least 30-40 litres (and a fridge!!!) over unsealed roads, which while doable with legs only, would mean 2 things: markedly reduced distance per day (30-40km max) and reduced enjoyment of the cycling. The reduced distance would mean an unacceptable number of days between services, and more importantly, sources of potable water.


4. Shelter from the sun will be a necessity and the hotter it is, the more water that will be required.

If I told you I rode a pushy across the top of Australia in the middle of summer 44 years ago, you will know that I understand this issue.

The overhead solar panel augmented on the sunward side with some shade material of some kind will contribute significantly to dealing with the radiant effects of the sun. Maintaining hydration plus the air movement of an open vehicle provide for the evaporative component of preventing hyperthermia, hence the need to be able to cart ridiculous quantities of water. If you were to pop over to Crazyguyonabike and have a look at one of our journals, you would find a photo somewhere of my wife or I in our riding gear. There is not a skerrick of skin exposed to the sun - we wear buffs around our necks and pull them up over our noses and faces when we are cycling in all conditions, hot or cold. We wear long sleeves and long trousers, both of which reduce the radiant effects as well as the skin cancer causing effects of the sun.


5. One could keep on going and the idea begins to look more than a little daunting.

Actually it is the construction side of things which is daunting to me; I have to learn to weld and cut in straight lines. Brad's plans and explanations are brilliant so I am hopeful.

Covid-19 has also affected my plans - see my eLecTricks thread elsewhere on this site. Heck, being from Victoria, I'm not even allowed out of the state at the moment, so I can't keep you company. A crook back as well as a recent leg injury and my construction is currently stopped. However, that doesn't stop the dreaming and planning. I have a few rail trails that I still want to explore when freedom returns and I am forced to only set my sights on those. I'm 72 and I wouldn't contemplate an outback tour. I would have to "put my affairs in order" first.

Yes I have a brother in Melbourne who has some health issues. He is quite scared. Overall we are lucky in Australia and as a retired doctor, my thoughts are with those in other places where Covid 19 has hit much harder, and especially the health workers who are daily risking their lives for the rest of us.

For me, outback touring is like all expeditions, rendered safe in planning and systems. We had some of our systems fail on our recent tour which is why we brought it to a premature close but we were not so exposed that it created any danger for us.




I'm looking forward to seeing how your plans develop. Please keep us updated.
First of all, thanks everyone for your input. It is great to have this forum and I will spending a few nights at least reading all the old posts to get as much as I can from them. Since Kevin has some local knowledge and has raised some issues in point form, I can discuss my thinking as above.

Alex
 
Joined
Aug 11, 2020
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250w on a high support is strong enough.
Even as you use solar, a second battery is useful. Than you have a backup.

But I am not worried about that part.
What sort of toad surface is it? Is it hardent or only loose sand?
Hi Emiel

A back-up battery for me is unused weight I do not need. I prefer charge as I go with sufficient charging capacity to stay ahead of use. Solar panels are a little lighter than batteries although much harder to mount. Some outback roads have sand; it's miserable stuff to try and cycle - I avoid them. The roads I would ride vary between good hard surfaces to loose stony surfaces but still rideable.

Alex
 
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If you watch the movies above, most of the participants of your age group do over 100 km/day, day after day.
To have 3 independent battery are not ideal, there is a chance of battery failure. You better have one 36 volt battery.
To charge a 36 volt battery from solar panels you need a "boost MPPT controller", you find chinese ones on ebay
or search for Genasun.
G'day

I have watched some of the movies of folk riding solar assist bikes - the distances are impressive. My purpose is specifically for Australian outback conditions and the distances between services. In Europe (where we should be now except for Covid) we prefer pedal power because services are never far away. With battery failure, surely a 36V battery can fail just as a 12V. In my searches, 3 X 12V 20ah batteries are cheaper than 1 X 36V battery.

Alex
 
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If you subscribe to the Every Which Way But Lost YouTube channel you will see how an Englishman is touring Australia on a tadpole. Started in Darwin, I think, headed south in Western Australia, across South Australia and is bypassing Victoria due to Covid-19. He has some off-road segments.
 
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Hi Emiel

A back-up battery for me is unused weight I do not need. I prefer charge as I go with sufficient charging capacity to stay ahead of use. Solar panels are a little lighter than batteries although much harder to mount. Some outback roads have sand; it's miserable stuff to try and cycle - I avoid them. The roads I would ride vary between good hard surfaces to loose stony surfaces but still rideable.

Alex
Hi Alex.

Yes the battery is extra weight. That is an disadvantage.
Roads as long as they are hard enough to ride on, will be no problem I think.
I ride over gravel on some places and that hoes good.

Emiel.
 
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