Help me to create my solar panel trike with caravan trailer

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Tangalle   100 mW

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Help me to create my solar panel trike with caravan trailer

Post by Tangalle » May 08 2019 10:32am

Hi everyone

I am Loic, 32, from France. Actually traveling in Colombia. But when I will be back in France, I want to keep travelling with a trike. And a caravan trailer.

This is a place to speak about the technical difficulties about the caravan trailer but I am here to speak about the system of electric part.

I will have a roof on my trike. And an another roof on the caravan trailer.

I thank to create a 1200wh battery. I think it's a good balance (my caravan trailer, where will be the battery and all electric system will be around 80kg).

And the last part the motor. First I wanted to take a brushless motor. Like a smart pie for exemple.
Because it's reliable.

I will drive mainly on road. But I like mountains, and taking gravel road will be not every days, but that's will happen . Obviously also in poor country where they don't have propre road.

The problem is : most of brushless motor are efficient around 20 25km/h. If I understood well. But it's too fast when you are off road.
But also because I will drive on road, I need a motor who is good at 10-15 but also able to cruise at 30km/h if needed. I need a very good torque to be able to climb mountains gravels road.

Do you know a motor as I need?

______


For the battery, because I have a small budget (1500e for solar, motor and battery). I think I have to create my own battery. I will be interesting. One guy on this forum sell some battery. I think I will take lithium because lighter but, because I need something very reliable, an another battery technology will be nice for me?

Having less power (800wh) but more reliable or 1200wh with lithium?

______


I would like to charge with my solar panel, but also by normal electricity plug.

I really would like to find a way to charge very very fast. The idea is, when it's cloudy since 4 5 days, to go in one restaurant, having lunch for one hours and drive again with full ou almost full charge battery.

Because battery are also expensive, I don't want to harm my battery with a too hight power.

Mostly in camping, we are limited to 10A for 220V in France.

______


I don't know if people here have knowledge about solar panel construction, connected with a battery. I will have more or less 10 solar panel 50w each (flexible one). The best will be having 10 mppt to improve the possibility to charge. But my bike have to be or try to be light and reliable. 2 big mppt are more reliable and light than 10 small mppt?

Charging the battery from the solar panel can harm it if the "power" is too hight?

____


That's a lot of question. As you see, I am not English fluent and also I am not a technical guys. I will learn, for sure.

I want to build a caravan trailer because I will not travel with it, but I will live with it. Without idea of destination and time.


____

Trike : hopefully a scorpion fs20, 18kg
With solar panel roof : 5-7 kilos more
Me : 62kg
My stuff (computer, clothes etc...) : 10kg
Trailer empty : 35kg
Battery : 8kg
Electric part, cable, I don't really know : 5kg?

____

Money
Second hand trike : 2000euros
Solar, motor, battery : 1500euros
Trailer : 500euros

I can push 1k more if needed.


Thank you all for your hard and advice!!

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dogman dan   100 GW

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Re: Help me to create my solar panel trike with caravan trailer

Post by dogman dan » May 08 2019 12:05pm

Charging fast is possible, up to the limits of the plug you find. One hour, not likely. But two is definitely possible. Only certain types of lithium battery can charge VERY fast. That is the RC type lipo. Other types of lithium can still charge fairly fast, but might last longer if charging takes 4 hours or more.

Regulate your solar panels voltage some way. Don't just hook panels to batteries. Solar charge controllers can be fairly inexpensive in 12v. But likely you will want one that puts out 48v. (48v to climb hills best) 4 50w 12v solar panels can fit on your trailer, and then a simple voltage converter can regulate your voltage to 48v, taking the voltage fluctuations out of your panels voltage. This would produce 50w of 48v. This is not much, but every bit will help extend your range. In a day, you would get about 1000-1500 watt hours from a system that size. So just about like stopping to charge one time.

Most likely, your best bet for motor will be a mid drive, giving you the advantage of being able to shift gears relative to the motor. With a hub motor, you would have to be stuck in a single gear relative to the motor, giving the limited efficient RPM range of your motor you spoke of.


One way to make a hub motor work better for a large cargo or trailer towing bike, is to use a 20" rim on the hub motor, and then use a large enough motor to run up the hills faster, restoring much of the efficiency. The smaller rim is the one way to change the gearing of a hub motor. So a larger motor able to stand long periods of 2000w will get up the mountains, towing a heavy trailer.


FYI, I have actually done this, and live in the rocky mountains of the US. Its not as efficient as a mid drive can be, but a good strong hub motor can do a lot, and pretty efficient if you run up that mountain at 15 mph, instead of a 5 mph crawl with a low wattage mid drive.


In my case, no worries about legal. Cops in the western US have bigger worries than e bikes.

Tangalle   100 mW

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Re: Help me to create my solar panel trike with caravan trailer

Post by Tangalle » May 08 2019 12:48pm

Thanks :)

Charging fast is possible, up to the limits of the plug you find. One hour, not likely. But two is definitely possible. Only certain types of lithium battery can charge VERY fast. That is the RC type lipo. Other types of lithium can still charge fairly fast, but might last longer if charging takes 4 hours or more.

The price is also important. Do you have a link about a 18650 rc lipo? It's lithium or kind of a123 18650 battery?
Do you think rc could be a good idea? Having a fast charge means also having a huge charger. I don't to carry 8kg 8A charger with me. I have to find right balance for weight.

Regulate your solar panels voltage some way. Don't just hook panels to batteries. Solar charge controllers can be fairly inexpensive in 12v. But likely you will want one that puts out 48v. (48v to climb hills best) 4 50w 12v solar panels can fit on your trailer, and then a simple voltage converter can regulate your voltage to 48v, taking the voltage fluctuations out of your panels voltage. This would produce 50w of 48v. This is not much, but every bit will help extend your range. In a day, you would get about 1000-1500 watt hours from a system that size. So just about like stopping to charge one time.

I will have :
-1 meters x 2 meters solar panel for trike
-1 meter x 2.3 meter dar panel for trike.
More or less depends on the size of cheap solar panel flexible.

But, sorry I forget the technical term but I can put solar panel together to additional voltage. No need voltage converter in this case?
Imagine 8 solar panel 50w

I imagine something like : 4 together (one mppt) x 2.
The mppt will regulate the 48v charger no?


Most likely, your best bet for motor will be a mid drive, giving you the advantage of being able to shift gears relative to the motor. With a hub motor, you would have to be stuck in a single gear relative to the motor, giving the limited efficient RPM range of your motor you spoke of.

When I saw trip as sun trip for exemple, every one have brushless motor. For reliability I imagine. That's mean I will have trouble without? With a hub motor with a big torque, that's will not works?
For mid drive : bafang02? Cyclone 3kw?

One way to make a hub motor work better for a large cargo or trailer towing bike, is to use a 20" rim on the hub motor, and then use a large enough motor to run up the hills faster, restoring much of the efficiency. The smaller rim is the one way to change the gearing of a hub motor. So a larger motor able to stand long periods of 2000w will get up the mountains, towing a heavy trailer.

I will use full 20" bike and trailer. Large hub motor? As magic pie?

Climbing fast a hill on normal road, I read I need a big one because it will overheat.
But if I want to climb slowly a mountain gravel road, I have to be slow. To not break anything.

Mid motor (or front for a recubent bike ;) ) looks fine but I don't like the problem of using transmission very quickly. When you do 2000km/month, I don't to have problem every ... Month :D

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Re: Help me to create my solar panel trike with caravan trailer

Post by Tangalle » May 08 2019 1:43pm

Topic where I can buy battery from the forum

https://endless-sphere.com/forums/viewt ... 31&t=61608


Edit : why I am not a fan about mid drive

http://thesuntrip.forumactif.org/t519-i ... ss0x-motor

This not reliable at all. Sun trip, 13km,use only brushless. So can we find a brushless motor good when I drive slowly in mountains off-road at 7km/h and good at cruise 40km/h

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Re: Help me to create my solar panel trike with caravan trailer

Post by amberwolf » May 08 2019 4:53pm

All the middrives I know of these days use brushless motors.

If you're looking for efficiency, DD hubmotors won't be as efficient as middrives that go thru the bike's gearshifting drivetrain, at such a wide range of speeds and loads.

They might be more reliable in that there are less moving parts, but easier to overheat in high load / low speed situations.

I recommend going to http://ebikes.ca/simulator and reading the whole page first, then playing with the simulator to see if you can find a hubmotor system that will do all the things you need it to without issue.


I highly recommend reading thru some of the solar bike threads, as well as justin's solar trip thread. There's a lot of useful info in there relevant to your plans, though I couldn't say which bits will be most helpful.

Most of the threads are in this list. Not every thread is relevant, but I think the titles should make it easy enough to pick the ones to skim.
https://endless-sphere.com/forums/searc ... mit=Search
That list just references stuff in the Electric Bicycles subforum, but there are scattered other threads that may have useful info for you, that you'd have to locate separately.

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Re: Help me to create my solar panel trike with caravan trailer

Post by billvon » May 08 2019 5:20pm

Tangalle wrote:
May 08 2019 10:32am
But also because I will drive on road, I need a motor who is good at 10-15 but also able to cruise at 30km/h if needed. I need a very good torque to be able to climb mountains gravels road.

Do you know a motor as I need?
Use a mid-drive so you can still use your gearing. If you are dead set on a hub motor, the Xiongda is a 2 speed hub motor that's gotten decent reviews. If you don't mind the weight, a big Crystalyte DD motor (~2000W or so) will get you up almost any hill.
For the battery, because I have a small budget (1500e for solar, motor and battery). I think I have to create my own battery. I will be interesting. One guy on this forum sell some battery. I think I will take lithium because lighter but, because I need something very reliable, an another battery technology will be nice for me?
Buy a lithium ion battery with a BMS. Your own design will not be as reliable.
I really would like to find a way to charge very very fast. The idea is, when it's cloudy since 4 5 days, to go in one restaurant, having lunch for one hours and drive again with full ou almost full charge battery. Because battery are also expensive, I don't want to harm my battery with a too hight power.
Most batteries will handle a 1C charge rate (1+ hours) - check the specs to verify. Meanwell power supplies make good cheap chargers.
I don't know if people here have knowledge about solar panel construction, connected with a battery. I will have more or less 10 solar panel 50w each (flexible one). The best will be having 10 mppt to improve the possibility to charge. But my bike have to be or try to be light and reliable. 2 big mppt are more reliable and light than 10 small mppt?
2 MPPT's (like Genasun controllers) should work OK. Or you could use 5 MPPT's for better tracking.
Charging the battery from the solar panel can harm it if the "power" is too hight?
Not an issue in your case.
--bill von

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Re: Help me to create my solar panel trike with caravan trailer

Post by Tangalle » May 08 2019 6:09pm

Amberwolf : I wanted to speak about direct Drive motor. When you see sun trip for 13k km, all of them use direct drive motor.

Efficiency are important, but reliability will be more important when I will be in Mongolia or Siberia (next year, Baikal lake is a possibility), from France. And keep on biking all the time.

I will read carefully the information I can have on this forum. For sure :)

Billvon

I heard so many time problem of reliability from no direct Drive hub motor (magic pie for exemple).

I have on my mind this things : I saw someone driving France to Japan. With a electric motor. In Mongolia, I got trouble. I fact, when he turn on the motor, he is getting too fast, and with the sand gravel road, the bike was not dirigeable. Driving with the help of the motor, with a small speed because we want a small speed.

That's my main question :)
The 2 speeds motor you gave me are a response but I don't like this kind of motor, no reliable for me for living every days with it. Like if the nylon inside the motor are dead, how can I do in deep Africa?

Battery : why my battery will be less reliable? With the 1000 of tuto on internet, looks ok to just copy. I just need to know the technical (and a forum can help me)

Genasun are frocking expensive. Do you know one cheaper? If I use one for each solar panel, it will be too expensive. Maybe 2 solar panel for one mppt.

Crystallyte : better than golden motor? You have an exact reference? The weight matter of course, but reliability too.


Thanks you for your time with me :)

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Re: Help me to create my solar panel trike with caravan trailer

Post by amberwolf » May 08 2019 11:12pm

Tangalle wrote:
May 08 2019 6:09pm
Amberwolf : I wanted to speak about direct Drive motor. When you see sun trip for 13k km, all of them use direct drive motor.

Efficiency are important, but reliability will be more important when I will be in Mongolia or Siberia (next year, Baikal lake is a possibility), from France. And keep on biking all the time.
Understood-it's actually why I am using twin DD hubmotors on my trike, as I had problems with my various DIY bike middrives on the previous build, due to frame flex from the high torque, etc., and I don't wanna be stuck roadside in traffic in Phoenix in the middle of a hot summer day (110-120F+, hotter on the actual road)....

Eventually, I'll build a middrive that *is* reliable and won't break things, and at that point the trike will change to that...but it will *still* have one hubmotor, in front, just in case. ;)

In my case, I will probably use an old DD hubmotor for the middrive's motor, and simply chain drive the wheels from it, most likely without any shiftable gearing in between. But I could also use a shiftable bicycle drivetrain, separate from the pedals, that lets me shift gears for high torque low speed, or just cruising, etc. Since that uses common off the shelf bike parts, it'd be relatively easy to get new parts for it if something breaks.

So you could do something similar; check out the system called StokeMonkey for one possible way such a DD-hub-powered middrive can be done, thru the pedal drivetrain, without using something with hard to get parts in remote locations. You can carry spares for all the essential parts easily enough.



But still, a DD hubmotor in the wheel may not do what you want, unless maybe you use two different ones, in different wheels--one setup for the slow, heavy-load (climbing) stuff, and one setup for the high speed stuff. The simulator I linked previously can help you decide if that's necessary or not, for your conditions.

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Re: Help me to create my solar panel trike with caravan trailer

Post by Tangalle » May 09 2019 9:02am

Waoo, thanks you.

The Stoke monkey looks really great. Until I saw the price.

Because it's a direct drive motor, the system inside should be easy. So can we find same system but in Chinese reference much cheaper?

I have many many things to buy, I thank spend 500dollars for the motor, not 1000dollars.

Thank you!!

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Re: Help me to create my solar panel trike with caravan trailer

Post by billvon » May 09 2019 10:49am

Tangalle wrote:
May 08 2019 6:09pm
I heard so many time problem of reliability from no direct Drive hub motor (magic pie for exemple).
Are you saying that you have heard that non-direct-drive motors are less reliable? If so, that's not really true; it depends on the motor. Plenty of motors use steel gears instead of nylon, for example.
I have on my mind this things : I saw someone driving France to Japan. With a electric motor. In Mongolia, I got trouble. I fact, when he turn on the motor, he is getting too fast, and with the sand gravel road, the bike was not dirigeable. Driving with the help of the motor, with a small speed because we want a small speed.
Then, again, if you want high torque at low speeds you are looking at a bigger hubmotor. For your applications, a Crystalyte H series could work well. If you want a LOT of torque at low speeds, consider something like the Crystalyte Crown.

Also note that you can make minor tradeoffs on torque vs speed by choosing the winding number. Fewer turns equals less torque but higher speed (at a given current/voltage.) More turns gets you more torque at a given current. However, you will still see thermal limits that aren't entirely solved by this problem, since current (not voltage) causes most of the heating in a motor.
Battery : why my battery will be less reliable? With the 1000 of tuto on internet, looks ok to just copy. I just need to know the technical (and a forum can help me)
Knowing "the technical" is the hard part. Read the entries on this forum; you will see dozens of posts about people getting far less energy than they expect out of their battery, about their batteries not balancing correctly, about their battery "cutting out" unexpectedly. These are generally due to simple problems, but they're not so much fun when you are on the road.

Getting an off the shelf battery will help you avoid most of those problems. The alternative is to start building batteries NOW and using them so you get some experience with these things.
Genasun are frocking expensive. Do you know one cheaper? If I use one for each solar panel, it will be too expensive. Maybe 2 solar panel for one mppt.
That works. Depending on your battery voltage, you could also use 4 panels for MPPT#1, 4 panels for MPPT#2, and 2 panels for MPPT#3.
Crystallyte : better than golden motor? You have an exact reference?
I have had good luck with both, but I have far more experience with Crystalyte. I don't have a recommendation; to recommend one I would have to know:

-what thrust you need worst case (in pounds) - alternatively, what's the steepest road you want to climb and the max weight of the bike

-what you want your top speed to be

-what battery voltage you will run at, and the rough A-H
--bill von

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Re: Help me to create my solar panel trike with caravan trailer

Post by Tangalle » May 09 2019 12:12pm

Amberwolf : what do you think about rh205 un short building (I don't know the word in english) to improve torque? Mutch cheaper

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Re: Help me to create my solar panel trike with caravan trailer

Post by Tangalle » May 09 2019 12:21pm

Billvon

Thank for the advice.

-what thrust you need worst case (in pounds) - alternatively, what's the steepest road you want to climb and the max weight of the bike

My bike, with solar panel roof : 50-60 pounds
Me : 140pounds
Caravan trailer empty : 80 pounds
Electric system (battery chargeur mppt cable) : 45 pounds
Clothes, computer , food, camping gear : 40 pounds

Steepest road : hard to say. Imagine a gravel road in mountains climbing hard. But good enough for a good 4wd.


-what you want your top speed to be

40 mph could me great.

-what battery voltage you will run at, and the rough A-H

I don't know. 48v sounds nice but I still don't know really.

Rough A-H : I don't know what is it.

I spoke with amberwolf about the rh205. Cheaper than the Stoke monkey.

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Re: Help me to create my solar panel trike with caravan trailer

Post by Tangalle » May 09 2019 12:38pm

For the battery : I wish 2 battery 48v (one on each side of the caravan trailer to balance the weight). I would like to spend a Max a 1000dollars on it.

After I am not totally sure about witch technology. Lithium or a123...

I am scare about the life time of lithium if I use them everyday 6 months year

When I see my LG g5 flashgrip phone from 2016 with a dead battery already...

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Re: Help me to create my solar panel trike with caravan trailer

Post by billvon » May 09 2019 12:43pm

Tangalle wrote:
May 09 2019 12:21pm
Weight: 365 lbs
Grade: Steep
Top speed: 40mph
Voltage: 48V
OK. You're not going to get the 40mph. With a draggy setup you're going to need >5kW and that means a very large motor and large battery optimized for speed, not torque.

Using a Crystalyte H3525 you can climb a 20% grade at 3.9mph. However efficiency will be horrible; around 25%. So you will want Statorade, plus external heatsinks, plus thermistor power limiting - and you better hope that climb is short.

On level ground you'll see about 23mph at a much higher efficiency, assuming the same drag as an upright bike. If you are really draggy (i.e. hauling a big box) you'll see closer to 18mph.
--bill von

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Re: Help me to create my solar panel trike with caravan trailer

Post by Tangalle » May 09 2019 1:07pm

A system as stroque monkey will not solve this problem of efficiency?

Why the H3525 especially? Big torque? After climbing huge mountains will not happen every day. And when this days will happen, I can make several stop to cool down the motor.

How much watt I will use for each kilometers you think?

With 1200wh battery. I thank around 15.

I am speaking for normal flat road. Not mountains one.

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Re: Help me to create my solar panel trike with caravan trailer

Post by billvon » May 09 2019 1:17pm

Tangalle wrote:
May 09 2019 1:07pm
A system as stroque monkey will not solve this problem of efficiency?
Yes. Any geared system works much better for climbing. But the Stokemonkey adds a lot of complexity (usually a new chain and crankset) and often utilizes a geared hub, although you can specify the SAW motor.
Why the H3525 especially? Big torque? After climbing huge mountains will not happen every day. And when this days will happen, I can make several stop to cool down the motor.
Or go slower. With a trike you don't have to maintain a given speed.
How much watt I will use for each kilometers you think?
I use about 25wh/mi when I ride normally, 50wh/mi when I am pushing it as hard as I can. I'd guess you will use in the range of 100-150wh/mi.
--bill von

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Re: Help me to create my solar panel trike with caravan trailer

Post by Tangalle » May 09 2019 2:34pm

150wh for one mile.... I don't understand because even with a quite huge 1k battery I have the ultra bad 8 miles autonomy.

Even if I order two... As this one
https://m.fr.aliexpress.com/item/329811 ... 7429917015

I heard more 5 watts each kilometers for a normal bike.
20 for a frocking huge one and trailer.

___

Complexity not afraid me. I will go deep inside it :D so a bit more or a bit less.

Stroque monkey have concurrence? I don't understand this crazy price!.

___

I would like something who keep good efficiency every kind of situation because I will have many kind of it. And with very good reliability.
A DD with good torque have shity efficiency in hill climbing? No?

Thank you :)

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Re: Help me to create my solar panel trike with caravan trailer

Post by amberwolf » May 09 2019 4:02pm

Tangalle wrote:
May 09 2019 9:02am
The Stoke monkey looks really great. Until I saw the price.

Because it's a direct drive motor, the system inside should be easy. So can we find same system but in Chinese reference much cheaper?
Nobody else makes them that I know of, except another still-expensive place that calls them M-drive. Wouldn't be a huge seller so not much reason for anyone to clone it. (part of why it's expensive is that there aren't that many made).

There are a couple for sale in the Items for sale Used section.
https://endless-sphere.com/forums/viewt ... =9&t=99919

And also just a motor, no mounts
https://endless-sphere.com/forums/viewt ... =9&t=96028

However, you can build your own mounting system for whatever hubmotor you wish to use, for your specific bike frame (which will be easier than buildign the adjustable mounts that the SM systems come with).

If you like, you can even leave the spoke flanges on the motor, and carry spokes with you to put it into the rim of one of your existing wheels, (or a spare to carry with you), in case the middrive system breaks in an unrepairable way, so you can still ahve a motor on the bike.

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Re: Help me to create my solar panel trike with caravan trailer

Post by amberwolf » May 09 2019 4:13pm

Tangalle wrote:
May 09 2019 12:12pm
Amberwolf : what do you think about rh205 un short building (I don't know the word in english) to improve torque? Mutch cheaper
Dunno, a google search shows it's a generic low power motor.

If you want to find the right motor for your application, I still think you need to go to http://ebikes.ca/simulator , read the whole page so you know what things are and what they mean, and then play wiht different systems in the simulator itself, to see what changes to the system cause what changes to the results, and which systems will do what you want at the low speed / high load end, and which systems will do what you want at the high speed end. Not every motor that's made is modelled there, but there's a sufficient assortment to help you see what size motor, controller, and battery may work, and then find taht one or something similar for sale, to see if the cost is within your budget.

Remember, buying something that fits your budget but doesn't do what you want is just a waste of money. YOu'd be much better off waiting, and saving up more money for the thing that actually does what you want.

I don't know if there will be any low or medium power systems that will do what you want in a single DD hubmotor in a wheel.

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Re: Help me to create my solar panel trike with caravan trailer

Post by amberwolf » May 09 2019 4:25pm

billvon wrote:
May 09 2019 1:17pm
But the Stokemonkey adds a lot of complexity (usually a new chain and crankset) and often utilizes a geared hub, although you can specify the SAW motor.
The originals used a DD (crystalyte, I think the 408 style but I don't recall for sure). The new SM system has a choice of geared or DD. The M-Drive (SM clone) uses DD, for the ones I've seen so far.

Doesnt' need a whole new crankset. Only needs a new left side crank that has a sprocket on it; A DIY version can simply use a second right side crank/spider/rings, as long as one keeps in minde the possible precession-unscrewing issues of the pedal there (loctite might cure that), or use a tandem's left side crank.

Then just needs the added chain from the output of the SM system to the leftside crank. When making a DIY version, one must make sure the output of the SM motor, via either jackshafts or direct sprocket-to-chainring gearing, is correct for the cadence desired.

Then practice with throttle to keep SM power/speed at the right level for the gear being used in the bike's pedal drivetrain.

(or use a Cycle Analyst to help automate this, but that adds significant cost and complexity, for a budget like the OP's).

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Re: Help me to create my solar panel trike with caravan trailer

Post by billvon » May 09 2019 4:27pm

Tangalle wrote:
May 09 2019 2:34pm
150wh for one mile.... I don't understand because even with a quite huge 1k battery I have the ultra bad 8 miles autonomy.
You sound like you have a huge vehicle. That means weight and drag. Weight will get you when you try to climb; drag will get you when you try to move fast. By keeping speeds low you can greatly improve your range. (I typically go 25-30mph.)
Even if I order two... As this one
That's an awfully small battery for a vehicle as big as the one you are considering. You're probably not going to be happy with typical small ebike batteries IMO.
I heard more 5 watts each kilometers for a normal bike.
That would be .16 amp-hours per mile with a ~50 volt battery. Maybe if you were doing 12mph on a flat surface with plenty of pedaling assist . . .

Again I find I usually use about .5 amp-hours per mile (25 wh/mi) and it's not a huge ebike. But then I am going relatively fast.
I would like something who keep good efficiency every kind of situation because I will have many kind of it. And with very good reliability. A DD with good torque have shity efficiency in hill climbing? No?
In general, yes. A direct drive hub motor is super simple/reliable but you pay for it with poor efficiency at low speeds.

Sounds like a good way to start would be to build at least a mockup of your bike and trailer and tow it around with a very cheap motor (like a used front wheel DD motor) just to see how fast you want to go and how much energy that will take.
--bill von

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Re: Help me to create my solar panel trike with caravan trailer

Post by billvon » May 09 2019 4:29pm

amberwolf wrote:
May 09 2019 4:25pm
Doesnt' need a whole new crankset. Only needs a new left side crank that has a sprocket on it; A DIY version can simply use a second right side crank/spider/rings, as long as one keeps in minde the possible precession-unscrewing issues of the pedal there (loctite might cure that), or use a tandem's left side crank.
True, as long as all your bits are compatible (i.e. they are all square taper.) I originally assumed he'd want an independent pedaling setup so the motor wouldn't drive his legs, but that's convenience, not necessity.
--bill von

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Re: Help me to create my solar panel trike with caravan trailer

Post by amberwolf » May 09 2019 5:05pm

Regarding efficiency, even on my heavy (500lbs-ish with me on it, no cargo or dog) SB Cruiser trike, in city stop and go traffic (up to a dozen stops/starts per mile), which is about as aero as a brick with a parachute, I get about 60wh/mile for 20mph max, and around 16+mph average.

This is another thing the simulator (though in this case the Trip Simulator) would help you with.

But some rough guesstimates without going there are:

If you had a regular upright bike shape at 350lbs total mass, at 40mph on the flats, you'd probably be using 60 to 80 wh/mile. More with even a slight uphill slope, and more with even a slight breeze headwind. It would probably take at least 2kW to keep you at that speed on the flats, with no wind, probably closer to 3kW.

So it will take a fairly big motor to handle that kind of power, without overheating.

Now, that doesn't account for the caravan's likely very poor aerodynamics, which will probably at least double your power usage, and double your wh/mile, halving your efficiency.

It also assumes perfectly smooth and level asphalt roads. If you're on dirt or gravel, power usage is going to go up, by what amount will depend on the road conditions, the tires you're using, the wheel size, inflation, and weather conditions (dry, wet, rainy, muddy, boggy, etc.).

I would guess that Billvon's estimates of more than double my city usage are likely close enough to go with, until you know what the actual aero of your system as a whole is, and the specific terrain and roads you'll be riding over, and weather/wind conditions.


You can go to the simulator to figure out what kind of power it will take to go up various steepnesses of slopes at various speeds. It's probably going to take at least as much power as it does to go fast, to go slow but uphill. And because of the lower efficiencies of DD hubmotors in wheels, at low speeds but high loads, the motor may overheat faster, and have to be capable of much higher power dissipation (or have cooling modifications, possibly active cooling like fans, etc).


It's possible my guesstimates are wrong; you can use online calculators and simulators to better estimate expected usages.

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Re: Help me to create my solar panel trike with caravan trailer

Post by amberwolf » May 09 2019 5:08pm

billvon wrote:
May 09 2019 4:29pm
True, as long as all your bits are compatible (i.e. they are all square taper.) I originally assumed he'd want an independent pedaling setup so the motor wouldn't drive his legs, but that's convenience, not necessity.
Yes, that would make a more complex system, especially since the point is to be able to shift the gears for the motor. ;)

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Re: Help me to create my solar panel trike with caravan trailer

Post by billvon » May 09 2019 5:58pm

amberwolf wrote:
May 09 2019 5:08pm
billvon wrote:
May 09 2019 4:29pm
True, as long as all your bits are compatible (i.e. they are all square taper.) I originally assumed he'd want an independent pedaling setup so the motor wouldn't drive his legs, but that's convenience, not necessity.
Yes, that would make a more complex system, especially since the point is to be able to shift the gears for the motor. ;)
An IPS lets you shift gears for the motor. Indeed, it allows you a wider variety of gear ratios, since your legs no longer have to be able to keep up with the motor's "cadence."

http://visionrecumbentinfo.com/pdf/IPS130.pdf
--bill von

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