Help me turn my touring bike into a car replacement

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Laibach   10 µW

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Help me turn my touring bike into a car replacement

Post by Laibach » Aug 06 2018 3:48am

Hi everybody!

My life has changed a bit suddenly, now I mostly live on top of a hill. Its only about 2km, but 15% average. My commute is about 20km/day with that climb the main obstacle, ohterwise its mostly flat.

I have a really strog touring bike with front and rear panniers, 26 inch wheels. I have normal gears (3x9) but the frame has an eccentric botrom bracket (in case I ever saved up for a Rohloff) so I imagine installing a mid drive or a torque sensor would be impossible.

I have NO desire for speed. Legal limit for ebikes is 25km/h here and I would like to stik to it.

But I do ride year round so a 2WD ebike is the end goal for snowy conditions.

Money is tight and I'm not rich enough to buy cheap components, so I'd like to do the conversion in two stages:

1. Front wheel geared hub motor with the CAV3 and a small battery that would get me through the Daily commute

2. Add a rear wheel motor (identical to the front one) and a huge, trailer mounted, 200km range battery.

With that I'll be able to go long distance touring with a trailer, so my wife can use only two panniers on tour.

What do you think of my plan?

ID like to buy as much as possible from ebikes.ca so ezee hub motors would be the Go-to it seems.

Could I use a 48V battery in those motor to increase climbing ability when full loaded?

Or should I just stik to 36V and get better traction (less wheel slipping)

Any advice, ideas very welcome!

Thank you!

billvon   1 MW

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Re: Help me turn my touring bike into a car replacement

Post by billvon » Aug 06 2018 10:35am

Laibach wrote:
Aug 06 2018 3:48am
1. Front wheel geared hub motor with the CAV3 and a small battery that would get me through the Daily commute

2. Add a rear wheel motor (identical to the front one) and a huge, trailer mounted, 200km range battery.
I'd skip the first step.

Start with a good rear wheel motor (I am partial to direct drive, but geared can work as well.) For that slope I'd recommend at least 1000 watts. You can start with a small battery for your commute then switch to a larger battery (and/or parallel them) for touring later. As always, the simulator at ebikes.ca is a good tool for such considerations.
--bill von

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wturber   100 kW

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Re: Help me turn my touring bike into a car replacement

Post by wturber » Aug 06 2018 12:47pm

A 15% hill for 2 km is a pretty serious hill climb. Is it really that steep for that distance? That's a 300 meter rise in just 2km!!

Unless you are substantially lighter than or more fit than me, I'm thinking you'll probably really want about 1500 watts to deal with that hill climb. You could either send that through one rear DD hub motor or split it through two geared hub motors. I wouldn't send it through one geared hub based on what I've read here. The DD is simpler, cheaper, less efficient climbing but could provide regen braking for the downhill - saving brake usage. The two geared hub motors would be better riding without power, have the benefit of motor redundancy, but will probably be harder on your brakes over time. Maybe you could even get by with 1000 watts using two geared hub motors?

On a budget, I'd probably go with a single rear DD and just live with the fact that it won't be as nice a ride in the case of a failure. Try to get a motor with 0.35mm laminations so cogging won't be as big of an issue if you have to ride with no power.
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
8 x 36v 4.3ah 10s 2P battery packs - 1500W 30A DC Boost Converter delivers 54v and about 1000 watts peak
53T/42T Sakae Road cranks - 30mph+ on flats
viewtopic.php?f=2&t=90369

billvon   1 MW

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Re: Help me turn my touring bike into a car replacement

Post by billvon » Aug 06 2018 2:55pm

Just to give you an example using Justin's sim:

A clyte H3525 with a 52V battery and good controller will give you the ability to climb continuous 20% grade at about 13mph. At that speed the motor is running at about 1100 watts. That means the motor will be running at max winding current almost all the time, so I'd recommend Statorade or equivalent additional cooling.

On the flats it will give you about 25mph.
--bill von

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wturber   100 kW

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Re: Help me turn my touring bike into a car replacement

Post by wturber » Aug 06 2018 4:50pm

billvon wrote:
Aug 06 2018 2:55pm
Just to give you an example using Justin's sim:

A clyte H3525 with a 52V battery and good controller will give you the ability to climb continuous 20% grade at about 13mph. At that speed the motor is running at about 1100 watts. That means the motor will be running at max winding current almost all the time, so I'd recommend Statorade or equivalent additional cooling.

On the flats it will give you about 25mph.
Yep - and you'll be pulling nearly 1900 watts from the battery and running at about 60% efficiency. So do we call this an 1100 watt configuration (motor power) or a 1900 watt configuration (battery draw)?

So anyway, if billvon was originally referring to motor power, I'm very much in agreement with his recommendation of around 1000 watts. I was thinking in terms of battery power, not motor watts, because that's what I monitor as I ride. (Battery watts directly relates to range, charge state etc.) My current setup described previously pulls a bit less than 1000 watts which yields less than 300 motor watts!! So you can see why I have to help out quite a bit when I hit my 14% grades. Using the Grin motor simulator and the speed of my climb, I'd estimate I'm putting out about 250 watts pedaling. This lets the motor work at a more efficient speed and I now get almost 500 watts from the motor (from the same near 1000 watts of battery input) for a total of about 750 watts sent to the ground. That gets me up the hill fine. But I can't put out 250 watts for very long. Certainly not for 2 km. :^)

As a side note, this is part of the reason why there's a lot of judgement involved in the watt limits specified in some legislation.
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
8 x 36v 4.3ah 10s 2P battery packs - 1500W 30A DC Boost Converter delivers 54v and about 1000 watts peak
53T/42T Sakae Road cranks - 30mph+ on flats
viewtopic.php?f=2&t=90369

markz   100 GW

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Re: Help me turn my touring bike into a car replacement

Post by markz » Aug 06 2018 5:50pm

BTW Speed limit is usually 32kph and its a good cruising speed, the faster you go the more battery you use.

For that steep a climb of 15% for 2km, or a lot of stop and go then a mid drive is your game.

If you want silence - go with direct drive (dd). If you want absolute silence, you go with dd + sine wave controller. There are no moving parts so the motor lasts a long time whereas the geared motors you can strip the gears. Geared motor including the mid drive you hear the gear sounds. I notice people looking behind them when I roll up behind them, but not so with the direct drive, even with the cheap trapezodial controllers.

A 200km range at say 15Wh/km and 36V you'd need a 15Wh x 200 = 3000Wh, divided by 36V = 83Ah battery pack. But you could get say a 30Ah pack and go 72km and just charge the pack up when you go to the bathroom or grab a bite or drink at Starbucks, Tim Hortons, Gas Stations, McD's, Subway, Parking Lot stall outlet, Schools, Train Stations, Malls, Strip Malls, Bars, Grills, Canadian Tires, Lowes, Home Depots. If you look, 120V(ac) outlets are everywhere. Buy a 30A charger for your 30Ah pack, (nice stable 1C charge rate) say some Meanwell power supplies and you can charge up in about an hour. My Meanwell's have been going strong with all the abuse I have given them (dropping them primarily).

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amberwolf   100 GW

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Re: Help me turn my touring bike into a car replacement

Post by amberwolf » Aug 06 2018 9:16pm

Laibach wrote:
Aug 06 2018 3:48am
I have normal gears (3x9) but the frame has an eccentric botrom bracket (in case I ever saved up for a Rohloff) so I imagine installing a mid drive or a torque sensor would be impossible.
Probably not impossible; some info here might help
search.php?keywords=eccentric+bbs*&term ... mit=Search
and there's others that don't come up with that list, would take poking around more to find.


Regarding the voltage vs traction: One doesn't directly influence the other. You can have high voltage and good traction, as long as you have control over your throttle hand. ;) (or you have a preset or dial for any PAS control, for conditions requiring less torque to prevent wheelslip).


Regarding front vs rear: in poor traction conditions, a front motor losing traction while under power, especially in a turn, is just about a guarantee of a crash, becuase you can no longer steer--you're now going in a straight line, until you can regain traction. The same isn't true of a rear in the same conditions. You still have steering control, and if you ahve to you can put a foot (or knee if you're already too far over) down to stop a complete wipeout caused by fishtailing around.

Going uphill with the motor you may also lose traction more easily on the front motor vs rear.

As long as you know the conditions in which not to use the motor in front, it doesn't matter which motor you start out with, as far as traction control goes. But most people only figure this out the hard way, if at all. :)

Laibach   10 µW

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Re: Help me turn my touring bike into a car replacement

Post by Laibach » Aug 07 2018 4:20am

Thank you all for your tips!

I've definitely reconsidered the idea for a front hub 250W motor. That hill is just so relentless that at this point I imagine any help would be great! But it would just start the "DIY ebike journey" and I'd replace all of the parts pretty soon, so it does make sense to think about it some more.

wtruber, yeah the climb really is that serious, unfortunately. The climb itself is probably a bit over a km, but then I have to ride some more on the ridge wich is not flat at all. Start to finish, the height difference is 271m, with total elevation gain well over 300m. It's a popular training spot for locals.

You guys are certanly right. I will go with a rear DD system.

Now I'm thinking I should just go big with the rear hub system so that I will have enough power to get over that hill with a fully loaded touring bike, towing a heavy Surly TED trailer.

I have no idea where to start looking for a good DD motor that would cover my needs. But I live pretty near to the Cromotor company, I know they make some pretty powerful and well engineered motors (do they really? Or is some other company well worth a look at?)

Just some idiot questions now... I can limit the Cromotor (or similar powerful rear DD) to legal speeds and power, right? Using the Cycle Analyst V3?

Is there a way I could get close to the "Giant Explore bike experience" with it? Torque sensing (again, Accentric bottom bracket)...

Or should I try harder to find a way to fit a BBSHD on it?

Markz

Thank you for doing the math for me! :D I'm still learning. For the "touring setup" 200km would be very welcome so I can spend a few days away from a plug. The battery will be mounted on a trailer so it can be quite big.

And last but not least, Amberwolf! I seem to have completely forgoten about the front tire slipping in bad conditions! I wouldn't survive the first descent from the hill! Thank you!

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amberwolf   100 GW

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Re: Help me turn my touring bike into a car replacement

Post by amberwolf » Aug 07 2018 1:05pm

Personally, for a hill like that, I'd run the motor thru the gears, whether that's a BBSHD or some other existing middrive, or using a hubmotor as a middrive (see the hubmotor middrive media group thread for ideas).

That way you can gear down so the motor isnt' bogged down at low speed and wasting lots of power as lots of heat, which can kill them. (and wastes your battery). The lower you can gear the motor, the easier it is on it (just like trying to pedal up that hill, you're going to be in the lowest gear you can possibly get).

But you can gear up for higher speeds on the flats.

Since you don't need actual high speeds, you can gear the whole thing so that the motor has really low gears, and the highest gear is the highest speed you'd run at.

Your main limitations on this are the chainline from gear to gear with some of the existing middrives, but you can make up a "custom" front triple with the chainrings you need, even if you have to get (or make) adapters to fit them to the crank spider (or replace the crank with one that fits what you need), including using spacers on the rings to get them to line up with the rear sprockets correctly.


As far as limiting to legal power levels with a big DD hubmotor...there's no point to that kind of motor if you're going to limit it's power that much--it won't be able to do the work you need it to, especially on that hill.

A geared motor with a high enough gear ratio and a slow enough winding, or a middrive thru the gears with the right chainring/sprocket low-gear ratio, might be able to do it limited to lower power.

My guess is that to make the climb on motor power you're going to end up with an unlimited power button somewhere, but you can always experiment with it at the other power levels first. ;)

LImiting power is easily done in the CA3.x, and you can make presets for various power levels/etc, or have a knob or switch for that. Teklektik's UUG (linked on the CA page at Grin) goes into a lot of detail on exactly how to setup various options. It'll also do torque-sensing BBs of a few kinds, and as noted in a previous post, there's info about adapters/etc for eccentric BBs.



Regarding loss of traction on the front wheel...I don't really have hills to worry about here, but we do have slick roads when it rains, especially at intersections where cars sit dripping oil, and that's usually where I have to make my turns. On CrazyBike2, which is 2WD, I found the hard way I have to back off or shut off the front motor approaching those turns, and not power it back on till I'm exiting the turn, or I could wipe out the front end, or simply lose steering entirely, etc. It's a lower bike than a typical uprright, so a sliding crash isn't a big deal by itself, but in traffic it would really suck. ;)

ScooterMan101   1 MW

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Re: Help me turn my touring bike into a car replacement

Post by ScooterMan101 » Aug 07 2018 1:18pm

You have a " strong " touring bike , but you want to ride in snow / mud / slush ?

Probably Not as strong as a Fat Bike/Plus Wheel Size Mountain / 29 er Mountain Bike.

I would just find the cheapest 29 er
or if doing year round riding with snow, and slow speeds , I would look into a simple inexpensive Fat Bike or Plus Tire size bike, they are easy to find cheep on the internet.
You can put racks onto any Hard Tail Mountain bike and/or Fat Bike easily enough, even a front rack as well for your touring needs .
Since you do not want to go fast speeds, a hardtail Plus Tire or Fat Tire bike will give you some cushion that is helpful in being able to use a bike for most/all of your transportation needs.
My first conversion ...

https://endless-sphere.com/forums/viewt ... 1#p1077497

It's 2018 already, lets get some real , improved e-bike / e-velomobile / e-motorcycle designs .

wayover13   100 W

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Re: Help me turn my touring bike into a car replacement

Post by wayover13 » Aug 08 2018 11:46pm

Here's a metric that is somewhat relevant but does not address your situation directly. I have a recumbent tandem trike (delta) to which I added electric assist a few years ago, using help gotten from this forum. My set-up has a range approximately close to what you're aiming for: when I first set it up I figured I could get 110-120 miles on a full charge. Following are some descriptions and caveats.

We have not yet faced any 2km long 15% grades.* I assume we could surmount such an obstacle, though perhaps with a break or two along the way. The bike has a single 250 watt geared hub motor on the front, mounted in a 16" wheel. The battery is a 20 Ah 36 volt Ping. Top speed is very low--only 12 mph. That is by design, since I wanted assist mainly for help getting up hills. We enjoy peddling and getting a good workout when we ride, so there was never any intention of having the electric assist do all, or even most of, the work involved in propeling us along, or for it to make us go any faster than unassisted bike travel. The bike with us, battery/kit, and limited touring gear must weigh in at around 600 lbs.

We've taken a few short tours (not exceeding about 300 miles) with this rig and it has performed well for us. So you can get by with far less power than has been recommended thus far--how much less depending on how hard you like to exert yourself when riding.

* The closest we've come was a roughly 500 meter long hill with grades mostly ranging between about 6% to 12%, with a short section at about 22%.
Minimalist-assist advocate. Minimal assist means only enough to ease some of the physical strain the rider must output to propel the bike at or near more typical unassisted cycling speed. Such assist usually plays no role in increasing the bike's top speed, being brought into play mostly when facing challenging terrain (steep uphill grades) or weather conditions (strong headwinds). Assist may remain completely disengaged for large segments of any given ride.

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Re: Help me turn my touring bike into a car replacement

Post by 81forest » Aug 10 2018 12:11pm

Just my $.02, but don’t give up on the dd front hub too soon. I am having a great time with mine, and I’ve never had an issue with traction (yet). Front wheel motor has a few advantages and I’m super glad I chose it. It is a 1500w 9C kit from Grin. It is simple, reliable, silent, and easy to remove and replace.

I had the same goal as you: car replacement. It is working great so far. I ride a couple of 12-14% grades every day, but nothing longer than a km at a time. My commute is 35km each way, and I charge my 23ah battery at work. I’ve never used even half of my battery charge.

Hope that helps. Good luck!

billvon   1 MW

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Re: Help me turn my touring bike into a car replacement

Post by billvon » Aug 10 2018 12:50pm

Laibach wrote:
Aug 07 2018 4:20am
I have no idea where to start looking for a good DD motor that would cover my needs. But I live pretty near to the Cromotor company, I know they make some pretty powerful and well engineered motors (do they really? Or is some other company well worth a look at?)
The Crystalyte Crown motors are good high power direct drive motors as well.
Just some idiot questions now... I can limit the Cromotor (or similar powerful rear DD) to legal speeds and power, right? Using the Cycle Analyst V3?
Yes, CA will do that.
--bill von

donn   100 W

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Re: Help me turn my touring bike into a car replacement

Post by donn » Aug 13 2018 10:52am

I'm just getting started with my 1500W hub motor setup, but judging from experience with lesser grades, like 6% ... I think my hub would be a lot of help on a 15% grade and I would sure be happy about the difference, but it's good that such grades are short around here, because this hub apparently isn't built for that.

I chose "6T (8.5 RPM/Volt)" winding over "4T". Are there options beyond that, that would deliver even more torque at the expense of top speed (if I understand that right?)

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