Return to the bent!

[Benjahmin]

I had to put the conversion of my Velotechnic street machine on hold for a while, but now I'm back.

I bought the bike with an existing 48v Dillinger kit that has got to go. The motor does not like hills and the battery is getting hammered, it may be past it's best anyway.
I have two 36v batteries, from my hybrid, that are good and will be used for now.
Following on from previous exchanges (particularly with Saneagle), I'm going with an AKM-128H with a dual voltage controller.
Here's the thing, I can only find the 128h with either 201 or 328rpm. Going into a 26inch wheel the 328 will be too high and, I suspect, the 201 too low.
On Topbikekit, the cassette version comes in 260rpm (which is lower wattage), but I have freewheel and they only do that as 201rpm.
Anyone got another reliable source?
Second issue is the display. As you can see it's mounted at the front by the chain wheel. It's the only place you can see it easily. So what I need is a display with seperate up/down buttons so I can mount it on the handlebars, like this:

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www.topbikekit.com

Can the cable to the buttons be extended without affectin operation?

 

[saneagle]

I had to put the conversion of my Velotechnic street machine on hold for a while, but now I'm back.View attachment 53313

I bought the bike with an existing 48v Dillinger kit that has got to go. The motor does not like hills and the battery is getting hammered, it may be past it's best anyway.
I have two 36v batteries, from my hybrid, that are good and will be used for now.
Following on from previous exchanges (particularly with Saneagle), I'm going with an AKM-128H with a dual voltage controller.
Here's the thing, I can only find the 128h with either 201 or 328rpm. Going into a 26inch wheel the 328 will be too high and, I suspect, the 201 too low.
On Topbikekit, the cassette version comes in 260rpm (which is lower wattage), but I have freewheel and they only do that as 201rpm.
Anyone got another reliable source?
Second issue is the display. As you can see it's mounted at the front by the chain wheel. It's the only place you can see it easily. So what I need is a display with seperate up/down buttons so I can mount it on the handlebars, like this:

KT-LCD10H Meter Display With SM Plug for Ebike [KT-LCD10H Display SM Plug] - $27.30 : Zen Cart!, The Art of E-commerce

Zen Cart! KT-LCD10H Meter Display With SM Plug for Ebike [KT-LCD10H Display SM Plug] - ★★★★★ KT-LCD10H Meter Display With SM Plug for Ebike 1:KT LCD10H display 2:Voltage: fits for 24V, 36V or 48V batteries. 3:Cable connector:standard 5pins connector. 4:Black Color...

www.topbikekit.com

Can the cable to the buttons be extended without affectin operation?

For a 26" wheel, you can use the 201 rpm 36v one at 48v to get 260 rpm, 260rpm 36v motor at 36v or 48v, the 328rpm 36v one at 36v or the 328 rpm one at 48v or 36v. Basically, the 260rpm 36v and 328 rpm 48v ones are the same motor, and likewise 36v 201 rpm and 48v 260 rpm.

260 rpm gives a maximum speed of 20 mph (constant 18 mph OTR), and with 328 rpm, you get a max of around 27 mph (constant 24mph OTR)

 

[Benjahmin]

What road speed would 201rpm give in a 26" wheel? (I don't have the maths skills)

I'll use the 36v batteries 'till they're spent, then I may go to 48v.

 

[Woosh]

What road speed would 201rpm give in a 26" wheel?

start with the circumference of your tyre:

26"	35-559	1990 mm
	40-559	2030 mm
	47-559	2050 mm
	50-559	2075 mm
	54-559	2100 mm
	57-559	2120 mm
	60-559	2160 mm
	37-590	2100 mm

Assume you have 50-559 tyres, circumference 2.075m,

speed: 201 RPM * 60 (minutes/hour) * 2.075 meter = 25,025meter/hour = 25kph

 

[saneagle]

What road speed would 201rpm give in a 26" wheel? (I don't have the maths skills)

I'll use the 36v batteries 'till they're spent, then I may go to 48v.

201 rpm with a 26" wheel is approx 15 mph, but that's not the full story. That's no-load speed. The power ramps down in the upper speed range, so it would give good power up to about 12 mph and maybe 13 mph on the flat. That's with the battery fully charged. When it's full, you'd get about 10% more, and 10% less when empty, so somewhere between 11 mph and 15 mph, depending on the state of the battery. At 48v, it will be 30% more, so something like 15 mph to 20 mph.

Topbike kit have all speeds. It doesn't matter if you have freewheel gears at the moment. All you need is a cassette with the same number of gears, or you can use the opportunity to upgrade your derailleur and shifter. You can buy used 9-speed ones very cheaply from Ebay because many people want to upgrade to 10, 11 and 12 spd.

The cassette motor is a bit wider than the freewheel one with 7spd, so you have to dish the wheel a bit, the same as 8spd freewheel. Also, the actual rotor inside the motor is a bit narrower for the cassette version, so it can't manage as much power as the freewheel one, but it's still pretty good.

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www.topbikekit.com

 

[Benjahmin]

Thanks guys.
I live in hilly west wales. I'm new to recumbent riding and I'm currently finding the hills painful, yet to build the different muscle set in my 70 year old legs.
So, we'd previously landed on the 800w freewheel as being more able to take the grunt to get me up the hills.
The bike has a bar end shifter indexed to 8 but currently restricted to 7 with a long cage deraileur. All sort of goes with the territory.
The motor you've linked comes in a 260rpm version but only in 48v meaning it would be even slower whilst using my 36v batteries.
This one comes as 36 0r 48 but only in 201 or 328

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www.topbikekit.com

Arrrgh!

 

[saneagle]

Thanks guys.
I live in hilly west wales. I'm new to recumbent riding and I'm currently finding the hills painful, yet to build the different muscle set in my 70 year old legs.
So, we'd previously landed on the 800w freewheel as being more able to take the grunt to get me up the hills.
The bike has a bar end shifter indexed to 8 but currently restricted to 7 with a long cage deraileur. All sort of goes with the territory.
The motor you've linked comes in a 260rpm version but only in 48v meaning it would be even slower whilst using my 36v batteries.
This one comes as 36 0r 48 but only in 201 or 328

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www.topbikekit.com

Arrrgh!

48v 328 rpm is ideal. It becomes 260 rpm at 36v, which is also good.

There are three versions of that motor. All of them are included in that listing. The normal way to specify the motor is by the Kv. The three versions have Kvs of 5.6, 7.2 and 9.1. To get the actual maximum speed, you multiply the Kv by the actual voltage.

The freewheel version would be better, but only the one with Kv 5.6 seems to be available. If you're happy with 15 mph, it should be fine, otherwise it'll suck.

 

[Benjahmin]

48v 328 rpm is ideal. It becomes 260 rpm at 36v, which is also good.

OK, gotcha. But will it develop the torque for west Wales hills?

 

[saneagle]

OK, gotcha. But will it develop the torque for west Wales hills?

It gets me up and down Ironbridge gorge, and I only run with 14A.

 

[Benjahmin]

Well then that's good enough for me and if I ever run it at 48v the speed limiter in the display had better work and I'll carry an anchor just in case.
So, just to be clear 'cos it's 10:15 and I'm on my second single malt, it's this

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www.topbikekit.com

48v and 328 rpm to be run at 36v so achieving 260 rpm,

Now to hunt for an 8 speed cassette with a decent range.

 

[Nealh]

My 201rpm BPM @36v tops out at 19mph with a 20a controller.

 

[saneagle]

My 201rpm BPM @36v tops out at 19mph with a 20a controller.

That's running at 48v, right?

 

[AntonyC]

As you can see it's mounted at the front by the chain wheel. It's the only place you can see it easily.

Works for me. You can just see the buttons alongside the display on the far side of the mounting bracket. I've ape arms but the buttons would probably fit on the stem too.

 

[jimriley]

I had to put the conversion of my Velotechnic street machine on hold for a while, but now I'm back.View attachment 53313

I bought the bike with an existing 48v Dillinger kit that has got to go. The motor does not like hills and the battery is getting hammered, it may be past it's best anyway.
I have two 36v batteries, from my hybrid, that are good and will be used for now.
Following on from previous exchanges (particularly with Saneagle), I'm going with an AKM-128H with a dual voltage controller.
Here's the thing, I can only find the 128h with either 201 or 328rpm. Going into a 26inch wheel the 328 will be too high and, I suspect, the 201 too low.
On Topbikekit, the cassette version comes in 260rpm (which is lower wattage), but I have freewheel and they only do that as 201rpm.
Anyone got another reliable source?
Second issue is the display. As you can see it's mounted at the front by the chain wheel. It's the only place you can see it easily. So what I need is a display with seperate up/down buttons so I can mount it on the handlebars, like this:

KT-LCD10H Meter Display With SM Plug for Ebike [KT-LCD10H Display SM Plug] - $27.30 : Zen Cart!, The Art of E-commerce

Zen Cart! KT-LCD10H Meter Display With SM Plug for Ebike [KT-LCD10H Display SM Plug] - ★★★★★ KT-LCD10H Meter Display With SM Plug for Ebike 1:KT LCD10H display 2:Voltage: fits for 24V, 36V or 48V batteries. 3:Cable connector:standard 5pins connector. 4:Black Color...

www.topbikekit.com

Can the cable to the buttons be extended without affectin operation?

I have a tandem bent, finally found a round tuit to get it sorted, it has an old crystalyte 400 series dd front hub, I've just fitted a new KT controller and display, the up, on/off, down switch wire had to be extended to fit on the handlebars. I soldered the wires with small heat shrink on each wire and then a larger heat shrink over the lot. Works fine. The same had to be done to tidy up other wires, mostly too long. Given the age of the original conversion I've legally got a throttle, useful for setting off.

PS... Whats the handlebar mirror? Could be useful, I find the helmet one a bit small. My handlebars are the other way round to yours but there will be a way.

 

[Benjahmin]

I was just going to press the order button and found myself hesitating. Sorry to labour this but I want to be sure before spending my hard earned.
So, I'm going to order a 48v 328rpm motor and run it at 36v to get 250rpm.
I'm assuming that running at the lower voltage it will need more current to get max rpm, so will a 22A T09s be enough?
In a 26" wheel (with 35-559 tyres), this will give a no load max speed of 28kph, so good for legal limit.
Am I getting there?

Thanks Jim, good to know.

 

[Nealh]

That's running at 48v, right?

No was at 36v, It was a Woosh kit thye came via John at Cyclezee.

 

[Woosh]

The RPM rating is confusing. There is no agreement between manufacturers for labelling. I much prefer Bafang winding code. We always make sure that the motors are at their best between 12mph and 15mph. That's because 12mph for climbing a moderate hill, 15mph for cruising. Maximum derestricted speed is 21mph for 26" wheels, 22mph for 700C. 48V motors have 30% more turns to yield the same sweet zone.

 

[saneagle]

I was just going to press the order button and found myself hesitating. Sorry to labour this but I want to be sure before spending my hard earned.
So, I'm going to order a 48v 328rpm motor and run it at 36v to get 250rpm.
I'm assuming that running at the lower voltage it will need more current to get max rpm, so will a 22A T09s be enough?
In a 26" wheel (with 35-559 tyres), this will give a no load max speed of 28kph, so good for legal limit.
Am I getting there?

Thanks Jim, good to know.

That's all correct.

 

[saneagle]

No was at 36v, It was a Woosh kit thye came via John at Cyclezee.

It's not 201 rpm then! Somebody might have said it was, but clearly they were wrong.

 

[Benjahmin]

Just putting the shopping basket together.
I need a display with seperate buttons, was looking at LCD3 - is this going to give me the best functionality bearing in mind I'm going to need to set cut off speed?
The shape of the LCD8s would suit the fitting location better (at greater cost) but not sure if it's trying to do too much.
Any thoughts?