custom ebike for commuting, choosing the right bike to convert

Electrically assisted bikes, trikes, etc.
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mephisto
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custom ebike for commuting, choosing the right bike to convert

Postby mephisto » 13 Aug 2018, 7:26pm

Hi guys,

I need to get a ebike for rainy days as I'm going to manage a couple of properties that are in a range of 15-20 miles. I ride a road bike normally and I'm used to cruise at 18-20mph with ocasional sprints of 26mph. I was reading here that motor are limited to assist up to 15mph only? I never cycled under 18mph to be honest, after cycling down to south france from london, also to germany and the swiss alps 15mph sounds a bit unrealistic.

What aim here is to be able to cycle to these properties without sweating like a pig, meet guests and change bedding and stuff so I'll be carrying stuff on a panier most likely or on top of a rack.

I found a bike that seems like what I fancy http://wooshbikes.co.uk/?karoo but the 250w motor and up to 15mph doesn't seem logical to me. Then I started to wonder about finding a city bike with brake disks that can accommodate a conversion kit of around 500w and a large battery to keep up with hill climbs. My idea is to get a good assist, I want to do most of the work, but avoiding the excess of sweat.

Any suggestions?

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willcee
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Re: custom ebike for commuting, choosing the right bike to convert

Postby willcee » 13 Aug 2018, 9:18pm

hi welcome.. suggest you have a look on here,its another section in here, imo exactly what you are seeking.. have a read............viewtopic.php?f=55&t=123853..

hemo
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Re: custom ebike for commuting, choosing the right bike to convert

Postby hemo » 14 Aug 2018, 8:59am

Doing most of the work on an a legal 250w ebike means you will most likely sweat as you would on a normal bike, the general idea is that ebikes do the work so you don't sweat. Nearly all legal 250w 36v ebikes in top assist level will generate 450+ watts at the wheel, crank drive bikes like Bosch, Yamaha can be as much as 600+w and are effortless to ride along on. Using top assist level though eats the battery range so often top assist is best kept for use on hill thereafter reverting to a lower assist level.
As long the motor is 250w rated/marked it is legal, Woosh bikes sell a 48v 250w rear hub kit using a Bafang/8fun SWXO2 hub which is very powerful. With 5 levels of assist the 17a controller can output 816w which is about 652 watts hub output as most hubs are only 80% efficient at converting the power.

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SimonCelsa
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Re: custom ebike for commuting, choosing the right bike to convert

Postby SimonCelsa » 16 Aug 2018, 7:50am

In my very limited experience of e-bike riding I would say in order to avoid sweating you will have to get used to riding a little slower. Doing 18 mph on an ebike would mean zero assist from the motor (unless you tinker with the settings) so you would basically just be pedalling a heavier bike.

Drop a couple of gears, reduce your speed, spin your legs easily and let the pedal assist take the strain.....I find it is not very intuitive if you are a regular cyclist. Basically you must learn to be a bit lazier!

Going uphill, & accelerating from a standing start on a heavy bike is when I feel the benefit really.

It's very handy for a heavy tandem but I don't think I'd convert a solo bike (unless some physical difficulties necessitated this). Each to their own obviously.

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mephisto
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Re: custom ebike for commuting, choosing the right bike to convert

Postby mephisto » 16 Aug 2018, 8:15am

I'm thinking about getting a light tourer bike with disc brakes and converting it, but also I'm looking for ready to run bikes. I've found one here that seems interesting https://www.ebay.co.uk/itm/1000W-Electr ... Sw24RbCHRe but I'm not that keen how tall it is.

I'm going to check these 250w models as I was not aware it could do more than 250W when climbing, thanks!

hemo
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Re: custom ebike for commuting, choosing the right bike to convert

Postby hemo » 16 Aug 2018, 9:58am

mephisto wrote:I'm thinking about getting a light tourer bike with disc brakes and converting it, but also I'm looking for ready to run bikes. I've found one here that seems interesting https://www.ebay.co.uk/itm/1000W-Electr ... Sw24RbCHRe but I'm not that keen how tall it is.

I'm going to check these 250w models as I was not aware it could do more than 250W when climbing, thanks!



That specific bike uses a direct drive hub motor (circa 5.5kg) these are wound for high speed often 390rpm or more and are rated 1000w, they are usually coupled with a 25 or 30a controller which means they will generate min 1200w in top assist.
The 40 -50 km/h assist speed says it all, battery consumption will be eaten up to soon.
The bike it self is not a light tourer and expect bike weight to be 25 -30kg.
They are very inefficient below 20 mph and at low speed are no better then a 250w geared hub.
Range will not be particularly good can be anywhere in the 15- 25mile range.

A geared hub you can pedal with no battery relatively easy on level terrain, direct drive you can't.

hemo
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Re: custom ebike for commuting, choosing the right bike to convert

Postby hemo » 16 Aug 2018, 10:12am

For a light assist touring style bike often they are not overly cheap.
Orbea Gain range are reportedly very good and don't even look like ebikes, range can be very good though require to be pedalled unassisted when need be. Light enough to pedal unassisted on level terrain and down hill and use of assist mainly for inclines.

The Woosh Karoo is relitively cheap and I know that a range of 70 - 80 miles has been had from one battery, though this is dependant on terrain, rider weight and riding conditions.
The new Karoo model under consideration is akin to the Orbea model with hidden lighter weight battery.

Light weight e touring bikes are light mainly for one reason and that is battery weight. 6 - 8ah or 200/300wh batteries are 50/60% lighter then most large ebike with on frame or rack batteries.

hemo
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Re: custom ebike for commuting, choosing the right bike to convert

Postby hemo » 16 Aug 2018, 11:30am

The rating is complicated and open to loop holes.
The 250w rating isn't about it's max output, the rating is a load test to confirm that the motor drive doesn't overheat.

A load is applied for a 1hr duration at max 250w output, if it passes it gets a 250w rating. Some of the same motors will be given a 350w rating as they will also not over heat given a higher amp load.

Amp loading for each drive test will vary depending on the efficiency of each drive tested for instance geared hubs are about 80% efficient at converting voltage to watts output.
Crank drive efficiency will be different so a differing amp load will be used to get 250w output.

Once given the rating manufactures use a loop hole to increase poss max watt output by increaisng the amp load. Most 36v controllers use a nominal 7a raing which is half its max capability so most will have a max 15a load.
The regs only state that motor rating is 250w and max voltage is 48v nominal, no amp load is specified which is why some 250w motors can use 25a controllers and some have been sold as such.


The fast wound 1000w hub motors don't pass as to get the high rpm speed thicker and more copper windings are used then the 250 - 500w motors. 1000w 48v would need a 5a load test to achieve the 250w output figure and would over heat, at low speed and low amp load they are very inefficient and overheat very easily, they waste/turn the battery voltage in to heat instead of power it is only at the higher speed and high amp load do they excel.

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Cunobelin
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Re: custom ebike for commuting, choosing the right bike to convert

Postby Cunobelin » 17 Aug 2018, 10:19am

Although limited to 15 mph, Bikes are still valid if you travel faster.

Firstly accelerating to the 15mph speed is assisted,, making that part of the work easier. Secondly if you do slip below 15 mph, you can boost yourself back up with less work (think of slowing at a junction or hazard). Finally it will also assist on hills if you have any

So... don't get caught up with the 15 mph limit, as it is still useful for what you require.

The only downside is the heavier weight which may make maintaining a higher speed more difficult, but in reality is is no worse than carrying a touring load or a few days shopping

One way to save that weight though is a smaller battery.

If your total trip is 15-20 miles then you can get a smaller battery rather than a big one that covers 50 miles.

You can also cheat if you re at a site for any length of time by "topping up" the charge (be aware differs batteries respond differently to this)

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mephisto
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Re: custom ebike for commuting, choosing the right bike to convert

Postby mephisto » 22 Aug 2018, 7:54am

Orbea bikes look nice but for over £2k with a small battery I think is too much of a niche

I get the 1000w limitations, but shouldn't it be the opposite with less turns move the torque curve to the higher end of RPM?

I still can't digest the 15mph limit, yesterday my average was 18mph on a 10 mile commute, just lowered to 18mph because of steep hills which I did at 12mph, of course would be nice to have assist and do them at 15mph but I think it is a big investment for not much of a improvement in my view.

If the ebike could help me maintain 20mph with some load that would be the sweet number I was hoping for, I think for 15mph it doesn't look that appealing

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squeaker
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Re: custom ebike for commuting, choosing the right bike to convert

Postby squeaker » 22 Aug 2018, 9:50am

hemo wrote:The Woosh Karoo is relitively cheap and I know that a range of 70 - 80 miles has been had from one battery, though this is dependant on terrain, rider weight and riding conditions.
Looks like a sensibly specified bike to hit the sub £1k mark; a bit overgeared IMO, but at least the optional mudguards and rack don't cost an arm and a leg.
"42"

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willcee
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Re: custom ebike for commuting, choosing the right bike to convert

Postby willcee » 22 Aug 2018, 4:49pm

E motors have torque from the get go.. ime you need to look at sourcing a good bike with the room for at least 32 tyres, a std 68 bsc b.bracket and fit a bafang motor , now whether you comply with the 250w is totally up to you, the bigger wattage motors are still exactly same size loom and fitting kit also.. 250watt is too little power for what you wish to do.. I have 2Bafang equipped and have built another 2 for converts to E cycling, 40 miles is nothing with the correct well built battery and i would guess i'm heavier than you . either of mine featured earlier in the thread will do way over the compliance regs that said i don't ride like the wind all the time.. both are less than 40lbs weight.. someone asked me what the feeling was like.. i said 3 strong guys on the pedals and a 25mph tailwind..hills just don't exist..will..

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mephisto
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Re: custom ebike for commuting, choosing the right bike to convert

Postby mephisto » 22 Aug 2018, 6:24pm

I'm going to start looking for a bike to use as template for this, thanks!

I've been doing some more research and it seems Magic Pie 5 could be a good option. I've found these guys https://ebikebatteries.co.uk/product-ca ... gic-pie-5/ and it seems they also redo batteries for people here in London and are quite good at it, so that gives me a bit more confidence.

I'm going to put a list of everything I need, so perhaps a city/tourer bike with pannier and direct drive and a large battery.

hemo
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Re: custom ebike for commuting, choosing the right bike to convert

Postby hemo » 22 Aug 2018, 9:40pm

mephisto wrote:I'm going to start looking for a bike to use as template for this, thanks!

I've been doing some more research and it seems Magic Pie 5 could be a good option. I've found these guys https://ebikebatteries.co.uk/product-ca ... gic-pie-5/ and it seems they also redo batteries for people here in London and are quite good at it, so that gives me a bit more confidence.

I'm going to put a list of everything I need, so perhaps a city/tourer bike with pannier and direct drive and a large battery.



Jimmy is the boss and also trades as Bga reworking / Insat intl he is the bees for battery recell. Located 10/15 mins walk from Bounds Green Tube.

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mephisto
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Re: custom ebike for commuting, choosing the right bike to convert

Postby mephisto » 22 Aug 2018, 10:40pm

Cool, I'll give them a call tomorrow.

So I'm pretty much decided for magic pie 5 and a hybrid bike. Just checking now if it is possible to use a bike with hydraulic brakes as I believe I will need to use the included brake levers from the kit, right?