Help choosing the perfect conversion kit....

[WillM]

I've been toying with the idea of an e bike now for about a year. Its complete laziness as my cycling commute is only 2 and a bit miles (Half of its off road through a park) however I work 12 hour shifts and having to ride either side is no fun lol.

Some of the things I want from my kit...

- It must be reliable. I need something that will cope in the UK all year round.
- Stealth and looks are important.
- I'd like to be able to hit 25mph and don't mind assisting a little with that.

The best I've seen so far is the bafang mid drive kits however I'm debating weather going above 250w is worth the risk. Also I'd like an off the shelf battery solution where size take priority over range.

Thanks in advance for any advice or suggestions

 

[Nealh]

To hit 25 with a bbs you will most probably need 500w @48v, really depends on your weight and fitness.
Mfj197 cyles 20 odd miles each way to work on bbs 250w hybrid and av's about 20mph.

 

[mfj197]

It also depends on the type of bike. As Nealh says, I use a BBS01 250W and on my bike, a flat bar road bike without suspension, it can sustain 27mph on the flat at full chat (a bit more if I'm contributing significant amounts). However suspension saps energy, so a suspended bike may not get to these heady hights - I guess you're using suspension if you're off road? The BBS01 has also proved reliable for me so far (2,200 miles and counting), although I only use it at half power myself. There are some stories of reliability issues and I've regreased my main bearings and freewheel which were lacking.

- It must be reliable. I need something that will cope in the UK all year round.
- Stealth and looks are important.
- I'd like to be able to hit 25mph and don't mind assisting a little with that.

I think I'd be inclined to focus on the first two, possibly at the expense of the third. It's only 2 and a bit miles - a 5 minute trip at 25mph, and in a park you might well come across other cyclists / walkers / dogs etc. For true stealth you can't beat something like a Q100CST hidden between the rear cassette and brake disk, and I believe they are good and reliable too. Bigger (and capable of 25mph) would be the Oxydrive 13Ah kit, but the motor is over twice the weight and is more noticeable in the wheel.

Michael

 

[Nealh]

Re the thread headline if you do find the holy grail of bike kits do let us know.

 

[WillM]

To hit 25 with a bbs you will most probably need 500w @48v, really depends on your weight and fitness.
Mfj197 cyles 20 odd miles each way to work on bbs 250w hybrid and av's about 20mph.

150lb and above average fitness. The 25 mph requirement is to have a real noticeable gain over unassisted riding.

Thanks for the input

 

[WillM]

It also depends on the type of bike. As Nealh says, I use a BBS01 250W and on my bike, a flat bar road bike without suspension, it can sustain 27mph on the flat at full chat (a bit more if I'm contributing significant amounts). However suspension saps energy, so a suspended bike may not get to these heady hights - I guess you're using suspension if you're off road? The BBS01 has also proved reliable for me so far (2,200 miles and counting), although I only use it at half power myself. There are some stories of reliability issues and I've regreased my main bearings and freewheel which were lacking.

I think I'd be inclined to focus on the first two, possibly at the expense of the third. It's only 2 and a bit miles - a 5 minute trip at 25mph, and in a park you might well come across other cyclists / walkers / dogs etc. For true stealth you can't beat something like a Q100CST hidden between the rear cassette and brake disk, and I believe they are good and reliable too. Bigger (and capable of 25mph) would be the Oxydrive 13Ah kit, but the motor is over twice the weight and is more noticeable in the wheel.

Michael

Thanks for the input. Glad to hear its been reliable and I think I'm definitely going to go for the Bafang mid drive but will need to have a think on which power output.

 

[WillM]

With the Bafang mid drive kit in mind, I've been looking over power options. With nothing of the shelf with a low capacity (Around 5Ah) I'm thinking of going down the RC LiPo route.

Would this be suitable for the 500w 48v motor? x2 in series offering 44.4V and 5Ah?

http://www.ebay.co.uk/itm/RC-ZIPPY-Flightmax-5000mAh-6S1P-20C-/131244414357?pt=LH_DefaultDomain_3&hash=item1e8ec6d595

 

[Deleted member 4366]

5Ah won't get you far at 25 mph. A pair of the 16Ah Multistars would be more like it.

Lipos are OK, but it's a lot of messing about to charge them. It's much easier to get a 09 bottle battery with branded cells. Plug and play!

 

[Kinninvie]

Personally I would get the BBS02 750W motor as (from EM3EV) its exactly the same price and exactly the same motor (but detuned in the 500W).
I have found,at great expense that what starts as wanting a few miles soon turns into more miles and once used to the power most folks then want more..

As for batteries,I suggest you read the ES LiPo charging tutorial before even considering them.
http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=52240

The batteries you have linked to are £22.59 from Hobbyking but Zippys dont have a very good reputation.
My personal choice (currently in stock) would be a pair of 10Ah Multistars (I run 3 sets of 16Ah on mine) and they are £48.78.
The 6.6Ah Multistars are £38.75.
Turnigy 5000mAh 6S 25C are better batteries than the Zippy and only £25.32.

When buying from Hobbyking always wait on the item page for a couple of minutes and a box will pop up offering you a discount.

 

[One_Box]

150lb and above average fitness. The 25 mph requirement is to have a real noticeable gain over unassisted riding.

Thanks for the input

Just to save a couple of minutes on a 2.5 mile journey, you must have other plans for your conversion surely ?

 

[mfj197]

150lb and above average fitness. The 25 mph requirement is to have a real noticeable gain over unassisted riding.

Thanks for the input

You will have a noticeable gain using any crank drive motor, because its power is provided to the cranks and is in addition to your own power. There is simply more oomph going through the drivetrain and, assuming you've got the gearing to go faster, you will.

I've gone for the 250W version. It actually draws over 500W even in 250W guise and in higher assist levels provides a big increase in power - it's comparable to a Bradley Wiggins or Chris Froome pedalling in parallel with you. It's marked to be legal, although it is the same hardware as the 350W version (indeed it can be altered in software to the 350W one).

Michael

 

[One_Box]

You will have a noticeable gain using any crank drive motor, because its power is provided to the cranks and is in addition to your own power. There is simply more oomph going through the drivetrain and, assuming you've got the gearing to go faster, you will.

I've gone for the 250W version. It actually draws over 500W even in 250W guise and in higher assist levels provides a big increase in power - it's comparable to a Bradley Wiggins or Chris Froome pedalling in parallel with you. It's marked to be legal, although it is the same hardware as the 350W version (indeed it can be altered in software to the 350W one).

Michael

I have a BBS01 250W, how can it be altered to 350W in software ?

 

[mfj197]

I have a BBS01 250W, how can it be altered to 350W in software ?

It's not something that can be done on the head unit but if you have the programming cable (or access to one) it's an easy change. The only difference is increasing the Limited Current(A) from 15A to 18A. This sets the maximum drive current through the motor - 250W versions are set at 15A and 350W versions are set at 18A.

Michael

 

[One_Box]

Thanks, will follow up when I have a lead.