Two wheel drive

[Paultr]

Hi

I am about to install a 250W rear hub motor on a hybrid bike. I am used to a lightweight road bike and although this bike is supposed to be light at 12kg it feels like quite a lump to me especially as I have fitted mudguards and a rack.

I am a bit concerned that I might not have enough power so if that does prove to be an issue would it be possible to add a second identical hub motor on the front wheel so I have two wheel drive ?

Any thoughts please ?

 

[wheeliepete]

It's doable, what motor/controller/battery combo are you fitting now?

 

[Paultr]

It's doable, what motor/controller/battery combo are you fitting now?

The MXUS XF08C from Woosh with the Panasonic 18Ah battery.

 

[wheeliepete]

Fit your kit and see what you think. You have around 600watts of pulling power, should be fine. Running two motors can be done using a second controller. The main problem you will have is your battery. It will need to be able to supply nearly 40 amps continuous at full power and I doubt Woosh builds his batteries to that kind of spec. because he dosn't need to.

 

[Deleted member 4366]

I've done that several times. You need an additional controller and a battery capable of giving enough current for both motors. I found that the best setup was to have the pedal sensor driving the rear motor for normal riding, and the throttle working both controllers for when you want the extra power. That method saves a lot of wiring and complication.

To connect one throttle or PAS to two controllers, you only connect the signal wire to the second one. Ground is optional, because all grounds are common, and you mustn't connect the 5v wire to two controllers because the 5v will be slightly different on each one, which causes problems.

 

[Paultr]

I have no real desire to go faster than the 15mph that the rear wheel drive will hopefully provide on the flat. I had the idea to use it very occasionally on particularly steep or long hills. It is probably too much faff and would certainly put extra weight on the bike and I am not at all keen on that. I will park the idea until I have seen what performance I am getting. Thanks for the replies though

 

[Nealh]

Speed is irrelevant with a two wheel set up, doesn't matter if 15mph or not as two motors are not permitted for illegality.

 

[flik9999]

If 250w hub drive isnt enough go and get a crank drive such as the bbso1. Its only 250w so is legal but can be programmed to easily get 25 mph with just using controller settings. You can also limit it to 15 mph.

 

[Paultr]

I had originally wanted a crank drive but reading on this forum seemed to suggest that a hub drive would give a more relaxed ride. This is what I want - just to truck around on cycle paths etc - nothing too hectic ! Am I correct in thinking this ?

 

[Deleted member 4366]

I had originally wanted a crank drive but reading on this forum seemed to suggest that a hub drive would give a more relaxed ride. This is what I want - just to truck around on cycle paths etc - nothing too hectic ! Am I correct in thinking this ?

Yes. You have to be in the right gear all the time with a crank-motor, but a hub-motor doesn't care what gear you use. Also, the gear-shifting with a hub-motor is much better for your nerves. A crank-motor only has an advantage on the road in some extreme situations, like for towing, for exceptionally steep hills or for very heavy riders. All the other pros and cons are more or less fly shot (with an i).

 

[flik9999]

If you only want 15 mph then you will be fine with pretty much anything. The 250w hub motors are normally geared.

 

[flik9999]

When I had a huh motor I never found it that relaxing. Ebikes kinda accelerate in a non bicycle way either way.

 

[Deleted member 4366]

When I had a huh motor I never found it that relaxing. Ebikes kinda accelerate in a non bicycle way either way.

It depends on which controller you have. You don't get that with KT controllers.

 

[Paultr]

Hi d8veh - what is a KT controller and can it be retrofitted to any e-bike system ? I have tried go ogling it and come up with a bluetooth link to put controls on your phone.

As regards relaxed or not I wonder if it is a function of the thumb throttle. I have no experience but did read somewhere that they were very immediate in action. My only experience was when I lived in China and had a large e-bike. This was virtually an electric motorbike with twist grip throttle and this was very relaxed to ride (if you wanted it to be). As a matter of interest can you swop out thumb throttles for twist grip type for most hub kits ?

 

[Deleted member 4366]

KT is Kunteng, but you rarely see them advertised as that. If you have a look at the LCDs on the BMSBattery website, they're all KT ones, so that's what you look for in any adverts or listings. After a while, you get to recognise the labels on them.

There are loads of them on Aliexpress:
https://www.aliexpress.com/item/24V-36V-250W-15A-Brushless-DC-Sine-Wave-Controller-LCD-or-LED-Throttle-Brake-Lever-PAS/32624191435.html?priceBeautifyAB=0
https://www.aliexpress.com/store/group/Controller-Set/738588_511617563.html?spm=2114.10010108.100008.19.2ef379ffruLzSO

You can also get them from PSWpower, who also sell on Aliexpress and from BMSBattery
http://www.pswpower.com/peng/pic.asp?ModID=PicS224&TypID=S210048
https://bmsbattery.com/48-torque-simulation