HI all,

 

been cycling and commuting for many years, looking to convert my current bike into a stealth ebike. my commute is 10m each way, usually 3-5 days a week. been perusing for quite a while figuring some of this out, im a mechanical engineer who dabbles in electronics, it should belong in Hogwarts but here we are......

 

I only have one bike, and i can only have one bike - storage / cost / wife.....

 

so id like to do a stealth front hub wheel convert to assist me on the commute so i can remove the battery / switch out the front wheel and get out at the weekends. or just keep it as an ebike with the kids in tow!

 

I am thinking,

front hub - maybe MXUS or bafang,

motor controller - decent sine wave - 20a - any recommendations ??

battery - Thinking bottle battery -36v 10ah -

PAS for hollowtech bb,

small display -

 

 

a few further questions -

If i only have PAS then i dont need break sensors right?

I only need low power assist levels - so a single 10ah bat can supply 20miles worth of support? i am already relatively fit - can ride over 40m in the peaks etc, i am only after some assist for the commute to keep me fresh in the evenings and for the weekend. I can charge each night so i only need charge for 20miles or so.

 

otther info - im 6'3 100kg, bike is a marin four corners, is 13kg on its own, all in weight with luggage is maybe 130kg ..

 

thanks in advance!

10am 36v should give you 20 miles on low assist as long as it isn't too hilly.

 

I wouldn't go without brake sensors (or at least one). If you are doing tight manoeuvres it can be really awkward if the motor suddenly kicks in when you aren't expecting it.

A 10Ah bottle battery probably won't be able to provide the current for a 20A controller.

36v 10AH would take you about 40 miles or more if you're a regular cyclist.

Whether you need brake sensors or not depends on the controller. Some run on a bit after you stop pedalling. You'll be OK with a KT sinewave controller because they have a very fasst response time.

A 10Ah bottle battery probably won't be able to provide the current for a 20A controller.

but as you only want low assist you probably don't need a 20A controller anyway.

Thanks both, valid points.

The Commute total ( both ways) is 21 miles with 900ft of climbing. There is one rise on the way home of about 300ft in 1.5m - as mentioned above total weight is around 120kg - any issues with overheating during the climbs?

 

So a 17a kt will be better suited for a smaller battery?

 

a further battery question - if I wired up a pair of battery packs In parallel, id have 20ah - thinking for a longer rides. - I have 5 bottle cage positions on this bike so plenty of space.

Wiring batteries in parallel is not as simple as it sounds, though it can be done. Which bottle battery had you in mind? It's much better to deal in specifics.

Thanks VFR

 

so I was thinking -

Controller and display - KT 17a sinewave and LCD8S

motor - swx02 or XF07 - anyone better for heavy weight and hills?

battery - 36v 10.5ah - such as this one from ALiexpress - or similar if anyone can recommend a supplier?

 

If i used ST 60 connections I could make two harnesses - one for a single battery and one for a double battery in parallels?

with a bit more looking and being open minded, Its probably easier to get a single battery that is a bit bigger (AH) and mount it somewhere else. I didnt want to have a battery rack permanently attached to the frame. so either in a frame bag? is this a thing? or I have a front rack which i could use.

 

any thoughts on this?

Front rack batteries s are popular with (eg) Brompton etc, and help weight distribution .. I'm always alarmed when I stop on the front brake going up hill and then slide backwards because there isn't enough weight at the front to keep the wheel on the ground!