Newb

[rhodrigo27]

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!

 

[sjpt]

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.

 

[vfr400]

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.

 

[sjpt]

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.

 

[rhodrigo27]

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.

 

[vfr400]

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.

 

[rhodrigo27]

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?

 

[rhodrigo27]

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?

 

[GSV3MiaC]

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!