Lightweight and stealthy to leave at train station

[stealthbike]

Hi everyone!

I cant resist new bike projects, my latest is something for my girlfriend. She needs a bike to get to work from the train station, it will be left at the station evenings and weekends.

The donor bike is an old Dawes Duchess, which is a bit battered and shouldn't attract the eye of thieves too much. Its got a front basket, in which I plan to house the controller under a false 'floor'. I don't want any screens / buttons on the handlebars (to not draw attention).

Looking for hub drive (front/rear undecided), 250W, with UK legal speed restriction. I want pedal assist, no throttle. Needs brake lever cut offs.

The journey to work is less than 3 miles, and the battery would be brought home every night on the train to stop theft. Therefore the battery can be very small I think as only traveling a short distance each day, and hopefully lightweight as going in a handbag.

Does a really small battery exist on the market, or would it need to be custom made? I've seen some people on here have squeezed them into drinks bottles, I probably need something like that or smaller!

Why you ask?! She loves using her 'purpose built' ebike on the home to train station leg of the journey, we have a spare bike and I love tinkering, so why not!

Any pointers or advice you can give would be greatly appreciated! Budget is lower the better.....I imagine the battery will end up the most expensive part due to the unusual size requirements?

 

[anotherkiwi]

I like your idea. A lot!

A tiny Xiongda front hub motor that looks like a dynamo. A 2P10S battery for 6 or 8 Ah = 200+ Wh. What could go wrong!

 

[stealthbike]

Yes I was leaning towards front hub as everything will be hidden up at the front of the bike anyway, which means I only need to run a cable down to the crank for the PAS.

I would make it look like an old dynamo but roughing it up a bit, maybe some black sticky tape and sharpie colouring in through the spokes!

Where am I best looking for a hub like that, places like blue my sky or are there European sources for decent prices?

Is that sort of battery something that could be purchased, or would it have to be custom made?

Cheers!

 

[anotherkiwi]

The hub you can buy direct from Xiongda and the battery will be a custom made one. If you are in the UK you are in luck there is a chap that does that very well for honest prices.

 

[chris_n]

You could use power tool batteries.

 

[awol]

The small Xiongda motor is in my avatar. For PAS control it will have an LCD so will have to hide that with the controller too. For throttle only you can trip the LCD connection so can do without it.

 

[jokskot]

For the front wheel hub, you could do a lot worse than buy a Voilamart at ca. £125 on eBay or Amazon.

 

[harrys]

I've been using hoverboard batteries to run my smaller ebikes. Something like this. One will last me 12-14 miles for sure at 12 mph. There's always the risk of fire, etc with cheap batteries. Mine were only about 28£ though. I keep them in a fireproof place, because I worry too much.

https://www.ebay.co.uk/itm/Hixon-20-Cells-4-4Ah-36V-Li-Ion-Battery-for-Hover-Board-Balance-Scooter-2-wheels/322371434262?_trkparms=aid=222007&algo=SIM.MBE&ao=2&asc=53677&meid=d871913e9a0047d4b9b1c3124f3d93be&pid=100005&rk=5&rkt=12&mehot=pp&sd=323262477125&itm=322371434262&_trksid=p2047675.c100005.m1851

 

[stealthbike]

The hub you can buy direct from Xiongda and the battery will be a custom made one. If you are in the UK you are in luck there is a chap that does that very well for honest prices.

What’s this chap’s name, is he on the forum?




Thank you everyone for your comments!

I’m going to look into power tool batteries too, that seems like a potential option as they would have a decent charger, and by cannibalising a spare charger I could make a battery dock in the bike basket.

I looked at the voilamart kit for £122, seems like that could be an option. It says you need a 36v battery no less than 8.8Ah. Why can’t I use a smaller battery, (4 or 6Ah) if I only need a small range?

Thanks!

 

[anotherkiwi]

What’s this chap’s name, is he on the forum?




Thank you everyone for your comments!

I’m going to look into power tool batteries too, that seems like a potential option as they would have a decent charger, and by cannibalising a spare charger I could make a battery dock in the bike basket.

I looked at the voilamart kit for £122, seems like that could be an option. It says you need a 36v battery no less than 8.8Ah. Why can’t I use a smaller battery, (4 or 6Ah) if I only need a small range?

Thanks!

She is called Bonnie and she is in China.

I think they want you to use a bigger battery because it won't sag so bad on hills.

If you go for a power tool battery grab one based on 20700 cells - 15 Amp output!

 

[wheeliepete]

I think you may find power tool batteries and expensive option esp. if you buy 2 chargers. Jimmy is the chap who can build you a small pack, I think he is away at the moment, but give him a call.

https://ebikebatteries.co.uk/18650-ebike-batteries/

 

[oldtom]

Why can’t I use a smaller battery, (4 or 6Ah) if I only need a small range?

Cytronex down in Winchester are still able to supply their original bottle battery and I actually purchased one recently from them as the original doesn't carry me too many miles after 6 years + of use.

They are not the cheapest and their style is a bit of a left-field choice as their priority is to use very lightweight bikes, with their kit helping out at the touch of a switch.

I have been using my Cytronex-powered Cannondale a lot more recently and it really is a joy at 17kgs including lights, mudguards, rack and seatpost bag crammed with tools, tubes, mini-pump, etc.

I rode nearly 7 miles the other day, using just my legs, thinking at the outset, I'd save power in case I needed it later in the ride. As it was all on the flat, give or take, I didn't switch on the power at all but the bike really does fly when power is called for.

There are several front hub motors small enough to keep the overall bike weight down but the Tongxin in my front wheel is plenty for me at 95 kgs. The battery for those previous generation Cytronex bikes is Ni-MH rather than Li-ion but provides plenty of power and can be recharged regularly for years, with a performance drop-off commensurate with use over those years.

You can have a look at the Cytronex site if you think a bottle-type battery might be what you need - 2.1kgs I believe.

Tom