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The eBike thread

unkel

A quick look seems that this doesn't really seem to fit in the cycling forum. So starting a thread here about all things eBike

I'll get the ball rolling. I have zero experience with eBikes. But I was going to build myself a battery anyway, for various reasons (like in bringing with me in my EV as a "petrol can")

I'm going to buy a solderless kit to make the battery (with 18650 cells I have removed from dead / old laptop batteries). This kit cah handle 20A max, and I would like the battery pack to produce 1kW constant. P=V*I so 1000W = 50V * 20A

This dictates that my battery needs to be nominal 48V (was thinking of making a 24V battery pack, but that won't be able to charge my car)

A quick browse on eBay and Amazon shows that you could buy a powerful 1000W bike conversion kit with everything needed except the battery for about GBP120 (a bit more from Amazon but peace of mind)

What to buy though, front wheel or rear wheel kit? Pros and cons? Any other advice?

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[Deleted User]

unkel wrote: »

Nonsense.

Acceleration is determined by torque of the motor (nothing you can do about that) and the power applied to the motor

Max power applied to the motor is voltage of the battery * max amps of your controller.

It has nothing to do with the max amps your battery can discharge at (very high for lipo). Power is only restricted if the BMS prevents those max amps to be discharged from the battery. Which doesn't happen with the hoverboard batteries (and yes I know it's not good for the life expectancy of an 18650 cell to discharge it at 3C )

Torque of the motor + amps give torque.

Turn down the amps you turn down the torque, why do you think people modd controllers for more current which = amps ? why do you think I suggested adding a dab of solder to the shunt in the controller ? to allow more current for more torque.

add voltage and you go faster Lover voltage and you go slower but overall current x voltage gives watts.

More amps require a battery capable of supplying the power.

If you had a controller and were able to adjust it via software you can also see that limiting current limits acceleration, speed can be limited by voltage or software.

unkel

Deleted User wrote: »

The Hoverboard battery is fine if you want to have poor acceleration lol

Nonsense.

Acceleration is determined by torque of the motor (nothing you can do about that) and the power applied to the motor

Max power applied to the motor is voltage of the battery * max amps of your controller.

It has nothing to do with the max amps your battery can discharge at (very high for lipo). Power is only restricted if the BMS prevents those max amps to be discharged from the battery. Which doesn't happen with the hoverboard batteries (and yes I know it's not good for the life expectancy of an 18650 cell to discharge it at 3C

)

[Deleted User]

You can find better much cheaper. lol. Don't have to go for anything over 20C LiPo,

The Hoverboard battery is fine if you want to have poor acceleration lol

unkel

Deleted User wrote: »

With LiPo you can make a cheap battery

Hardly. The cheapest way to do this would be with 2 * 5Ah 7S packs for USD70 each. This will give you a 5Ah battery (tiny, just for a very small local trip) for USD140. Plus expensive balance charger and charger power supply.

Using 2 7S hooverboard batteries you get a 6Ah battery for €50 and a charger would be about €10

For a novice who doesn't want to get involved in the sparky world of batteries (see what I did there?), the pswpower route is probably the safest...

[Deleted User]

You could use hobby king LiPo or LiFeP04, LiFeP04 isn't really suited for ebike use as it's bulky and heavy.

With LiPo you can make a cheap battery that can pull mega amps if you wish and charge at high amps.

Use 30 Amp "genuine" anderson connectors, there are a lot of fakes. I have a crimp tool also, dead handy. The 30 Amp andersons act as very convenient fuses should you cause a short by accident,. they vaporise in your hand.

LiPo poses obvious risks if abused they can go up in a ball of fire but never happened me, never store/charge in the house unattended.

You can use the LiFeP04 batteries also, you got to manage it yourself as there is no BMS so you need to watch that the cell voltages don't go too low or they could be damaged and that can become dangerous.

A BMS has it's own risks, especially for DIY use as it can cause catastrophic failure to the battery if it should fail.

The downside of course in the beginning is that you need an R.C battery charger to balance the cells and make sure they're not overcharged + you need to buy an external power supply for the charger.

Joe1919

SCOL wrote: »

EU 48V 13Ah lithium ion silver fish electrical ebike battery fits 750W motor for $220
this comes with a charger ?
I like the idea of making my own battery, could I make a better battery for less money ?
and also I would need to buy a charger ?

The silver fish battery slides down on a rail. It was really designed for older ebikes and usually went between the seat tube and the rear wheel/mudguard.

Pswpower have a good selection of 48V 'Hairon' batteries with chargers from 217 to 365 dollars. Be sure to get 48v.
http://www.pswpower.com/ven.php?cargo-s210052

SCOL

I'm thinking just to get started I might just buy a battery so would the motor and controller be able to handle either one ?

what's my best option there seem to be about €100 in the difference.
48v 13ah 750w
52v 13ah 1200w

unkel

SCOL wrote: »

I like the idea of making my own battery, could I make a better battery for less money ?

Time for a bit of YT. See if this is something you would be interested in. Start with Micah Toll. This is the easiest way, using his Vruzend kit (no soldering / welding)

https://www.youtube.com/watch?v=rylbFnTgFI8

Not cheap though as the kit is expensive. But you get the idea. You can buy chargers on eBay from about a fiver including shipping.

SCOL

EU 48V 13Ah lithium ion silver fish electrical ebike battery fits 750W motor for $220
this comes with a charger ?

I like the idea of making my own battery, could I make a better battery for less money ?
and also I would need to buy a charger ?

unkel

There's different options. PSW Power is a very decent supplier, if you want an all in one solution, go with them. Unlikely you get a better price elsewhere for a similar pack. Their BBS02 motor kit was also the cheapest I could find. And shipped from within the EU, so no customs implications

If you don't have the budget for that, you will have to cut corners like I did and buy some very cheap overstock scooter / hoverboard batteries and connect them in series / parallel. Or build your own battery from dead laptop battery packs or other 18650 cells you source yourself. There is a learning curve here. This is not for everyone.

To update my own situation: I got the new nylon gears, degreaser and grease, so I will refurbish the hub motor from my fat bike with these. And then most likely put it up for sale (provided I am happy it is working perfectly)

I've more or less decided that my end game, and the only bike I will end up with, will be a full suspension 29" MTB (with as wide a tyre as it will fit, hopefully 3"), with a Bafang BBSHD motor. So that's what I will be working towards over the next few months...

John Hutton

SCOL wrote: »

I bought the Kit yesterday, so now I need a battery and a charger.

what's my best option ?

I got a battery, with charger, from PSW power too, they have a website

SCOL

I bought the Kit yesterday, so now I need a battery and a charger.

what's my best option ?

unkel

Yep. All click and play. Very easy setup provided fitting the motor itself into your bottom bracket isn't causing issues.

SCOL

Now to order the batteries and a charger.

Am I right in saying that the controller is built into the motor ?

unkel

It's a good seller BTW. When I bought mine it read like it included the light and the sensor. And when I contacted them they were quick enough to reply explaining that was a mistake. I then suggested they change their ad and they literally copied and pasted my suggestion

"(includes connector for 6V light and connector for Gear/Shift sensor. Light and sensor do not come with this kit and have to be bought separately)"

Copyright: unkel!

unkel

I ordered one as it was not much more than a tenner including delivery (still haven't got it). You don't really need it as John Hutton has explained. I might fit mine at some stage just to see what it's like. Or I might not

SCOL

https://www.ebay.co.uk/itm/EU-NO-taxes-48V-750W-8fun-bafang-motor-BBS02B-crank-Motor-electric-ebike-kits/253794681242?var=553275505340

I've ordered the same do I need to order the sensors as they don't come with the kit ? or do I really need them ?

SCOL

I did say commute but It's all on private roads, just to make that clear.

[Deleted User]

SlowBlowin wrote: »

I think the controller has gone on my bike, the original one showed a max of about 1200 watts at full power (52v), can you recommend a modern replacement ? I guess I would go for a new screen and throttle too, would it be best to replace the pedal sensor at the same time ?

You could get a Lyenn controller. I got one from him before and it was great, should be programmable too so email him if you got questions.

http://www.lyen.com/ Expensive yes, but good.

Or try ebay.

I got no experience with pedal assist systems on DIY ebikes so can't recommend anything.

You could also try em3ev.com also good controllers and programmable so you can make it road legal too when you want to take it on the road.

I must admit though, I'm well out of experience with DIY kits these days. It's years since I built an ebike.

[Deleted User]

Oh right, never noticed the "commute"

Well, I was talking about Mount Leinster which is a private road so that gets me off the hook

SlowBlowin

Deleted User wrote: »

There's nothing illegal about buying or building/modding an off-roading ebike that does not need to comply with the road traffic act.

If there is then close the thread.

Its obviously a very touchy subject, and as the poster mentioned using it for a commute I was not surprised a warning followed.

I only use my high power ebike on private roads, so hopefully this thread will remain, although I share your frustration as there are numerous threads on fast car tuning and fast (illegal) motorbike riding all of which seem to comply with the same policy.

I think the controller has gone on my bike, the original one showed a max of about 1200 watts at full power (52v), can you recommend a modern replacement ? I guess I would go for a new screen and throttle too, would it be best to replace the pedal sensor at the same time ?

[Deleted User]

There's nothing illegal about buying or building/modding an off-roading ebike that does not need to comply with the road traffic act.

If there is then close the thread.

liamog

SCOL wrote: »

I'm going to use this for commuting. Start off on the peddle setting and build up speed I'm not looking for good takeoff speed
but I want it to cruise over 50Km per Hour at full throttle for about 10 miles.

Mod Note: Please be aware that any discussion of modifications to an e-bike must stay within legal limits as per standard boards.ie policy

[Deleted User]

SCOL wrote: »

I have a 66cc 2 Stroke on a bike keep it at around 40 / 45Km per Hour and I have thousands of miles put up on it
I do use the engine to slow the bike down and no problems with breaking but I understand that doesn't happen with
an electric engine.

Yes, some electric bikes can use regen to brake but usually this is limited by the amount of current the BMS + battery can take unless of course your run LiPo and have no BMS and LiPo can take much higher charge current than most Li batteries.

[Deleted User]

SCOL wrote: »

I'm looking for "top Speed" so should I be looking at a rear wheel kit ? I was looking at a mid drive.

As I said on before my problem is I know nothing about electrics.

What speed are you looking for ? and how fast do you want to get there ? and do you want speed on hills ? what size hills etc ?

Most important will be your bikes brakes, if you're not prepared to upgrade then you should forget about it. You're talking about needing 8 inch disks front and rear along with hydraulic brakes.

Direct drive hub motors are very reliable and need no maintenance but are hard to pedal without power to the motor.

Geared hubs provide more torque and need a little more maintenance but probably not for a few years. But it's no harm to open it, clean all the grease out and apply new grease.

Getting speed is easy but you'll use a lot more battery energy depending how fast you intend going.

SCOL

I have a 66cc 2 Stroke on a bike keep it at around 40 / 45Km per Hour and I have thousands of miles put up on it
I do use the engine to slow the bike down and no problems with breaking but I understand that doesn't happen with
an electric engine.

I'm hoping to use a Trek Hybrid with 29 Inch wheels for my "upgrade to electric" it has standard break pads on the bike
probably go for the mid drive as I don't want to buy another bike. If the breaks are a Issue I'd change the kit over to another
bike something 2nd hand with discs.

I'm going to use this for commuting. Start off on the peddle setting and build up speed I'm not looking for good takeoff speed
but I want it to cruise over 50Km per Hour at full throttle for about 10 miles.

John Hutton

Going over 40 on a push bike is asking for trouble, only safe, imo, if you are in the drops going downhill on a good road.

In any other circumstances you need great brakes and should really be wearing motorbike helmet and gear if you're gonna go 50 or 60 regularly!

[Deleted User]

unkel wrote: »

Are you saying a 5kW direct drive hub motor will be quicker at accelerating from 0-20km/h up a 20% incline than a BBS running at 1.8kW (58.8V * 30A) with zero human effort in either case?

Any link to where I could buy such a 5kW motor? I've seen links for 3kW motors alright, but these typically do not get their full power unless you feed them with 96V. And there's no way one of those will out accelerate a BBS at even 58.8V

Depends, it would be tough enough to start either motor without doing wheelies @20% grade.

that's if of course you're talking about starting at 20%.

You don't need a 5Kw motor but of course one rated for continuous 5 Kw would help due to heat lol.

I was running 5 Kw through 1 Kw hubs though admittedly not at 20% but close.

I did run the magic pi at 3 Kw at 20+ % grades but that wasn't a motor for the job in reality.

You could also run a 16 inch wheel for more torque and easier on the hub.

You need more experience with high power hubs, the BBS02 is naturally going to feel like a rocket compared to your earlier builds.

By the way, any plans to upgrade the brakes on your bike ?

SCOL

unkel wrote: »

For very high top speeds, you'd be looking at a direct drive motor (can be front or rear wheel). A 1500W rated 48V direct drive motor, fed with 96V will produce 3kW, probably good for at least 80km/h :pac:

Will a 48V motor take 96V ?

I was going to buy those batteries off Ali Express that you said a while back. I also need to get a battery charger.

unkel

For very high top speeds, you'd be looking at a direct drive motor (can be front or rear wheel). A 1500W rated 48V direct drive motor, fed with 96V will produce 3kW, probably good for at least 80km/h :pac: