First E-bike Conversion advice

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SkinZ
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First E-bike Conversion advice

Post by SkinZ » Jan 07, 2018 12:55 pm

Hi,

I have been researching and reading the forums for a couple of weeks, and am about to take the first plunge into the exciting world of Electric Bikes!

I have got an old steel framed mountain bike sitting in the shed, that is asking for an electric conversion!

My use case is for riding in the UK on gravel tracks at weekends, probably using pedal assist more than throttle, so may not be hammering the battery too hard (not too concerned by the legality of throttle/wattage- as long as I don't ride like an idiot then no-one will know or care plus some use may be on private land).

For my first attempt, I have decided to go for a 1000w 48v ebay special with LCD display from here.

I am considering going for 52v 20ah battery made up from a 6s, and 2x4s from HK listed as "Multistar High Capacity 5200mAh 4S 10C Multi-Rotor Lipo Pack" here and "Multistar High Capacity 10000mAh 6S 10C Multi-Rotor Lipo Pack XT90" here. Is this a suitable setup or have I made any glaring errors?

I understand that I need to carefully select a decent LiPo balancing charger and power supply.
Can anyone point me in the right direction as to a decent balancing charger, that doesn't cost the earth or would it be cheaper and less hassle to bulk charge with a cheaper charger and then check with a standalone balancer periodically (every 10 cycles maybe) without a nice warm LiPo fire?

Also I have been reading about BMS. Is BMS necessary with this setup? How is it used? Does it strap to the battery group, for both charge and discharge whilst riding? is it one per block or cells (4s or 6s) or 1 for the entire block in series (14s)?

Thanks in advance for any help that you can give me! And I hope I have got the terminology correct as it is quite a steep learning curve!

Kind regards

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Re: First E-bike Conversion advice

Post by ScooterMan101 » Jan 07, 2018 1:17 pm

First : Those " not so special " e-bay kits , sell hubs that are Very Heavy DD hubs.

Most people here do not need such a heavy hub.

You have someone in your country ( D8veh , he lives in Telford ) that has been using the little Q100 c or freewheel Q100, or the Q128 , either the cassette version or the freewheel version which has a little more torque and can use / run on a little more wattage for the same hub. He has gone through and done all that you want to do .
A Q128 or a Mac hub motor is all you would probably need.

Now in regards to H.K. lipo's , If you get them you do ... Not need to use a BMS, the controller you get will have a low voltage shut off, what I do is tape a voltage that I will not go below when riding it is around 3.65 v per cell with lipo's.
Also
You can just buy a few Lipo low voltage alarms and plug them into the balance wire connectors and they will sound an alarm when there is a cell in the pack that reaches the voltage you set. Example you can set it to 3.5 v per cell or 3.6 v or 3.7. etc .

https://hobbyking.com/en_us/hobbykingtm ... 2s-6s.html

When using any Lipo's from any source like H.K. or elsewhere , make yourself a home made Lipo Bunker. I use a combination of Concrete Bricks and large Concrete Paver Blocks.
Best to charge them outside, if you must charge inside make a separate lipo Bunker , smaller in size to hold the pack/s you are charging at the time, Concrete Paver Blocks under and on top with sides of bricks , so that if there is a fire nothing else catches on fire, just allot of smoke.

Read what D8veh has done on his conversions.

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Re: First E-bike Conversion advice

Post by markz » Jan 07, 2018 4:46 pm

Be extra careful with them LiPo's.
iCharger would be ideal, but has a higher cost.
HobbyKing sells Balance Chargers - Just dont buy a low wattage unit, find something that can charge up your LiPo's in a half decent time. So you are looking for 6S Charger

https://hobbyking.com/en_us/0620-20a-30 ... ion-2.html

Then buy a Dell PSU to power it.
These units are dirt cheap on fleabay
https://www.ebay.com/itm/Dell-PSU-Power ... SwbF1Z8PtG

easy to mod

Also you forgot TORQUE ARMS
www.ebikes.ca sells them

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Re: First E-bike Conversion advice

Post by wturber » Jan 07, 2018 5:52 pm

Many people build something similar, and I think that approach is pretty darned good for a commuter bike in the U.S. They are simple, durable, and give you pretty good speed. It is what I chose to do over here in the Phoenix metro area of Arizona.

But in the UK, they have much stricter power limits and you'll need to decide if you care about that or not. As described, your design won't be legal on the roads in the UK. I have no idea how that will translate to the gravel tracks that you mention. So, if you haven't considered the possibility of riding it on the roads, then now's the time. Of course, if the laws aren't enforced rigorously, then maybe you don't care. It would be worth considering a smaller geared hub motor - even if you are going to run it at more than the 250 watt legal limit. The smaller hubs are less conspicuous. So if you pack the battery with some stealth, the bike will look more "normal" and attract less attention.
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Re: First E-bike Conversion advice

Post by Raisedeyebrows » Jan 07, 2018 10:43 pm

I used one of those same ebay hubmotor s on a steel MTB frame for my first hubmotor experience, I have a couple mid-drives but just wanted to assemble one and see what they were about. I will confirm that they are indeed very heavy. Running it at 52V, it gets up to somewhere around 30 mph pretty quickly with flyweight me on it, it's heavy and not fun to pedal without the power of the motor on. I have no other experience with other hubmotors, I'd like to try lighter ones. That said it has plenty of power and is lots of fun to ride.

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Re: First E-bike Conversion advice

Post by ScooterMan101 » Jan 08, 2018 2:14 am

Here is what is probably the best charger for the price , to charge lipo's
Not only is it AC or DC input , but output is for 2 batteries at once , this saves allot of time for charging.

The only drawback to this charger is that it will only charge up to 6s packs, Many of us are using 7s packs these days , and more of us will be using 8s packs in the near future. For you and the packs you will be buying this charger is the best for the price.

These were not available a couple of years ago when I bought my batteries, too bad, I have to charge one pack at a time since HK no longer sells the charger I bought back a couple of years ago.
The one I will link to is a AC and DC charger , most lipo chargers are DC only and you need to buy a Power Supply , when both are bought it comes to the price of this charger.
The link is to the ISDT with U.S. plug, it is the same unit only a different plug than what you have in the EU, when I click on the $ 144 dollar EU version the page goes to an ISDT DC only charger.

https://hobbyking.com/en_us/d2-smart-ba ... -plug.html

https://hobbyking.com/en_us/batteries/b ... ac-dc.html

Write to Hobby King and ask for them to get the company iSDT to make the same charger that will charge up to 8s packs.

* For anyone living in the U.S. or Canada here is the link to one sold by Buddy RC
( Call Buddy RC and ask them to get iSDT to make the same charger with 8s battery pack charging )

http://www.buddyrc.com/isdt-d2-smart-ba ... utput.html

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Re: First E-bike Conversion advice

Post by SkinZ » Jan 08, 2018 3:59 am

Firstly, thanks for all the replies!

I may now forget the 1000w kit, as I didn't realise quite how heavy it was despite ticking most of my boxes.

I like the idea of a smaller geared hub motor staying smaller in size and therefore less likely to be noticed, but similar power output once over-volted. I have since seen smaller motors in a wheel kit form from bmsbattery (Q128h) @ 94USD, but the shipping to the uk is 169USD, so unless I can find a reasonable UK/EU supplier it might kill the cheap ebike dream.

Thanks for all the charger advice, I'll definitely look at those once I've got the motor part sorted.

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Re: First E-bike Conversion advice

Post by Patchogue » Jan 08, 2018 2:34 pm

Hey SkinZ

Great to see another enthusiast taking off with another build. I used to build electric bikes in a shop in Mid Wales but I had to close it last year.
If you're close to London, it's very worthy to talk with David from this website: https://ampedebikes.myshopify.com/
He has some stuff in stock that might suit you and the prices are quite good. Small bafang hub motors (geared or not) with small custom made batteries. Cool stuff, he runs a tiny bafang with 800w and no issues.

I had a magic pie vector 4 with Lipos on my first ebike, had so much fun. Learned a lot and never had any issues with Lipos. If you take care of them, they can last a good amount of years / cycles without a problem. The bike was sold to a friend and it still goes great.
But in reality, you can buy very cheap batteries from aliexpress with all the juice you need and a charger. I really like Lipos in many ways but the comfort of not having to worry about them is priceless. The other day I've just ordered a 52V 15Ah 30A constant w/ charger included in a bottle cage with BMS for £250 with shipping included. Lipos will cost you the same once you buy the balancer, power supply and connectors plus labour of putting this together.

If I can be of any help let me know. G luck and don't forget to keep us posted with pics or vids.

Cheers

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Re: First E-bike Conversion advice

Post by SkinZ » Jan 08, 2018 6:57 pm

Thanks again everyone for all the help.

I like the sound of a physically smaller decent discreet motor running a bit over volted.

What is my cheapest route to buy in UK?

I've had a look at the links provided but think I'm confusing myself but lots of good projects undertaken by so many talented people.

I'm not too concerned by warranty if I go for a decent brand such as Bafang- I just want to start and get some bits together.

There is a swhx 48v 350w on AliExpress for £105 delivered without anything else here which could be a potential start?

Obviously got a steep learning curve coming with attaching it to spokes. What do you think? Too complicated? Should I just buy a kit and be happy? I feel like that would be cheating!


Thanks again

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Re: First E-bike Conversion advice

Post by wturber » Jan 08, 2018 8:23 pm

SkinZ wrote:
Jan 08, 2018 6:57 pm

Obviously got a steep learning curve coming with attaching it to spokes. What do you think? Too complicated? Should I just buy a kit and be happy? I feel like that would be cheating!
Starting with a kit isn't "cheating" at all IMO. I think kits provide a greater likelihood for success while also giving you some hands-on that lets you learn a bit about things. Having good success early is generally a good thing.

OTOH, if you've had a hankering to learn how to build a bike wheel, and/or you want to make sure your wheel is built to a high standard then buy the motor either build the wheel yourself or have someone else build it. Most kit wheels aren't built with the best components. So having the wheel built locally might be a good thing. OTOH, my cheap kit wheel is doing just peachy after 1500 or so miles.

This is your project. Read lots on this forum, and do what you think you'll enjoy most.
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
7 x 36v 4.3ah 10s 2P battery packs - Wangdd22 1500W 30A DC Boost Converter delivers 54v and about 1175 watts peak
53T/42T Sakae Road cranks - 30mph+ on flats
https://endless-sphere.com/forums/viewt ... =2&t=90369

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Re: First E-bike Conversion advice

Post by Drunkskunk » Jan 08, 2018 8:54 pm

Skip those 350w motors. They aren't robust enough to survive off road. a 500w Bafang or MAC is what you need.

And if cost is an issue, the direct drive hubs are still a good option. Heavy, but bullet proof with only 1 moving part. They make a great motor to get started out with. They have some advantages, too.

Don't go for Aliexpress for a battery. Forum member Dogman had his house burned down recently by one of those. And he's someone who preaches battery safety to newcomers. Battery fires are rare-ish, but he isn't tho only member of this forum to have lost a house. Buy the best battery system you can afford, skimp on other parts if necessary. The battery, not the motor, is the heart of a good ebike.

Lipo from HK works. it is risky and not always the cheapest option. you need a good balance charger to make it safe, and usually several chargers to make it practical. those chargers are expensive. Since you need to monitor Lipo while it charges, it's better to have a bunch of chargers so you can get it Finnish faster. i use Lipo. my bank of 4 chargers plus power supplies cost more than many people spend on conventional batteries and the charger.

Here's a video of a single HK 5000mah cell i caused to burst. your 52v 20ah battery would have 56 cells this size.
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Re: First E-bike Conversion advice

Post by MadRhino » Jan 09, 2018 10:54 am

I use RC lipo too, yet I don’t recommend using them if you don’t need the Amps.

Your requirements are well served with a much safer battery, and one that you can let charging without supervision.

When you need RC lipo, you need to be strict with the rules. Lots of rules, that one could describe generally: When you can’t be with them, they have to be where it is safe to start a bonfire.
Make it fool-proof, and I will make a better fool.
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Re: First E-bike Conversion advice

Post by SkinZ » Jan 09, 2018 11:57 am

Hi guys, thanks for all the advice.

I'm fairly confident that I won't burn my house down with a LiPo pack, as I've read so many guides about BMS, balancing rules, charging rules, maximum minimum voltages so I'm quite happy.

Also I think I'll just charge them outside in my back garden under a metal cover if I need to leave them unattended.

My first purchase problem is still with picking the best rear hub motor I can afford, without it being too heavy or having to pay £150 to ship from China..

Ideally I'd like either a 250 or 500w rated motor that isn't too large to run about 750-1000w using a 52v battery pack at 20ah. I'd like to pay about £150 for the motor alone delivered to UK. I can worry about the controller and wheel mounting and battery requirements afterwards as some of the kits tend to cut corners on these bits and I don't mind paying for decent separate components but don't want to spend all my budget on shipping.

Am I asking too much? Be honest!

Thanks again

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Re: First E-bike Conversion advice

Post by wturber » Jan 09, 2018 1:15 pm

SkinZ wrote:
Jan 09, 2018 11:57 am

Ideally I'd like either a 250 or 500w rated motor that isn't too large to run about 750-1000w using a 52v battery pack at 20ah. I'd like to pay about £150 for the motor alone delivered to UK. I can worry about the controller and wheel mounting and battery requirements afterwards as some of the kits tend to cut corners on these bits and I don't mind paying for decent separate components but don't want to spend all my budget on shipping.

Am I asking too much? Be honest!

Thanks again
I don't know if you are asking too much or not. But I will say that one of the main advantages I found with purchasing my ebay kit was that all the parts were selected to work together properly. This was especially true of the controller, motor, throttle, connectors and LCD display. The LCD display in particular was a fairly important unit since it provides an interface to change option is the motor controller. I had no clue about that when I purchased the kit.

If the kit at the link below had a 48v controller, I'd think it might be a reasonable choice if you are budget minded (interestingly the large photo of the kit shows a 48v controller while the group photo of the kit shows an obviously differently shaped controller). The parts are generally on the cheap side of things (though there are common reports of such kits working fine for many thousands of miles. So with a kit like this you may find yourself wanting to upgrade things later. And if that's you, then perhaps an inexpensive kit like this doesn't make sense. OTOH, if you enjoy fiddling/modifying/learning then perhaps it does. :^)

https://www.ebay.co.uk/itm/LCD-Display- ... emftijY4wg

You could spend more time and research in-depth the parts. You'll probably pay more, but the overall quality of what you get will probably be higher (if you choose and shop wisely with advise from the veterans here). But you may still find yourself wanting to fiddle and upgrade later. It seems that few of the long term ebikers here just build one bike and then ride it without changing things.
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
7 x 36v 4.3ah 10s 2P battery packs - Wangdd22 1500W 30A DC Boost Converter delivers 54v and about 1175 watts peak
53T/42T Sakae Road cranks - 30mph+ on flats
https://endless-sphere.com/forums/viewt ... =2&t=90369

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Re: First E-bike Conversion advice

Post by SkinZ » Jan 11, 2018 8:59 am

Hi,
Just a quick update.

I've ordered a 250w eBay kit for £105 delivered.

I'm sure that I will melt or burn something whilst playing around with it (hopefully not a LiPo pack!), but it's a dirt cheap disposable kit to test how far I can push 250w and the controller as a bit of an experiment.

I can't imagine it lasting the year, but that's ok, I'll know more for the next one!

Thanks to everyone for their help, it's been a real learning curve! Pictures to follow soon!

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Re: First E-bike Conversion advice

Post by Patchogue » Jan 11, 2018 7:17 pm

what's the make and model?

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Re: First E-bike Conversion advice

Post by SkinZ » Jan 12, 2018 3:22 am

Hi,
Not sure it has a make and model. Generic Chinese kit: here

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