Looking for input on my ebike build before I order it

[cyphear]

I'm looking to upgrade a bike that I ride on paths and run short errands on to an ebike for fun and to extend my usable range a bit. I'm looking to do this cheaply because I dont want to go "all in" on a hobby i've never tried before (I'm not sure how often i'll actually use this bike).

I'd like any input on my setup that you have to offer. Looking for 20+miles or range and 20+mph of flat ground speed for a 150lb rider. I'd like the setup to be light and unintrusive, and it looks like the magic pies don't fit that bill as well as a geared hub, and I can always upgrade to a direct drive hub if I want more speed. I realized geared hubs are less reliable, but I'm just looking for something that's pretty reliable (not a piece of junk), so i'll be happy if it lasts >500 miles.

Kit
$235 + shipping? rear drive ebike kit w/ 7 sprocket and LCD display - http://www.ebikeling.com/#/kits/8
Torque Arms - None of these sellers carry them, but i'm not sure which to get. It seems like I can get $10 cheap ones or $38 for nice ones. 500w on an aluminum frame (and dropouts) seems like it'll be okay for a few test rides without them, but feel free to disagree. EDIT: ebikeling carries these http://www.ebikeling.com/#/accessories/torquearm no idea how good they are.

Batteries
$26*3 4s1p 5ah batteries http://www.hobbyking.com/hobbyking/store/__18631__Turnigy_5000mAh_4S1P_14_8v_20C_hardcase_pack_USA_Warehouse_.html
$40 charger http://www.hobbyking.com/hobbyking/store/__12105__HobbyKing_8482_ECO6_10_200W_10A_6S_Bal_Dis_Cyc_Charger_w_acc_.html
power supply - going to make one from an old CPU PSU.
Additional connectors - what do i need?

Total cost of kit = ~$385 shipped

Questions
Anything else I need?
Any idea what motor this is?
Will a 7 speed hub work okay on a previously 9-speed bike?
Is it better to mount it on a front steel shock, or a rear aluminum dropout?

I suppose one step up from this kit in power handling for a geared hub would be the MAC hub motor from em3ev, but that'd step me up another $200, which does not seem worth today if if my ~20mph goals are met with this kit.

Thanks!

 

[Drunkskunk]

Welcome to the forum.

Geared hubs are usually more expensive than a direct drive for the same power rating, because far more goes into building them. More parts, higher labor costs, etc. So if you find a kit that's cheaper, be very cautious.

The motor's site you linked I can't see. I get an untrusted site/scam warning when trying to get to it through the firewall here. That might be nothing, but combined with a too-good-to-be-true price for a 500 watt geared hub kit, I'd say steer clear.

You chose Lipo as your battery. That's not a problem if you have an electrical background and understand it's high risk. However, the amount of battery you chose is good for a reliable 6 miles at 20mph. You need around 720 watts of battery for a reliable 20 miles range at 20mph. If you don't know how to do the math to convert watts to volts and amps, you realy realy don't need to be messing with Lipo.

Ebikes are the kind of thing where you either go all in, or you get nothing usable for your money. So before you halfass it, try finding an ebike retailer near you, and see if they will demo one of the bikes, or even let you rent one.

 

[cyphear]

Thanks for your input. It looks like a cute hub (it's a polished hub). Here is a direct URL link to the image http://www.ebikeling.com/images/bikes/8/1.JPG and here is an amazon link (http://www.amazon.com/Geared-Ebikeling-Electric-Bicycle-Conversion/dp/B00QJAE498/ref=sr_1_5?s=sporting-goods&ie=UTF8&qid=1424706066&sr=1-5).

Good point about the cost of construction. I agree, but if someone can tell me good things or bad things about the hub, that'd be ideal. There are a lot of cheap hubs that people have had good luck with. This is a lower powered hub than the similarly priced and higher powered GM magic pie yescomusa kits, so it does make some sense with respect to price.

What do you mean by "720 watts of battery"? Watt is a unit of power, not energy. In you calculations, you realized I am running three (12s1p), right? I can redo my math, but I want to see where you're meaning by "720 watts of battery". Do you mean 720 watt hours? If so, that would be 36wh per mile, which is still pretty high compared to what i've read around this forum. I'm basing my calculations on about half of that: 240watt hours at 15wh/mile is 16 miles or predicted range.

 

[wesnewell]

Take your pick.
http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=48v+1000w+rear&rt=nc&LH_PrefLoc=1
10ah of 12s lipo and 12s charger, or 12s bms and charger.

 

[DAND214]

Drunkskunk knows what he is talking about.
A 12s1p (5AH) pack is good for 5 miles if you go by the 1ah per mile rule. Yes you can get more or less depending on your riding.
As said if you don't use or know LiPo you might wanna look at a difference chemistry.
Yes it's watt hours. so 44.4x5=222 watt hours, Yes some use that but they don't expect 20 mile range 20mph maybe 5. You don't wanna run them dead, unless you throw them away after each discharge. As said geared hubs are more complex than DD's and also lighter. Cost of a GOOD geared hub is normally more than a DD. Yes a MAC is a GOOD geared hub and almost all the cheap DD's are also GOOD now.

A rear hub is more work than a front but also safer. Aluminum fork or frame needs torque arms. Yeah you could do a couple test runs without them and get comfortable with it. Then you think it's gonna be fine, next think you know your laying on the ground with the wheel rolling down the path without you...

If you try a prebuilt be sure to try one that isn't under $1000 or you would get a bad feeling of what it really can be like. Cheap prebuilts are just what they are, CHEAP and disappointing!

Dan

 

[cyphear]

Thanks. 5AH per mile does not make sense without giving a voltage, so I'd be very wary of anyone who gives that as a rule. Is that assuming 48V? Resources like ebikes.ca/learn/batteries.html have suggested ~15wh/mile. You're suggesting 44.4 wh/mile, which is higher than I've found from any source. Good point about not running it down all the way. I can always add more batteries later. It looks like Wes gets 96v*10ah=960wh for 45 miles, or about 20wh/mile.

Do you know the lowest wattage someone has broken dropouts on? It seems like they are a valid concern, but I didn't find too many moderate setups that have broken them. It is hard to search for that sort of thing, but information like this would help clarify the FUD.

 

[Drunkskunk]

36 watt hours per mile is based on the capacity needed to ensure the range over time, and not as a representation of the best possible range. You can get 15 Wh/m on flat ground and no headwind, slick tires at full pressure, no loose clothing, no large cargo racks, and temps above 70 degrees.

On a bone chilling day with a strong headwind, baggy warm clothing, and a weeks worth of groceries in bags hanging from the handlebars, while trying to go up hill with a tire that's gone half flat, you're going to get much less range.
You're also going to need a reserve of 20%, if you plan to use the full range normally. While Lipo can be fully discharged, doing so often shortens their lifespan considerably.

So 36Wh/m is what works out to be the capacity of battery you need to ensure you get the range you want not just in perfect conditions, but in real world conditions, day in, day out. This is the capacity that we have found as a community works best when planning a battery size, through many member's experiences, but also from careful study of the power requirements involved.

So you want a bike with a range of 20 miles at 20 mph, you need a 720 watt hour battery.
If you want a bike that sometimes can get up to (but normaly less than) 20 miles at 20mph, you can get a smaller battery.

 

[cyphear]

Great info. I am on 1.25" tires, which will greatly increase efficiency, but all of your points about wind and weight still hold true.

Any thoughts on the rest of the setup? Are no-name geared hubs a bad idea for stock power loads?

 

[cyphear]

The kit seller just replied and said, "As far as we are told by our supplier geared motors are 8Fun.". I think i'll go ahead and give it a shot.

 

[TheBeastie]

Looking at that kit you posted. It looks like if you get the LCD kit you are getting a modern sinewave controller kit, so its a pretty modern nice little kit that one..
Also it shouldn't matter what voltage battery you connect onto it as that controller can deal with it automagically.

Just to be a tad negative, when you build a lipo pack for an ebike you got to be a bit more mindful of fire.
As lipo is meant for hobby air toys and not ebikes.

This is what a single lipo does, you will be building a whole stack of them together.
[youtube]zQheOtdCTjs[/youtube]

As long as your good with that, should be great

 

[2old]

Might want to take a look at Dillenger with several satisfied ES customers (look at threads in the review section). My 36V, 10 ah kit ($699 plus $17 shipping) goes about 20 mph and I've used it for a 16 mile ride, mostly throttle, but I like climbing so provide major assist on the hills. Of course, this is socal so usually perfect conditions. Also, the front hub, mid battery arrangement balances the weight nicely if you care about that; otherwise a rear hub system would be preferable IMO.

 

[cyphear]

Looking at that kit you posted. It looks like if you get the LCD kit you are getting a modern sinewave controller kit, so its a pretty modern nice little kit that one..
Also it shouldn't matter what voltage battery you connect onto it as that controller can deal with it automagically.

Just to be a tad negative, when you build a lipo pack for an ebike you got to be a bit more mindful of fire.
As lipo is meant for hobby air toys and not ebikes.

Good to know about the controller!

Most ebike kits, some cars, and all phones are lipo, right?

Thanks 2old. I am checking them out now. Seems nice and sanely priced.

 

[Drunkskunk]

Most ebike kits, some cars, and all phones are lipo, right?

Yes/No. Lipo stands for Lithium Polymer. That can be any number of Lithium battery chemistries that uses a polymer electrode instead of a liquid electrode. They generally are always in a flat or pouch form, but they can also be used in the traditional round can cells as well.

RC Lipo is Lithium Cobalt, LiCo2. A rather unstable but high power density chemistry battery that does really well for high performance applications like RC planes and high end RC cars, but has a short life and a high fire danger.
Generally when we say Lipo on this forum, these are the cells we are referring to.

LiFePo4 is a "safe" formula of lithium battery and can also be made with a Polymer electrode. It would then be a Lipo cell, but it almost never referd to as such.

There are a number of other Lithium-Ion chemistries that can be Lipo as well.

Only a few phones will use LiCo2, along with some lap tops, and usually in a safer form like LiMnCo2.
Cars use a verity of chemistries, but few would be LiCo2. For example, the Nissan Leaf uses LiMnO2, which is far more stable, though heavier and less capable.

As for that motor, it looks like a 250Watt motor. The 500 watt rating would be it's peak output. Some vendors make motor power claims based off the peak power, but it's more normal to rate an electric motor by it's normal power. Running a 250w motor too long at 20mph would likely overheat it. A 350 watt motor would have a higher peak rating, and would just be able to maintain 20mph without overheating. unless 20mph is your desired top speed, you should probably keep looking for a 500 watt motor.
On the positive side, 8Fun is a trade name for Bafang motors, who build some great motors.

 

[dogman dan]

As always, store and charge RC packs only in a place you'd build a fire. Houses have burned, likely due to inexpensive manufacturing defects. Lucky me, I have a fireplace.

But in fact a fire would smoke damage the shit out of my house with toxic crap.

20 miles at 20 mph, is kind of all the way in on the sport.

Not sure if you will really get 20 mph out of that 24v kit. I thought the majority of such kits are more like15 mph. So you might look at nearly as cheap 48v kits that can go almost 30 mph, or 36v ones able to go 20-25 mph.

On a windy day in Kansas, a small 24v kit will crawl. Day like that you need more power to actually enjoy riding in 30 mph wind.

For 36v, going up to 25 mph, 1 ah per mile.

 

[cyphear]

The kit I linked is 48v 500w.

I have plenty of areas for a safe fire, but is lipo the best chemistry for ebikes? I really like the extensibility of non-proprietary battery packs, so I'd rather not order a purpose built battery that can't be reconfigured.

 

[wesnewell]

1000W kits aren't much more and more power is never a bad thing to have if you need it. My first kit was a 48V 500W kit, I bought a 48V 1000W kit 2 weeks later for only $50 more. I consider rc lipo the only battery and have been using them for 4 years. The high C rates, size, reconfigurability, and weight make them ideal for ebikes imo. They are not near as dangerous as some people lead you to believe when handled properly. All batteries can be made to explode if you want them to.
http://endless-sphere.com/forums/viewtopic.php?f=14&t=27241

 

[motomech]

The kit I linked is 48v 500w.

I have plenty of areas for a safe fire, but is lipo the best chemistry for ebikes? I really like the extensibility of non-proprietary battery packs, so I'd rather not order a purpose built battery that can't be reconfigured.

8fun? Maybe, but when I first looked at the picture of the kit, I thought it looked like a product from this Co., which also makes the Cute Q100 motor systems.
http://www.tsbicycle.net/products_list/&pmcId=26&pageNo_FrontProducts_list01-004=2&pageSize_FrontProducts_list01-004=12.html
Either way, both are good motors.
BUT, that site is showing a 250W geared mini-motor, while the spec.s are for a 500W DD motor.
Which are you interested in ?
If you are thinking geared mini with Lipo, I would say stear clear of that kit, mostly because of the lack of controller spec.s.
Lipo needs a controller/display that will read the correct Lipo Voltage and give a correct hard LVC of 41V to 42 V for 12S Lipo.
Here is a thread to a build using what I consider to be a very good mini geared kit for use with Lipo;

http://endless-sphere.com/forums/viewtopic.php?f=2&t=55477&p=1009919#p1009919

 

[motomech]

The kit I linked is 48v 500w.

I have plenty of areas for a safe fire, but is lipo the best chemistry for ebikes? I really like the extensibility of non-proprietary battery packs, so I'd rather not order a purpose built battery that can't be reconfigured.

The latest "Plug and Play" Li-on batteries from BMS Battery are pretty good, but I started with Lipo and have stuck with it.
I a nutshell, I started with rather complicated battery builds with involved harnesses, but over time I realized, that for me, simplier is better.
For years, I have averaged 1.5 miles per Ah. for mini builds and since most of my rides are not long, I use 12S/1P(5Ah) modules that I configure or swap as needed.
For example, for running to the store, etc., I just plug-in a a two brick of Turnigy for 12S/5Ah.
If I'm going further, I'll carry an extra 2-brick pair that I will swap-in if needed.
For even longer rides(rare), I'll start with a 12S/2P pack and carry an extra 12S/1P. That's 15 Ah(22 miles or so), more than my longest rides.
Bottom line-Using the Thunder 1220 charger and keeping everything very simple, Lipo can be good for a beginer.
If you permenately need 15 Ah and the pack is not easily removable, I would rethink the plan.
Advanced Lipo packs have a long learning curve.

 

[Drunkskunk]

The kit I linked is 48v 500w.

I have plenty of areas for a safe fire, but is lipo the best chemistry for ebikes? I really like the extensibility of non-proprietary battery packs, so I'd rather not order a purpose built battery that can't be reconfigured.

That's what they claim, but the picture is a 250w-350w motor, the specs match a 250w motor, and the price is about right for a 250 watt 8Fun/Bafang conversion kit. If it's shaped like a duck, walks like a duck, and quacks like a duck, it's probably a duck, even if they call it a chicken.

RC Lithium Cobalt Lipo is not the best battery for an Ebike. It's like adding racing fuel to a commuter car. You get lots of drawbacks with no real benefit, unless you're building a performance bike that needs them. You're going to find many of us on this forum using them, but we're the 0.1%. We're the insane nuts who are squeezing every last miliwatt out of our bikes in a quest for more speed, more torque, and more grins. Just because many of us have jumped off that bridge, doesn't mean it's smart to follow.
The Li-ion batteries sold by places like EM3ev.com, Ebikes.ca, and even the cheapos from places like BMSbattery.com are all better suited to a normal Ebike.

The only "proprietary" battery i know of is sold for the Bionix Ebikes, and only works with their bikes. Anything else is interchangeable with other bikes, as long as it meets their minimum specs.