Try to build a better e-bike than this

General Discussion about electric bicycles.
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dogman dan   100 GW

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Re: Try to build a better e-bike than this

Post by dogman dan » Jan 01 2017 7:36am

Well, it's a bike shaped object,, and that motor will eat that battery alive,, but it won't last long enough to wear out the cheap bike much.

That battery is rated 30 amps continuous, but if you want it to last,, more like 20 amps. And you want to pair it with a 60 amps controller, and a big hungry motor.

And that bike,,, the last thing I'd want to do is ride that piece of shit 45 mph.

That said,,,you can build a 45 mph bike shaped object, and poke around on it at 20 mph, and all will be fine. We have guys here that do that, and never notice that their bike is crude. But if you do plan to ride it like a motorcycle, you need a really strong frame, serious brakes, etc.

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Re: Try to build a better e-bike than this

Post by Lurkin » Jan 01 2017 7:44am

or its just clickbait/advertising.

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dogman dan   100 GW

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Re: Try to build a better e-bike than this

Post by dogman dan » Jan 01 2017 8:14am

At least not for kitchen cabinets if so... You would not believe how many times that guy tried, and we nuked it before anybody got up.

If that seemed harsh,, just look at those who ride fast all the time. Very few run the bike shaped object for long. They gravitate in the end to two things, custom built or modified frames, or very strong mtb's intended for actual downhill riding in places like Whistler.

Everybody should agree that battery is good for a 30 amps controller at most, but not a 60. You could just clip a shunt on the controller to tone it down. Get a watt meter to see what you are pulling, and clip two shunts if you must. Then you can get away with a cheaper bike, since about 35 mph is all you will get out of 2000w or so.

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MadRhino   100 GW

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Re: Try to build a better e-bike than this

Post by MadRhino » Jan 01 2017 9:36am

If your question was "can you build a cheaper ebike", I would say that It is not something I would even try.

To "can you build a better ebike", after seeing what it is I can say most of us are building much better, and I personnally like to build so much better that I would not trade my brake set alone for this whole bike and kit fully built.

When you are building to ride fast, there are safety requirements that can't reasonably be avoided. The bike need to be stiff enough, with adequate braking and handling to make it reliable riding that sort of performance that it has. Better and cheaper usually don't match very well together. Those are kind of opposite requirements and one that prevails, eventually does kill the other. :wink:
Make it fool-proof, and I will make a better fool.
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LewTwo   100 kW

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Re: Try to build a better e-bike than this

Post by LewTwo » Jan 01 2017 7:53pm

He has another post with the same links ...
https://endless-sphere.com/forums/viewt ... 5#p1252645
beginning to look like
Say-NO-to-SPAM-325x321.png
Say-NO-to-SPAM-325x321.png (129.37 KiB) Viewed 2210 times
to me.
The more I learn the more obvious the immensity of my ignorance becomes.
Weight Wennie E-Bike https://endless-sphere.com/forums/viewt ... 3#p1173723
Shaft Drive Grocery Getter https://endless-sphere.com/forums/viewt ... =6&t=90718
...and thanks to Justin!

EbikeAdvocate   100 W

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Re: Try to build a better e-bike than this

Post by EbikeAdvocate » Jan 02 2017 12:14am

LewTwo wrote:He has another post with the same links ...
https://endless-sphere.com/forums/viewt ... 5#p1252645
beginning to look like
Say-NO-to-SPAM-325x321.png
to me.

Well it's not I'm just a 19 y/o kid trying to get a nice e-bike for college and not waste any money that I don't have

2old   100 kW

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Re: Try to build a better e-bike than this

Post by 2old » Jan 02 2017 12:27am

State your needs and budget; the guys here are very helpful, especially the ones who have responded, Spinning Magnets and wesnewell (with a couple of exceptions that will become obvious immediately; they'll belittle a manufacturer, then talk over your head about something they don't understand).

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Re: Try to build a better e-bike than this

Post by LewTwo » Jan 02 2017 12:47am

EbikeAdvocate wrote:Well it's not I'm just a 19 y/o kid trying to get a nice e-bike for college and not waste any money that I don't have
If not then my apologies but double posting does raise question.
The more I learn the more obvious the immensity of my ignorance becomes.
Weight Wennie E-Bike https://endless-sphere.com/forums/viewt ... 3#p1173723
Shaft Drive Grocery Getter https://endless-sphere.com/forums/viewt ... =6&t=90718
...and thanks to Justin!

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Dauntless   100 GW

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Re: Try to build a better e-bike than this

Post by Dauntless » Jan 02 2017 1:11am

Well, let's see---What I think they were hinting at is what I'd want to come right out and say:

Interesting looking bike, but nothing special. Look for a smoother ride that won't beat you to death. 3000w on that thing?

Okay, once you beat everybody in the quarter mile, how you gettin' home with a dead battery?

They asked you to state your needs because that's the only way to figure out if this is a good idea or not. Half so powerful a hub with twice the battery might be far better suited. If we had any way to judge. Their comments get less oblique once they know what to talk about.

But it's your bike, build it your way, if you must.
Last edited by Dauntless on Jan 02 2017 11:41am, edited 1 time in total.
Any sufficiently advanced technology is INDISTINGUISHABLE FROM MAGIC!
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amberwolf   100 GW

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Re: Try to build a better e-bike than this

Post by amberwolf » Jan 02 2017 1:42am

Well, his needs are getting up into motorcycle territory according to this wanted post of his:
https://endless-sphere.com/forums/viewt ... 8#p1245708
EbikeAdvocate wrote:Hello,

I am looking to buy a high power e-bike that has full suspension at will reach speeds of 60MPH+.

My budget is $2,000-3,000 shipped to my door fully built.

To the OP of this thread, if you really want help building your project, stick to a SINGLE thread about it (this one would be fine), and ask all of your questions there, so that those helping you can continue to do so, and any new helpers coming into the thread can easily see everything about your project and add information for you based on that.

If you keep starting new threads, then those responding have to keep asking the same questions, and you have to keep answering them over and over, or else they dont' get the right information from *you* so they can give you useful answers.

Eventually you might get enough info to do what you think you want to do, even with what will end up being dozens or hundreds of threads...but you'll get much better info and help with decision-making if you stick to just one thread, and answer the questions asked with as much detail as you can.
Last edited by amberwolf on Jan 02 2017 1:53am, edited 1 time in total.

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Dauntless   100 GW

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Re: Try to build a better e-bike than this

Post by Dauntless » Jan 02 2017 1:52am

Then suddenly he wants a hard tail? I think he's going to have a hard time making his final selection.
Any sufficiently advanced technology is INDISTINGUISHABLE FROM MAGIC!
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Matador   10 kW

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Re: Try to build a better e-bike than this

Post by Matador » Jan 02 2017 11:34am

Dauntless wrote:Okay, once you beat everybody in the quarter mile, how you gettin' home with a dead battery?
Best line I've read in a long time ! I laugh so hard

And it's true, you're better off with an overbuilt battery that will last you for years with a moderatly powerfull motor/controller kit that is still quite fun to ride, than the other way around. A powerfull motor is completely useless with a dead battery. A 3000W motor/controller kit with a ~ 50 Volts battery will be pulling around 60 amps of current ( 3000 W / 50V = 60 A) when working hard­. A battery that is 30A-rated (Note : in reality, eBay seller sometime even overspec their batteries.... Maybe it's really only 20A rated or even lower) will suffer so much from pulling 60 Amps, you might kill the battery in just 50 charge cycles or even less !(overheating, and loosing capacity at a dramatic rate from charge cycle to charge cycle).

Personally, I would like a long lived battery.... Lithium batteries cost a lot of money so they better be long lived anyways, right ? I would chose a battery that can conservatively handle at least 60A for a 30amp motor/controller kit. IMHO, the battery amperage-rating is not an exact cutoff value. It's more of a value to give you a rough idea of what the battery is capable of. The more amp-capable a battery is, the less it will heat up for a given load.

Let's take an example. You have a ebike with a 30amp kit (motor and controller) that is intended to run on 48V nominal.

If you buy a 48V 21Ah battery made of 78 Panasonic NCR18650B cells (each cells is 3500 mAh capacity - MAX 4.87A discharge, battery in 13S6P configuration), that battery is then rated for a maximum of 29A discharge and will not last a long life if stressed at 30A load all the time. NOT A GOOD CHOICE FOR YOUR TYPICAL 30A SETUP ! EVEN WORST FOR A 60A motor/controller setup.

If you buy a 48V 20.3Ah battery made of 91 Panasonic NCR18650PF cells (each cells is 2900 mAh capacity - MAX 10A discharge, battery in 13S7P configuration), that battery is then rated for a maximum of 70A discharge, it will probably last an average good life at 30A.... I WOULD NOT CONSIDER THIS FOR A 60A motor/controller though.

If you buy a 48V 21Ah battery made of 91 Samsung INR18650-30Q cells (each cells is 3000 mAh capacity - MAX 15A discharge, battery in 13S7P configuration), that battery is then rated for a maximum of 105A discharge, it will probably last an very long good life at 30A....

If you buy a 48V 21Ah battery made of 91 LG Chem INR18650HG2 cells (each cells is 3000 mAh capacity - MAX 20A discharge, battery in 13S7P configuration), that battery is then rated for a maximum of 140A discharge, it will probably last a very long good life at 30A....

If you buy a 48V 21Ah battery made of 130 Sony US18650 VTC4 cells (each cells is 2100 mAh capacity - MAX 30A discharge, battery in 13S10P configuration), that battery is then rated for a maximum of 300A discharge, it will probably last ten years at 30A :wink: .... But a 130 cells battery gets a bit heavy.

Theses guidelines are very rough and crude estimates. To get to know batteries more (and I encourage you to do so), you have to study their discharge curves (volts versus mAh) at different discharge rate (ex: 2A, 5A, 10A, 20A, etc...), their temperature rise curves at different loads (too high temps will dramatically shorten cycle life ... a cell that reaches 80°C all the time will most likely die very prematurely), their cycle life curves. Also look for low internal resistance cells/batteries, as they will heat up a lot less and live longer when submitted to high amp loads. For choosing good lithium cells, look for their datasheets (mostly available on internet via PDF files) and discharge curves.
This is another great tool for curves : http://lygte-info.dk/review/batteries20 ... arator.php

eBay batteries might be made of cheap 18650 cells. Sometimes they are even made of very cheap, low amp rated, hign internal resistance, rewraped (or even rewraped fake) recycled used laptop batteries. You dont want that crap for a battery, as it will probably boil or transform into magma if you put that on a 30A eBike.
Last edited by Matador on Jan 02 2017 10:33pm, edited 1 time in total.

Voltron   10 MW

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Re: Try to build a better e-bike than this

Post by Voltron » Jan 02 2017 12:28pm

That is a great break down of how cell choice affects the performance and weight of the same-ish 48v 20ah bracket battery.

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Re: Try to build a better e-bike than this

Post by GeoffS » Oct 11 2017 5:41pm

Ultimately, I may do a couple of ebikes, a more conservative one on a t.t. rig ( so that'll handle like absolute rubbish even when I figure out the weight distribution as well as possible) for speed and distance at lower stress on the system for getting to work in summer. Hence I'm trying to learn about batteries as much as possible. Thanks for your post before BTW Matador....highly enlightening!
I've ordered my BBSHD mid-drive, and given my basic nature, I'm likely to modify it at a later date.
The bikes I'm putting this in to are a specialized SX trail with Marzocchis up front (170mm junior T's triple clamps). The rest of the bike is solidly built. The issue with that bike is frame space. Is it possible to "split a pack" and /or repack the various 14/15s components to different locations?
The other potential donor bike is a largely standard Giant AX. which has more space (especially if I turn that shock around the other way (if it fits like that))...
I've attempted tocopy in an SX trail image too (hopefully it works ) so you can see the battery placement issue.
http://forums.mtbr.com/attachments/spec ... -bike4.jpg
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MadRhino   100 GW

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Re: Try to build a better e-bike than this

Post by MadRhino » Oct 11 2017 5:56pm

The SX trail is harder to build. Go for the Giant or else, one that is even easier to build. Use a long frame, even if it is one size too large for you. Those bikes are made compact, and power does make them wheelie very easily. It will be more stable with a longer wheel base, with more frame space to build as a bonus.
Make it fool-proof, and I will make a better fool.
Current bikes
Street:
Trek Session 10 mod. Variable geometry. 70mph
Dirt:
Santa Cruz V10. 50mph

GeoffS   1 mW

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Re: Try to build a better e-bike than this

Post by GeoffS » Oct 13 2017 5:28am

Cheers, MadRhino.
I've done a bit of looking and (keeping within budget)...perhaps an older Epic may be the go. Initially that may seem like a strange choice BUT since I ride a large in Specialized Stumpy...I could go an XL in Epic and with the early ones having the shock on the seat stay....check out the frame space! Run a shorter stem and rake out the headtube angle with the JuniorTs or use one of those angle adjusting headsets to see if I can get "semi-modern handling" characteristics. Sounds like a plan :)
https://fseminario.files.wordpress.com/ ... _epic1.jpg
That even leaves room for a fully programmable sine wave controller later (I hope)...and I'll be hunting for one with disc brake set up.

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