E-Bike Improvements , questions

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E-Bike Improvements , questions

Postby Alastor » Tue Apr 24, 2012 12:57 pm

Hi all ,

I am new to the site .I am so happy that i found a forum so rich in technical information in the field of electric bicycle .

To the point now :D well i own two electric bicycles.The one i made myself for my girl with a folding bicycle and an 8Fun front wheel kit .I want to make some improvements on it if i don't find someone to sell it because my girl dose not like it as a bicycle :P But from my point of view its project that i worked in and i am sure you are getting me i like it and i still want to improve it if i keep it and learn something new while doing so.

The kit came with a no name controller that feeds the motor 7A .My battery is a LIPO4 36 volt 10 ah pack.If i upgrade the controller will the motor run better ?

Also i was wondering if someone can use capacitors as a power supply .If anyone tried this i will really appreciate the input.

Thanks a lot in advance and sorry for my bad English :twisted:
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Re: E-Bike Improvements , questions

Postby dogman » Tue Apr 24, 2012 2:00 pm

Your controller is about perfectly matched to the battery it's running on. Go to a 20 amp controller, and it will over discharge the battery, likely tripping it's bms.

So yeah, your motor will run with more wattage if you get a higher amp controller, but most likely you will have to get a new battery as well, one more able to put out more amps. It's quite possible your battery can tolerate a 15 amp controller, but we can't say it will, just that it might. Any more will tend to harm the battery, if it doesn't just simply shut off.

If you really want to step up performance, larger motors, strong batteries and 20-30 amp controllers are the way to do it.

But you could easily get a bit more pep, with a 12 amp controller. But you won't go and climb a wall.
THE LIPO RULES. NEVER ABOVE 4.3V NEVER BELOW 2.7V DON'T PUNCTURE

Ideal charging /discharging range for Lipo, 3.65v minimum 4.1v maximum

See battery technology section, FAQ thread at the top of the page for lipo noob info.
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Re: E-Bike Improvements , questions

Postby amberwolf » Tue Apr 24, 2012 3:28 pm

Alastor wrote:I want to make some improvements on it if i don't find someone to sell it because my girl dose not like it as a bicycle :P

This might not matter at this point, but in my experience it is better to have someone find the bicycle they like *as a bike*, and then convert it to electric, keeping in mind how they like to ride it and what performance degradation it will have on riding it as just a bicycle (extra weight, changes in steering/handling due to weight placement, etc--all of which can be tested beforehand by placing just weights or bricks or whatever in the same places the ebike stuff will be, riding it, and seeing which placements make it a better bike).


The kit came with a no name controller that feeds the motor 7A .My battery is a LIPO4 36 volt 10 ah pack.If i upgrade the controller will the motor run better ?

Depends on what you mean by "better". If you want to go faster, you'd need higher voltage. If you want better acceleration, especialy from a stop, a higher-current controller might help, but only if the battery is capable of putting out that current without major voltage sag.

What you want first is a wattmeter, like the http://ebikes.ca Cycle Analyst or Watts Up or a number of other wattmeters, so you can monitor the voltage and current out of the battery into the controller while riding the bike in various situations. THen knowing what is actually happening with the existing equipment, you can decide which parts need replacing to improve it to the point it does what you want it to.

Also i was wondering if someone can use capacitors as a power supply .If anyone tried this i will really appreciate the input.

If you mean in place of a battery, then with typical caps you would need a huge bank of them, perhaps the size of a car, to run your bike as well as the battery you have now. ;) With really good and expensive caps you might be able to use something a lot smaller, but it would still be bigger than you and the bike, because you must store enough energy so the voltage remains high enough to be useful.

Basically you have to have probably ten times or more the capacity in capacitors than you would in a battery, because the battery's useful storage is all at higher voltages, but capacitors store it across the entire voltage range from zero to max voltage. Controllers and such can only use that narrow higher voltage range, so you're stuck with wasting almost all of the energy storage space in the capacitors just to have enough energy to run your system.

It's possible to create a controller that would use a much wider voltage range, and use more of the energy, but none of the typical ebike controllers are capable of it.
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Re: E-Bike Improvements , questions

Postby Alastor » Tue Apr 24, 2012 4:14 pm

Thank you both for the answers :)

This might not matter at this point, but in my experience it is better to have someone find the bicycle they like *as a bike*, and then convert it to electric, keeping in mind how they like to ride it and what performance degradation it will have on riding it as just a bicycle (extra weight, changes in steering/handling due to weight placement, etc--all of which can be tested beforehand by placing just weights or bricks or whatever in the same places the ebike stuff will be, riding it, and seeing which placements make it a better bike).


You are so right that's what i am doing now that i learned me lesson :P

Depends on what you mean by "better". If you want to go faster, you'd need higher voltage. If you want better acceleration, especialy from a stop, a higher-current controller might help, but only if the battery is capable of putting out that current without major voltage sag.
What you want first is a wattmeter, like the http://ebikes.ca Cycle Analyst or Watts Up or a number of other wattmeters, so you can monitor the voltage and current out of the battery into the controller while riding the bike in various situations. THen knowing what is actually happening with the existing equipment, you can decide which parts need replacing to improve it to the point it does what you want it to.


Yea i am talking about acceleration and torque.I don't really have a clue about lipo4 limitations maximum load and voltage sag's :) but my goal is to improve the bike in a point that i will not damage the battery or over discharge her.I never discharge the battery more than two thirds because i wanna keep her in a good shape.I will chk the meeter you suggesting because now i am kinda blind meeter wise so i can play with other controllers and know when the battery will shut down.

If you mean in place of a battery, then with typical caps you would need a huge bank of them, perhaps the size of a car, to run your bike as well as the battery you have now. ;) With really good and expensive caps you might be able to use something a lot smaller, but it would still be bigger than you and the bike, because you must store enough energy so the voltage remains high enough to be useful.

Basically you have to have probably ten times or more the capacity in capacitors than you would in a battery, because the battery's useful storage is all at higher voltages, but capacitors store it across the entire voltage range from zero to max voltage. Controllers and such can only use that narrow higher voltage range, so you're stuck with wasting almost all of the energy storage space in the capacitors just to have enough energy to run your system.

It's possible to create a controller that would use a much wider voltage range, and use more of the energy, but none of the typical ebike controllers are capable of it.


Yea i forgot that basics about caps not good in high capacity.
A discharged lipo4 will have around 30-34 volts if i am right and if there was a controller that could manage a wider voltage range discharging the battery further will not damage it ? to 25 volts for example ?

sorry for bad English again :D
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Re: E-Bike Improvements , questions

Postby dogman » Tue Apr 24, 2012 6:56 pm

Likely your battery has a bms, that will shut it off before you lower voltage too much.

But you could still damage it by pulling more amps from it than it's designed for, by going from 7 amps controller to one of 20 amps or more.
THE LIPO RULES. NEVER ABOVE 4.3V NEVER BELOW 2.7V DON'T PUNCTURE

Ideal charging /discharging range for Lipo, 3.65v minimum 4.1v maximum

See battery technology section, FAQ thread at the top of the page for lipo noob info.
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Re: E-Bike Improvements , questions

Postby Alastor » Wed Apr 25, 2012 3:25 am

Ok i got you :) i will leave the bicycle in peace .I am puzzled concerning the max amp's that i can pull from my battery...is there a chart or some sort that can help me understand its limitations easier ?

>>> http://www.saracen.co.uk/bikes/trail/mantra This is my Hardtail bicycle.Going in the mountain with it and making some downhill.Can you suggest a kit for this bicycle ? top investment with battery 800 euros.Magic pie and battery or something else ?I only care about torque and acceleration top speed.Magic pie also can be programmed via usb if i am not mistaken.Can i use magic pie 2 with my battery with the internal pies controller and the pie set up in 250 or 350 watt without damaging the battery ?

I hope you don't hate me for asking all this crap :D
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Re: E-Bike Improvements , questions

Postby Alastor » Wed Apr 25, 2012 3:43 am

oooo yea i almost forgot ...dose anyone knows someone that makes custom frames enclosures to house the batteries in a MTB ?Something like a frame triangle frame bag but more durable and beautiful .

Thanks
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Re: E-Bike Improvements , questions

Postby dogman » Wed Apr 25, 2012 6:40 am

I can only guess about your battery, Likely it's good for 500w. But that is not performance, not by our standards here anyway.

If you only care about performance, then you have to stop caring about money. I don't know about the conversion rate to euros, but about $1500 USD can get you pretty nicely into the 40 mph club. The rides have to be relatively short, but most don't want to carry, or pay for, that much battery anyway.

The basic recipe is this.

One generic hubmotor. 9 continent, golden motor, muxus, conhis. Just a 500-1000w rear hubmotor. 9c and muxus are the ones that are pretty easy to source in the USA.

One 72v 40 amp controller. Many sources.

72v 10 ah of RC lipo batteries such as sold at Hobby King. Plus charging and voltage monitoring stuff for it. 72v of any battery will do, provided you can pull 40 amps from it. So A123's work too.

One remote sensing thermometer. The sensor goes into the motor, so you know when to stop in time.

Lastly, you have to make a good set of strong torque plates. 4 horsepower will rip a motor right out of the dropouts if you don't controll the torque right.

This recipe is for hauling ass on flat, or moderately hilly terrain. For trail riding, it's completely different, unless your trails are very straight and smooth, allowing you to ride them fast.
THE LIPO RULES. NEVER ABOVE 4.3V NEVER BELOW 2.7V DON'T PUNCTURE

Ideal charging /discharging range for Lipo, 3.65v minimum 4.1v maximum

See battery technology section, FAQ thread at the top of the page for lipo noob info.
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Re: E-Bike Improvements , questions

Postby Alastor » Wed Apr 25, 2012 1:11 pm

Here in our market things are back to the stone age really :D imagine that they sell the oxydrive front wheel kit for 900 euros with the 250 watt motor and 9ah 36 volt small battery :P

Well i took some time considering all the options and i think the best way to go with my next project is probably a magic pie 2 with an external controller .
The issue is always money as always...

1st round of the project :
I found a store here the only one with professional equipment that sells the magic pie 2 and they saying that my battery 36 volt one will take me up to 36km/h up 38 km range with no effort.
Setting the pie in 350 watt using a 36 v 10ah battery i think that the battery will be fine what do you think ? 400 euros all included setup , configure the motor , regenerating braking , seat-spot rack for the battery and all.

2nd round of the project :
Secondly i am thinking the possibility of making a custom cable with connectors that will feat in my 2 lipo4 36v 10ah packs and join them together in forming one 72v 10ah pack cheap and easy.I just don't know if its safe to do so .
I can provide you with pictures of the battery packs if you think it will help.I just don't wanna spend more money for new battery at the moment if my idea is possible ofc.Taking a nice controller as well .

3ed round of the project :

Build a custom frame for the batteries and make the bicycle centered correctly and all .

To the trails now .Well the trails i do are rated 5 to 10 in downhill difficulty they are quite short and rocky.
I just need to be able to climb the mountain from normal road a lot of times because going up the mountain for 5km for enjoying a nice downhill ride for top 2 mins it shucks really bad :)

i really appreciate all of your replies and thank you again in advance :D
p.s.
did i say sozz for bad English ?
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Re: E-Bike Improvements , questions

Postby Drunkskunk » Wed Apr 25, 2012 2:38 pm

Your post about capacitors got me thinking. A 1 Farad capacitor is what some car audio nuts use to smooth out the power flow to their amps. They are roughly the size of a 16oz Guinness Drought beer can, and weigh 2.5 to 5 pounds each.

Not that anyone needs to know, but 1 Farad = 1 amp second divided by the voltage. (1 F = 1 As/V) 3600 seconds in an hour, 36 volts in that battery, so you need 100 Beer cans to get 1 amp hour. Or 1000 beers for a 36 volt, 10 Amp hour battery like yours. That's a lot of beer.

Or by weight, thats a medium sized car, by American standards. 2500 to 5000 pounds of beer... I mean capacitors.. to replace a 5 pound battery. Amberwolf wasn't exaggerating.


As for your plans, Skip step 1. The motor you have can do more than you're asking of it, but your battery may not be able to. Getting a Magic Pie, but then castrating it to 350 watts is going to give you something slower, weaker, and heavier than what you have. The limitation is the battery.

Now if you want to get a good battery, then the magic Pie is a good motor to go with. I like the idea of the external controller version, is should be good for 3000watts maybe.


But for step one, I think you should consider your current bike disposable, since you planned to replace it anyway, and experiment with it. Get a 15 amp controller, or do a shunt mod to the one you have, and see if it works better for you. Its cheap to free, with parts you planned to replace anyway. If it does fine at 15 amps, push it to 20 maybe. You might find you're more than happy with it. Or you might make it smoke. either could be fun. And if the battery can't hold up to that, it was going to be useless for anything else anyway. In the end, you'll have learned a bunch of stuff you'll need to make step 2 and 3 work.
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Re: E-Bike Improvements , questions

Postby dogman » Wed Apr 25, 2012 2:45 pm

The skunk is right, battery is your weak link. Invest in a good quality 48v battery now. Then you can run lots of better stuff with it later.

http://www.emissions-free.com/catalog/i29.html

Costly yes, but lame batteries will hold you back forever, even if you do string two together. They still won't put out any amps.
THE LIPO RULES. NEVER ABOVE 4.3V NEVER BELOW 2.7V DON'T PUNCTURE

Ideal charging /discharging range for Lipo, 3.65v minimum 4.1v maximum

See battery technology section, FAQ thread at the top of the page for lipo noob info.
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Re: E-Bike Improvements , questions

Postby Alastor » Thu Apr 26, 2012 3:08 am

Thanks once more for your replies.

LoL skunk you made me laughed out loud just making a picture in my mind of a bicycle Overbeard by capacitors :P

The thing i understood is that the lipo4 packs even if connected together to form an 72v 10ah lipo4 pack will not give me the juice i need.I found out that each battery can be discharged without any serious problems at a rate of 15 A each so two of them together will give 30A.But i guess working this two packs on there limits all the time will kill em quick.

I will try to sell the second one i made and then focus in part 2 and 3 of my experiment :P And i will probably go with the serious battery pack you suggested that by accident took my attention before opening this post.

I am confused with the pie in some points.If i want to work it with an external controller do i have to let the ppl i will buy if from in order to get one without the internal controller ? or do i have to remove it and all .Also the pie is working better with external controller and cooler if my research was correct :P .If anyone give me a feedback about this as well :) i will appreciate it .

I will try to find someone here that makes battery packs because the shipping will cost me half the battery if i order it from the US .....damn European battery market !
The battery packs that i need to use are the A123 26650 cells .If i find some of this cells here i will try to build up my own.Or try at least :D What do you think its better to try this out or pay 600+300=900 euros for the triangle battery pack ?
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Re: E-Bike Improvements , questions

Postby Alastor » Thu Apr 26, 2012 3:45 am

Also i found this 38120 LIFEPO4 BATTERY'S are they any good ? thanks :D
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Re: E-Bike Improvements , questions

Postby amberwolf » Thu Apr 26, 2012 4:08 am

Alastor wrote:Also i found this 38120 LIFEPO4 BATTERY'S are they any good ? thanks :D


Without detailed specs or a link to what you are asking about, it's tough to say. ;)
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Re: E-Bike Improvements , questions

Postby dogman » Thu Apr 26, 2012 6:37 am

RE the two 10 ah batteries. 15 amps discharge rate means you are limited to, at most, a 15 amp controller. This is what I assumed. So you can upgrade your controller some, and get a big improvement on hill climbing, but no improvement in speed.

You can run a 15 amp controller at 72v, by connecting the two packs in series for 72v 15 amps.

Or you can connect the two batteries paralell, and get 36v 30 amps capacity. This would allow upgrading to a 36v 20 amp controller. That would be a practical solution for now. No faster, but a lot more zip leaving a stop sign, and tons of range with double the battery.

When you can, get a good 48v battery from cellman at Emissions Free. He's in china, a very trusted seller, and has genuine A123 batteries at the cheapest prices in the world. LOTS of counterfiet, or real but defective A123's sold on ebay so beware those.

The last possibility is not recomended to beginners, but RC lipo from Hobby King in China is how experts get batteries that put out huge discharge rates. You have to treat them right, or they can catch fire if abused. NO bms, so it's up to you. Plus they don't last as long as Lifepo4.

Performance costs $$. But moderate performance is not so expensive, such as 20 amps from a 48v 15 ah pingbattery lifepo4. 48v 20 amps is 1000-1200w, pretty zippy for Europe.
THE LIPO RULES. NEVER ABOVE 4.3V NEVER BELOW 2.7V DON'T PUNCTURE

Ideal charging /discharging range for Lipo, 3.65v minimum 4.1v maximum

See battery technology section, FAQ thread at the top of the page for lipo noob info.
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Re: E-Bike Improvements , questions

Postby Alastor » Wed May 02, 2012 6:05 am

Thanks again for all the details mates you really helped me to push my project to the right direction .
I will come back soon with pictures and all .
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Re: E-Bike Improvements , questions

Postby Alastor » Fri May 04, 2012 4:21 am

Hello again ,

I have been reading all this days trying to see an alternative way for the battery and i found something interesting.If i am right i can use ZIPPY Flightmax 5000mAh 6S1P 30C battery packs that are cheap in European market 69 euros each so i can make a 44v pack for like 140 euros.And even a 66Volt pack at 210.Also i read that the this type of lipos can be discharged in higher rates than the typical 36volt 10ah battery kits that have 15Amps continued.

So i was thinking going with the magic pie 3 kit and 3 x 30C 6S1P total 66 Volts 5 Ah.

But as always i have some questions about this kind of packs.

A )They will last 800-2000 charges with a nice balanced charger as the typical lipos ?
B )I wanted to ask something concerning this packs.Are there separate BMS systems to prevent over discharging the battery that i can use in this setup ? or i will have to monitor the system and avoid heavy duty use ?
C )How far will the battery pack last ?
D )How fast will i go with the magic pie 3 with the internal controller ?

I hope i didn't lose my way :P
Thanks again
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