First Build/Conversion, Double Check Me?

[akrenits]

Hi ES,
Been lurking for a while and it's time for me to start my first build. I am planning on ordering parts this weekend, so any thoughts that save me time, money, and failure are greatly appreciated. I am new to all of this, so pointing out flaws and explaining alternatives would be great. I know most of you would caution me about going full suspension for my first build, however this is the only bike I own and I need it for next school year. I have questions for each part listed and also a few at the end. Thanks so much everyone! Looking forward to contributing to ES in the future.

Before we begin, I'm pretty well stuck on having a middrive, unless you really believe a hub will get me up long, near unclimbable steep slopes without overheating. Even so, please tell me where I have compatibility issues with my parts below:

About Me
- My Weight: 160lbs
- My Bike: 26" Full Suspension, GT XCR2000, Approx 25lbs
- First Year Mechanical Engineering Student
- Live in California, but not worried about legalities ("Off Road Use Only" is what we call it around here right?)
- Pretty good machining ability/access

Goals: Going to be using it as a commuter, as well as a steep incline off-roader
- Top Speed at least 35mph
- Mountain Climbing at least 5mph
- Range at least 15 miles on relatively flat ground, without pedaling
- Optional: Cruise Control
- Classicly, Cheap as possible!
- Not too worried about weight/bulk, I plan on building custom mounts for everything.

To my understanding, the most efficient way to achieve what is essentially a lightweight dirtbike is to go Mid-Drive and run it through a freewheel front crank to take advantage of the bike's own gearing. That would also not interfere with my suspension. Don't really like the Hub Motor shenanigans: seems a bit hard to service, less torque, my dropouts won't fit the power I'm looking for.
Before I list my current ideas for parts, please let me know if there are similar, cheaper, or otherwise preferable parts I should be aware of!

Proposed Parts

- Motor, Controller, Throttle, Cruise Control: http://www.cyclone-tw.com/order-motors.htm

- Motor: Non-Geared 840W-2000W without controller - $139
- The 840W refers to the continuous rating? 2000 for temporary maximum?
- What are the dimensions? Can't find them anywhere.
- Do I want a geared motor or nah?
- Non-geared means more reliable long term?
- Do the non-geared come with a freewheel? Can't tell. If not, will that make pedalling unassisted difficult?

- Controller: 36-72V 40A - $38
- Compatibility for any monitoring system in a future upgrade?

- Throttle: Half Hand, Keyed, with voltage display - $29
- Thoughts on the half-hand style? Comfortable? Will it interfere when mountain riding/climbing?
- The key will help avoid some turd wasting my battery when locked up, correct?
- The voltage readout will basically be my battery monitor correct?
- I think I would prefer the thumb throttle if there is potential for a cheap, easy auxiliary monitoring system, any suggestions that are compatible?

- Cruise Control
- Since I'll be changing gears often with the mid-drive setup, would it be helpful at all?

- Battery: https://bmsbattery.com/ebike-battery/663-high-c-rate-polymer-lifepo4-battery-heat-shrink-battery-pack-battery.html#/335-voltage_capacity-48v_10ah
- OR, 2 of these in series, giving me 72v: https://bmsbattery.com/ebike-battery/663-high-c-rate-polymer-lifepo4-battery-heat-shrink-battery-pack-battery.html#/7-voltage_capacity-36v_10ah

- Monitor System: CA is a bit out of budget, looking for the cheapest compatible option, if one exists? Desiring the essentials (Voltage, Amps, maybe AH used)
- Quick explanation of how to install your suggestion?

- Front Freewheel: http://www.sickbikeparts.com/catalog/product_info.php?cPath=21&products_id=178
- Is this strong enough to take 1.5kw during climbs or do I need this stronger one: http://www.sickbikeparts.com/catalog/product_info.php?cPath=21&products_id=62
- How big a freewheel should I use for the drive sprocket, or should I sacrifice one of the 3 existing front sprockets?
- Are there any complicated aspects of installing/modifying the front crank for this purpose?
- I'll need to get threaded cranks, correct?

- Chain: Regular old bike chain? or should I go with something beefy for the drive chain like #40? Obviously the regular bike chain must remain for the rear derailleur's sake.

Other Questions
- A regen system is impossible with my type of mid-drive set up? I know its not efficient, simply curious to save my rim brakes on long downhills.
- Are there any incompatibilities between my parts?
- What kind of connectors will I need? Especially to go from battery to controller? Most everything else will come with long enough, compatible cords right?

Thanks for reading and for your help everyone, trying to order parts this weekend, greatly appreciating all replies.

 

[greg_p]

I would go simpler with rear hub motor.
And you are going a bit too cheap with the battery and charger... You'd better take RC lipo than these lifepo4 that looks crap. You should't charge a lifepo4 cell over 3.65, 3.9 is too high.
48V is a 16S lifepo4 type, should charge at 3.65/cell, so 58.4 instead of 60 but it should support. But the plug looks like cheap, you will have to rework it. I would say it's more a symptom of very cheap material, so very cheap cells (probably second hand, no idea about the real capacity). And Do you know wehre to fix it on the bike? looking at the bike, on a rear rack (but 7.5kg is heavy and disturbing there - believe me I lived with that).
That's sure bmsbattery will deliver better quality here: https://bmsbattery.com/ebike-battery/430-48v-15ah-40152s-lifepo4-battery-16-cells-ebike-battery-pack-battery.html
but it has a price.
You can go Li-ion too: https://bmsbattery.com/ebike-battery/786-48v116ah-case-08-bottle-panasonic-battery-pack-battery.html
And the bottle format may better fit to the bike - up to you to check. I have no profit here, i was just pleased with the quality.

I think you can go cheap on things that are not expensive, because you can replace it. But the battery, choose them well, figure out where you place it (especially on a full susp bike) and put the price.

By the way you will be able to do daily move with 10Ah I think.

I didn't see the motor you are interested in, into the cyclone website.

And I didn't see disks on your bike, but I just looked at google image...

 

[akrenits]

You can go Li-ion too: https://bmsbattery.com/ebike-battery/786-48v116ah-case-08-bottle-panasonic-battery-pack-battery.html
And the bottle format may better fit to the bike - up to you to check. I have no profit here, i was just pleased with the quality.

I didn't see the motor you are interested in, into the cyclone website.

And I didn't see disks on your bike, but I just looked at google image...

EDIT: Thanks for the link, some good stuff on there

- Motor is in one of the drop down menus toward the bottom of the motors
- Bike has rim brakes, not disc. Not sure if/how thats relevant though

 

[dogman dan]

Put that 40 amps controller on that 15 ah lifepo4, and you can kiss your battery good bye. it'll quickly kill it.

If you think you can just go easy on the throttle, you will be the first person on earth that actually did it.

Once you kiss 40 amps goodbye, kiss 35 mph bye bye too.

You could do a 30 amps controller, if you are careful.

On your budget, look for the cheapest 48v 1000w hub kit you can find. You'll have 30 mph or very close to it, and your battery could last. Even better a 22 amps controller, which btw, still puts out 1200w peak.

Monitor with the cheap blue watt meter on e bay. It goes on the wire between the controller and the battery. Don't worry about being able to see it while you ride. Good enough to ride, stop, and see what you used then.

 

[akrenits]

Put that 40 amps controller on that 15 ah lifepo4, and you can kiss your battery good bye. it'll quickly kill it.

If you think you can just go easy on the throttle, you will be the first person on earth that actually did it.

Once you kiss 40 amps goodbye, kiss 35 mph bye bye too.

You could do a 30 amps controller, if you are careful.

Totally would not have the restraint, good call 8)
How about this battery: https://bmsbattery.com/ebike-battery/623-high-c-rate-48v10ah-lifepo4-alloy-07-case-battery-pack-battery.html
- Rated for 30Amps, Temporary good to 60.
If I get a monitor that lets me watch my amps while I ride, I can definitely keep that throttle reasonable right?
Also, what are the big differences between li ion and LiFePO4 besides weight? Is one more forgiving than the other for idiots like me?

One more really stupid question:
Does linking batteries together in parallel double the rated output as well? if so, could I string 2 of these together to get my 40 amps: https://bmsbattery.com/ebike-battery/728-48v8ah-bottle-09-e-bike-battery-charger-battery.html My intuition is telling me probably not.

 

[greg_p]

Yes, lifepo4 can sustain much more than rated continuous discharge. But once again, you don't know what kind of cell is in the box, so you can't really ensure the real rated amps. These a commercial information and you can't rely rely on, nor oppose a correct use in case of failure, and it will double the price.

 

[2old]

Since you're in CA, you might look at Luna Cycle; should be able to get a BBS02 kit for < $1000. If that's too steep, YESCOM rear wheel and Luna battery for about $650; 52V will produce about 30 mph.

 

[greg_p]

Don't look too much at bmsbattery either. I just read some reviews on this board that makes me think it may be more complex than planned. btw I also experienced some trouble with them, ordered a 10ah 50-100 lifepo4 battery and received a 30-60 version. It doesn't really bother me but it may in a close futur... You have to ask them to take a great care. And if they ask you to pay some more $$ for shipping, just tell them you don't have to pay for a wrong shipping quotation. A quotation is a quotation.

 

[Drunkskunk]

If you are a welder and can fabricate your own designed parts, then the non geared motor you picked could work. You would need to design and build your own Mount for that motor to your bike.
I'd suggest not using that motor, or anything where you need to design your own parts for your very first ebike.

35mph takes ~2000 watts of power from a hub motor, a mid drive would need a bit more. Any controller that can only do 52V 40A is going to struggle to pull a bike up to 35, but it's possible.

Yes, if you hook two batteries up in parallel, they can handle twice the output. However, using that as an excuse to buy crap batteries is false economy. crap is crap. Your bike will only be as good as the battery. What you were looking to build is a very high performance bike. Would you build a Corvette, then fuel it with some $0.50 a gallon fuel you found sold in unlabeled jars in some back alley vendor? A good bike needs a good battery.

You want to climb hills, but you also want to commute. That really calls for two very different kinds of bikes, and you may fail miserably trying to combine two types of bike on your first build. Start with the commuter. For your needs, a basic hub motor kit from Lunacycle will meet your needs. A quality 48v10Ah battery from them will get you 15 miles at 20mph no pedaling every time. More in many cases. 35mph top speed is ambitious, but 30mph is pretty reasonable for one of their kits. It should be fairly capable off road, too.
Build a high performance hill climber as your second bike, once you have the experience of the first bike.