New ebike build

[johnsteve]

New noob (Ebikes) noob here, so be gentle.

I am wanting to build a front wheel system, but I have a few questions here. I am look to buy this motor. Its the QS 205 35H V. I want to install it on the front forks, with a rack for the batteries above the wheel.

What kind of controller should I get with this motor? I really have no idea. A three speed system would be ok, I guess. 72V? What is the difference between brand names? What do you look for in a controller? I really have no idea here.

Batteries, How big should 4 or 5 brick be? Will they fit on the rack, mounted in the front? Do I really need 4 bricks, or could something smaller be better? Where would the bricks come from? Any links or recommendations?

Also I have heard that vibration is not good for the system. I guess its not good for any system, but the electronics in particular could be reduced, if possible. Would there be a difference in mounting the batteries, and controller in front or on the rear rack?

 

[Jax Rhapsody]

You don't want all that wieght up front.

 

[johnsteve]

Yes I do, because I want a reclined seat post, and I worry about not fitting back there, I also would like to put some kind of rack for transporting things.

 

[bakaneko]

This seems very cool and potentially fast. I bought my ebike from a kit and added other "things" to it. But, if you have the resources go for 72V, a good controller, and a beefy battery 1kW+. I am running Lithium ion but there are also Lithium Polymer (RC packs) and Lithium Iron Phosphate. From my understanding, Li-ion is light weight, Li-Po has high C, and Li-Fe-Po high discharge cycle and flat discharge curve.

What are you looking to do with this bike? Replace gas bike?

 

[johnsteve]

I want something that will climb hills and mountains without struggling. I need more torque. My bike does not have the torque I require without sacrificing speed. I dont need to do 50, but I want power on demand. A hybrid would pull me up those peaks and the gas motor would fly on the straightaways and downhills. I still cant decide on the E system I want to put on it. It should fit on 100mm dropouts. Also, I am not fond of prepackaged kits, because they usually have some inferior parts included. What do you look for in a controler?

 

[johnsteve]

You don't want all that wieght up front.

I am comfortable with weight in the front because I use to tour on a bike, that was loaded down in the front and the back. I know that it will be squirrely. I also dont plan on making turns at 40mph

 

[bakaneko]

I am using the standard controller. It is not sine wave but works fine for me, but I have a lower power motor (500W, limited to 20mph) so the jerking acceleration is not much of a problem. I think you just need to make sure the controller can handle the amps you need to make it up the hills and mountains.

Sine wave is better if you can afford it; with a gas motor bike + electric motor + rider you will need near 75%-100% power. But, I don't think there is an issue starting with a standard high amp controller and then upgrading later. On my 500W bike, it is not even worth upgrading. But, if you are going to do the 1500W then yeah an upgrade is probably in the books. How are you going to manage the throttle for two engines at the same time? PAS and gas throttle? I know others have done it already but seems like learning to ride all over again to be safe with two powerful motors.

Also, be cautious of the kits without the LCD display. They either have one setting for PAS (max) or three settings (low, med, high). While 3 settings might be okay, you might want finer granulation to dial in the needed electrical assist for hills if you are going the PAS route.

 

[johnsteve]

I just want to use the electric motor for climbing hill. My 2 stroke is not a hill climber, It has a 36 tooth sprocket, so you can imagine. The hills I want to climb are steep and it should also handle small mountains, since I am thinking about relocating to an area where they are prevalent. Once the hills are out of the way, I can use the 2 stroke on the downhills and straightaways. Just simply shut down one motor and start the other. I am not thinking about running both motors at the same time.

Do you have a particular sine wave controller which I can use with that motor listed in the opening post?

 

[bakaneko]

Nope, I am just on the stock controller since my bike is purely for an assisted high efficiency ebike. Will go for 90 miles today. But, I think the motor wires are the same for most controllers so you just need to put on new connectors to match the controller.

I do look at a ton of high power ebike videos and drool as they all talk about a controller than can handle the amps, high voltage, bms to support high amps or bypass the bms and draw directly from the battery pack (not charging), and sinewave to smooth and improve acceleration. I think you can do both use either two throttles or throttle and PAS to make it up the hills efficiently. I am a bit concern if you only use 1500W motor to go up hills with both a rider and idle 2 stroke engine. I think combining both engines on hill will be best.

 

[johnsteve]

I have decided to use a different kit.

This one is https://www.amazon.com/gp/product/B06XPX2B4D/ref=ox_sc_act_title_1?smid=A82RUP8N11HNY&psc=1

Now I have to decide on the battery. I prefer a rack. Now my question is what is the difference between 14.5 AH and 17.5AH? I think that the 17.5 ah gives the motor more power, however the 14.5ah has longer charge, so I wont have to recharge as quickly. Am I right about this?

THis is the one I am thinking about getting.

https://www.amazon.com/dp/B07C15TR3...olid=2836AWA2VLFNU&psc=0&ref_=lv_ov_lig_dp_it

I have also seen ones with a 20ah load. Would those be better? Should I get this from another site for cheaper? Please let me know.