Spec'ing Out My Utility/Commuter Bike

[vwhammer]

I am just getting into the details of my 2WD "utility" bike and would like to clear up a few details before I order the rest of the parts.

First let me start with the bike I am starting with.


Here it is loaded for a longer trip.


It is a 2010 Hary Mary XC 29er
Is all steel and obviously has zero suspension.
The bike as seen in the first pic weighs 28.85lbs (13.8kg) so it's no lightweight.
Loaded with all my gear and some extras that I probably did not need the bike weighed a bit over 80lbs (36.3kg)

This is a commuter and is used for groceries so I want to build it to take some abuse (relatively short term) while loaded down.
The city of Athens is in the heart of the Hockin Hills so, naturally there is some pretty hilly terrain.
We have the second steepest paved roadway in Ohio at 24% and there are several others real close to that number.
None are terribly long but there are several longer less steep grades (5-15%) that go on for 1 to 3 miles that I would likely have to traverse with some gear on board.
I intend to pedal most of the time but would like some assist to flatten out some of the steeper stuff.


For the record I am 6ft 1in and tip the scales at 240lbs (108kg)
I don't know that I need to go much faster than 20mph (32kph) but anything more would be a bonus
I would like to run a 48v 15ah battery in one of the more stable chemistry and am shooting for about a 30 mile range.

So with that said here is what I am thinking.
I currently have a 36v, 201rpm Q128H rated at 800w for the rear and a 36v, 201rpm Q100H rated at 350w for the front.
I have a pair of BMS Battery S12S controllers.
https://bmsbattery.com/ebike-kit/552-s12s-500w-torque-simulation-sine-wave-controller-ebike-kit.html

Where I need help technically is in how to control all of this.
Do I set up a PAS and/or throttle for both?
Do I use two LCDs to control the assist level to both?
I could do PAS for the rear and a throttle for the front but can I set it up so the throttle overrides the PAS on the rear.
I am likely going to run one or two of these LCDs if that helps anyone https://bmsbattery.com/ebike-kit/670-s-lcd3-lcd-meter-for-s-series-controlers-ebike-kit.html
What are my options?

I suppose, Ideally, I am trying to split about 1000 watts between the two motors so they both run cool while tackling some of the bigger and/or longer hills while loaded with 30lbs (14kg) of stuff. (~300lbs/136kg total vehicle weight)
Just to be safe I am thinking of oil cooling both motors.

Also I do not believe that either of these motors have a speed sensor so I would need to get one.
Can most speed sensors for sale on BMS's site be wired to work with the LCD and controller I have spec'd out.
There is not a lot of info on them in regards to compatibility.

Well I think that's all I have for now.
Obviously I am more than happy to answer any questions anyone may have that can help me sort this out.

Looking forward to ironing all of this out to get this thing on the road.

 

[handbaked]

Unfortunately i have nothing to add knowledge-wise but will be following the thread as it's certainly of interest to me! Good luck with your build!

 

[wesnewell]

[off-topic post removed by moderator]

 

[d8veh]

I would get a different controller for the front motor. Ideally, you want one that doesn't need a LCD/LED control panel. The old KU63 would have been ideal, but the new ones are reported to be not as good. I think Motomech recommends the 17A controller from Elifebike.

Connecting them up would then be simple. You connect the rear motor to the S12S with the LCD, PAS and throttle, like normal. You then splice a wire onto the throttle signal wire, which you run to the second controller's throttle signal input. You must not double up the throttles 5v wire to the second controller. It won't do any harm to double up the throttle ground, but it should be unnecessary. The throttle will then work both motors and the PAS just the rear. The LCD will control the level of assist from the PAS for normal riding, and it'll give you speed and distance information.

If you want brake switches on both controllers, I'd run the back brake switch to the back motor's controller and the front to the front's. You can double up both if you want, but it's just extra wiring. You don't really need them on the front anyway.


The battery is going to be a problem. Ideally, you want it in the triangle. Have a look at what Em3ev offer to go in a triangle bag. It might be worth considering welding up your own pack out of18650 cells to get a custom fit like I did on this one. Note the S12S on the outside. It's fairly easy to make a custom GRP case like that:

 

[vwhammer]

Once again d8veh your info has been most useful.
You mentioned a similar set up in my previous thread in the general e bike discussion section but I needed some more clarification on the set up.
It makes much more sense now.

According to BMSs wire diagram it says the s12s can be run without an LCD if a couple of the wires are joined from the controller.
I suppose as long as this is done then the throttle will simply be my assist regulator, correct?

This sounds like a pretty good set up.

Yeah I am still on the fence on the battery set up.
Initially I was going to just go with a 48v 15ah headway kit and arrange the cells along my down tube then cover them with a custom enclosure.

However I have been reading up on building an 18650 pack with Samsung's 25R cells to make a nice pack that fits in the triangle but then I need to get a welder for the task.
Anyone have any good recommendations on an entry level welder?

 

[d8veh]

If you want to run without the LCD, you've chosen the wrong controller. The advantage of the S12S is its PAS control that makes your bike a joy to ride. Also, there's lots of settings in the LCD that you need, and error codes when things go wrong. Many people don't think about PAS because they haven't used a system like the S12S offers. Once you've tried it, you wouldn't want to use anything else.

 

[vwhammer]

Can anyone suggest a sine wave controller that I can run without an LCD on a Q100H?

 

[wesnewell]

l still don't get why this is such a craze.
http://www.aliexpress.com/item/2015-Free-Shipping-48V-1500W-Brushless-DC-Sine-Wave-Ebike-Controller-Regenerative-Function/32385453795.html
https://www.electricbike.com/sine-wave/
https://www.google.com/search?client=ubuntu&channel=fs&q=sine+wave+brushless+controller&ie=utf-8&oe=utf-8

 

[motomech]

Can anyone suggest a sine wave controller that I can run without an LCD on a Q100H?

If you wouldn't believe what Dave is telling you, maybe you will believe both of us.
I have been riding 2WD for years and YOU DO NOT NEED A SINE WAVE CONTROLLER ON THE FRT. MOTOR!
In fact, much of the time you will not even turn on the frt system. The Q100H will only add much climbing and on top speed(plus 2 mph) and that means your only inter-action with it will be grabbing the throttle. All the features of a sine wave controller will not be a factor at all!
And the S12S is too much for the Q100H and is even more so for a frt. motor. Under power, the Q128 will lift the frt. wheel and with even just 17 A, the frt. wheel get light sometimes.
More or less, the only thing you need in a frt. controller is a way to turn it off and on while seated on the bike.
Focus on the battery, for that will be the challenge.
EDIT: You can not run the S12S without one of the three displays. When the connector is "pinned", it defaults to speed level 3!
I suspose you could use the SLCD-1 and hide it, but you will lose many of the S12S features.

 

[vwhammer]

After a little more reading I totally believe what you are saying.
I am just trying to come up with the right controller for the situation.
I have bailed on the S12S for the front and have already ordered a single S-LCD3 and PAS for the rear.

So along the lines of a simple controller am I looking for 6, 9, 12 FET stuff?
I guess I just need someone to point me to a controller that they have had some experience with and does not cost $100.

Other than that I think lunacycle has some battery choices that will work given my space constraints and I will not have to go through all the trouble of buying the equipment to build a battery myself.

Also no one really confirmed whether I need to purchase a speed sensor or not since neither of the motors has a speed sensor.
Do I need this for proper LCD data or does it calculate it by some other means?

 

[vwhammer]

would this work for the front motor controller?
http://www.elifebike.com/peng/iview.asp?KeyID=dtpic-2012-8W-QNK2.073KQ

 

[d8veh]

You will need the external speed sensor. The last Q128H I bought didn't have a speed sensor in it.