First Build: 1.4 KWh Full Suspension Wheelie machine

Take a look at my Specialized Bighit build! It's taken a while to get this stuff on here, but ill have more complete stuff to post soon.

Shout out to sllikskills, charleyhaze, grindz145, and all you guys on the facebook page who have answered some of my more difficult questions!

1. So my spec's so far are as follows:
2. (4X) 16Ah 6S 22.2V Multistar packs (2 series, 2 parallel)
3. Crystalyte HT3525 motor
4. Lyen 12 FET 4110 MOSFET Extreme Modder Controller
5. Crystalyte Advance Battery Management Display
6. Three speed switch
7. Full Twist Throttle
8. and a few torque arms I'm experimenting with

Also check out this custom ebike stand I made! It lets me get on and pedal whenever, and test if everything is working right.

Here are the battery boxes before paint and the 3D printed velcro strap holders:
I also covered them in gorilla tape so that they were more water proof and seal better on the fiberglass to ABS sealing surface

Nice frame and good work on the battery boxes.

Couple of queries though, what batteries specifically are you purchasing? 4x multistars doesn't seem like nearly enough. You appear to be a bit off on the power calculation, there's absolutely no chance of getting 14kw out of a 12 fet controller and a handful of Multistars... I presume you mean HT3525? This motor/controller combo is good for ~4kw not 14. Hopefully you made a typo rather than being out of the ballpark in terms of expectations!

Oh wow. Ohbse, thanks for fact checking me. It shows I need a little more practice with circuits/power calculations. I think 1.4KWh is more reasonable? I plan on having (2X) in series and (2X) in parallel.

These are the packs in question: http://www.hobbyking.com/hobbyking/store/__66310__Multistar_High_Capacity_6S_16000mAh_Multi_Rotor_Lipo_Pack_EU_Warehouse_.html

OrganicFat said:

Oh wow. Ohbse, thanks for fact checking me. It shows I need a little more practice with circuits/power calculations. I think 1.4KWh is more reasonable? I plan on having (2X) in series and (2X) in parallel.

These are the packs in question: http://www.hobbyking.com/hobbyking/store/__66310__Multistar_High_Capacity_6S_16000mAh_Multi_Rotor_Lipo_Pack_EU_Warehouse_.html

Click to expand...

Ah yes, that makes more sense - without the all critical "h" on the end it appeared you were talking about power output. 14kw of power will turn a 35mm stator Crystalyte motor to plasma quite quickly.

How fast would you like to go? The HT3525 is a relatively slow wind, meaning that top speed will be somewhat tepid on 12s. Go Here and punch in the details of your bike. The motor is listed as Clyte H3525, input a custom battery with 49v and 0.06 ohm resistance, you can vary the other settings as you see fit and you'll get a feel for top speed etc. Assuming you're running a 26" rear rim you're looking at about 37km/h top speed.

Personally I would run 18s, effectively 3x of those packs in series and ideally two in parallel. This improves your top speed to a more reasonable 51km/h. Alternative configuration if you're on a budget for your batteries is purchasing the 6s 10ah packs and connecting these 3x in series, 2 in parallel. This should cost roughly the same as four of the larger capacity packs and give you roughly the same energy potential in total but with the benefit of the higher top speed.

If speed isn't your thing then feel free to proceed as planned, but I can assure you that bike is capable of much more

Soooo Ebikes.ca rocks! Yeah, I've got 26'ers on there with Hookworms for some corner hugging.

Unfortunately I've already purchased the 4x 16Ah packs. I wasn't quite sure if it was ok to have an unbalanced series/parallel circuit.
So the 3X series and 2X parallel circuit won't pull more power from one or the other pack configuration due to different resistances?

Sorry if I'm asking a dumb question, but what is the difference between having 3X series and 2X parallel (4 cells total), and 3X series consisting of 2X parallel packs each (6 cells total)? Wouldn't they have the same capacity, but more watts?

Think of what you have in parallel as just single larger cells, so as long as the series string consists of the same size single cells then you're good. eg the pack I'm building is 30 cells in series for 111V nominal. The parallel structure is 30s strings using packs made up of 5ah cells x 2 plus 4.5ah cells plus 5.8ah cells for 20.3ah total. I will connect the parallel balance taps, so electrically (and for balancing) my 30s pack will be made up of 20.3ah cells.

Your 6s14ah packs in a 2s2p configuration will electrically be 12s28ah with all the same size and rated cells, which is perfect. I'm not sure what you mean by 3x2. If you add another 2 paralleled packs in series for a higher voltage, then the pack will be 18s28ah...same amp-hours of capacity at 50% higher voltage for 50% more total energy in your pack.

BTW, can you give us a closeup of how the stand connects to the bike? Axles are pretty strong with the dropouts close to the motor, but it's not a good idea if your weight is supported by a long lever attached to the axle. Members have put tire marks on their ceilings, the type of accident you don't want to duplicate, but do always have video running just in case.

So I think I get what you are saying Jonn in CR, but I'm still a little baffled by ohbse's last comment about series and parallel with 4 cells. As opposed poorly explaining myself with words I drew up some wiring diagrams for pack configs.

What are your thoughts about a backpack pack? I'm seriously thinking about putting 2 cells on my back to make 2 cells in parallel and three of those parallel in series. Also I realize that this exists: https://endless-sphere.com/forums/viewtopic.php?f=3&t=78623&p=1160433&hilit=backpack#p1160433

I'm thinking of a hybrid frame/backpack build...

So John in CR I've attached photos of my ebike stand! This thing is bullet proof. I took those pipes that the axle rest and shoved white ABS rod down them after I heated them up with a torch (otherwise known as a heated press fit). Then I cut a profile out of the pipe that would give me clearance for the axles. I designed the bike stand to work with almost any ebike.

The steel axle supports are being held in place by U brackets that I double nut from the other side with washers (sorry no pictures of that).

Its kinda a pain in the BUTTTTT_T to get the bike in and out, but its rock steady. I can pedal on that thing all day long and it doesn't move.

Sooooo I couldnt attach the wiring diagram due to file size constraints, so check it out:

So I chose to only put 3 of the 16Ah in series because I'm not confidant in the structural rigidity if
my seat mount rear rack.
Also with about 75V coursing through that 12FET Lyen controller is MORE than enough for this build.

I did however buy 3 more Multistars so I can have a swap-able pack or make something in the future with twice the range or speed

Here's a nice look at the (almost) finished ride. She tops out at about 50mph and has a range of about 30 miles. If I can make it home to swap pack or wear a backpack with my other cells to double range.

Ok, I lied about the finished thing... I'm always adding little things on it.

Video to come with a few rides in it.

Hi
Do like the look of that stand. But supported by axle, does look ok but would not trusted it with body weight. You want to make one like the motorbikes use. Supported by rear swinging arm. Make a U bracket to hold rear forks. Then weld on the arms and so forth.......

Just an idea. If you move the rear battery right up to the seat and bolt the controller underneath, it'll handle a lot better and there will be less stress on the rack clamp. If your rack clamp is aluminium, it will break sooner or later. See if you can find a rack with a steel clamp.

Headmaster said:

Hi
Do like the look of that stand. But supported by axle, does look ok but would not trusted it with body weight. You want to make one like the motorbikes use. Supported by rear swinging arm. Make a U bracket to hold rear forks. Then weld on the arms and so forth.......

Click to expand...

I've welded up a (steel) Motorcycle stand before when I worked with RIT's Electric Vehicle Team, so I understand the concept.
I still don't own a welder so its a bit harder for me to get those pegs on there. I'm still unsure of the type of Aluminum that was used on the swing arm. If it was cast Aluminum there's a good chance I'd screw it up.

Another reason for the Aluminum extrusion construction is because I got it for dirt cheap at work 8)

It does hold up really well if you tighten down both sides. The base is wide and heavy so getting on and off isn't scary, but I want to move the tubes forward because my heel may clip the stand from time to time.

d8veh said:

Just an idea. If you move the rear battery right up to the seat and bolt the controller underneath, it'll handle a lot better and there will be less stress on the rack clamp. If your rack clamp is aluminium, it will break sooner or later. See if you can find a rack with a steel clamp.

Click to expand...

That seat post clamp has been one of my worries from the start. It pivots sometimes, (especially in a crash ) and has peeled off all the paint from the seat tube.
I'll have to move that weight closer to that fulcrum to reduce that angular force. Looks like I'll have another reason to 3D print a mount for my controller now!

Can you fill out your profile.
I'm curious where you can ride that bike and not have the Cops all over you?

@motomech
I think the local cops have bigger fish to fry than just some guy on a bike lookin' thing
We have a pretty robust pedal bike community that the police largely ignore.
I even pal around the local parks without much problem....

nice

I used to have a "key" or jumper for my on/off switch to the controller... But after I had to hotwire the bike after it dropped it off my keychain I decided to 3D print a switch body: