Descendence Astro 3220 mid drive build

i have had great fun and learnt heaps tonking around on my old 4080 hub motor build, but its time to start playing with the big boys

i have all the parts, the design is finished, building started today! she's using an Astro 3220 with a Tangent Drive gearbox; 32ah of lipo @52v; a castle creations 160A fan cooled ESC and a CAv3 with the grin tech thumb throttle.





im using a custom-valved Avalanche Woodie 3.5" stroke rear shock, Fox 40's with again a custom Avalanche re-valve kit, big fat 42mm 26" rims front n back with a 150mmx12 rear wheel custom-made for me by the lovely chaps at municycle.com, 3" spikey rubber, ill be running two-speed to the rear (geared to 55 and 80km/hr) assuming it is reliable enough (single speed if it isnt); iv got fan cooling on the batteries; solid wratchetting driveside cranks by trialtech.

the frame itself is a concentric BB pivot design (im using two monster sealed bearings pivoting around a 100mm titanium bottom bracket shell) with a fairly linear linkage-driven rear shock, topping out at 8" of travel on the 3.5" stroke shock. using what i learnt from my last build, the geometry is more aggressive than the last frame; lower bottom bracket, lower center of gravity (the CoG is roughly between the riders' shin level and dead central to the bike, horizontally), shorter chainstay length, but with the same reach and head angle. iv got a taller stack height thanks to 2" 800mm wide rise bars but a lower standover height.

today i made the big monocoque chainstay yoke for the swingarm, and the dropouts. check out these babies-



although i will be using a rear deraileur (of sorts), i made the dropouts to accommodate single-speed setup without needing chain tugs to keep the rear wheel in place. they took a lot of effort to make, i hope they work as well as i imagine they will

Looks awesome! How are you planning to do the 2 speeds?

I can't wait to see how well this rides. Long live the privateers.

-dave

Yeah, I'm jelly! Win in the unsprung weight department.

Will you gusset the head tube to down and top tubes?

Yay tangent Dave, the man himself! Couldn't have fine it without ya mate!

Two speed has been tested on a pushbike only at this stage, but I did it by modifying a sram deraileur to accept a bmx chain, and altered the index distance of a front deraileur shifter so I can change gears with my left thumb. It shifts pretty good!

Gusset wise, it's got a Gusset on the dt joint, that'll be strong enough.

The last piece of the puzzle that I'm trying to sort out is the dreaded on/off switch! Figure someone here must know how to do it!
I realize I could put I monster 200a Anderson plug in there as a pull out breaker, but it's not a very elegant solution. I'm more trying to work out how to switch off the castle controller instead, but I don't know if that's a satisfactory on/off switch really.
I have designed it so you need to pull out the batteries (I.e disconnect them) to charge them, being lipo. But putting a 200a breaker switch on the main power lines is so huge it'll look crap! I'm at a bit of a loss.

Something like this between the battery box and ESC on the positive lead: http://www.onlinecomponents.com/crydom-hdc100d160.html?p=45159043

Not the cheapest, just did a quick search. 120-160A solid state relays (SSR's) aren't very cheap. You could also use 4 40A relays in parallel, I see those online for about $30. To use this thing you'd run a wire from the hot line from the batery through a single throw switch, into the SSR input terminal (this is the 'turn on' signal) and run the other side of the input out to the battery ground. This won't spark or wear out but we will have to solder a resistor inline with the input signal to lower its voltage (easy).

There are other ways also, maybe just a big ass switch:

One of those switches is what I'm looking at, breaking the hot wire physically is the most reliable option. I was thinking about using an ssr but they burn out every now and then so don't wanna go there.

The only problem with those battery isolator switches is the physical size. They would not look big in a truck cab, but would look huge on an ebike

Those switches are big, but not too big. Here's the one on my latest battery pack.



-Warren

Awesome looking build! Great CAD work I really like the design. Looking forward to seeing the finished product and how it works for you. I've always been interested in the 3220s but have been detered by the nature of such a build and the price/custom machining and parts required. If something like this or recumpence's mid drive kits are ever commercially available for a reasonable price I would definitely consider it for an off road/trail bike!

Very cool. Looking forward to following the progress. Very fancy drop outs. Cutting those teeth must have been tricky.

im tossing up between these two-

http://www.jaycar.com.au/Power-Products-Electrical/Storage-Batteries/Battery-Accessories/High-Quality-500A-Battery-Isolation-Switch/p/SF2245

or monster heavy duty-

http://www.energyconnections.net.au/product/482/1284/48372/battery-isolator-switch-high-quality-6-48vdc-500a-continuous-2000a-10-sec

but these things are just so damn biiiiiig....like 7cm round and 10cm long, but i presume thats just the handle side. i gotta work out how to mount it with the terminals hanging out so they allow access to the nuts/lugs and still mount on the frame...i have no idea at all where i can put it where it wont look ridiculous or catch your nut sack and give you new openings if you crash wrong.

im quite tempted to try to design my own damn switch.

hi this book mark for me , you need a Active pre-charge/inrush control .. like iceman,

https://endless-sphere.com/forums/viewtopic.php?f=3&t=40142&start=150

happy to buy a few broad from you , if get you get a few, iceman had run out,

thank you

yep i suppose could do that, but im kinda against using FET's or any kind of SSR simply for reliability reasons.

how about this for an idea- a continuous duty solenoid? id obviously have to use a small key switch also (i have absolutely no idea where the key switch would wire to in this case, but the solenoid would need it to switch on).

https://www.waytekwire.com/item/77008/Cole-Hersee-24144-Insulated-Continuous-Duty-/

they arnt that big, and would be easy to mount because of the mount plate on it.

the good thing about these is that they're remote switching, so the unit would not need to be mounted somewhere where hand access is convenient like you would a simple on/off switch. im thinking it could fit down between the cranks in the gap between the motor and the bottom bracket. a little key ignition switch could go on the gap between the top tubes.

was just put onto these badboys from a fella at EV works-

https://www.motiondynamics.com.au/125a-emergency-switch.html

that is a monster switch...125A constant at anything up to 120A. might do the job nicely.

@tangentdave- you recon it'd handle the constant current from the astro? you've got the most experience with them on here i would assume

Interesting idea. Yes, 125A continuous is plenty, I doubt you'll be able to pull more than that even momentarily. I don't know anything about that particular switch but I would think it'll spark as you close those contactors and maybe eventually corrode them. Maybe not?

tangentdave said:

Interesting idea. Yes, 125A continuous is plenty, I doubt you'll be able to pull more than that even momentarily. I don't know anything about that particular switch but I would think it'll spark as you close those contactors and maybe eventually corrode them. Maybe not?

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i am a bit worried about the arc. if i use a contactor it wont be an issue (it'll still arc but you wont see it) but they add a fair bit of wiring and complication.

recon it'd be possible to wire an arc supressor into the switch power wire? arnt they just resistors of the correct rating? forgive my electrical ignorance, iv not wired/made an arc suppressor before (i just usually buy the xt90's with them in them already)

Awesome design. I am just underwhelmed with just one 3220 having done it. Matt has done three. Now you are talking.

Your engineering looks sound. Use some multiple gearing or it will get boring quick.

motomoto said:

Awesome design. I am just underwhelmed with just one 3220 having done it. Matt has done three. Now you are talking.

Your engineering looks sound. Use some multiple gearing or it will get boring quick.

Click to expand...

three?? last i saw he did a double, sureley not a triple>?

Yes he make 3x 3220 motor cool idear, But the only Fool in world dam , who pay for it is from au i will not name the user ,, and plan to use it on the road , to kill other riders,

i told him, i hope the cop get him.. before he give us a Bad name in au,

i done 2x motor before wight too much and snap Chian to ez, .. and blend the frame

water cooling is the only to push more power. to wight, and i only use my ebike off road, and not s silly rider

get some of AMASS AS150 7mm Anti-Spark 150A LiPO Connector Black/Red Pack
http://www.ebay.com.au/itm/281998195576?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

cheap i could find, in ebay

all the best

I use one of these solar breakers for my main system I/O: http://www.solar-electric.com/installation-parts-and-equipment/midnite/cipr1/stfubr1/pamodccibr.html

Then I just use a small electric keyed switch to toggle my controller I/O: http://www.digikey.com/product-search/en/switches/keylock-switches/1114205

Gorgeous design btw!!

I use a Busmann (Eaton) 187-series breaker. It's marine rated and can be had in up to 200amps @ 48v. Busmann is an industry leader and milspec supplier for this type of stuff.


http://www.cooperindustries.com/content/public/en/bussmann/transportation/products/circuit_protection/circuit_breakers/series_187_marineratedcircuitbreaker.html

For keyed type of disconnects, I only use Hella branded ones in my racecars. They have a cleaner feeling engagement compared to the other brands (German engineering and all that).

The bike looks cool, but I can't help but think you could just redo the battery pack and use an off the shelf frame. But maybe that's the point.

Haha yep that is indeed the point. Can't really get my head around working with an existing frame and teeing to deal with all the resulting compromises when I could just make my own and not have any. Lower cg, geometry that suits me perfectly, tire clearance for 3.5" rubber, much stronger frame than anything out there etc etc.

I like the look of that breaker. I bought a 150a truck battery iso switch already, and will probably just use a 150a ANL fuse box for protection of the motor, but that thing might be the best of both worlds. its a big large tho...that sort of sized rectangular object really needs to be designed into the frame before one finishes the design ;s

MM that will be a sweet sweet ride. Plenty of power and all centralized low COG mass. And the strength to do big drops and catch some air time too.
Due to the light weight it will probably work just as well as a modern DH bike in those DH tracks, and you don't have to struggle to get up top or wait in line for chair lifts 8)
bet you the climb to the summit will be as much fun as the DH ride.

An off the shelf frame may have what seems all the same components, but it will never achieve the way everything fits and works together the way it does when its been designed that way, for that purpose from scratch. Have a look at any Bafang middrive/dolphin pack vs Bosch unit, integrated battery and frame suited to it. Battery mounts have far superior lateral strength, Mid drive unit snugs in, aesthetically a much, much nicer finish.

Is your battery positioning high enough/close enough to the seat pole given the thoughts from your last build?