USA Leaf owner wants to convert Derbi supermotard

[T Rush]

anyone out there ever electrified or know what the Derbi Senda X-Treme SM 50 is ?
https://www.ultimatespecs.com/motorc...eme-50-sm-2008


it looks small, but its actually pretty tall like a normal supermotard/dirt bike, has 17" wheels...however only a little over 200lbs

a few years ago I saw an ad for one on Craig's List, and didn't know anything about them...so called the guy
...the price was very low, and the guy said he had it in the back of his truck...if I wanted to see it, he could stop by my house right then and there
next thing I know, he was lifting the thing out of his truck and carrying it(by himself) up into my driveway...I said: "it looks like it will roll?"
he said: "eh, it dont way nut'en"(this is Iowa, and he was a big ol' farm boy) "get on'her an have a go...she'd look lik it'd fit'cha better dan me"

I already had 3 other motorcycles then(up to 8 now counting this one) and my Wife was out of town...so I jumped right on this crazy thing, fired it up on the second kick, and took off to run my little local test loop....came back and my ears were ringing, but had the biggest smile stuck on my face so that my teeth had dried out...was trying to quickly get off the bike so I could run inside and grab my cash, but the kick stand had fallen off on my test ride(I had forgotten to put it up, so knocked it off on the first corner, and didn't even know it) so I zipped back out on the Derbi and found it in the middle of the street...I said: "well, I guess I have to buy it now"


anyway, it came with a moped title, as it was supposed to have a 50cc and been limited to 30mph...but he had stuck a 80cc Kawasaki engine in there to try and help pull his size around(said he didn't have the Derbi engine anymore)... so I had to title it as a motorcycle, as I have gotten it up to 60mph a few times....but not long ago I started with recovering the seat, painting the fairings, and wanting to 'clean up' the kinda hack job he did on the motor swap
....I've always wanted to build an EV 'car'....but now we have been leasing a 2016 Leaf(my Wife loves that car)....so I starting looking at my Derbi again, thinking now batteries are lighter and can power a big eBike or small motorcycle(the Derbi is right in-between the two)


thanks for having me...and tons of questions will be coming
(like 'how many modules can I take out of my Wife's Nissan before she notices?' hehe)

[T Rush]

I'll tell you more about my plan...at least my early first ideas(which likely will change with more research/help)


* I'd like this to mostly run 'sporty' @ lower city speeds 0~35mph...so gear reduction for that?

* commute range is not large:
... 3.5miles from my home to my shop(7 miles round trip, tho I'd be able to charge at either end)
... 9miles out to the marina from home(we keep our 30' cabin-cruiser in a slip out there, so I do have power and I would be able to ride it out on the dock to the boat)

so those requirements are really fine for a small electric motorcycle?


however: on both commutes, there are 1~3 mile stretches where the speed limit gets up to 55mph
...and esp. on the mile or so stretch out to my shop, its a killer as people tailgate you like crazy unless you are going more than 60mph(even if I'm pulling a trailer with crap falling off) as that road connects the city with the interstate(I-80) and then goes out to a smaller town that people zip back and forth to as fast as they can

...also I'd like a pretty good 'run time'...it would be great to 'play' on it for an hour without recharging

ok, so thats where this gets harder:
* as while 'range' isn't so important, i dont want to have to charge after every 20min.
* and it might be nice that this bike was originally designed and built for spirited low speeds, I'm gonna still need to 'kick it into high gear' and make a run for it to get out of peoples way on the highway



as for parts I'm looking at lower cost and ease of use, as well as doing a pretty simple build
...this will be my first adventure into DIY EV, so I want it to be as straight forward as possible and achievable

* battery cell modules
seems like I have to use the recovered Nissan Leaf modules
people seem to love these, but I wont have tons of space to fit a big 'block' or stack of them(but I have an idea on how to arrange them in the Derbi) so while using a bunch 18650 cells stuck together would be great, weigh less, fit better; I just dont want to spend all my time~energy figuring that all out
... so 9 Leaf modules for 63~75volts ?

* motor
looking at the goldenmotor HPM3000B
these seem small, light, and I think I've seen them installed in bikes of this size...not sure if I'll need to water cool it or not
price is right at only ~$300...and it might even be more powerfull than the 8.5hp 50cc engine the Derbi used
... so 3KW(6KW peak) 72volt 5000rpm ?

* controller
goldenmotor has the VEC200/72Vdc sine wave controller at $260 to go with that motor, so I just use that ?
https://www.goldenmotor.com/frame-bldcmotor.htm


I dont think I'll need a BMS(I guess I can just manually check each module?) but Contactor and Fuse, twist throttle ...gonna have to do some wild wiring if the Leaf battery modules aren't in a neat stack

and I dont know about a charger(but I think it would be cool to use the Nissan 120v charging cord/brick the Leaf comes with, and the standard plug they use at charging stations)...seen those on eBay, and it would be nice to have another one for the car...but can I get it to work on the Derbi ?

DC to DC 12v and 5v (yeah, and LED lights) , also one of those Cycle Analyst meter things


one of the interesting things Im thinking of doing is the drive-train, I'd might even change to belt(s), as to get the Leaf modules in: I'm looking at moving the motor up under the seat, just behind the top shock mount...then run a pulley system down to a cross shaft, and that shaft goes over to the normal front sprocket location and belt or chain to the rear wheel....this would give me the proper gearing ...and/or it might be nice to install a 2 or 3 speed transmission vs direct connection or with that single speed cross-shaft
hmmm ?

[Stevo]

This is the perfect size bike for a little ME0909 motor and AXE4834. Get 3 Nissan leaf modules and a can opener, rewire the cells in series and that little bike will rip! (Bad choice of words...errr... I mean tear it up!)

Warning! Don't over volt that motor! It will RIP!!

Those goldenmotors look interesting and keep us posted if you go that route. This can be a very interesting build indeed!!

[T Rush]

This is the perfect size bike for a little ME0909 motor and AXE4834. ...

oh, so that motor is down to 6"OD...that might fit just alittle nicer than the 7.5"OD HPM3000B which is gonna be real tight in the spot I'm looking at(up high, under the seat, rear of the mono shock, where the air box is for the ICE)...does the Motenergy transfer more power than the Golden? (i cant tell, as one rates the specs in "HP" and the other in "Nm" and "KW", which I'm struggling to compare those terms)


so I pulled the chassis out today, found my tape measure, and a piece of cardboard about the size of a Leaf module(I'll cut some Styrofoam blocks to size for a better mock-up) ....just to see if I was anywhere close in my brain to what could really fit.....some things will work better than I thought(like I can have 4 models wide within the frame where I thought only 3 could go), and the pulley system from the motor down to the drive sprocket cross shaft(or trans) looked good to run in-between the mono shock and inside the frame...but, where I gained space for one more module in width down low where the ICE is(and those 3 or now 4 would almost completely fill that area, with just enough room for a controller, and no room for the motor as I thought) I do not have the space to fit 6 more up higher in/around the frame more towards the front....ok then, maybe only another 4 might sorta fit there near the steering head(2 mostly inside the twin spar frame straddling the center down tube single cradle, the other 2 outside the frame high up just under the radiator shroud fairings)....that means only 8 modules(67.2volts max)....so I think I could add 2 more modules back under the rear fender side shroud things(whatever you call those)....I kinda didn't want to add more weight(going up to 10 vs 9 modules) and I dont need more volts(aiming for 72v system), and I dont want to bust the modules open(as at least 50ah for run time preferred) so maybe I can just run the 10th module in parallel for greater amp hours ? at the same ~72volts with 9s + 1p ...is that how it works

(kinda found a cool place for an on-board charger that might work...but it is a very small bike so I might be asking too much from it, and would rather take advantage of its size vs wanting a larger bike to fit this much stuff...eh, hmmm)


[attached photo of 'rear fender side shroud things' with white card about the size of a module under it]
[... and yes, I really did paint the bike and recover the seat in Zebra!]

[frodus]

No, you only parallel cells at the cell level. Paralleling a cell at the pack level would mean you're putting 72V across it.

If you have some 50Ah cells, and each leaf cell has 4 cells in each module. First they put 2 cells in parallel and then put those in series with another 2 cells in parallel.
http://hybridautocenter.com/HAC4/ind...=72&Itemid=631

If you wanted to 100Ah, you'd have to parallel 2 modules together, and then put those in series with other paralleled modules. i.e. you have to have a bunch of 100Ah modules.

[Stevo]

^^^^ What Travis said...
You can't compare those two motors...that's apples and oranges. The lil Motenergy wont provide the speed you require for your hwy leg.
Also, you need to consider the weight of 10 Leaf modules. At about 8 1/2 lbs each, your looking at 85lbs plus the weight of hardware, mounting brackets, etc. That little chassis will be stressed out to it's max.. which is why I suggested opening up the modules with a can opener.... or consider a different battery type all together

[T Rush]

so if each 7.6v 58ah module is a dot • , and two in parallel is this : , I can NOT connect them like this?
(even if it only provides a minor ah increase at the same voltage)

•-•-•-•<:>•-•-•-•

crap


yeah, I've been trying to keep my eye on the weight...but I also want run time...and I did ride that bike once with my 200lbs stepson on the back of it
...tho it would be nice to keep the bike weight around its 216lbs stock, or get a bigger bike, or do a smaller battery, or set it up to go 55mph or 0~30mph but not both, or be OK with charging every 20min, or... I would like it better to remain "reasonably clueless" about some of those things and try it anyway
failure is an option(as long as I stay open to criticism, guidance, and educationalized) maybe?

maybe not...well, I've got a big drawing board and lots of paper, so I guess back to that

[frodus]

it won't increase the Ah. The current will always flow through the pack. It'll help only that paralleled cell group last longer, but the amperage through the pack, and Ah capacity will depend on the lowest capacity of any series cell-group. I'd say add it to the top of the pack, in series, to increase voltage slightly.

[Stevo]

so if each 7.6v 58ah module is a dot • , and two in parallel is this : , I can NOT connect them like this?
(even if it only provides a minor ah increase at the same voltage)

•-•-•-•<:>•-•-•-•

crap


yeah, I've been trying to keep my eye on the weight...but I also want run time...and I did ride that bike once with my 200lbs stepson on the back of it
...tho it would be nice to keep the bike weight around its 216lbs stock, or get a bigger bike, or do a smaller battery, or set it up to go 55mph or 0~30mph but not both, or be OK with charging every 20min, or... I would like it better to remain "reasonably clueless" about some of those things and try it anyway
failure is an option(as long as I stay open to criticism, guidance, and educationalized) maybe?

maybe not...well, I've got a big drawing board and lots of paper, so I guess back to that

If you wire the modules that way, you will only have about 32 volt pack with a doubling of the aHr rating.
I'm in the middle of my third version build now. I've learned important things along the way on each version build.
If you really want to learn how to build your own emc, go for it! The education is priceless!! And you'll be spending plenty of $$ on that education!! LOL!

[T Rush]

yeah, ok ok

after thinking about it for a bit, part of my imagined module arrangement just wasn't working well when I was over at my shop measuring and looking at the chassis
...even when cutting back that area from a planed 6 module location to only 4(2 inside the frame and 2 outside under the radiator shroud plastics) still 2 of those modules were very 'forced' into place...I thought I'd build the styrofoam mockup modules to know for sure if those 2 would fit or not

this 'cramming' technique and making things 'barely work' or 'over complicated' are all things I was trying to avoid in my basic-clean-simple build

....so with the new location I found under the 'rear fender side shroud things' for 2, and the lowest main bulk in the engine location being able to hold one more in its width comfortably at 4; just having 2 up forward and higher on the chassis(the ones outside the frame) under the radiator shrouds, and NOT squeezing those other 2 inside the frame ....those locations locations give me 8 Leaf modules....so really all I'd have to do is find a location for one more(like seeing if one will fit just forward of, but flat acrossed, the 4 in the lower engine location), to give me my 9 module(each usable 7~8.4volts discharge~charge) configuration of 63~75volts

I just need to make up my styrofoam mockup modules...yank the ICE, radiator, 12v battery box, and petrol tank out...and see how things physically fall into place