FarGrin -- Time to push some amps

[chuyskywalker]

Ever wonder how much the Grin Max45 can handle? I plan to push one hard.

Components:

• Grin Max45 Motor; std wind, ferrofluid injection; snipped connector for direct wiring
• Fucare Scorpio Frame
• Fardriver ND96450 (170 battery amps, 450 phase amps)
• A 96v (26s) battery (no details yet; awaiting frame to see how much I can stuff in it)

The rest of the build is likely to be pretty barebones and somewhat dull. I'm posting in the escoot/emoto section cause I likely won't bother adding pedals to it.

The battery may not have too much range capacity (and likely I'll need to use some absurdly high drain cells) -- but, it'll be a lot of fun to push the motor and find out just how much abuse these can take.

If it works out, I may go down the rabbit hole to see if I could get it legally registered as a Specially Constructed Vehicle. I always have the option of de-tuning it to something, ahem, more bike like and add in the bit's needed to get back to that. Or I could dual motor another ride Who knows!

 

[chuyskywalker]

Took advantage of the brief pause in tariff hikes, and now parts on the way:

• Frame, (bits and pieces like fork, wheel, etc)
• BMS
• Motor

Most of the rest I'm hoping I've got pars in the bin to get it going.

 

[bananu7]

I'm posting in the escoot/emoto section cause I likely won't bother adding pedals to it.

Makes sense. With a ~15kW power budget they're just a waste of space. I wonder how big of a battery you'll fit in this frame if it's meant to be 26s. 170 amps is comfortably within the limit of small E-series pouch cells in a 26s1p configuration, but it seems like you'll need to maximize volumetric efficiency and go with 21700 to squeeze something like 26s4p in there.

 

[chuyskywalker]

170 amps is comfortably within the limit of small E-series pouch cells in a 26s1p configuration, but it seems like you'll need to maximize volumetric efficiency and go with 21700 to squeeze something like 26s4p in there.

Yeah, I'm currently eyeballing some of these 70A 21700's like the EVE 40PL that can, apparently, handle 70A discharge. A 3p could do the trick (210A), but I'd certainly like to hit 4p for better overhead margin. Getting 26s4p (104 cells) onto the bike somewhere (along with the bms for that) could end up being a challenge. Heck, even a 3p build (at 78cells) is more than the largest pre-made case can accommodate.

I'm hoping the "cradle" shape of the frame lets me build a bit larger than the standard ebike battery shape, and then up a bit to get it to fit. Probably just hold the battery in with some ratchet straps or something, lol. It's a bit of a gamble, if I'm being honest.

 

[bananu7]

I'm hoping the "cradle" shape of the frame lets me build a bit larger than the standard ebike battery shape, and then up a bit to get it to fit.

Ah, just realized it's indeed open at the top. That should allow you to go a good couple cm above the top tube, and then 26s4p should fit fine, especially if you put the controller "outside", e.g. at the bottom.

 

[chuyskywalker]

Ah, just realized it's indeed open at the top. That should allow you to go a good couple cm above the top tube, and then 26s4p should fit fine, especially if you put the controller "outside", e.g. at the bottom.

Yup; one of the big reasons I picked this frame as a base. And I'm pretty sure I can jam the controller in that little triangle at the bottom. But I won't know till the frame gets off the boat and over to me.

 

[chuyskywalker]

Took advantage of the brief pause in tariff hikes, and now parts on the way:

Everything came in today -- that was a lot faster than I had expected. I'll get things unpacked in the new few days, but I'm excited!

 

[AdR]

How the project going?.hoping your result will help my intent to build using that motor

 

[chuyskywalker]

How the project going?.hoping your result will help my intent to build using that motor

I've been swept up in a big house move and the garage is a severe casualty of the process. Gonna be a while yet till I can make progress on this.

 

[slaphappygamer]

I've been swept up in a big house move and the garage is a severe casualty of the process. Gonna be a while yet till I can make progress on this.

Oh man, the garage always gets heavily abused during a move. It is not a fun process. Kind of like traveling, the worst part is getting there.

During our last move, we rented a uhaul from a Valero gas station. When we arrived to pick up the truck, they had rented them all out and we had to go somewhere else to rent the truck. We have never gone back to that Valero gas station. I wouldnt even buy rolling papers there. This was a move from San Jose to Aptos, so we had to drive over 17 many times, which was it's own headache. Our next move< which will be a long while from now, will most likely be out of California. It's just getting too expensive (much more since 12 years ago) here, especially on a retirement salary......whenever that time comes.

I hope all goes well and don't rent a truck from a 3rd party seller.

 

[OkinawaJapan]

I'm really looking forward to more updates on this build. Nice frame! I may get one of those actually. I just bought a folding ebike and am looking at upgrading the stock motor to the Grin Max45. But it's so expensive. So I'm looking around to see what alternatives there are that are comparable but much more reasonably priced for a DD drive motor.

My main intent is regen with DD silence. For a value price.

So far I see a lot of people used the old G062 geared hub motor and welded it. But I think that will be too loud for my tastes. But the price is right. Or the G063. If I can't find a reasonably priced DD rear hub motor alternative I may try the G062 or G063 or just foot the bill for this MAX45 and see...

 

[OkinawaJapan]

Well... I ordered the Grin Max45 Slow wind tonight. I couldn't find anything on the market comparable really for regen safety. It really has no competition. Price is double other options like the Leaf DD hub alternative I found, but it had no integrated torque arm and weight a ton more.

Really excited about it arriving. Got it going into a brand new Samebike RS-A02 I just got. But think I may order that Fucaro Scorpio frame at some point as I'm liking the battery cage option it has.

Really hoping you get back to your testing soon. I want to hear your updates.

Just noticed I joined ES back in 2012 when I was first going to get an ebike, Took me 13 years to finally get one. My post above is my first one on ES finally. lol. Well, it's a great thread you've started here. Looking forward to your future posts.

 

[MSF]

Well... I ordered the Grin Max45 Slow wind tonight. I couldn't find anything on the market comparable really for regen safety. It really has no competition. Price is double other options like the Leaf DD hub alternative I found, but it had no integrated torque arm and weight a ton more.

Really excited about it arriving. Got it going into a brand new Samebike RS-A02 I just got. But think I may order that Fucaro Scorpio frame at some point as I'm liking the battery cage option it has.

Really hoping you get back to your testing soon. I want to hear your updates.

Just noticed I joined ES back in 2012 when I was first going to get an ebike, Took me 13 years to finally get one. My post above is my first one on ES finally. lol. Well, it's a great thread you've started here. Looking forward to your future posts.

I just started a build thread with the Max45. If you need any ideas it may be useful Salsa Blackborow with Grin Max45

 

[chuyskywalker]

Oh man, the garage always gets heavily abused during a move

Boy does it! Fortunately, all the cabinets are installed, shelves hung, and things put away ... finally!

Well... I ordered the Grin Max45 Slow wind tonight

It's definitely a "buy once, cry once" kind of purchase. This max45 is actually my second (I was a pretty early adopter, back in the "fat all axle" naming days). So I can say you will not be disappointed with it from a silence and regen perspective. It's a true gem of a motor.

But now, some updates!


Frame is all mostly all built up today. Also slapped the front tire and motor-in-rim on as well just for fitment. Installing double shocks isn't something I've had to do before and required some...creativity to get the bolt holes to line up:



But no major issues on the build up of the frame otherwise. Granted there are zero instructions but...it's also really not complicated.

I do have one dilemma -- where to attach the torque arm. I have two good options:



In picture one, it could be clamped (with the standard, official clamp setup) on to this cross member here. There really isn't any other frame component I can clamp to without grinding off the kickstand support.

Option two is to drill a hole through the kickstand support, put in a spacer, and just bolt it on to that.

Not sure which way I'm leaning more at the moment. I suspect the framing member is probably the better option, but I do like the simplicity of the kick stand bolt. Though, losing the kickstand would be unfortunate and require the purchase of a gimmicky after-market clamp-on style one.

 

[slaphappygamer]

I don’t think I would sacrifice my kickstand mount either. I really like my kickstand. Use it all the time.

What does it look like if you mounted the torque arm at the seat stay?

 

[chuyskywalker]

So, I can get it on the red line one ok'ishly.

The tube with the blue line, the mount can technically go on there and interface, but it requires being on the inside and would require the steel clamp cable things to go around the kickstand tab (no bueno). I can't go "under" on the tube either, because to avoid the kick stand, it'd end up being too far away.

I can't use the green marked tube beacause rotating it that far would cause the wires to bind/pinch.

I don't plan to put pedals on this -- maybe I can try flipping the motor around and seeing if the TA lines up better on the other side. Though...that might just for the wires immediately into the dropout. But I'll double check.

 

[OkinawaJapan]

Hey! Glad to see you back at it after the move. Very nice set up. Beautiful bike.

I wouldn't want to lose my kickstand either. Is there no way to drill and use a spacer and still keep the kickstand? That's what I'd try to attempt.

Been meaning to ask, did you order the frame from that link you posted in the first post? Is it a verified supplier? If so I'll order one of these frames in a month or so.

And how are the stock shocks? Not too stiff? Adjustable? That would suck having to replace them as that'd be another $100 bucks right off the bat since there are two.

Thanks for the confirmation that I'll love the Max45. Yeah, it looks like the highest quality hub motor on the market hands down. Looking forward to receiving it. They're having to build it on a 90mm wide 20 inch rim for me as that's all they have in a 32H. But I will probably be running scooter tires on it anyway, so should be a rock solid ride on this frame.

So glad I came across your thread here. Exciting times!

 

[kuromaku]

View attachment 376239

How about fabbing a new TA to capture the mounting holes for the brake caliper? Either from the inside or outside... whichever fits better.

 

[chuyskywalker]

Ordered all the battery bits today. I could probably fit another P group in, but it'd just make things tighter and just a bit more difficult to assemble/attach/etc and the extra few miles of range won't be a big deal. I've crammed batteries before and I'm taking a bit more of the easy road on this build. Plus extra room for a rather large BMS and a chonky disconnect/breaker.

It'll be a 26s4p pack, split in two halves stacked on top of each other. I picked up the 104 cells from 18650batterystore.com and went with the BAK 45D cells sine they're on a KILLER deal. The pack will hit the proper nominal voltage of 96v and should be able to output 240A, which the controller only can handle 170 so lots of margin there. Based on some spreadsheet math I have, I expect about 35mi range minimum.

I did some quick prototyping with the controller/battery placement -- (two 13x4 rows stacked on each other with some placeholder cells; bike is upside down)



Since the battery is basically two 48v's stacked on top of each other, there's no issues with size/clearance. It'll definitely stick out the top of the tray area a bit, but nothing a strap or two won't handle adequately.

For welding up the pack, I'm picking up some pre-made 0.3mm copper strips



Pretty excited that these are just readily available now. I've done my own custom copper-nickle-sandwich in the past and it was a lot of work. This should be much easier.

---



Finally, I put out and order for tires. Going to give the oft-lauded Shinko 244's a go. I've mostly used "quiet" tires like the V-Speedsters, but had to pair them with Tannus liners to avoid flats. Apparently the shinkos are basically immue to flats and nearly indestructible -- which makes sense as they are for proper moto's and weight a ton. But, since I ain't peddling.... ;D

I am, however, going to start mentally preparing for the fight of my life to get them on. Maybe I'll leave them on my black, metal roof for a few days to soften up first...

 

[chuyskywalker]

How about fabbing a new TA to capture the mounting holes for the brake caliper? Either from the inside or outside... whichever fits better.

I'd have to get 3d cad files from grin for that to happen. The TA interface on the motor is a complex spline shape, and this motor is a through axle, so there's no axle to place a normal TA on to. (I have done this for previous builds that use the more common motor ta style.)

Ultimately, I'm going to go with the cross member. It's the best option I've got at the moment. Every other option it too far away or starts to crush the wires. Flipping the motor puts the TA pointing straight back, so totally not going to happen

 

[bananu7]

Pretty excited that these are just readily available now. I've done my own custom copper-nickle-sandwich in the past and it was a lot of work. This should be much easier.

This looks great, actually. AliExpress has them for half of that price, which makes it even better.

I am, however, going to start mentally preparing for the fight of my life to get them on. Maybe I'll leave them on my black, metal roof for a few days to soften up first...

Warming up is not a bad idea, but I'm becoming increasingly certain that if you need to use excessive amount of effort when putting tyres on, your technique could use improvement. Those are still relatively skinny tyres (compared to diameter) and so should go in quite easily. Are you going to run them tubeless? Probably a good idea if you'll run road pressure most of the time.

 

[OkinawaJapan]

Cool update. It's too bad I can't order batteries from the US and have them shipped to me here in Japan or I would. I have to order my stuff from Alibaba. Still not sure if there are any good sellers there. Just ordered a pack from one of the bigger sellers and they are selling me Samsung cells. No idea of how to tell if they're genuine... Maybe someday I'll get into building my own packs but I have enough on my plate for now.

So is it possible to use a car tire machine to install bike tires that are difficult to get on? My son-in-law has one in our garage I could use if I have trouble with the scooter tires when I eventually go that route. But wondered if it would be too strong for a bike rim.

Thanks for the tire recommendation. I'll check into those.

 

[bananu7]

is it possible to use a car tire machine to install bike tires that are difficult to get on?

Probably not a good idea unless the machine can specifically work with motorcycle tyres. What widths are your rims and planned tyres?

 

[chuyskywalker]

Are you going to run them tubeless? Probably a good idea if you'll run road pressure most of the time.

I'll start out with some moto tubes since it's what I'm used to currently. Haven't done a tubeless setup yet and it looks like it can get...messy.

AliExpress has them for half of that price, which makes it even better.

I bet -- these will just get here a heck of a lot faster. Always that trade off.

 

[OkinawaJapan]

Probably not a good idea unless the machine can specifically work with motorcycle tyres. What widths are your rims and planned tyres?

80mm wide dual wall 20 inch fat rims with some Shinko or Pirelli Angel scooter tires. 110/70-16.