A2B Metro (Gen 1) Restoration and Upgrade

[amberwolf]

I might even have enough room to hide the Phaserunner inside the tube. Not sure how I'd mount it, but there seems like there could be room.

Missed this before, but if you do put hte PR in there, put it so it's heatsink is on a surface that is flat, and drill holes from the outside to line up with the PR's mounting holes in that heatsink. Then you can bolt the PR to the frame and let the frame be the heatsink. Otherwise, you should put the PR *outside* the frame so you don't have issues with heat buildup causing the PR to derate itself as you ride.

 

[amberwolf]

This is the thread where I did that to a Stromer version of the motor that was meant for a 26" wheel, which should help you with wiring, too. Some of the pics seem to be missing, so if you need those I can repost them.
https://endless-sphere.com/forums/viewtopic.php?f=2&t=86600
I redid the wiring that was done in that thread with new cable from Grin Tech (the stuff that they sell by the meter that has integrated phase, hall, etc wires in it; was a tight enough fit I did have to trim some insulation off the outer jacket for the axle pass-thru).

I'm now running that motor in my heavy SB Cruiser trike in a 20" (22" with the moped tire on it), and it has quite a bit of torque with only a "40A" (ish) crappy generic controller. But it does get pretty warm (added a thermal sensor in the windings while I was rewiring it) before leveling out at 40-50C-ish. By the feel of the pushing on each side, this one does a fair bit (probably most) of the startup work, cant' tell at cruise. (I don't have current monitoring per-controller, so don't know how much work the MXUS450x on the left side is doing vs this motor on the right, and they have a common throttle signal).

 

[chuyskywalker]

if you do put the phaserunner in there, put it so it's heatsink is on a surface that is flat, and drill holes from the outside to line up with the PR's mounting holes in that heatsink.

Yup; I don't think it actually will fit realistically -- but if that's possible, it'd be a clean as heck solution.

I redid the wiring that was done in that thread with new cable from Grin Tech (the stuff that they sell by the meter that has integrated phase, hall, etc wires in it; was a tight enough fit I did have to trim some insulation off the outer jacket for the axle pass-thru).

Good to know as that's the cable I have sitting in a box right now waiting to be used. Not super excited about skimming the insulation, but...

(added a thermal sensor in the windings while I was rewiring it)

Where do I pick up something like that? I believe the wire harness has an extra pin just for that so it can go to the CA (via the PR).

 

[chuyskywalker]

Ah, something like

https://ebikes.ca/thermistor10k.html

(Cept, they're closing for a few weeks for a move). You just wire a few in series and...glue them to the windings?

Well, this one's available: https://www.amazon.com/dp/B07P5QC26X/

 

[amberwolf]

You only use one. I simply inserted the insulated thermistor under one of the windings (doesnt' matter which one), and superglued it in place.

If you want to use more than one, you'd need to wire each one out separately and switch between them.

Wiring them in parallel or series means that all of them change resistance separately based on their temperature, but there is no way to determine what the readings actually are for any one of them. (and the CA is preset to use the resistance of just one; you'd have to figure out how to use it with more than one simultaneously, if it can be)

I have separate thermistors in each motor wheel, and keep intending to install them in other things like controllers and batteries, but never get around to it. Then I would have a switch right at the CA that would let me look at the temperature of any particular thing whenever I like. Right now I have to move a plug to connect to whichever motor I want to monitor...but I only really installed them for experimental testing purposes, to give myself an idea of how well things behave when first installing them--once I know how well or poorly something works, I can then fix or optimize it, and then don't have to worry about it.

Regarding the one in the link, I've never used that type so I don't know if they work or not. The ones I got from grin are little blue blobs on the end of a pair of very thin wires.

 

[amberwolf]

Good to know as that's the cable I have sitting in a box right now waiting to be used. Not super excited about skimming the insulation, but...

You might not have to, as your motor axle might be slightly different than mine (both UltraMotor, but made for different bikes). It's been a while now, but I think the way I did it was to remove the outer main cable jacket on the side that sits against the wide flat part of the axle, so that the round side would sit against the bearing ID, and the "flat" side would sit against the axle's flat "wire channel'. I also put kapton tape on the axle's flat area, to ensure that an insulation failure on a wire wouldn't allow a short to the axle itself.

I ziptied the cable to the axle while installing the covers, to keep it all straight while working on it. I also ziptied a loop of the cable down to the former controller-mount-plate, thru the old screw holes, so it couldn't be pulled accidentally around in the axle channel.

I wish I had pics of that to show you, but if I took any, I can't find them now. :/

 

[chuyskywalker]

I wish I had pics of that to show you, but if I took any, I can't find them now. :/

No worries; the descriptions are useful in their own right.

The thermistor; I assume one end goes to the thermistor wire (duh), but the other tied to the +5v coming in from the harness, right?

As for type; perhaps closer in resemblance to this one then? https://www.amazon.com/dp/B07DHMQX52

The other "glass" one is the same resistance rating (10k) just like what Grin sells, but has a much wider operating temp range.

---

In other news, I just got the battery spot welded up, need to add the BMS next and get it to fit in the bike. Seems light my shape is slightly off in that I can't squeeze it past the hanging kick stand. And to take that off, apparently I need a 17mm wrench. The single size I don't have. Bah.

 

[chuyskywalker]

Got the motor out of the wheel.

[youtube]d9dxtX6mcPA[/youtube]

Note to self: clean and apply "alignment tape" for later re-assembly alignment after removing, duh

Freewheel socket should show up today so I can get the cassette off and then pull it apart.

 

[fechter]

Are you going to try using the stock motor?

 

[chuyskywalker]

Are you going to try using the stock motor?

Yup. Figured I should use what I've got before trying to source/assemble a whole rear setup.

 

[chuyskywalker]

Did the battery up, just the primary spot welding:

[youtube]3JzxDVxN4Do[/youtube]

The little $20 welder works fine, but needed a cooling fan or it'd stop every 7-10 welds.

 

[amberwolf]

The thermistor; I assume one end goes to the thermistor wire (duh), but the other tied to the +5v coming in from the harness, right?

Depends on what you're using to measure it. Most things that measure a thermistor are wired so they use ground and signal; the only exception I have run across was the SFOC5 which used 5v and signal.

As for type; perhaps closer in resemblance to this one then? https://www.amazon.com/dp/B07DHMQX52

The other "glass" one is the same resistance rating (10k) just like what Grin sells, but has a much wider operating temp range.

The new link looks more like the Grin one, but the appearance isn't the issue; it's making sure the specs are the same. You should match the specs of the ones on the Grin site if you want to just hook it to the CA and use the regular 10K NTC setting. Otherwise you're going to have to figure out how to scale the thermistor's reading to give you the right readout on the CA for the whole temperature range you'll be using it at.

 

[chuyskywalker]

Motor disassembly is going...poorly. The freewheel seems completely seized, perhaps even fused/welded to the motor at this point. I mean, if a wrench setup like this can't get it off...



Next up, impact driver? Torch? Perhaps you can split the motor with it still attached?

Also, ended up having to completely scrap the first battery setup as it was too wide to fit with the BMS anywhere sensible. Redone up in the same curve (using the machined parts) but with just hotglue hold togethers. This works out nicely because 1) it makes it thin enough to host the BMS with no issues and 2) it's even shorter now.





The shortness is a really awesome perk because, hey hey hey, the Phaserunner will fit inside the downtube -- even the HigoL10 cord fits through the internal routing holes! I'll drill some holes to mount it up and slap a smidge of thermal compound between em -- should be pretty awesome

 

[amberwolf]

The freewheel seems completely seized, perhaps even fused/welded to the motor at this point. I mean, if a wrench setup like this can't get it off...
2021-01-17 21.47.23.jpg
Next up, impact driver? Torch? Perhaps you can split the motor with it still attached?

AFAICR, there's nothing to stop you from disassembling the motor with it still on there.

As for getting it off, in general it's a LOT easier to take freewheels off while the hub is still in a wheel (the larger the diameter, the easier it is). Not that that helps you much at this point. :/ The problem you're having is likely that the steel freewheel body has wedged itself in really well into the aluminum cover / threads, from pedal torque, and it's likely no grease was used to install it (which can help when removing one).

You can try using a "straw", with the motor placed axle vertical, freewheel side down, to get PB Blaster or some similar stuff into the thread interface between motor cover and freewheel. It cant' be gotten in there except between the freewheel and cover, and there's not much space, so it's hard to see and get the "straw" in the right place up against the cover's freewheel mount. Let that sit overnight, then try the freewheel removal procedure again.

But you don't want to apply too much torque to it, or you may break the motor side cover. That would suck. So unless you really need to take it off, I'd just leave it where it is.


If the puller does not simply begin to pull it off, you can use a few methods to help:

Heat the covers up significantly but not excessively (hairdryer on high, etc), so they expand more than the steel ring inside.

Tapping with a rubber mallet around the seam as you slowly increase tension on the puller.

Use some of the same lubricant in the seam between the covers. Just a few drops, in equally spaced points around the circumference of the seam, then let it sit a while, then more drops in different spots, and so on. You don't need it to be dripping off--just to get into the space between the cover and the magnet backiron ring.

 

[chuyskywalker]

That's be pretty insane if I applied enough torque and the motor body sheered before the freewheel popped.

I'll give the puller a try -- maybe with the casing removed, it gives me some more options for getting it off a bit more elegantly.

 

[chuyskywalker]

LoL, 10 minutes later I've solved all my motor problems!



Gear puller ripped the flange straight off. Probably my fault for putting the puller near the hole, but kind impossible to miss with all three legs.

Oh well, off to motor shopping I go!

 

[fechter]

It might be for the best...

I used a pair of thick aluminum bars. Later I replaced the fulcrum bar with a threaded bolt that goes through the plates so it was adjustable. Big C clamp on the other end of the bars to squeeze the halves apart.



If the motor had been sitting outside for a long time, it could be corroded to the point where it may not come apart in one piece anyway.

 

[amberwolf]

Well, if you aren't going to use the motor, it's still usable for other projects (I can think of a couple here).

 

[Audisport09]

Are you looking for motorbike rim or Bicycle rim. I managed to get my 3t QS 20” Bicycle rim pre-made last year from Alibaba. The guy was called Tom Tang from Nyclebike Co USD 418.20 all in.

 

[chuyskywalker]

Are you looking for motorbike rim or Bicycle rim. I managed to get my 3t QS 20” Bicycle rim pre-made last year from Alibaba. The guy was called Tom Tang from Nyclebike Co USD 418.20 all in.

Thanks; I actually found that store a few days ago! While their ad for the V3 is a 5t winding, I contacted them and they can also do a 3.5T. 3.5 would probably be right enough for my desires, but I ended up deciding to go with a DD45_FST from Grin instead. I know, I know, it won't be as powerful a motor, nor quite as fast, but it's lighter by a good bit and will come with a matching connector and, frankly, a rim build I trust a little bit more.

Just gonna sit on my hands for a month or so while Grin moves. It's kinda just like waiting on shipping from China anyway though, sooooo toss up there

 

[chuyskywalker]

Been a quiet couple of days while I wait on part shipping. In the mean time I finished up the battery:



And ran a capacity test:



Numbers came out just where I expected them to. Gonna toy around with upgrading one of these testers into a semi-absurd 10000w+ tester. Should be a fun little diversion while waiting.

 

[fechter]

Nice!

They make huge PTC resistors for large test loads. Handy because the resistance increases suddenly when it reaches a certain temperature so it will dissipate as much as it can without overheating.

What was your measured capacity?

 

[chuyskywalker]

What was your measured capacity?

Roughly 660wh @ 350watt draw -- that's about what I would expect from 20s2p with 5Ah cells. Ideally 72v10Ah would be 720wh, but that's at, like, .2C. Realistically I'd expect closer to 500wh usable once you start using 10-20A and 10-20mi range depending on how hard I push it.

I'll definitely be adding more, lol

 

[fechter]

That's probably pretty close to the stock battery energy. The "yee-haw" effect will reduce range (once you have more power available, you tend to use it). At 20mph with pedaling, the range should be pretty good.

 

[chuyskywalker]

What's a good shock to buy as a replacement?