RLT Project #1 - 2 wheel drive. (Now startingMk2)

This was really supposed my project #3; I was planning on just slapping an old Amtek motor I bought years ago to build a wind generator with on to an old 10 speed for Project #1, just to learn a few things, then Project #2 was supposed to be a kart with a treadmill motor and my modified 120V YiYun 42 controller, just to prove that it could be done cheap.... But things just kind of fell in place for what was to be my first serious build to come before the practice ones.

The main intention for this bike is for stealthy off road travel for my landscape / wildlife photography. I need long range, (I was hoping for 30 miles, but I'm only going to get about half that in the steep terrain that I will usually be traveling in) power for those long steep hills and my portly self and my camera equipment, ruggedness, and some comfort for my old 'stove up' back and knees.

Started out with a $130 Walmart special full-suspension mountain bike I bought about 6 years ago... A Mongoose 150. Aluminum frame, steel forks and steel rear swing arm. 21 Speed, Rim Brakes


Added two Wilderness Energy BD 36 hubmotors from batteryspace.com:


Sure, I'd have liked to use a couple of crystalites or some other high quality motors, but I was trying to do this as cheap as possible, at least until I knew if the concept was practical.
I'm very disappointed in the QC on these two WE brushed motors... three of the spokes were stripped on one of the them when I got them, both wheels badly out of true. Even after I replaced the bad spokes and trued the wheels, it was obvious that there was something out of weight balance in both of the motors, one much worse than the other. :x Added a little weight to the opposite sides and kind of smoothed things out to an acceptable level.
And since then, with very little use or abuse I have had to replace 10 more spokes. :x :x :x I should just replace them all and be done with it, because there are several more that look suspicious. PLUS, the joint on both rims were misaligned, had sharp edges and burrs internally and externally, enough to shred brake pads and inner tubes. I had to bend, grind and polish them out. :x :x :x :x

Decided to put both controllers inside a larger enclosure, add LED volt and amp meters and a three parallel 37-72 V DC-DC 5V 1A converters to power the meters and give me an output to power lights, Pocket PC-GPS etc.
View attachment 6


Decided to take Fechters advice ( http://endless-sphere.com/forums/viewtopic.php?f=2&t=278&start=270#p47990 ) and add a couple more freewheel diodes and a couple more capacitors to each controller. They are on a single board, but are isolated from each other:

The 8X6X3 project box got crammed pretty full by the time I finished:


Put the heatsinks from the original controllers on the bottom of the new box:


Oh, yeah... I also added a little solder to the shunts on both controllers to boost the amperage from the original of about 35A to a little over 40Amps each... They aren't perfectly matched... One will handle 44.1A the other 44.8A. I suppose it would be smart to see if I can get them better balanced. (no photo of shunts.)

Here is the top of the box with the meters:

Those meters turned out to be another mistake.
First of all, even though the ammeter was supposed to be internally isolated, the first one I installed blew fuses and surface mount components when I first turned things on powered through the DC-DC converter. So I ordered another and installed it with its own battery power supply. (4X) AAA Eneloops made into a tight pack. Should be able to power the meter for 30 hours continuous on a single charge. And the project box gets crammed even more full. There is a small jack on the front of the box to charge the battery pack, and a switch to turn it off to conserve power when you don't need it.
Unfortunately, You just can't read these meters in the sunlight... even on a moderately cloudy day, they are washed out. The green volt meter is worse... You can kind of read the red ammeter if you are in dark enough shade.

I think I'm going to go with using a couple of Cycle Analysts instead of the meters in Project #1 Mk2 if I can afford them. Or maybe buy an Eagle Tree for one pack and use the Watts Up I already have on the other if I decide I can't afford the CAs.

I had intended to be able to unplug one battery pack and just run one motor off of the other, since I had separate leads from each controller going to each motor, but I guess that tying the inputs from the battery packs together to run through the shunt for the ammeter, that the controllers outputs aren't isolated.... cut the power into one controller and the other one continues to send power to both motors... I guess by some sort of feedback through the inputs. I wasn't expecting that. It doesn't seem to bother either controller under normal use, and it may help keep the two battery packs in better balance because of it. But I think that in P1Mk2, I'm going to keep front and back batteries, front and back Controllers and front and back motors completely isolated, other than the single throttle input to both.

Oh, a word about throttles: I originally went with the thumb throttle that came with the motors. But between a mild case of carpal tunnel and a moderate case of arthritis, My thumb wasn't happy after even a short ride. So I went to a twist grip throttle. Another mistake; When I'm bouncing around offroad, hanging on for dear life, I was applying power when I wanted the exact opposite. So, I'm going back to the thumb throttle and minor pain, rather than the major pain of speeding up and running into a tree, a rock or off a cliff when I'm trying to slow way down.
.....
Let me save this before something happens and I lose it.

To be continued::::

Ok, on to the power: After some thought, I decided to go with two separate packs of 36V 20A of old chemistry lithium Ions for a total of 40AH... But in a larger size than you normally run across. Not your little 18650s... I used 32650s 5Ah each:
from here: http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=3069
(edit: I got a good quantity discount on them. The last batch of 70 cost me $12.something each, just ordered another 110, and they cost $11.34 each.... about $1,300 for nearly 2KWH if my arithmetic is correct.. Not too shabby ... Since I have my own CD welder and can build the packs myself, This works out to be cheaper than duct tape packs, no gambling on quality and consistency , plus, they are actually a bit lighter yet tougher packaging. The only real downside is the safety factor is so much better with the LiFeOs)

The first batch of 30 I ordered were only slightly disappointing in capacity; I ran them all through my CBAII, and they averaged from a low of about 4.2AH to a high of 4.8, average about 4.5. When it became obvious that 3P10S of them wasn't going to supply enough amps to get me up the hills or enough watt hours to travel very far, I ordered enough more build two packs of 4P10S (plus some spares). The newer batch had more capacity: at a constant 3.5A draw each, they averaged about 4.85AH on the CBAII... a few of them actually beat their nominal 5AH claims.

So balancing each 4 cell sub assembly as best I could by putting no more than one sub 4.8AH cell in each group and putting the higher capacity ones in harness with the lower ones, things averaged out to give me a little better than 4.8AH @ 13.5A constant current draw with each 4P sub assembly.
Packs went together like this, using my homebuilt CD welder, .5X.005 nickel tabs to build each parallel group, then a sheet of .005 copper to top it off and to connect each group in series.:View attachment 1.

While there are some advantages to doing it this way, I'm considering another way for when I rebuild the packs for MK2... .

At first, I planned to run without a BMS, but then I chickened out and bought a couple of the 40A BMS from batteryspace... Some of you may have already read what happened with the first one in this thread: http://endless-sphere.com/forums/viewtopic.php?f=2&t=3649&p=56329#p56329...

So, I chickened out again, and removed the BMS from the first pack and didn't even try to put the other one into the second pack.... Which led inadvertently into destroying the second battery pack during and after my first real ride. (more on that later).

One battery pack just managed to fit perfectly into the bag on the rear rack that I had on there since it was new; Ordered a handlebar bag to fit the other battery pack.

At first, that extra 12 pounds hanging on the handlebars made the steering feel kind of 'hinky' but it only took a few minutes for me to adapt and have it feel pretty safe.
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to be Continued:

MOTOR MODS.

Unfortunately, the WE motors only come in a front version. So, How am I going to pedal? (not that I really WANT to pedal) :wink:

Building a freewheel adapter to add to the rear motor is the most logical solution, but even though I have a small lathe, I was a little intimidated to take on that project. So I drilled a few holes in the side plate and bolted on a fixed sprocket:

Then to keep the pedals from spinning constantly and dangerously, I ordered a freewheel crank set from Cyclone:
http://www.cyclone-usa.com/store.php?crn=203
That's the lazy mans way out, and here is just one reason it wasn't a great idea:

They were out of the freewheel sprocket size I wanted, so I just welded the closest size sprocket I had laying around to a small freewheel assembly... I would have just bolted it but there was no practical way to get the holes aligned, even by drilling new ones. It works, but I'd have preferred a slightly higher front tooth count.

So, in MK2, I'm going to go to the extra effort and build an adapter for putting the freewheel on the motor.

I also ended up with spacing that no matter what I did with chain links and half links, it was too tight or too loose, so I had to make and weld on an idler.

Here is the whole pedaling assembly :

Sure, I could have just ordered an idler Cyclone, but THAT I CAN do on my lathe and I had all the materials laying around that I needed: Turned the idler pulley from 1 inch delrin rod. Bored it to fit some skateboard type bearings, ran a 1/4inch bolt through it, tapped a piece of square steel tubing, and welded it on where the kickstand used to bolt on.
(I'm hoping that in Mk2 I can get the chain to fit properly and not have to use the idler.)
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TBC

Suspension mods / torque arms:

OOPS, I can't believe that I don't have any photos of the front fork torque arms. I ordered some of those pre-fabbed ones from the powerrider store, but they wer so poorly manufactured that I had to return them... It wasn't the design, but the execution. You know how on most of our hubmotors, the axles are 12MM with flats ground to 10 MM? Well the bolt hole in both the arms I got was about 15mm X 11.5mm... you could spin the axle inside the torque arm with very little hand pressure. Useless when you are putting 40 amps into that front motor.... So, I built my own... sort of a combination between the J shaped powerriderstore design and MarkAWs really strong fork reinforcing design....

Only I kind of messed part of my fork cover tube up and couldn't cut a nicely matching replacement piece after three tries, so I gave up and just used hose clamps to finish it. Not as elegant or as strong as Marks, but I think it will do. Will post pictures of that in a day or three.

As to the rear I kind of did an overkill:
First I cut out plates of o-1 steel for the outside of the dropouts that bolt onto holes already in the arms around the dropouts. I actually hardened and tempered them to 'spring' hardness.... Then it dawned on me, that if the worst happened and the axle spun anyway, I'd rather chew up the torque plates than chew off the axles. Oh well.... maybe I'll anneal the darn things before I put them back on.


Then I bent a couple of 10mm wrenches to fit on the inside of the dropouts and welded them to the lower swing arm tube. I don't know if it adds any strength to the swing arm but the spacing worked out perfectly.... Although I'm going to have to remove the right side one when I get the freewheel installed on the motor side plate in Mk2.

The rear swing arm / width between the dropouts was way too wide to bolt in the hubmotor, so I bent it in by tying a piece of seatbelt webbing around the arms and twisting with a three foot long piece of pipe:

I lucked out in that the arms bent in perfectly the first try. alignment is as precise as it was originally.

Great thread! When making the freewheel crank, did you take apart a left crank, or use a right?

And here it is all put together:

That camouflage paint job is about tacky as you can get; I'd NEVER paint a street vehicle like that; I think it looks stupid and juvenile; and Yeah, I even got paint on the tires....
But this thing IS supposed to be stealthy off road and not only do I want it to be that way when I'm trying to sneak up on the wild critters to take their pictures, If I have to leave it in the woods somewhere and hike away from it, I don't want it to be bright and shiny where someone will see it and steal it.

I only got one good ride in on it before I ruined a battery pack, but overall, I was pretty pleased with its performance. I don't know what the top speed is, since my speedometer wouldn't function due to all the magnetic fields floating around, regardless of how far out I put the magnet and sensor, and my GPS wouldn't get a satellite lock either :x . But on the flat, it goes nearly as fast as I imagine I'd ever really need to go. And it hauls its 100 pounds and my 250 pounds up some pretty steep hills without pedaling (but at 88Amps... ouch.). Works pretty well off road, but with our total weight, I got to be careful of drop offs or bumps of more than a few inches, and think well ahead of the terrain. The steepest roads we have around here (and we are talking nearly as steep as Filbert or 22nd st in San Francisco) do require some pedaling... but not a painful amount.

My one good ride was about 15 miles: 5 miles of fairly flat paved, 5 miles of fairly steep up and down paved, and five miles of pretty rugged off road, up down and sideways.

And that leads to the very embarrassing and expensive battery pack destruction.:

A little after I turned around on my off road section, I stopped to tighten some screws on my rear rack assembly. It was real loose. (lesson #1: Locktite or lock washers on every screw , nut and bolt.)
Well, I didn't notice it until 400 ft from home; (after 2 more miles of off road and 3 more miles of hilly paved road), but when I was fixing the rear rack I flipped the switch on the inside of the rear battery pack to off by accident. So, I rode 5 miles on just my front battery pack. Sucking 88.8 amps out of it several times, for more than a minute. That is 4.4C... out of a batteries pack rated at maximum of 2C.. (lesson #2: if you are running more than one battery pack, don't put in a switch in them that can get turned off accidentally)
The 40A Maxi-fuse in the battery pack didn't blow even at fairly extended periods of 80+A. (Lesson #3 Don't trust Scosche brand fuses from WalMarts car stereo department. (my other pack uses 40A BUSS ATC fuses and they have blown right where they are supposed to)

So, when I got to the house, My rear battery pack was pretty hot.... just short of alarmingly so. I took it out and stuck it in the refrigerator to cool it off quickly. Let it sit there for a few hours. When I checked pack voltage, it showed 31.4 V... well... not good, for a resting voltage, but not necessarily a disaster. Hook it up to the lower amp (1.3A charger). Check often.... Seems to be recovering OK. After a few hours it is up to 3.66V ; not getting hot... OK, lets hook up the 3A charger instead. After a couple of hours, it is up to 38.7V, and only slightly warm. YAY! Looks like it will be OK! Maybe a little diminished capacity, but I can live with it.

Then I did the really stupid thing... The thing that could have led to a real disaster: The thing that I knew better than to do, but just wasn't thinking.: I put it in parallel with the other pack, which was at about 40.5V, and hooked in the charger to top them both off and went to bed.

Got up the next morning and the abused battery pack was hotter'n a two dollar pistol after a whole box of magnum loads in one minute. The hot melt glue I used in constructing the packs was in liquid form. (Lesson #4, and the BIG one: DO NOT hook two unbalanced packs together: In this case I was, in effect, charging an already abused pack at over 2.2C.) As Red Foreman would say: "You are a dumbass RLT"

The really amazing thing is that none of the batteries 'vented with flame'. I think that maybe four of them blew their safety valves slightly, but I can't tell for sure without doing a further autopsy, that I think I'd rather skip.
Not even one bulged case.

Way, Way Way past my bedtime: Next installment tomorrow: the rest of my plans for Project 1 Mk2: It will still probably be a rolling time bomb,,, but hopefully a more refined one.

TylerDurden said:

Great thread! When making the freewheel crank, did you take apart a left crank, or use a right?

Click to expand...

I just bought the crank set from Cyclone... both sides... and used a regular $7.00 freewheel 16T sprocket form TNCscooters that I already had laying around, to weld the larger cog to. the freewheel is on the normal (right) side of the bike...
Although It could just as easily be flipped and used on the left side... Just install the fixed sprocket on the other motor side plate, or flip the wheel and reverse the current. Pretty flexible setup, now that you got me thinking about it that way.

I'm going to bed.
Later guys..

RLT said:

That camouflage paint job is about tacky as you can get; I'd NEVER paint a street vehicle like that; I think it looks stupid and juvenile; and Yeah, I even got paint on the tires.

Click to expand...

It's perfect. 8)

:lol:

you rock TD


cheers,

D

A nice stealthy build and a descriptive thread! Well done! Hope you got the rest you needed, RLT.

I've considered building a rear-wheel drive with a front-mount battery. This would drive the rear for better traction, and balance the rear motor weight with a front-mount battery.

But you took it a step further, and made a 2WD bike with both front & rear batteries!

Does the front battery bag sway forward & back when you ride?

When I tried a handlebar bag with 10 lbs of li-ion I noticed some sway. The only way I thought of to cure it would be to build a bracket to steady both bag & battery.

On connecting the front & back batteries: Have you considered a Schottky diode pair?

http://ebikes.ca/ has 40A ones, or you could make one from DigiKey parts. This would soak up some watts though.

Another idea is to build 5s8p packs (instead of 10s4p) and connect front & rear packs in series always. This way, both packs have to be connected or the bike just doesn't go.

For charging, I would never connect the packs in parallel. It's too risky IMO, but I can understand if you were in a hurry for another ride.

I make it a personal rule to *never* charge li-ion while I sleep, or otherwise am unable to react quickly if something should go wrong.

Does the front battery bag sway forward & back when you ride?

Click to expand...

I have it tied down, so sway is minimal. I'm 85% sure I'm going to build a beefy metal rack for the front and 99% sure I'm going to replace the rear rack with something with more structural support in Mk2.

On connecting the front & back batteries: Have you considered a Schottky diode pair?

Click to expand...

Yes indeed. Unfortunately I found out about it AFTER finishing Mk1. I've been meaning to ask how to build / connect one, since I'd rather build it myself rather than buying the one from ebikes.ca... (although just buying it would be easier). However..I have several 20200s and a couple of 20100s left over from my 120V controller upgrade project, and I might as well do it myself if it makes any sense to do so..

For charging, I would never connect the packs in parallel.

Click to expand...

Me neither, anymore.
I'm actually going to give the single cell charger idea a try for the next battery packs... Even if I get those BMS boards to work properly.

I make it a personal rule to *never* charge li-ion while I sleep, or otherwise am unable to react quickly if something should go wrong.

Click to expand...

What can I say.... I like to live dangerously, and that's about the ONLY excitement I get in my old age.
While I never do it that way on the first charge/discharge cycle, I've been charging LiIons and LiPos overnight for years with no problems, willing to accept the risk (I do charge them either in my metal charging can with ceramic tile on the bottom for the small batteries, or in my ceramic tiled shower for the big packs.
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OK, lets see: plans for Mk2:
Already mentioned probably going to run the motors, controllers and battery packs electrically isolated from each other other than the throttle.
I'm not absolutely sure about that though: I can think of as many good reasons to do it independently, as I can to keep the power 'blended' like it was set up originally.
I wouldn't mind some input from you more experienced and technically savvy guys on which way would be best.

One reason I decided to go with using both of the OEM controllers rather than modding a single YiYun or other cheap controller to handle the the combined power (or buy a Kelly controller) is I wanted the redundancy... If one motor / controller / battery pack blows, I want to still be able to cruise home under something more than pedal power.... So reliability/redundancy is still a major requirement.

Already mentioned making the freewheel adapter for the rear motor. I might crank up the lathe and try to get partially started on that tonight. Not sure whether to keep the freewheel chainring, or go back to the fixed derailleur pedals and chainring. .... I'm sort of planning on making both the front (if I keep it)freewheel, and the rear one with two cogs, (Equal size/ tooth count, but opposite gearing to give me a two speed pedaling range with a single sized chain and no idler. Probably manually shifted since rigging up derailleurs to do it is a little too tricky to be worth the effort for my needs.

Already mentioned the front and rear racks to secure the batteries.

Headlights.... Going to be fancy homemade with Cree and/or Seoul high power LEDS. Probably three of them with some semi-exotic optics..... Before I got interested in e-bikes building LED lights was my hobby/passion/part time business . So no problems there other than getting up the time & energy to do it.

Figure out what kind of mount to make for my Watts Up /Cycle Analyst / Eagle Tree meters and for my PPC GPS.

And of course power source:
After much consideration, I'm sticking with the 32650s I started with. If I don't do many more stupid things with them, it gives me the longest range at the lowest price. Maybe in a year or two, the safer, higher C chemistries will come down in price enough to make switching over a smart idea financially as well as for the safety factor.

When my new batteries get here from China, the still good 4P10s pack is going to be rebuilt ... I'm definitely going to go to 5P... Give me a little more safety margin on the current draw even if I do stupid stuff again. I think I'm going to go to 11S as well. With single cell charging it should work out just as easy to manage as 10S, and give me just that much more get up and go. So. twin 25AH packs, at either 36V or 40V... That ought to get me closer to my 30 mile range goal. Course if I lived or intended to ride in the flat lands, 50AH would haul even my lard an impressive distance. But I like the mountains.

Well, there must be more, but that's all I can think of for now.

RLT: Why is the Mk1 picture altered? Specifically, the background clearly is wrong, except for the part within the wheels. A weird question, I know.

TylerDurden: Wow, that's really stealthy -- you can park it in front of a junkyard and it'll blend right in!

I love it, 88 amps uphill hell yeah! And the paintjob is awesome altho paint on the tires was indeed a faux-pas imo.

Wow! What a nice build. Great job. I hope you can get some awesome pictures.

CGameProgrammer said:

RLT: Why is the Mk1 picture altered? Specifically, the background clearly is wrong, except for the part within the wheels. A weird question, I know.

Click to expand...

I didn't use a flash and the shadows messed up some of the significant details, so I photoshopped the stuff that was annoying me out. Didn't want to spend any more time than necessary on it, so I did a sloppy job around the edges, and didn't even try to clone stuff out between the spokes. I'm good enough at "fauxtography' to get a job working for Reuters, but it takes too much time to try to achieve perfection for something like that shot. I was originally going to post a lower resolution photo where the sloppiness isn't as obvious, but decided to use the higher res one after all.

If that photo creates so much cognitive dissonance , I can re-shoot it with proper studio lighting if you wish

For any one interested, I do have some nearly halfway decent landscape photos of the west/southwest USA up at cafepress:
http://www.cafepress.com/southwestphoto/

As I get started on the MK2 modifications, I want to let you all know about another QC related problem with the Wilderness Electric motors before I forget.

I took the 'power input'' side plate off my rear motor for the first time when I ran into some dimensional problems after putting a freewheel hub adapter on the other side (more on that in a day or so).

I discovered that the screw holding the + lead to the brush connection was very loose... About three turns from falling off. Because it was so loose, it was causing some significant electrical inefficiencies, and actually scorched the brush holder. Not really bad: didn't char it or anything, but it was slightly discolored from the heat. I imagine if I hadn't burned out the front battery pack and gotten in a few more serious rides, it would have led to some bad things happening inside. I'll see if I can post a photo or two on my next big update.

And I also noted that the braided wire leads on the brushes are pretty thin... I'd guess only about 16ga. And the leads into the motor seem to be only 14ga cheap primary wire at best; about like lamp wire with slightly heavier insulation. I'm going to use some braided solder wick wire to beef up the brush wires and some 4mm silicone wire to replace the leads. That means that I'll have to slightly widen the channel in the axle that the wires pass through; I hate to weaken it any further, but .02" should be enough, and having some decent wires to handle the 40 amps that go into this motor on the hills will be worth it, I think.... (I hope).

Guess I'd better open up the front motor and do that too.

And I also noted when cleaning up the stator after doing some threading on the axle that a few of the magnets weren't very well glued on. I hope that the super glue and epoxy putty I put in the gaps keep them from flying off somewhere down the trail.

Wilderness Energy / Wuxi Aote Mechanical Electrical company needs to really work on their quality control.

After looking at the closeup photo of the brush holder that had the loose connection there WAS some actual damage.... I couldn't see it by eye, but the photo shows that there is a tiny crack in the center of the overheated area:


Ah the wonders of an old Nikon 950 in Macro mode. I love that camera even if it is only 2.1 MegaPixels

Wow, they are here already... And they weren't shipped from Hong Kong until Friday.

Can anyone tell me why it takes UPS two weeks to get me something from a neighboring state, but only over the weekend to get something from CHINA ?????
Same company, same driver on the last leg of the journey, and not much more cost for shipping

Anyway, here are my 110 new 32650 Lithium 'hand grenades' as my old friends from Candlepowerforums call them*, and the 11 new single cell chargers to get them ready to explode.
View attachment 1


Well, time to start charging 'em and running them through the CBAII so I can get my sub assemblys balanced and weed out any 'duds'. I hope they are at least as good as my last batch... which were blue.... Black heat shrink means that they are more powerful, right? ?

Doing the testing will give me time to get some 5.5mm X2.1mm power jacks (to fit the plugs on the chargers ) from Mouser or Digikey... Wouldn't you just know it, I have plenty of 2.5mm pin 5.5mm jacks around here already, but I only have 2 of the 2.1mm pin ones. ... I'm going to build them into the packs; seems like the easiest solution for charging and non-BMS balancing etc.. Maybe a little bulkier than using JST or similar connections, but a little less trouble and more durable ?.

Do you guys think I ought to stick with running dual 10S5P packs, or bump it up to 11S5P? From the standpoint of overall reliability of the machine and making for a little less stress to the batteries themselves. The little extra speed provided by the 10% greater voltage isn't really something important to me... But the other stuff is. The controllers should handle it OK without further modification.

* (My misadventures with one of the first packs as related above kind of proves that they are pretty well made and not as dangerous as they could be.

Here is the first step in improving -upgrading and plain old fixing things:

Beef up those wimpy brush connecting wires:

What I did was open up some of my .193 wide solder wick and slip it over the original braided wire. Soldered with higher temp silver bearing solder...
(Hopefully it won't melt, drip down the sides of the brushes and short out the commutator.... I'm not really sure how hot those brushes get when the connections are proper... I know that bad connections get real hot, as I showed a couple of posts above.)
I also used '4mm' silicone wire to replace the 14 ga wire for the motor power leads. Had to widen the slot in the axle that the wires pass through a bit. Thought I took a couple photos of that, but I can't find them.

Had just about psyched myself up to start making a freewheel adapter from scratch on my lathe, despite my 'threading anxiety' when I came up with an easier way. I cut the end off of a BMX freewheel hub that I already had,

Then chucked it in the lathe and profiled it just a bit to more perfectly fit the motor side plate; then bored the other side of the hub a little larger to replace the original 10mm bore bearing with a 6001 bearing with a 12mm bore to fit the hubmotor axle... I don't know if the bearing is absolutely necessary, but I feel a little better with it in there.


Also had to put the side plate in the lathe and trim down the - whatever you call it- ridge over the bearing/axle. There seems to be plenty of excess material, so given the reinforcement provided by the freewheel adapter, I'm not worried about having weakened it.


Then drilled and tapped the sideplate to match the spoke holes in the old hub. (36) 3mmX.7mm holes. Didn't fully trust the threads in the aluminum to hold... the side plate isn't very thick at that point, so I put nuts on the inside too. Probably overkill since there ARE 36 of them, but I feel safer with the nuts there too. And of course, put Loctite on every one of them.

Of course the axle on that side was too short with the added width of the freewheel. I could only get about half the nut threaded on without the torque plates and one thread on with the torque plate (Which, of course, I managed to strip). There was plenty of room on the other side... an unneeded inch or so of thread... So the elegant solution would have been to grind off the welds holding the axle to the stator, and press the axle through a little farther, and re-weld it. But I was afraid that I might warp the stator and possibly damage the adhesive holding the magnets by doing that.

But I have a lot of faith in my torque plates being able to keep the axle from spinning,... (Maybe not with a high power single motor like a 5403 at 72V, but with my torque spread between two motors and four dropouts with torque plates/arms, I'm not worried.)... so all I really had to worry about is keeping the rear dropouts from spreading. So, I drilled and tapped the end of the axle for a 6MM bolt.
View attachment 1

That and a couple of washers should keep everything secure.

That's it for now. More to come

RLT said:

Ah the wonders of an old Nikon 950 in Macro mode. I love that camera even if it is only 2.1 MegaPixels

Click to expand...

I still have my 990

990s & 995 are good too. I wish they had kept on with that design, while keeping pace with the other developments in sensors and image processors. I have tried to get the last of the breed, a 4500, but they sell for more $ used than they did new when they were discontinued.

I have a Minolta 7D now but I still use my Coolpix a lot. I think the 990 was the peak of that design - just enough megapixels and before they started dumbing it down!

My Minolta 7i can't take a bad photo no matter how hard I try. It's by far my favorite camera, even though I have several much fancier, newer and vastly more expensive ones including a couple of DSLRs. But for macros, my 950 is the one I turn to if I don't need a lot of pixels.

RLT said:

But for macros, my 950 is the one I turn to if I don't need a lot of pixels.

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Same here. The swivel design is perfect for macro work plus small sensor size and close focusing

OK- Finished testing the cells for the replacement battery pack with my CBA. So, I'm going to start tab welding tonight.

Kind of interesting results from the testing. This new batch must be a slightly different chemistry or construction than the previous ones... (Or maybe that Black heat shrink DOES make a difference )

These new cells have significantly more capacity than the previous ones. At 3.50 amps, of the 55 cells tested so far, I got an average of 5.05-5.06 AH out of them, compared to an average of around 4.90 AH out of the others. Several of the new ones actually made it to 5.2 AH and only about 4 of them were less than 5.00AH with a low of 4.94.

But while the older ones with 3.5A on the CBA held somewhere between 3.93V and 4.10V for a couple of minutes, the new ones all drop to 3.82-3.87V within a few seconds.

Since I decided that I'd change to 5P 11S instead of the 4P 10s of my original packs, I had planned to just add another of the new batteries to each parallel string of my still good old pack, and another string of 5P to the end of it to make it 11S.

But due to the different performance curves, I don't think that is a very good idea, from a balancing standpoint.

Fortunately I bought enough of the new ones to build two identical packs, but only exactly enough. So if any of the remaining 55 test bad or I mess something up building them, or one or more goes bad somewhere down the road, I'm kind of screwed. SO, wish me luck.

At least I'll have an extra 36V/20AH pack to start the next project with. (I'm now thinking a trike, geared, with a big box on the back to haul groceries and firewood when Gasoline and Natural Gas double in price after the next election. )
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I just asked the following questions over on Truckerzero's dual motor thread ( http://endless-sphere.com/forums/viewtopic.php?f=2&t=4073) in the technical section, but let me repeat them here, in case you miss them over there:
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Now that I am ready to start building my replacement battery pack, I need to decide pretty soon whether to stay with the controllers being 'blended' as originally set up, or if I should completely isolate both battery packs, and both controllers. I see as many advantages as disadvantages in both methods, so I need help deciding which way to go.

And assuming that I do go for isolating things, when I don't need that extra torque, is it smarter OVERALL to just turn off one whole system, or let the two share the load? I do believe that by sharing the load it will be easier on all the electro-mechanical components. And with both systems operating (basically) equally, there won't be a big power differential between the two battery packs when I do have to switch that other motor back on....

Although I COULD also keep the controllers and battery packs 'blended' and just switch off the unneeded motor, instead of the controller.... That would keep the two battery packs balanced so there isn't that big power differential between motors when I do switch back on.

If anyone knows the answers to those questions, you can save me time and frustration (and maybe even money) rather than figuring it out by experimentation. I'd appreciate your thoughts on the subject, even if you don't know them for absolute facts.

Thanks!