Tube frame Ebike build

GoldenMotor.com

Tony01

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Nov 28, 2012
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Hey Tom. yeah it is a known problem. The cables come out the same side as rotor. I never ran one because of that, and I had the very strong variable regen. But I did now and this happened. I’ve been running sensorless the last 24 hours and it sucks. Up to ~7mph it’s super rough. I haven’t left my city yet though cause it’s not legal. After I get it legal I’ll take the rotor off and fix the wires.

Today I fabbed up this custom jack for the bike. It will fit the tubes front and back. Used mostly .083” wall 1.5” square tube. For the top I cut that tube in half lengthwise as well as cut the corners and bent reliefs, then spray glued on some carpet. Put a left handed swivel on the jack screw with a piece of heat shrink to sort of keep it straight as tbr socket I welded on can never be perfectly aligned. Now taking a front or rear wheel off is a one man job. I do not own a floor jack yet but if I did I would have made a custom insert for it. I would like to have one just don’t feel like spending money on it.
 

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Tony01

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Nov 28, 2012
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Been riding a lot. Did an 84 mile mountain ride too, maybe 80 miles of pure twisties. Lots of takeaways.

Need a little bit more range. Going to an 80v system by adding two cells in series. Have barely enough space in batt box on the vertical. Gonna make a custom bus bar with a half inch radius 90 bend to connect the little string along bottom of battery and run a super long power cable from end of box (11 strings).

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Smoked my motor hall sensors and/or damaged wiring. Big job to fix for only $8 of parts. Have to tear the motor down completely. Been running in squarewave mode, which runs ok except under 5-6mph, it stutters on takeoff because the controller has no way of knowing rotor position without the halls. Topping out at 69mph for now. With field weakening and higher volts I should see 85mph again.

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Handling. Large rear tire has weak sidewall and just feels super muddy sometimes. I’ll be replacing the 90rr with the 80fr. Put a 70fr, what an unbelievable improvement in performance. Also need to fab up a fork brace.. tighten up the front.

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oh I remember why I put the bigger tires. They looked better.
 

Tony01

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Nov 28, 2012
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So I made a great deal of mods.

Fixed my motor hall sensors. They may not have been smoked, but the wires were completely torn. I found evidence of water damage all over.

Riding it now the controller cuts out at 360amps phase indicating a shorted winding likely due to water damage. But now I can run field weakening and increase top speed above 69mph.

The motor was full of gunk; ferrofluid mixed with bits of black hot glue and wire debris all over. Cleaning it all took 2 hours on its own. PB blaster worked great. The bearing seals separated on the inside and cleaned and repacked those too. Sealed side covers with fresh RTV.

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Put the 80rr tire while the motor was out, what a difference in handling.

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Increased battery voltage to 80v nominal or 22s by adding two cells in series, making a custom 90 degree bus bar and running a long cable back due to odd number of series strings.

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Full charge now technically 92.4v, but my controller is warrantied only to 90v so I only charge to 4.09v per cell. Will increase battery cycle life significantly.

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I hit 78mph on 88v but ran out of road. Yesterday I overcharged to 4.23v at 93v total and hit 86mph. With better fitting pants and jacket I could probably hit 88mph.


Since I’m using the middle ~70% of the battery, charging 80% of that takes about 30 minutes on a Level 2 station at 4100-4500 watts (3900wh pack).

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my best build yet.

Since I have to replace the motor and the rim too, I may go to a higher speed wind and a wider rim to run a fatter tire and have more strength in the rim to prevent dents. Just dented the rim again somehow. Just want better efficiency at freeway speeds. The higher speed wind motors can also handle higher phase and battery amps. Currently with smoked 14.4kv motor I am pushing 17kw, before was pushing 23kw. The 16kv motor can handle ~26kw.
 
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Tony01

Well-Known Member
Nov 28, 2012
1,840
1,947
113
sf bay area

Tony01

Well-Known Member
Nov 28, 2012
1,840
1,947
113
sf bay area
Heat is a big problem. When ambient temp is over 85F I have to take everything easy. I still haven’t put fresh ferrofluid in the motor so it overheats quickly. Hot day and a few hard pulls and it hits 300F internally. Ferrofluid will bridge the gap between the stator and magnets allowing cooling of stator thru heatsinks mounted between the spokes. Been holding off because it’d be $30 worth of wasted FF if I were to replace the motor soon.

Battery gets pretty hot charging at 50 amps, and the charger overheats at 85F and up so I must turn it down to 40 amps. I coulda built the battery with watercooling but it would be difficult as it must be evenly cooled, and that’s an engineering problem on its own. Working towards getting that 500 motorcycle running but the seasons may get cold again by the time I finish it.
 

Tony01

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Nov 28, 2012
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Tom the cheapest way to go is to overspec components. My next projects batteries are 2-3x over spec’d (and this is for a build pushing 70hp). They were very cheap too at just $115/kwh. Regular batts are rated for 1500-2000 cycles, these are for 6000 cycles. That’s 16 years of a cycle a day. Their only drawback is they are 50% heavier and larger than regular batteries. However I could care less, I can make that up in other ways. One of my batt customers did the buy on them with me and I’ll be making a frame for both of us to use them. They’re rated 225a continuous charge or 20kw in a 24s/88v system, but a single handle can provide only 4900-7300w and I’m at 4500w charging now. I could be okay with a 6-7000w charge.
 

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Greg58

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May 1, 2011
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Im old school, I came along in the 60’s - 70’s hod rod era. I ran an auto machine shop for 3-1/2 years and still remember a lot of performance secrets, especially for the 18 degree small block Chevy. Time has passed me by now with all of the engine management systems.
 
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