Dave's 80:1 RC mid drive kit build log

knurf said:
Those ekfan rings seem to be made of some kind of sturdy cheese rather than 7075. I never seen failures like this with the expensive stuff, and I've tried a lot bigger rings before (hope 44t @ 3kw+ just fine).
Wow--I havent' seen that kind of destruction on a middrive since I had the overvolted powerchair motors on CrazyBike2. :shock: (repetition of that problem was why I eventually went hubmotor on it).
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Hello !

I want to move the talon on the top of the motor and make a plastic housing with my -new- 3D printer, because in France there is a lot of mud and water during the winter.
At the same time, I will try to improve the thermal dissipation, during summer I've sometimes a thermal fault.

Someone knows where to find a better thermal dissipator for the Talon?


@knurf: I was close to order the same. Thanks to you for the feedback!
 
The Talon has a nice flat back side for attaching heat sinks or an aluminum plate. If you enclose the Talon, I'd suggest sealing around the back so it remains exposed for heat transfer. There are a variety of easy heat sinks available on Amazon or electronics retailers, look for computer heatsinks. These can be super cheap and the smaller size may let you arrange them easily:

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Been a while since I updated here as I spent much of last year rebuilding 3220 kit I have here into something else entirely different from it's original build.

I have now modified a stealth style frame and mounted the tangent set up as a mid drive still directly to the swing arm, built a new sony vtc5a 18650 12s16p pack (with lots of help) that sits inside the frame. The ESC is mounted to a thick aluminium heat sink, again inside the frame box and all connectors (except the shunt...working on it) and cabling is 8awg and xt150.

I have been running it with the alfine 8 for about 700 miles or so now at a guess and it is just starting to show signs of slipping gears in the middle range since this new pack can pack such a huge wallop.

I have a new much bigger shunt to be installed as the stock one is only 50 amp continuous rating and 75mv...guessing this along with xt90 and series connectors running 10awg (!) were not helping voltage sag issues. (sag has reduced by simply upping to xt150 so far)

Just working on figuring out the correct wiring of the shunt to the CA3 and I'll see how this 300amp 50mv rated shunt helps!

Then I will play with single speed set ups and sprocket sizes for a while to see how it goes.

Thanks Dave, this little unit is holding up very well!
 
Using my old 3210 in a 40:1 gearbox, a large front chain ring, a snowy uphill section and more than 90 amps, I finally tore through my frame (Specialized Epic 2006). It cut the weld clean through, in about the beefiest place of the frame, my money would have been on somewhere in the complicated linkage. Was good for about 2.5 years of Tangent bashing, including 1 year of winter commuting.

Very undramatic and no risk for injury but a 4km walk of shame, dragging the corpse.. Luckily I have a spare 2005 frame laying around so I ain't even mad :D

 
Good effort! What kind of mileage do you have on it?
Maybe 5000km human powered + around 4000km under Tangent power, more than half spent commuting. I could feel it flex considerably at peak power, so I'm very proud of it..
 
knurf said:
Good effort! What kind of mileage do you have on it?
Maybe 5000km human powered + around 4000km under Tangent power, more than half spent commuting. I could feel it flex considerably at peak power, so I'm very proud of it..

Proud of the frame for lasting so long or the kit for having the power needed to snap it?:)
 
Proud of the frame for lasting so long or the kit for having the power needed to snap it?:)
Haha obviously both :)
But I'm probably not going to venture much into 4kw land with the replacement frame.
 
I am just about to up the shunt size and have uprated all connectors to xt150 to see what happens :)
 
Well I have just test run the bike with the new shunt in place...holy cow is all I have to say...gears? Which is good because this upgrade fianlly tore my alfine 8 apart:) Who needs them now?! What a nuts upgrade...at first...


1) I perhaps wrongly assumed I then needed to alter the CA3 rshunt ohm value to match the new shunt (old grin rshunt value was 1 ohm) so I changed it to show 0.1666 (new shunt is 50mv and 300a = 0.16666?) and the next test ride the power "upgrade" has gone and power levels feel about the same as they were with the old shunt in place...did I need to alter the rshunt value at all?!

3) I wired in a key switch for the CA3 for completeness, which was just a simple break in the power wire. So I now have a main breaker on the battery power line in the form of an anti spark xt150 loop key which arms the ESC and the key which powers the CA3. If I leave the main battery breaker connected but turn the key for the CA3 off and then on again the bike enters some kind of cruise control and just sends power to the motor that can only be stopped if I turn the key off again...a little disconcerting especially as I have the three power modes set so that it is in low speed activated mode on first power up :) This doesn't happen if I pull the loop key and restart the whole procedure.

Any help or direction pointing is most appreciated?

I have also asked these questions in the CA beta thread fwiw
 
Ham said:
Well I have just test run the bike with the new shunt in place...holy cow is all I have to say...gears? Which is good because this upgrade fianlly tore my alfine 8 apart:) Who needs them now?! What a nuts upgrade...at first...

What is this upgrade, I'm not following, must have missed it in the thread.

Is it just a different resistor? What does it allow for?
 
Dave

I've got one of your earliest kits, v2 I think. Does the new maintenance protocol and internal apply? Mine has a screw cap to inject the lube. Is that no longer the way to do it?

Thanks
 
12-C said:
Ham said:
Well I have just test run the bike with the new shunt in place...holy cow is all I have to say...gears? Which is good because this upgrade fianlly tore my alfine 8 apart:) Who needs them now?! What a nuts upgrade...at first...

What is this upgrade, I'm not following, must have missed it in the thread.

Is it just a different resistor? What does it allow for?

The shunt from grin is 100 amp peak rated and 50 continuous so in an effort to track my voltage sag issues I have been uprating parts along the line...moved to a massive shunt (300amp), all awg 8 and xt 150's everywhere...better so far. Now just to add another few strips of nickel to the battery pack for even less resistance in the line
 
There's no need to disassemble the kits with the grease port. Just add 2-3mL Vigogrease RE0 every 3 to 4 rides or about every 100miles or so. Old grease forced out by the fresh, happy gears.
 
Evening folks,

I have just, finally, destroyed my crank freewheel on my Tangent kit and need a replacement. I am happy with either the Cyclone heavy duty or the White industries heavy duty one:

does any one know where I can get either in the UK or EU as I could really do with it being back on the road ASAP as it is my commuter bike.

Thanks in advance
 
Has anyone heard from dave.

I am having problems with the electronics and he has stopped replying to emails.

Its been about 3 weeks now.

Kinda worried he is in hospital or something as he always replied super promptly in the past.
 
Just as the forum suggested, I did not check the torque on the crank arm bolts, and I lost one during a ride. Found the crank and pedal, but the bolt is long gone.

Does anyone know what standard those crank arm bolts are? I tried one I had laying around and the threads were not right.
 
Hello guys!

Just a message to praise the dave engine. Already more than 1000km without engine break. A real joy. Buy it with your eyes closed. This engine is crazy !!!

:bigthumb:
 
davius1911 said:
Just as the forum suggested, I did not check the torque on the crank arm bolts, and I lost one during a ride. Found the crank and pedal, but the bolt is long gone.

Does anyone know what standard those crank arm bolts are? I tried one I had laying around and the threads were not right.
I don't have Tangent, but if you post a high resolution photo of a bolt that you still have next to a penny I should be able to tell.
 
My crank bolts have a stamp inside the allen socket - M12

I assume this is what i would need to replace

https://www.ebay.com/itm/Truvativ-M12-Capless-Steel-Crank-Bolts/302916381265?epid=1300141998&hash=item4687392a51:g:rAkAAOSw0kRbvkj7
 
Solaire said:
My crank bolts have a stamp inside the allen socket - M12

I assume this is what i would need to replace

https://www.ebay.com/itm/Truvativ-M12-Capless-Steel-Crank-Bolts/302916381265?epid=1300141998&hash=item4687392a51:g:rAkAAOSw0kRbvkj7

Bingo.
 
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