Cuda-E - 4000 watt Shumaker drive upgrade

[www.recumbents.com]

Several years ago I build a recumbent electric bike using donor parts from a Mongoose 450 watt electric motocross bike.


Here's the ES thread: viewtopic.php?f=6&t=5132
And my build log: http://www.recumbents.com/wisil/e-bent/e-cuda.htm

It went 30 MPH, but didn't get there fast, and was wimpy on the hills. Since then I have learned a lot, and am ready to take a foray into the RC world. This bike will be upgraded with a Shumaker single stage drivetrain, and powered by an Astroflight 4000 watt motor.



I looked at a bunch of option for batteries, but finally decided on the four 6s 30C Li-Po pack solution for 10Ah and 44V.
Here's the new build blog: http://www.recumbents.com/wisil/e-bent/ ... efault.htm
I'll post updates here as well.

Next steps are to build up a new set of wheels and mod the rear subframe to accept the MTB hub.

-Warren.

[spinningmagnets]

Looks like you've got the fever bad....recumbent....making your own frame...RC motor...44V of LiPo...Schumaker reduction...

We've seen this type of thing before around here. Try very hard to get your wife involved as much as possible as soon as possible, before you drift too far apart!

Soon she'll be meeting other women once a week. "Hi, my name is Helen,...and my husband is an Endless-Sphere member".

"Relax Helen, you're among friends...tell us how it all started...we're listening"

edit: "... have not kept up with the hours, but I would guess that I have at least 24 hours in just cnc time to date. I have not been in a hurry with this build because I have two functioning ebikes, but I do need to get it finished, so I can start build 6. -Bubba"
http://endless-sphere.com/forums/viewtopic.php?f=28&t=20245&start=60#p330558

[www.recumbents.com]

Oh she should be used to it by now, but she still doesn't like it.

I have been building stuff like this for about 15 years now.


-Warren.

[liveforphysics]

Oh she should be used to it by now, but she still doesn't like it.

I have been building stuff like this for about 15 years now.


-Warren.

NICE!

5-10kw in that thing with the right gearing and the right road would be REALLY fun.

[AussieJester]

Soon she'll be meeting other women once a week. "Hi, my name is Helen,...and my husband is an Endless-Sphere member".

"Relax Helen, you're among friends...tell us how it all started...we're listening"

ROFLMAO...that got me by surprise very funny

*subscribed* anything involving a Matt Shumaker drive and 'rc' motor has to be worth a second look...

best of luck buddy, with both the build and continued success with the wife's approval haha

KiM

[recumpence]

Hey Warren,

It will be good to see another RC build happening. It seems strange I do not see more builds considering the number of drives I have sold.

I like seeing the differing applications used for each.

Matt

[www.recumbents.com]

Today was a holiday, and I had a bit of free time, so I built up the drive wheel:



That's a 52 tooth chainring on a 20 inch (406mm) wheel.

I'm not sure why more people don't build their own wheels. You do need a truing stand, but other than being a little time consuming, it's not too difficult.

I also ordered the Breezer dropouts which I'll braze into the old Mongoose rear subframe.

This is the current rear dropout. "Opus the Poet" suggests that I just spread the dropouts a 1/2 inch rather than building a whole new rear subframe. Good idea. If that works I'll cut out the rear facing dropouts and braze in a Breezer style dropout.



-Warren.

[www.recumbents.com]

I removed the old rear wheel and 450 watt drive unit from the rear sub-frame. I was able to wedge the new rear wheel in, so I won't have to expand the dropouts too far. The new drive unit also fits in and lines up well. In this picture the drive drive unit is sitting on a pedal to provide the proper clearance for the drive pulley.


I need to make an adaptor bracket to hold the drive unit in place. It will allow the drive unit to bolt to the existing mounting plate in the subframe.

The Breezer dropouts should arrive soon.

I will be wiring the motor in "Wye" configuration, which means I'll tie all the red wires together and then run the black wires to the RC controller. Does it matter what order the wires are in, or does the controller do magic and figure out what order to fire the windings in?

-Warren.

[recumpence]

Warren,

Motor direction is reversed by simply reversing any two of the three wires from the controller to the motor. Easy as pie.

The setup is looking really clean. I am glad you do not need to build and entire new triangle.

Your controller showed up yesterday as did the regulators for throttles. So, I will have them all programmed and assembled for you very soon.

Matt

[jmygann]

Looks great ... gives me ideas for my 20" rear wheel

what RPM will the reduced motor be most running at ?

with the 52T gear and 20" rim/wheel, what speed are you looking at ?

[recumpence]

His motor will run at about 7,000 rpm max. I would guess most cruising will be at, or slighly below this number.

I believe top speed will be in the 28 to 31mph range with his current gearing. This seems to change depending on a number of factors, though. The 10 turn 3210 motors are hugely efficient and like to be run in their peak efficiency range.

Matt

[jmygann]

His motor will run at about 7,000 rpm max. I would guess most cruising will be at, or slighly below this number.

I believe top speed will be in the 28 to 31mph range with his current gearing. This seems to change depending on a number of factors, though. The 10 turn 3210 motors are hugely efficient and like to be run in their peak efficiency range.

Matt

7000 max .... is that without load ?

peak efficiency range is ??

What would be the real world rpm at 20-25 mph ? .85 factor ?

[recumpence]

These motors do not bog down much under load.

Peak efficiency is a touch over 94%.

Matt

[jmygann]

what is the motor reduction ? at 7000 rpm the 16t sprocket will be turning ?? rpm

[www.recumbents.com]

The Astro 3210 is rated at 275 RPM per volt. I'm planning on running it at about 48V, so that means a potential top speed of 13,200 RPM, I'm assuming that is unloaded. Matt says it's more like 7,000 RPM under load. It is attached to Matt's single stage step-down drive unit which is 3.5 to 1. This reduces the RPM to 2,000 RPM.

The output from the drive unit is a 16 tooth BMX freewheel, which drives the 52 tooth chainring. The gear inch calculator (http://www.recumbents.com/wisil/gearinches.asp) with an 18" dia tire and this gearing shows a speed of 32MPH.

I fabbed up the mounting bracket yesterday, but only got it about half brazed before my torch ran out of gas. Fortunately, it's tacked together enough to test mount it.

-Warren.

[recumpence]

Hey Warren,

The 6 turn 3210 is 275 KV. Yours is a 10 turn. So, it will be closer to 7,000 rpm. I do not remember the exact KV off the top of my head.

Matt

[www.recumbents.com]

Here's the drivetrain mounted in the new bracket, with the chain in place and the wheel in the right position. This shows me where I need to mount to Breezer dropouts. The bracket allows the drive unit to slide fore and aft about 3/4". This (theoretically) is enough to adjust it so the chain is tight and no idler is needed. I may need to add a chain guide on the return side of the big chainring to ensure that the chain does not pop off under load.



The drive unit is a snug fit in the frame, but it fits! The chain has a couple clearance issues. On the top side it hits the canti-brake mount. On the bottom it hits the frame bracket. I can solve this by using a slightly smaller chainring, OR I can file chain clearance on the bottom, hack off the canti brakes, and try to fit a disk brake.

A disk brake requires about 3/4" clearance on the back side. Currently I only have 1/2". It looks like there may be room though for a 1/4" spacer and there may still be clearance for the brake rotor. Hmm...

-Warren.

[recumpence]

Warren,

If need be, I can get ahold of a micro freewheel adaptor so you can run a Odyssey 13 tooth freewheel. That will drop the chain and allow for a smaller chainring.

Also, the guide would need to be on the slack/return side of the chain (bottom) not the power side to funnel the chain onto the large sprocket.

At any rate, it looks really nice!

I have your controller here and I just need to solder up your throttle assembly.

Matt

[www.recumbents.com]

Hi Matt,

Cool, the freewheel adapter would be perfect, can you source that for me?

Let me know when the throttle is ready and we can meet up for lunch again. I can test it with my old 24V 20Ah 1C battery pack until I get the LiPo solution built up.

-Warren.

[recumpence]

OK, Warren. I will contact the shop that makes those adaptors and source one for you.

I will get ahold of you soon.

Matt

[www.recumbents.com]

While I wait for the new freewheel to arrive at Matt's house, I am firming up my decisions for the battery system.

I'll be buying four of the 5Ah 6S 30C Li-Pos from HobbyKing soon. Looks like they are now on backorder from the USA warehouse. I will run them in series and parallel for 44V, 10Ah.
I just ordered a MeanWell 12V 29A power supply from China via e-bay. - $55
I am planning on ordering two of the Bantam bc6dc balancing chargers soon to allow charging all 4 packs at once each night.

If it ends up that I need to top off the battery pack at work, I'm thinking I'll just need a small 2A - 48V charger, to charge the whole pack at once. Are there any small, low power chargers with a built in cutoff at a specific voltage?

I'd like to charge the Li-Po pack at night in my garage without removing it from the bike, but I may be dreaming there. If I built a box for the Li-Po out of Carbon Fiber, would that be enough of a fireproof box to allow me to charge the batteries while still on the bike? Would it be better to just buy a LiPo battery bag?

-Warren.

[www.recumbents.com]

Matt says that to top off the pack between nightly balance/charges, I can use something like the Meanwell 48 volt 350 watt power supply to charge the whole pack at once. He recommends a voltage meter to ensure the voltage is set properly and to let me know when it's done charging. When the power supply gets to the set voltage (49.5V looks safe), it will stop dumping current into the batteries.

Because i will be making the battery pack so it can be easily removed, I'll just make a nice fireproof spot in my garage for charging.

-Warren.

[AussieJester]

I'd like to charge the Li-Po pack at night in my garage without removing it from the bike, but I may be dreaming there. If I built a box for the Li-Po out of Carbon Fiber, would that be enough of a fireproof box to allow me to charge the batteries while still on the bike? Would it be better to just buy a LiPo battery bag?

I charge my packs on the bike in a fiberglass enclosure with a meanwel PSU in my garage during the day, so no i don't think your dreaming, some might say your a lil over concerned about the whole 'fire' thing with the fire proof box and lipo battery bag though, but then i guess we can never be too careful about fires. Be sure to buy the MeanWell Current Limiter/Charge Controller for the 48v meanwel if you decide to go with it for the bulk charging side of things

Best of luck

KiM

[www.recumbents.com]

Thanks Kim. Looks like an excellent addition. I especially like the LED to tell you when it's charged!

I ordered four of the 25C 5000ma 6C Turnigys today from the HK USA warehouse. No turning back now!

I was thinking about LVC and looked at the TPPacks solution and a couple LV noise makers but hey! It turns out that the Castle Creations controllers have the LVC functionality built in. Matt is busy programming all the spiffy settings in the controller so it reduces power if the battery drops too low. Because I will be balance/charging nightly, the only way the batteries will discharge unevenly is is one of the cells is fried, so an LVC on the entire pack rather than each separate cell should be fine.

-Warren.

[www.recumbents.com]

It sounds like a lot of the folks here are bulk charging rather than balance charging. I can see why, to balance charge a 12s 2P pack properly, you have to break it apart and charge each pack separately, which is a PITA. Mattt says that he usually just balances each pack when new, and that they stay balanced after that (unless they are abused by running them down too low!) I'm now thinking:

* Balance charge each pack when new.
* Bulk charge on a daily basis
* Balance charge each pack on the weekend, or even less frequently if it looks like the packs are staying in balance.

So I need two separate charging systems.

1) 12V Meanwell + Bantam e-Station BC6DC (balance charger) (ordered!)
2) 48V Meanwell + TPPacks current limiter (bulk charger)

I have a seat back bag that the batteries should fit into the bottom of. I'll build a fiberglass box to hold the batteries, wires, etc. Controller will be fastened to the outside of the box so it's kept cooler. Box will have a downward facing vent tube that will go through a hole in the bag.

Has anyone found a nice box that the Meanwell power supplies fit in? I don't want to damage the TPPacks board when it's bouncing around in my bike bag.

-Warren.