Giant DH-team offroad build. R&D thread

[manitu]

Hi guys!
I'm new to this forum. I've been interested in EV for some time , but e-bikes used to make me giggle.
We sell those Giant pedelecs at the store I work in , but 250W / 25kph , pedal-assist only bikes does'nt do it for me.
But then I came over a youtube video of the stealth bomber, and now I want one!

So I've decided to build me a commuter ride.

The ride to work is about 6 or 7 miles , first two miles is mostly flat with some 3-4% climbs then comes a short but hard climb wich is like 20% for half a mile . From there , its all downhill at 3-8%.
When going home , I could take the road wich is a 5 mile steady 3-5% climb + 3-4 miles level road , but I would prefer the offroad route.

Got the bike stuff mostly sorted out , as I work part-time in a bike-shop.

*edit: I had a choice between two frames , but I've decided to go for the Giant DH team frame.
Its brand new , has lived on a shelf in the shop since 2004.

I've found one of these electrified on this site , And it sounds like it is a balanced , well handling ride.

Suspension:
I'll use the Marzocchi 888 RC2X fork. (in the giant picture) This is a 35mm DH fork with proper compression and bottom out adjustments. For the rear , the giant has a manitou swinger 6-way with the pedal platform removed, the mongoose has a Fox air-can wich will be swapped for a proper coilover if I go with that frame.

Motor:
The motor goes in the rear hub. I think I'm going with the 9C motor for now ( if you guys think it's strong enough , that is) to save my money for contoller , batteries and machining costs.
My main concern with the motor is its structural integrity. It must have good bearings and a solid housing since jumping will be invoved.

Controller:
This is the hard one. Here in europe we only allow 250w / 25kph (16 mph) AND Pedal-assist only , that means no hand throttle! The speed and wattage problem should be easy to fix , whith this data analyzer/current limiter/dashboard most people here seems to use.
Is there a decent controller available wich can do both hand throttle , and pedal assist? Is it easy and most of all fast to switch settings on the analyzer? can you store two set of settings on it , or do you have to change the actual parameters each time?

Batteries:
I'll get the bike working on four 12V8Ah SLA batteries I've got lying around before I decide on how much LifePo I need.
edit: I'll go for about 80v15ah Lipo from the start.

One problem I see coming is how to mount brake switches on the avid hydraulic handles.. anyone?

Now I need to read a bit more on controllers , to see if I can find the one I need.. Guess it will be easier now when I finally registered on the forum , and can use the search function.

.manitu

 

[itchynackers]

Here is how I tackled the brake problem. I don't have hydraulics, but mechanical trigger shifter disks. This may give you some ideas...
http://endless-sphere.com/forums/viewtopic.php?f=2&t=26221&p=383997#p383997

 

[MadRhino]

If you want to use the bike offroad as you seem to, speeding and jumping, I would recommend to forget about lead batteries. They will deliver poor performance climbing, and add alot of weight. If you want a good climber, you'll have to feed alot of power. Buy a programmable controller and powerfull batteries, so you can easily modify your power setup to meet your expectations.

Build a very tough wheel, my Sun BFM laced with 12 ga spokes and rim washers is beginning to fatigue already, and need frequent trueing after 1000 miles of mountain riding. It doesn't stand jumps as well and I'm about to lace a new one.

 

[manitu]

Hi guys.

I will defo go for LifePo batteries.. The SLA's is only for testing the concept. I'll order a shitload of batteries as soon as the bikes works.

I'm not that worried about the spokes and rim of the back wheel. I got a trueing stand at work , and a master wheelbuilder as boss. The wheel will most likely be built with a sun-ringle MTX-33 and DT-swiss 12ga spokes.

No , the controller is the part wich worries me.
My setup has to be as follows:

1: full power , hand throttle.
2: legal mode , pedal actuated.

It does'nt matter if is no power/full power in legal mode and if there is a 3 second lag when you stop peddeling, as long as the bike is limited to 25 kph, the motor goes of instantly when braking and the power feels about right. It's only for legal purposes , but the hand throttle must be disconnected in this mode.

I'll use a pull-out key wich has to be inserted trough a hole in my switch-box , to get full power mode.

About the motor.. Looks like some of you think a geared motor is a must off-road for low-end grunt, while others says that a geared hub won't survive off-road use... Does anybody know wich motors Stealth use ?

.manitu

 

[manitu]

It looks like I can legaly use the throttle to adjust the power, but only while pedaling. and the motor-assist must cut at 25kph/16mph.

Looks like the Infineon controllers can do this with a some small mods .. Anyone?


.manitu

 

[Alan B]

A pedaling sensor set up to shut off the throttle signal is how I'd do it. Or you can go into the ebrake input. Brake switches can do the same. That way you have good throttle control but pedaling is required. You can set up the pedal sensing to have a couple second timer before it disables the throttle signal. One interesting side effect is you can pedal backwards, most pedal sensors don't care.

One nice thing about Lipo is that just two or three batteries an handle the current for testing, so you can test with a light battery without making a large investment.

 

[manitu]

ahh..
OK.. So then I need to build a circuit wich read the pulses from the crank-sensor , and disconnects the throttle when the crank stops turning. Guess it would work with most controllers.

Then it's on to the watt and speed limiting.. Are there any controllers you know of , with two independent current/voltage/speed settings wich I can switch between?

.manitu

 

[Drunkskunk]

No controllers to speak of, But any controller capable of using a direct plug in Cycle Analyst can. the CA can be set to cut off at various currents or speeds.

 

[manitu]

OK...

with the crank-sensor circuit , three-mode switch for setting power at 10% and a CA to limit speed , I should appear street-legal.
Guess I'm gunning for a infineon-based controller then.

Next question: Wich one ?? I would like run 48-72V , I guess , would'nt hurt if the controller can handle a bit more.
Is there any serious down-sides when using overkill controller?

Going for a 9C motor at first. Could go for a 5x motor , but I don't think it will be worth the price difference performance-wise.
will test the bike with 48V SLA batteries (cause I have them lying around) , then order lifepo or lipo-batteries , come next paycheck.

.manitu

 

[Alan B]

The infineon controllers have a speed switch which can do something similar. It is set in different units but folks use it for that.

The Cycle Analyst has current and speed limiting but only one setting. I believe there is a way to limit against an external input which could be a switched signal, but I have not looked into that.

 

[manitu]

So it's possible to add both a power-limit switch AND a speed-limit switch to the infineon based controllers?
That would be perfect!!

I'll have to check out the different guys here on the forum wich modifies and sells those controllers.

.manitu

 

[Alan B]

Get a 100V controller for 75V operation. I got the Lyen 12 FET IRF4110 unit, there are others as well. See the for sale new section of ES.

The better controllers have very low impedance FETs so no real downside to the higher voltage. You want some margin for reliability.

I'm running 75V peak and 30A average with this into a 9C 6x10 motor. Getting about 25 mph and great climbing capability. See about 3000W at times. Goes about 15 mph up a 15 percent grade. See my thread linked in my sig for more info.

 

[manitu]

The Infineon/Lyen controller seems to be quite popular , so it should be easy to get tips and help for the setup.

Now , the only thing I muste decide vbefore I can order the stuff is wich version of the 9C hub to buy.
The 6x10 seems to be the popular choice for hillclimbers and offroaders.
The 9x7 Is also popular , but seems to lack the low-end grunt I'm looking for.
There is allso a 7x9 version to be had.. do you guys know if anybody on the forum have tested both the 6x10 and the 9x7?

And once again , thanks for the input , this forum is the s**t!!

.manitu

 

[Alan B]

The torque capability of the 9C is essentially identical for all of the winds. The main difference is the voltage and current. Let me see if I can find the spreadsheet I did:

https://spreadsheets.google.com/ccc?key=0Av_rcFhwbIYVdEphUnhvbXQ2bW13dGd6OGlXNmtrNUE&hl=en&authkey=CMCZsLkB

The different winds trade voltage for current. Note that the stock motor leads are not very beefy, so a wiring upgrade may be needed to get full torque. The higher turn motors develop torque at lower currents but require more voltage. Higher phase current is also harder on the controller so you might need a beefier controller with a lower turn motor, or a higher voltage controller/battery with a higher turn motor. Top speed and battery voltage is one way to select the motor winding setup.

One issue with which motor wind is finding them available. Not all are available all the time. 9x7 is the most common and available.

 

[manitu]

After a bit reading , I think I understand this. A 7x9 delivers the torque at a lower current but need more volts, compared to a 9x7
I'll defo go for a 7x9 with 72 V batteries , as current is the father of heat , the destroyer of all things electronic.

I even found a shop in Finland , wich stocks the 7x9 version.

Now , I just need to decide on the frame.. Think I'll go for the DH-team. It has more space in the frame triangle , beefier swing-arm , and it's totally outdated as a downhill bike. Still a great freeride bike , wich is perfect for a all round terrain ebike. It allso has a proper coil rear-shock with hi/lo compression adjustments so it can be tuned quite soft but progressive to be kind to the rear wheel without bottoming out. The mongoose is my visitors bike for regular mountain biking.

I guess I could get by with the 9FET controller , but I guess I'll get the 12FET one to be safe.

.manitu

 

[Alan B]

After a bit reading , I think I understand this. A 9x7 delivers the torque at a lower current but need more volts, compared to a 7x9.
I'll defo go for a 9x7 with 72 V batteries , as current is the father of heat , the destroyer of all things electronic.

I even found a shop in Finland , wich stocks the 9x7 version.

...

I guess I could get by with the 9FET controller , but I guess I'll get the 12FET one to be safe.

.manitu

The first number in 9x7 is the number of strands of wire in parallel, the second is the number of turns. So the 7x9 is the higher turn motor which is higher voltage (and lower current). The 9x7 takes more current. Essentially torque is proportional to amp-turns. Higher turns means lower amps.

The 12 FET is a good and popular choice. It is not that big, and it is nice to have some margin on the electronics. The 9 FET or 6 FET can work if you restrict the power.

 

[manitu]

Sorry , that was a typo, I'll defo go for the 7x9 motor.

.manitu

 

[manitu]

Just when I thought I had it all figured out, I read the thread about the new xclyte ht35 motor.. And a thread about a new 9C motor too..

Seems like the HT35 har space for my Avid Juicy brakes , AND a 9speed frewheel!
The New 9C on the other hand , has tight space for brackes , and even less frewheel space than the old one??

Hmm.. I guess it boils down to how the HT35 compares to the old 9C 7x9. Thinking about climbing ability and power limit.
I know , use the simulator... Problem is , I use linux.. I'll have to go to a friend sometime , to check out the simulator on a windows computer..

.manitu

 

[Alan B]

I think the ebikes.ca sim is on the web so browser based. Might work from Linux. And one is Java so should also work.

 

[Mark_A_W]

Nice bike. I like the colour


I have a couple of points/questions:

1. Brake Switches??

2. Legal????


Other than that, carry on, looks good, perfect frame for it.

 

[Andje]

i can offer some real world "feeling" to your simulator stats between 9*7 and hs35. At 100v 50 battery amps my max speed on the 9*7 is 85 km/h on flat, on the HS i hit 95 km/h and there was more k/v there to play with, my wheels weren't true enough to go faster.
The acceleration on the 9*7 is peppier, you have to ramp the throttle up a lot more carefully, and you can hit top speed in seconds. The hs35, mine was a 12*6, so it ramped much more naturally and took a full 5-8 seconds to go from 75 to 95.
The 9*7 takes less watts overall; the hs35 is a bit of a power whore, sucking amps all the way up to it's efficiency speed, at about 70 km/h i saw a drop. If you noodle with block time and max amperage, either motor would wheelie you instantly, and both will charge up hills at max speed. I burnt my hs35 at about 5kw (although it had handled 8 kw + before that on a different ride; final death reason is unknown apart from winding melting), whereas my 9c is still going strong. That is not to remark on their quality, merely my real world experience.

So far, I'd pick 9*7 for a commuter bike, 12*6 if i wanted to push speed records. I just don't need that top end speed to accomplish what the bike is actually for; commuting to school and back at about 70 km/h.

 

[LegendLength]

Definitley go for the HT35 over the 9C, but perhaps try to get a lower winding (I believe they will be available). The HT35 goes 38 mph / 60 km/h at 72V by my rough calculations and you may want less than that.

The downhill frame is a great choice for any type of offroad. The strength of downhill frames makes them unsnappable even with large battery packs on them (IMO). I'm using a kona stinky (below) which isn't technically a DH frame but is close enough and so far I have taken it over 2 foot high ramps at 20 mph without any issues. And that's with the stock rim and spokes (9C motor). I have the lesser version of your 888 marzocchis (the 66 RC) and they feel spectacular.

The only bad thing I can report about the 9C (which is similar in weight to the HT35) is bad handling down rocky trails. The 16 lbs / 8 kg weight of rear hub motor seems to punish you a bit with its unsprung weight. Unfortunately I think RC / mid-drive motors are still too difficult for the time being so you are making the right decision with a hub motor.

 

[manitu]

@Mark: Yeah , daft , isn't it? Well , I got a great off-road commute to work , but there's half a mile on road from the woods to my job. It's just a extra precaution for when I eventually get pulled over. Regulations here: 25km/h , 250w max , pedal assist only , and motor must cut when you brake.
I don't think I'll do much more on-road riding than that.
Oh, I see you have a beauty of a bike too.

@Andje: This is going to be more like a dirt-bike. We got some massive hills in my area , steepest klimb on my offroad route to town is over 20%incline. Im going for 70-80 volts , and a safe current limit for endured climbing. I'll be happy if I get 40-50kmh (25-30 mph) whith killer torque and big climbing ability. So the engines I'm interested in is 9C 7x9 , 9C 6x10 and Clyte HT35.

Oh , I just discovered that there is yet another rule for e-bikes. Must not be heavier than 40kg (88 lbs). ARGHH!
Well, batteries will have to be Lipo then. Is this the one people here uses? http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=14384

Any recomendations on a charger and balance equip? That BMS stuff is mostly for LifePo batteries , right?

edit:
@LegendLength: I'll most likely go for the HT35 , based on it's weight alone. The hub alone is 5,5 kg, the rim and spokes cannot be 2,5 kg ,so it will be a bit lighter. Every gram I can shave off the rear suspension gives me a smoother ride.
If the performance close to the 9C , that is. Hillclimbing is the most important factor here.

.manitu

 

[LegendLength]

I'll most likely go for the HT35 , based on it's weight alone.
If the performance close to the 9C , that is. Hillclimbing is the most important factor here.

Performance is better than 9C by all accounts (see the huge thread if you haven't on the Hx35). But like I said you may wish to get a higher winding version than the HT if you can find one. The weight is the same between the two motors I think.

My friend is interested in moving to a HT35 with a 24 inche wheel (instead of the standard 26 inch). We calculated it out to be 35 mph / 57 km/h with no load, so I guess that means 50 km/h with a person on it. So with a 26 inch wheel it will be faster. I think 26/24 times faster which is like 35 mph loaded.

For batteries definitely go lipo. There's like a 30% saving in weight and size and money. The difficultly of balance charging and safety are not that great in reality.

I recommend the iCharger 106b+ or 206b+ with an iCharger power supply. 80 USD + 70 USD .

http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=6792

http://www.progressiverc.com/index.php/p350-power-supply.html

 

[Andje]

i should have read this thread more comprehensively before jumping in
didn't see you were after more of a dirt bike; in that case yes, all reports of the high torque windings of the new crystalytes have been positive. If hill climbing is the MOST important factor that breaks down into two things i would say; top speed up hills and acceleration from a stop up hills (im assuming here that heat wont be a problem, but it might . Your 80v should give you great stats in both of those categories; i will say i like my 100v mostly because of the way i can accelerate up hills to full speed without pulling too many amps, but with these lipos being capable of 15-25c i know i could do it the other way round too, ie 80v and more amps. Since Infineon style controllers seem to be more reliable pulling volts then amps, i opted to go that way. Each to his own.
I was scared to drill my covers, but now that i've done it i see a substantial heat decrease. I would say definitely just drill the virgin motor even if you plan on taking it dirt biking; all reports indicate that the heat from hardcore offroading/hill climbing will kill your motor before dirt gets into it through quickly rotating cooling holes.
Those batts you linked are fine, most reports indicate little difference between turnigy/zippy etc (at least, as ordered through HK). I would buy lowest c rating and go for cheapest price to make your v/ah combo that you want. Im personally using the Turnigy 5ah 20c ones and they are more then i need to go almost 100 km/h without taxing them; even 20c with three in parallel is huge overkill, my 24s3p pack should be able to put out like 35kw if it didn't melt every wire involved, and it only weighs 11 kilos or so, i actually have it in a backpack.
I bulk charge my pack at 100v and balance with battery medics, but if i had to do it again i'd probably go with a proper balance charger up front like a Hyperion capable of 14s and then split my pack for charging. I have a one plug solution, but it is slow and not entirely reliable compared to charging individual cells independently. I chargers are good too, some people have had trouble, some have not, much cheaper then a hyperion, no doubt.
You will definitely be happy no matter what if you are already planning lipo and 80v; at those voltages the bike really does charge up things like no tomorrow. It's like being on a horse but with real control; it still feels like it's pushing to go faster then you can let it, like you are almost always holding it back a bit.
Don't know if you've thought about it, but one thing i have noticed is how twitchy the throttle is when i go over jarring bumpy terrain; hard vibration causes involuntary hand movement which can really screw with you. I don't know how i'd solve this, but i know my bike would be difficult to handle offroad at the moment because one small twitch can wheely me off the back with the current levels i have the controller set too. I have a hardtail dj though, so again, may be very different on a proper dh. But something to think about; you may want to plan on upgrading to one of the other after market throttles, and at the very least getting the three speed switch going so you can set your controller for different situations.