Giant DH-team offroad build. R&D thread

[manitu]

I've been busy thee last few weeks , barely had time to sleep. Bike season started..

I've moderated my build plans a little bit. I guessI'll be using 18S3P 5Ah Lipo's, just to save cash on charging equip until the next big investment. You see , I was offered a sachs xtc 125cc motorcycle the other day. Thinking of running a Mars/Etek -r ME0708 and get it road legal with plates. (max 15hp and keep whithin registered max weight. Easy , if I ditch the passenger seat and footpegs)
Then I'll need a kick-ass charger and a shitload of lipo's anyway , and can upgrade the DH-bike at the same time.

My plan as of now is to run nine 6S packs in 3P groups, using the 3P groups in serial for riding , and in paralell for charging.
This should make me get away with bying a decent 6S charger capable of charging nine 5ah packs. Eventually buying a Turnigy 4x6S charger and balance the three groups each time. I'll have to buy a bulk charger for the motorcycle later, I'll reconfigure the charging layout then.

The motor is being ordered as we speak , a HT35 from Crystalyte europe.

When it comes to the controller , I must decide on the right one. Lyen has two different 12FET 4110 controllers. A new non-infineon based sensorless controller , wich seems to be the preferred choice , but regen braking is not implemented yet.

Then there's the infineon-based one , wich seems to have a speed-limit , something about how the phase signals are decoded. However , it's been tested with the HS35 to 38mph/61kmh , wich has me covered for now.

I really would like to have regen braking , as it would increase range on steep hills, but I would prefer to go with the current technology , and not the tech of yesterday..

Any thoughts?

.manitu

 

[MadRhino]

Buy the motor with hall sensors, then you can have all that you want in a controller.

 

[kfong]

I would not go sensorless, to me it's not an improvement as much as a cost savings for the company. Low speeds require good feedback from the motor to the controller to be effective. You end up with sync issues without it.

 

[manitu]

Oh? I was under the impression that running sensorless on a low-rpm motor with straight laminations was as good , or better than using sensors?
I know there's been problems with slanted laminations and high-rpm motors, but that should not be a problem here.
Offcourse , I could just put sensors in it , and go with the original plan.

Another thing I.. Batteries:
Is it OK to have 3 packs permanently paralelled , balancing them together? Is this as good as balancing single packs?
Is It best to make three 3P6S batt's and running them in series (easy charging) , or three 1P18S batt's in paralell?
Could I charge all nine 6S 5Ah packs in paralell, or should I get three chargers and charge three packs in paralell?

.manitu

 

[Andje]

Parallel first, then series, so yes you want three 6s3p packs to get your 18s3p. Parallel the balance taps as well in those 6s3p packs, and you can balance then as one 6s block and it will be as good as balancing them individually; just make sure they are all at the same voltage when you first put them together.
For charging, I personally have tried the "bulk charging" method where you hook your battery up in series to a psu running at the appropriate voltage and then disconnect when the pack hits max voltage. I balance with the HK Battery Medics. Personally, it is not working for me; i find that one or two cells overall in the pack go high fast and the BM can't shunt enough away in a reasonable time span to balance. Another member, Icecube has had the opposite experience; for him, the exact same solution is working well.
A lot of the RC people that run only 48v (12s) are using the Hyperion charger from tppacks.com; it intelligently charges, discharges, monitors, etc. up to 14s at a time and takes up to 500w from a 24v psu to power it. I have ordered one and am planning on charging my whole pack in two different 12s chunks; i will have to charge each half individually, but I am ok with that.

In terms of safety, you want to figure out a solution that involves the least amount of connecting/disconnecting as possible. A lot of veteran members have had accidents where they hooked up a series/parallel connector wrong, or series-ed the pack while the balance taps are still paralleled, either way they have accidents even with a lot of experience. Most now tout as few disconnects/connects as possible: whatever you decide to do, keep this in mind when building your charging solution.

 

[manitu]

If I go for 6s charging , I'll use a 6 pin plug and parallel the main leads in the plug . DB25 or similar plug for balance leads , alas no paralelled wires on the bike itself. Then I'll mount the charging plugs under a cover with a switch, unplugging the batteries from the controller. That is as close to foolproof as I can come up with.
So its either a kick-ass RC charger at 6s , or a 900watt bulk charger from Bmsbattery + a small 6s balancing charger.

OK.. As the motor makes it's way to my doorstep, I'm starting to look more seriously at the dropouts. The width between the dropouts are 138mm , not 135. I can easiy pull them to 142mm without exessive force. there is also a about 2mm wich could be removed inside the left dropout if needed ( but do I want the wheel closer to the disk brake?).
The big problem with the dropouts is the 12mm clamped axle hole. I'm looking at two options: Either glueing the clamp gap with scotchweld DP , and cut a 12mm vertical dropout. Then glue a 1mm steel sheet around the inside of the dropout. Or just cut off the clamp , and let the torque-plates take the full load.

Controller.. I'm not ordering the non-infineon based sensorless controller. I'm leaning towards the infineon-based sensorless controller with the optional hall inputs, but I understand that it has a different design than the standard infineon sensored controllers? Lyen said that the 3-way switch was not compatible with the "dual-mode", but a interface could be made.
If there's no downsides to the "dual-mode" controller , I'll go with that one.

.manitu

 

[Doctorbass]

I've noticed the dropouts , it's actually a 12x135mm maxle, only the 2005 model and replacement swingarms are 12x150mm.
It's the same design as the 20mm front maxle.

I'm not shure what I'll do with the dropouts.
This one http://endless-sphere.com/forums/viewtopic.php?f=6&t=15439 has welded dropouts.
Doc's DH-comp has custom made plates with dropouts glued(!) to the swingarm.http://endless-sphere.com/forums/viewtopic.php?f=3&t=18473&start=60

I would like to have clamping dropouts , so I guess I'll have to get two plates machined.

The left side is easy , just mill down the elevated area on the outside and put a steel plate on the outside. the right side however..

.manitu

I know what you need for the dropout!!
http://www.endless-sphere.com/forums/download/file.php?id=60254

Doc

 

[manitu]

@drbass: I guess that design is for the 150mm 2005 swingarm. I got the 135mm swingarm , and will not have space for any plates on the inside of the dropout.

No , I'm gonna mill down the bump outside the left dropout , to make it completely flat. The right one will get milled down a bit , but I can't remove the whole bump because of the gear hanger.

Lyen is making me a dual-mode controller from his 12fet infineon-based sensorless controller, so I'll try it out in sensorless config first, adding sensors if needed.

.manitu

 

[Doctorbass]

@drbass: I guess that design is for the 150mm 2005 swingarm. I got the 135mm swingarm , and will not have space for any plates on the inside of the dropout.

No , I'm gonna mill down the bump outside the left dropout , to make it completely flat. The right one will get milled down a bit , but I can't remove the whole bump because of the gear hanger.

Lyen is making me a dual-mode controller from his 12fet infineon-based sensorless controller, so I'll try it out in sensorless config first, adding sensors if needed.

.manitu

I have also the 135mm but i would have need the 150 when i assembled my hub motor due to my disk brake adaptor.

I bended the swing arm with hydraulic equipment and take care of not stressing the welded joints. it work like a charm!

Doc

 

[manitu]

@ doc: No bending the frame for me. I got the torque-plate design pretty much nailed. Only thing i struggle to decide on is if I'll make removable torque-plates with axle holes , or open dropout plates wich I can glue to the frame..

I got the motor yesterday , and this thing is HEAVY! Wouldn't like to have a 5-series, they must be like the e-bike version of Porche's.
The people at crystalyte europe must have come straight from the coffee-shop when packaging my order. I got 39 150mm spokes , not the 40 I ordered. I also ordered 40 184mm spokes , got 34 , and 6 190mm ones.. Luckily , I got all 3 hall sensors. The spokes are not the optimal length , but they were cheap , so I just ordered 40 spokes of the dimensions they had wich were closest.

I Laced the motor into a 26 inch wheel today. I laced it radially , using the 150mm spokes. I know this is not the best solution , but it will have to do for now. I looked at a two-cross pattern , but it is next to impossible with 2,3mm spokes. We dont carry spokes under 200mm in the shop so I'll order some DT Swiss alpine tapered spokes for a one-cross pattern. These are expensive , but great spokes. 2,3mm at the bend and 2mm at the nipple, made for tandems and touring bikes.

.manitu

 

[manitu]

The weight of the hub motor got me thinking..

I wonder if I would be better off making a chopper frame for the HT , and using a turnigy or astroflight for the offroad build..
I do fear that the weight would compromise off-road performance , and as soon as I modify the swing-arm , there's no way back.
I've allso fallen in love with Ypedals chopper build. Would like one with a bit longer frame and motorcycle rim at the back , a bit bigger than the 20 inch bike rim. A marzocchi tripple eight at just below 60 degrees in the front would complete the bike. maybe a custom offset dual crown..

I'm really not shure what to do.. go on with the DH team or order a RC motor , and start on a chopper frame..

.manitu

 

[manitu]

My project is at a standstill until the first. Had to replace some apliances after a lightning strike , so no money for batteries and controller until the first of july.

But.. I mentioned the chopper idea to the guys at work , and they told me there were custom bikes in a room at the storage. They've been there since before I started working there , so I had to take a look. And what a look!! A Schwinn stingray with red flames , a Pacific bikes Kustom Kruiser , and a special edition of our main (norwegian) brand, Hard Rocx.

I've secured the stingray for myself , and I'm thinking about converting the other two too.

.manitu