Giant DH Team, Cromotor, 18fet Lyen, 111v Lipo

[Andje]

at 111 volt... with lipo... no you don't need to worry about the acceleration in any band; just consider a human can never ouput even 500w through the pedals. If you are dumping several thousand watts, you are at best adding 10-15%... so drop in the bucket, much easier to squeeze the throttle slightly harder since you will almost certainly have enough torque to just wheely flip the bike from a standstill, and indeed probably up TO the 20-30 range you are talking about. You can definitely deal with a single speed in the rear, lots of people run a triple ring up front with a mid derailer to keep some speeds, but I NEVER pedal my 100v bike. It's really a motorcycle at these power levels you are entering; you will see.
Oh, and all those batteries are totally fine. The rule is 4.2V max, and 3.5V min. There is GOOD argument to keep you batteries between 4.15v and 3.6 to prolongue their lifespan; essentially the less taxing you can be in terms of depth of discharge and full charge the better. A dead battery from hobbyking would have to be much lower then that to be a "dud". Just make sure you balance charge it to full; that is the most important thing, keeping the individual cells in balance. It's not "great" that it came that way, and it could indicate a weak cell, but you may see no noticeable effect day to day. I would mark the pack with something and watch it, but your 10ah at 30c would be 300amps to tax the battery; you will not be close to that, so the battery will essentially always be baby'd in terms of current demand. If you can try and use 8 ah of your 10 availiable by charging to 95% and keeping 15% in the pack you will get the most cycles out of your battery.
Putting it in perspective; I have drained single cells and overcharged cells. I have done everything wrong with my 12 25c bricks. They still hold 90% charge and are not puffed. I do not reccomend this strategy; only to point out that it is at THAT point, when things co wrong, that you learn you have won lipo roulette or not. And losing can be firey. A lot of people neglect to put a smoke detector above their charger; please get one. Watch your charge cycles.

[binlagin]

Andje thanks for the words of wisdom! This is exactly why I love this forum.

[izeman]

.. You can definitely deal with a single speed in the rear, lots of people run a triple ring up front with a mid derailer to keep some speeds, but I NEVER pedal my 100v bike ...

i can confirm that. even though i have only a 12s setup with 1500w max i almost NEVER use the 9 gears at the hub. i just switch between the front middle gear (for launching) and then after some meters switch to the big one (for cycling), the rear gear's always set to the smallest one.

[kfong]

Nice setup, I had the same issues about battery placement. It wasn't until I went to smaller capacity lipo's did I find a workable solution. I wanted to be able to pedal my bike, so having anything that got in the way was not an option. I was able to fit a 12s 14ahr pack in my frame. Working on the enclosure, but have posted how I was able to fit it all. The smaller capacity packs have a better form factor for space optimization. viewtopic.php?f=6&t=12654&start=150

[veloman]

The point is definitely valid that the OP has no need to pedal this thing, at all.

However, I will strongly challenge anyone claiming a human can't output more than 500watts during acceleration. Do the math on what it takes to go 0-30mph in under 6 seconds on pedal power alone :D
(1800watts) (18lb road bike)

[veloman]

.. You can definitely deal with a single speed in the rear, lots of people run a triple ring up front with a mid derailer to keep some speeds, but I NEVER pedal my 100v bike ...

i can confirm that. even though i have only a 12s setup with 1500w max i almost NEVER use the 9 gears at the hub. i just switch between the front middle gear (for launching) and then after some meters switch to the big one (for cycling), the rear gear's always set to the smallest one.

That's exactly what I do on my ebike.

I like the middle of the cassette if I only want to go 10mph without using the motor, and have to start on a steep hill. If not using the motor, its a LOT harder to get my ebike rolling.

[Andje]

However, I will strongly challenge anyone claiming a human can't output more than 500watts during acceleration. Do the math on what it takes to go 0-30mph in under 6 seconds on pedal power alone
(1800watts) (18lb road bike)

hmmm I thought I was right, but upon searching wikipedia

Amateur bicycle racers can typically produce 3 watts/kg for more than an hour (e.g., around 210 watts for a 70 kg rider), with top amateurs producing 5 W/kg and elite athletes achieving 6 W/kg for similar lengths of time. Elite track sprinters are able to attain an instantaneous maximum output of around 2,000 watts, or in excess of 25 W/kg; elite road cyclists may produce 1,600 to 1,700 watts as an instantaneous maximum in their burst to the finish line at the end of a five-hour long road race. Even at moderate speeds, most power is spent in overcoming the aerodynamic drag force, which increases with the square of speed.[4] Thus, the power required to overcome drag increases with the cube of the speed.

So I was wrong! You learn something every day! It's us "amateur" people that get under 5w/kg that don't generally make more then 500w.

[crusoe]

How many volts are you running at kfong?

[Doctorbass]

I see that the DG comp seem to gain in popularity

My experience with lipo and tmy giant is that the best removable way to put 15 packs of 6s 5000mAh is this way:

( that's 1.75kWh of energy)... right in the middle of the frame!

What i can say abouut this battery lcation: THIS REALLY IMPROOVE THE HANDLING !!!!

I can do the same manouvers than any DH bike can do. the feeling of the center the mass is similar to a motocross.

[hillzofvalp]

Holy crap that's a lot of power? Doc, your bike looks like a pod racer from star wars

[crusoe]

Is that white piece of plastic your main support/mounting bracket for everything Dr bass?

[Doctorbass]

Is that white piece of plastic your main support/mounting bracket for everything Dr bass?

Yes, it's made of thick nylon and hold by being clamped to the big frame tube and the seat lower frame tube.

I can remove the battery easy.
Doc

[izeman]

i personally like the roast thermometer

[kfong]

Looking from the top, it seems like my knees would constantly bash into the packs Doc. Those corners also look painful. How do you like this setup when pedaling? I suppose with that much voltage and power, pedaling isn't done much?

[binlagin]

I believe the way he has it configured there is JUST enough clearance for the pedals. 3 batteries wide is the same length as one battery lying down. In my case, I JUST barely have enough clearance for my pedals.

I don't see why everyone thinks this width is a problem. Aslong as the pedals clear, you shouldn't notice the width? Your legs don't really bow inwards when your pedalling. There might be light rubbing with your calves... but I don't' see it being an issue.

Thanks Dr.Bass... your creations and work is what really made me believe in myself to build something like this.

[kfong]

That is not quite true if you are trail riding or doing any type of agressive riding. You use the saddle and frame to hold the line. I've had bruises even from my setup. I am curious about the maximum width that is reasonable for trail use. If all you do is street riding, then I can see you getting away with it.

[crusoe]

Ya, I agree with kfong. but then again, i'm sure if a body was built around the battery case it would alleviate those problems and turn into a motoX style.

what are you running battery wise kfong?

[hillzofvalp]

How man magic shines total do you have, doc? 2 for trike, 2 for dh...

[kfong]

I'm currently redoing the battery setup to lipo's this year. I've been avoiding them due to the fire hazard until I had a setup that I felt comfortable with and I think I have a way to prevent the fire from getting out of control. I also had the problem of not fitting 5amp hr packs into my triangle space without making it wider than I liked. I plan to put 14.8 Amp hours in my triangle (12S 6P 2650mah) I was able to keep the width narrow by going with smaller capacity packs. This involves more wiring but I was not willing to sacrifice any pedaling performance. With the way I ride, I know my knees don't stay parallel to the frame. Single track requires a lot of body movement. My battery cover is very smooth and I still get bruises on my knee from time to time. With the new lipo setup, it's just slightly wider than my konions. I would stick with the konions if I could but need the higher capacity and voltage. I'm not even sure the lipos can take the trail abuse, so I will be doing everything I can to keep them secure and protected. The Konions took 3 years of solid pounding and until recently they have shown to be rugged. I had a bad spot weld that eventually failed from fatigue. Here is the build viewtopic.php?f=6&t=12654&start=150

Too bad there isn't more ebikers where I live, I would like to try a bike with such wide packs to see if it's something I could deal with. Moving to 1kw this year but have the rest of the pack in the rear. Not ideal for performance but it's the setup I like currently. I'm only interested in single track trail riding so this bike setup works very well for that. My requirements are a bit different from street riding. The bike gets constantly bashed as well. Even replaced the frame last year.

Ya, I agree with kfong. but then again, i'm sure if a body was built around the battery case it would alleviate those problems and turn into a motoX style.

what are you running battery wise kfong?

[Doctorbass]

How man magic shines total do you have, doc? 2 for trike, 2 for dh...

2 for the trike,
4 for the DH
4 for the mongoose

Doc

[crusoe]

How is it running only at 44v kfong?

[waynebergman]

I have found a width of battery that works low like under my down tube can be just fine but when I move it up on top of the top tube it is very uncomfortable for pedaling out of the saddle. I have two duplicate packs and tried at one point to put my front fork pack on the top side of the top tube and it was bad. So if its low enough as long as the crank arms clear its fine but up higher your knees may hit bump into things if pedaling out of the saddle. I like my set up with one pack under the down tube and one pack on the front forks up high.............wayne

[kfong]

At first I thought it might be a bit too quick on single track. I like to pedal the whole time. If I'm not tired I'm usually standing and more than half the time peddling. At full throttle I can no longer keep up with the peddling which was a concern. Max speed now is close to 24mph. The good thing is the throttle response is very smooth, so I can usually find a good compromise. It's the higher torque that made me want to go to this voltage. The bike is a riot on hills, the more technical the better. Another reason for the higher voltage and capacity Is I can ride to my trails and get there faster. Then cruise at the slower pace that single track demands. It's very much like tree skiing for me. You need to be focused or you end up eating bark. I'm pretty sure I would not want this setup to be any faster. This bike was built only for single track use. I have other bikes if I need speed, but then it would not be for single track. Even my new DH bike might not be my first choice, since it's more for wider trails. It won't be as nimble. It is setup better for speed and wide trails. I have not ridden a DH Giant, so I don't know if it would be similiar. DH have a higher rake angle.

How is it running only at 44v kfong?

[binlagin]

A quick update and new problem!

It's been a while since my last update but I figure I'd wait until I have some good news to post about!

Today I received my dropouts from Kiwi!



I had todo a little bit of filing to get the dropouts to fit nice and snug. Great work!

Every thing was moving along smoothly... until I slid my cro-motor into place.




As you can see the tire is rubbing on the swing arm. Where do I even begin to start to straighten this out?

I also completed my battery casing with Method's LVC protection. This turned out quite well... it holds 10 batteries inside the frame nice and snug! I've even taken it out and pedaled it around the block and the batteries did not budge. Due to the lack of a proper camera, I apologize for the low quality and low number of photos.

[briangv99]

A bit of dishing should fix that, loosen all the right hand spokes half a turn and tighten the all left spokes half a turn. Repeat if more clearance is required.