Need more torque! (sorry wrong section :()

Hi all,
I've recently moved my electric stuff off my commuter and on to my old mountain bike.

Old:


This is a Crystalyte 408, 36v 9Ah LiIon, 20A Journey controller.
On this bike I top out at about 21mph and have a usable range of about 40 miles (with average pedalling)

I'll get a pic of the mountain bike when I get home from work, battery is hung low, below the bottom bracket and between the cranks.
On road, the speed is slightly reduced to about 20mph, but off road and up hills it just doesn't have enough grunt
Sure, if I put in plenty of effort there's not much I can't climb, but it feels like I am straining the motor. On steep off road climbs I find my speed drop waaaay down (5mph or less) which seems to be a long way below the motor's "happy speed". At these speeds, I am worried about damaging it.

I really don't want to reduce top speed if its at all possible, since 20mph is boringly slow anyway.
Mid drive *might* be an option, but then I'd have to relocate the battery, probably onto a rack. I don't really want the battery up high, and I like how its placed right now.

My best option seem to be pointing at a geared hub motor.
More power is fine More noise isn't really! Although I do appreciate that geared motors are always going to be noisier than direct drive.

Can you guys offer some options for me? If possible, easily obtainable in UK.

Thanks

Edit: Just noticed this is posted in wrong section of forum. Could a kind moderator move it to general Ebikes? Thanks

I think MKeefer is doing a thread on one of those 200 dollar EBikekit geared motors and said it was not very loud. Not sure how it climbs but did sound better at low speed curb hopping and such.

pending on the battery discharge rate you have,if there higher than 2c dicharge,maybe get a different controller and pump more amps thru it,mabye a 48v pack would help too..

theres a bit of differenrce power wise between 36v and 48v..but generaly i think electrically pumping more amps thru your controller you get more torque,but drain thru your batts quicker...

i reckon your cheapest option is to buy thru the for sale sections of this forum..

hope this helps
Alex

Definite on the go up to 48v. The volts will fill up your coils better.

Often people mistake torque for max power. You wont stop the wheel at 20 amps too easy. You can feel more acceleration with the higher volts and this feels powerfull.

If a motor can have 10 times more torque and go only 2mph or a motor have 10 times less torque and go 25mph which would satify you the most? Which motor would you feel the power most come from?


This is a fun tool to play with


http://www.ebikes.ca/simulator/

Its not accurate on all motors but the sim does show the improvement of torque on a a single motor or your 408 with different configurations 36v compared to 48v and the improvements with a 25, 35, 40 amp feed.

Honestly the 408 should not be needed to be changed as it has plenty of torque, more than any man could need. But wants may be different from person to person.

IMHO just try a higher volt and bigger AH pack you will be suprised of the difference and be happy with more speed too. The controller can be fixed to do more volts, and a little more amps if your disatisfied but I doubt you will care after you get more volts.

Memran said:

Hi all,
I've recently moved my electric stuff off my commuter and on to my old mountain bike.




I don't really want the battery up high, and I like how its placed right now.

Click to expand...

Inertesting a high battery pack on the top bar is OK.

I havent got any math to post as to why but in my experience with heavy SLA the lower the battery seemed to make the bike lean slow, like weird slow, and the high pack made it hard to get a bike stand to work with heavy packs. Your pack shouldnt make too much difference as my SLA's did.


I drew this picture just for observation sake it really proves nothing.




Just observe the weight distribution and where centre of gravity (C.O.G) lies. The higher pack gives the rider higher controll over the lean of the bike where as the lower pack reqiure leverage to lean the bike. This leverage adds more power from the rider over the resistance of the centrifugal forces the wheel applies to the bike however the rider needs to use the leverage to get the same result.

The higher pack introduces a topple effect over the C.O.G and the rider can just shift a little weight to lean.

If you saw my bike with 27kgs of SLA's on top bar you would wonder how it stays up, when I put the weight lower it was a slug to lean, terrible it was. The higher pack becomes more part of the rider and not part of the bike.

Wow lots of info!

317537 said:

If a motor can have 10 times more torque and go only 2mph or a motor have 10 times less torque and go 25mph which would satify you the most? Which motor would you feel the power most come from?

Click to expand...

I take your point, but I am talking about off-road, steep climbs, mud and sand. Not your average road use

Changing the battery to 48v or more is difficult with my current battery position.
I made a post in the e-bikes bit, which describes my build and has pictures: http://endless-sphere.com/forums/viewtopic.php?f=3&t=18851
Take a look There's no room for larger battery in that location, sadly, so I would need to get a rack on the back.

Nice diagram for CoG but for me, the pink square is below my wheel axles but I do see what you mean. Its not just about weight. With my battery down low it is pretty inconspicuous! lol

Memran said:

Wow lots of info!

317537 said:

If a motor can have 10 times more torque and go only 2mph or a motor have 10 times less torque and go 25mph which would satify you the most? Which motor would you feel the power most come from?

Click to expand...

I take your point, but I am talking about off-road, steep climbs, mud and sand. Not your average road use

Changing the battery to 48v or more is difficult with my current battery position.
I made a post in the e-bikes bit, which describes my build and has pictures: http://endless-sphere.com/forums/viewtopic.php?f=3&t=18851
Take a look There's no room for larger battery in that location, sadly, so I would need to get a rack on the back.

Nice diagram for CoG but for me, the pink square is below my wheel axles but I do see what you mean. Its not just about weight. With my battery down low it is pretty inconspicuous! lol

Click to expand...

That sort of usage will takes its toll on a set of nylon gears, so you go for steal gears and you have the noise.

Hmmmm.

It soundls like you need to wipe the slate and start again.

The dual MP is a torque master because of its large diameter hub. GM has got a casted 18" 16" and 20" hub



Yeah baby the ones on the far left. They all have internal contollers.

Id put a pie 20" against any 408 for the same current draw. and that casted 18" could land a 747 jumbo jet.

I am not a big fan of the controllers ATM. Like , but I would still buy one of those 20" hubs anyway. They are torque city for gearless. These would require less amps on the hills and it seems the speed is all that on the smaller rims. But ithe design is rather loud if you wanted stealth. But hey, off road or on road, it would be hard to have you pie (cake) and eat it, and hard to design a trail ebike that looks like a grannies cruiser.

Greetings!

First let me say.. that is a very clean and tidy build, I might even go as far as sleek

Now to answer your question... I've no idea what controller you really have, never heard of a Journey... if you can shoot pics of it (inside would be best) maybe we can identify it and you may be able to open up your power level a bit to get more torque from your setup...

As it stands everyone recommending 48v is right but torque comes from current and not more voltage.. the higher voltage would move your torque curve and as would be expected your top end... The issue would be just jumping to 48v wouldn't likely get you much more "useable" power offroads or in trail, etc conditions... but would get you better speeds (given the same current you run now whatever it may really be) on the flats of roads and downhill and such.

The absolute best solution (imho) would be to replace (if it's not programmable) the controller with a 6-9 fet (believe me a good 6fet would be more than enough for your needs and to gain a kick in the ars of torque offroads) infineon that you can re-program to adjust the current / power settings to your specific tastes...

AND

Dump that 36v pack... go to 48v minimum, personally I would hit the 15S LiPo route...

AND

Add a multi speed selector to your bars, this will allow you to program up to 3 unique current / power limits from 50% to 120%... Then you can configure your Primary current limit for a few more amps (maybe 10A more would make all the difference in the world) and use 100% mode offroad... onroad the 120% would get you even better top end than otherwise and when you want lower power saving mode... engage 80% or 70%.

If possible I'd pack Lipo into that neat little enclosure the LiIons are in now... shouldn't be an issue to fit equiv Lipo.

I would normally say just reprogram the controller but... your battery if 2C just can't handle much current which would be equal to a boost in torque.

Geared is an option to go, may be a tad lighter and have more starting torque than a DD motor... but really I see the battery being your issue and bottle neck.

On the issue of Nylon geared motors - I know everyone says they fail out but your not trying to run 60A through them... maybe 25-30 would be sufficient for torquey 20mph trail riding... I do beat the living crap out of my nylon geared rear folding 26" (launching off curbs, hopping up curbs, bunny hopping speed bumps at 25mph or so, pot holes, etc)... some minor trail riding but even my roads are very similar to trail riding... only have a few hundred miles on it so far and still working well...

That said, steel geared motors with good lube aren't that horrible...

Perhaps the ultimate method would be RC drive ? Light, powerful but still needs more current than that LiIon can likely put out.

Hope it helps!
-Mike

mwkeefer said:

Greetings!
As it stands everyone recommending 48v is right but torque comes from current and not more voltage..
-Mike

Click to expand...

Hi Mike!

There are more ways to skin this cat.

He could lace a 24" rim on to that 408.

What's the current stand with torque on 24" 20", 18" and 16" rims on the 408 clyte?

That Ebikes.ca fails to register any torque gains at lower speeds with a 16" compared to a 700c rim. Just stretches it out to meet top speed.