problem autonomi
- Thread starter almaul2
- Start date
If I understand correctly, you're not getting the range you expect from it?almaul2 said:
To find out why, we'll need to know some more info.
What is the power consumption of it? Meaning, what Wh/mile does it get, according to the Turnigy Watt Meter?
What terrain is it used on? Hills, flat, mix of both? Steep slopes or gentle ones? Hills will take a lot more than flats.
How fast are you going on it on which kind of terrain? Faster you go the more power it takes.
Is it just constant going or lots of stops and starts? The latter will probably take more power.
Do you pedal at all, or just use the motor?
I don't see any reason why the Alfine would hurt your power consumption. If you're using lower gears for startups and hills and higher gears for flats and faster runs, then it should actually help.
liveforphysics
100 TW
5Ah isn't much.
But it should get you at least 2-3times the range you're getting.
What is the total reduction?
What is the current draw with the tire off the ground and at full throttle?
What speed does the tire spin with the bike off the ground and at full throttle?
But it should get you at least 2-3times the range you're getting.
What is the total reduction?
What is the current draw with the tire off the ground and at full throttle?
What speed does the tire spin with the bike off the ground and at full throttle?
recumpence
1 GW
OK, the problem/s you are having are;
#1 Inefficient motor (this is not the major issue, but it is one issue)
#2 Four reduction stages.
#3 Those 4 reduction stages terminate in a geared hub motor.
Those items, if paired with tall overall gearing (looking for top speed) will give you the range you are seeing.
Matt
#1 Inefficient motor (this is not the major issue, but it is one issue)
#2 Four reduction stages.
#3 Those 4 reduction stages terminate in a geared hub motor.
Those items, if paired with tall overall gearing (looking for top speed) will give you the range you are seeing.
Matt
I won't argue with the reduction loss issues (which is actually five stages), but I don't understand #3--where's the hub motor? All I see is the Shimano Alfine 8-speed IGH? That probably has some efficiency loss, too, I guess, but it shouldn't be that much.recumpence said:
EDIT: the italicized part below is wrong:
THe problem I see with the reduction stages is that one of those stages (the second) is a wasted one--it is going the other way round:
First stage is a belt with what looks like 3:1 or so.
Second stage is a chain for about the same amount but in reverse: I'd guess about 1:3. (didn't bother counting teeth)
Third stage is a chain for what appears to be 2:1 or so.
Fourth stage is the regular bike drivetrain about 1.5:1.
Fifth stage is whatever ratios the Alfine provides.
So really that motor is only being reduced about a factor of 3 before reaching the Alfine. If it is a high-kV motor (I dont' know RC motors) then it's going to take a pretty big hit on current demand because of that--it may give the bike a high top speed but the starts and stops are going to have a high power penalty because of it. If they are frequent, it'll waste a lot of power getting back up to speed.
almaul2 said:
50km/h is a lot--that's 31MPH. It takes a lot of watts to do that, especially if you're not pedalling to help it at all, plus the stops and starts.
8.9Wh/mile is actually very good for that kind of speed and conditions.
So assuming you've got those two 5Ah packs in series for 44V (well, really it's the same evne if you have them paralleled), you've got 220Wh total to play with. Let's say you have it setup for 80% DoD LVC cutoff; that gives you 176Wh to use. At 8.9Wh/mile you should get almost 20 miles out of that setup.
Either the LVC is set wrong on your packs or controller, they are out of balance so that a cell or cells are running dry before the rest, or the packs are simply not getting charged fully.
Amber,
I'm not sure why you are seeing the second stage as reversed?
To me it seems to be approximately:
1st 3:1
2nd 2:1
3rd 1.5:1
4th 1:1.5
So, around 6:1 with the lowest ratio on the Alfine taking it to 11.5:1
Still far too tall, though....
I'm not sure why you are seeing the second stage as reversed?
To me it seems to be approximately:
1st 3:1
2nd 2:1
3rd 1.5:1
4th 1:1.5
So, around 6:1 with the lowest ratio on the Alfine taking it to 11.5:1
Still far too tall, though....
recumpence
1 GW
Oops, sorry, I meant "Geared Hub" Not hub motor.amberwolf said:
Sheesh, I am tired today..........
Matt
I guess because I must be tired like Recumpence.Miles said:
I must've looked at that like a dozen times and it looked reversed everytime I did, until now. 
I'm going to go back to breaking spokes trying to lace CrazyBIke2's new motor wheel instead. It's safer. :lol:
recumpence
1 GW
I think his packs are in parallel. He mentioned "8.9wh". I think he meant 8.9 AH.
Matt
Matt
liveforphysics
100 TW
Teasing apart those phase leads to terminate in wye would be a good call in this situation.
It won't get him all the reduction he needs, but it would be free.
It won't get him all the reduction he needs, but it would be free.
John in CR
100 TW
How did the controller survive?
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