Author Topic: Regenerative brake stops braking after parts of a second  (Read 6424 times)

Offline eGhostRider

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Regenerative brake stops braking after parts of a second
« on: June 08, 2014, 03:15:45 PM »
Hi Bike Mad.
That's my first posting.

I have a MP3 on the front wheel. The initial setting of the reg. brake was at 20%. It worked well unless I climbed up a steep hill. The motor started blocking, so I turned around. At first it looks like the motor was still blocking, but some meters later it returned into normal operation, exzept the Reg. Brake. If I pull the brake the Reg. brake starts, the regenerated power climbs up, but after some parts of a second, the reg. Brake stops working and the wheel runs free. The 20% setting shows a regenerative power of up to 290w, a 30% setting shows only 190. Today I trief a 116% setting, it didn't showed any reg. power, but the reg. brake is much stronger as the other settings, but only for some tens of a second. After release and pull again, the brake does the same, brake for a short moment and release.
Any idea?

Offline Bikemad

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Re: Regenerative brake stops braking after parts of a second
« Reply #1 on: June 08, 2014, 05:27:07 PM »
Hi andto the forum.

If the motor started to play up while climbing a steep hill it could be because the controller has got too warm and the high temperature caused it to cut out. Trying to use the regen with a hot controller could also explain why the regen cuts out almost immediately.

I have mine set on maximum and have a good amount of physical braking, but no charging current is generated below 10mph.

It might be worth trying different voltage settings on the controller (unless you are using a 24V pack) to see if it makes any difference to the regen, as one of my controllers does not give any regen braking force on the 24V setting with a fully charged 29.6V LiPo pack (33.6V), but seems to work fine after the battery voltage has dropped a couple of volts.

Alan
 
« Last Edit: July 05, 2017, 04:36:17 PM by Bikemad »

Offline eGhostRider

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Re: Regenerative brake stops braking after parts of a second
« Reply #2 on: June 09, 2014, 07:10:46 AM »
 :)Hi,
Forgot to mention that I'm using a 48V 20Ah LiPo pack with a 48V setting. Tried also at different charge of the pack, the reg. brake behaves the same. Most of the time I'm crusing with a speed of 25kmh, but good point to check the speed.
Next step I will change the Controller and see if something got burned.

Offline Aliasssss

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Re: Regenerative brake stops braking after parts of a second
« Reply #3 on: June 09, 2014, 10:01:32 PM »
Hey mate.

You know the saying ... "if it ain't broke don't fix it" ? Well ... don't split (open) the pie just yet.

I had the same problem but once I use the regen breaking above 16km/h it regenerate enough energy. If you start to brake when you onli ride at 12km/h you will only see energy regenerated for about 1 second, or even less. Weird though your regen settings seem to work kinda in reverse... 116% no regen and 20% more regen than 30% ... and you really lost me when you said " It worked well unless I climbed up a steep hill " ... why on Earth would you need to use regen breaking while climbing UP a steep hill? Never really understood that. Please explain what you meant. Try to ride downhill, then use regen. If you cannot ride downhill, at least ride on a flat when testing regen breaking.

Because your pie is front mounted you should really have no breaking at all while climbing a hill because your Center of Gravity is way backwards and the forward momentum further move the CG backwards, so there is really almost no weight on the front wheel... that is why a front pie will always have lower efficiency in transferring the power into forward motion and also be almost useless on a wet or slippery surface. The only thing a front pie will give you is better regeneration ... at least in theory. While standing still on  a bike your weight is distributed about 70% on the rear wheel and 30% on the front, but while riding forward your CG moves to the back a bit as the weight is distributed more like 90% on the rear wheel and only 10% on the front wheel. This make me wonder why would someone choose a front pie? Yes on a front pie when riding forward you can only use at most 20% of the traction the same pie would give you when rear mounted, and that is on flat, uphill a front pie is almost a no go!

Anyway, true enough a front pie can drive backwards almost as efficiently as a rear pie can drive backwards (yes I ment backwards) ... almost but not quite ... so no win here either :(

What kind of watt meter are you using?

Sorry, just stating the facts.

Cheers!

Offline Rodmiami

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Re: Regenerative brake stops braking after parts of a second
« Reply #4 on: June 10, 2014, 01:43:17 PM »
The reason some of us use front wheel Pies is because we have bicycles that don't have a geared hub in the rear . So you can spend $800.00 on a kit and then have to buy a bicycle . Also if you pay attention to the blog . More troubles are reported with the bearings of the rear wheels than the fronts .

Offline Aliasssss

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Re: Regenerative brake stops braking after parts of a second
« Reply #5 on: June 10, 2014, 02:01:26 PM »
Please explain mate. I didn't quite get the part that you must buy another bike ... Why?

I assume that by geared hub you mean freewheel or cogwheel. Geared hub is a rear hub that has internal gears by the means of which it can vary the ratio at which the pedal power is transformed into forward motion. So which one is it?

I am not a blog type of guy but If you read any bike forums you will see that in general at bikes most problems are with the front wheel bearings, because there is where the most shocks are absorbed. Now if a bike wheel uses ball bearings (instead of bearings and cone) then all the problems are gone for good ... at least for a very long time ;)

It's not the e-bike that generates bearings problems, it's a general bike issue when not using front ball-bearings. Same goes for rear wheel.

Cheers!

Offline Rodmiami

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Re: Regenerative brake stops braking after parts of a second
« Reply #6 on: June 12, 2014, 01:40:23 PM »
  This is not a bicycle forum . Its an electric bicycle forum . I will repeat . On this forum more people have expressed problems with the bearings on the rear wheel than the front . I also meant that I prefer coaster style breaks in the rear .

Offline eGhostRider

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Re: Regenerative brake stops braking after parts of a second
« Reply #7 on: June 26, 2014, 07:57:55 PM »
Hi Aliasssss,
Sorry might be not Clear enough at the time.

I live in Neuchatel, Swiss. I took a ride to one of the landmarks here. The last part of the road was very steep. Even with pedaling support the motor brake and stopped working. No other joyce than stopping, turning and try to get down the hill. On the first meters the motor was still blocking the bike, but released more and more. Since then the reg. Brake is not working anymore continously, as I discribed. Blocking for tens of a second and releasing, whatever the setting is. This is the same for all speed, mostly faster than 20km/h. I assume, that a capacitor in the Electronics is gone. I ordered a new controler and will exchange and have a close Look on the old one.
i'm using the Cycle analyst for speed and charge control.