Don't remember the weight capacity. All i remember is a forum where the engineers gave a very conservative value and if you followed their recommendations, u wouldn't be able to carry another person on the back. I've carried a lot more than a full grown person's weight.
Looking for hub motor for regen purposes
- Thread starter Potato011
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ebike4healthandfitness
100 kW
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I personally think your open drop out fork would be a lot safer with 160mm mechanical disc and front regen hub than it is with four pot hydraulic 203mm disc with metallic pads. Just make sure you use two Grin v7 torque arms and get a hub with decent spacing between spoke flanges.
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I NB that the new Freegen hubs DO NOT have a braking torque issue:
All the braking torque goes through the brake rotor and caliper.
In the video linked earlier Justin says/shows that they forgot to fasten the torque arm to the frame and had no issues.
ie: Besides no 'cogging losses' (planetary gears etc excepted) you also have no brake torque loosening bolts etc issues.
So I'm surprised at the lack of Freegen enthusiasm and advice here.
Perhaps few have watched the whole video..?
See 12min38 here:
2: MPPTs and DIY Supercaps for regen:
MPPTs, as used in solar charging, have the ability to take any voltage and turn it into the optimum voltage for charging batteries.
If the voltage from early/late day solar is too low; the MPPT will change that into shorter pulses of correct voltage.
I NB that there is a lot of DIY supercap talk online thx to easy access to various graphite/graphene foils etc.
I also NB that these supercaps can be made cylindical, or flat, or made to wrap around various cylindrical parts of a bike frame.
DIYing a supercap wrapped around the bike frame seems like a great, cheap way to make lots space for such, dont it..?
(A lot of the Youtube videos may be complete BS, but not all IMHO)
That means that you may be able to use a SMALL bank of Supercaps to take the high current of effective regen and use it to charge the batteries correctly, via a MPPT..?
Also at low speeds = too low regen voltage; a MPPT might be used to turn that low voltage into high voltage pulses to a battery bank or supercap..?
ie: More effective regen over a wider speed range, where low speed regen braking isnt wasted.
So ye; the complete 'write off' and 'dont waste your time thinking about it' attitude towards regen and supercaps seems 'short sighted' to me..?
All the braking torque goes through the brake rotor and caliper.
In the video linked earlier Justin says/shows that they forgot to fasten the torque arm to the frame and had no issues.
ie: Besides no 'cogging losses' (planetary gears etc excepted) you also have no brake torque loosening bolts etc issues.
So I'm surprised at the lack of Freegen enthusiasm and advice here.
Perhaps few have watched the whole video..?
See 12min38 here:
2: MPPTs and DIY Supercaps for regen:
MPPTs, as used in solar charging, have the ability to take any voltage and turn it into the optimum voltage for charging batteries.
If the voltage from early/late day solar is too low; the MPPT will change that into shorter pulses of correct voltage.
I NB that there is a lot of DIY supercap talk online thx to easy access to various graphite/graphene foils etc.
I also NB that these supercaps can be made cylindical, or flat, or made to wrap around various cylindrical parts of a bike frame.
DIYing a supercap wrapped around the bike frame seems like a great, cheap way to make lots space for such, dont it..?
(A lot of the Youtube videos may be complete BS, but not all IMHO)
That means that you may be able to use a SMALL bank of Supercaps to take the high current of effective regen and use it to charge the batteries correctly, via a MPPT..?
Also at low speeds = too low regen voltage; a MPPT might be used to turn that low voltage into high voltage pulses to a battery bank or supercap..?
ie: More effective regen over a wider speed range, where low speed regen braking isnt wasted.
So ye; the complete 'write off' and 'dont waste your time thinking about it' attitude towards regen and supercaps seems 'short sighted' to me..?
Last edited:
ebike4healthandfitness
100 kW
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In the world of motorcycles (and other industries like automobiles) they use castle nuts with cotter pins to make sure the nut cannot loosen. Not sure why this method is not used for locked clutch regen and non geared direct drive regen? Castle nuts for M14 axles are available.
Always was interested in freegen. However, it's probably going to take quite a bit longer for grin to bring a product to market (not to mention the price). This bike has towed solar panels so pretty familiar with mppts. The super cap combo seem like quite an interesting idea tho... gonna need to look into that.
Is the concern that under heavy braking, the front wheel might pop out of the dropout?
Freegen:
NB that DIY turning a geared hub motor into a Freegen hub is actually a breeze!
See j3tch1u's later posts here:
New Geared Hubmotor variable-regen e-braking system that still freewheels, by ChargeBike
The only safe and practical solution was to mount a small hydraulic brake (from a 1/5 rc model car) plumbed into the main brake line using the bleed port from the main caliper. The 80mm aluminum rotor is connected to the clutch planet carrier thru a hub. That is a really cool solution and...
endless-sphere.com
MPPT:
Glad you see the possibilitiies. Thx Patato011
If I can be of any assistance...
there appears to be some hardware mods that I cannot fabricate rn. Will wait for more documentation to appear before attempting.Freegen:
NB that DIY turning a geared hub motor into a Freegen hub is actually a breeze!
See j3tch1u's later posts here:
New Geared Hubmotor variable-regen e-braking system that still freewheels, by ChargeBike
The only safe and practical solution was to mount a small hydraulic brake (from a 1/5 rc model car) plumbed into the main brake line using the bleed port from the main caliper. The 80mm aluminum rotor is connected to the clutch planet carrier thru a hub. That is a really cool solution and...
MPPT:
Glad you see the possibilitiies. Thx Patato011
If I can be of any assistance...
ebike4healthandfitness
100 kW
- Joined
- May 19, 2012
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Yes.
8" rotor, QR skewer + open drop out facing downwards not recommended by companies like Hayes and Avid for that reason.
bit hard to describe in words so here's a sketch. the fork has this recess where the QR goes through. when tightened, its pretty much impossible for the QR to be removed. The QR is tightened using an allen key instead of the usual quick release latch.
Hmm should I be concerned running 203mm with Magura mt5's on QR skewer?
I've survived my last heavy loaded tour with a lot of crazy descents, 70+kmph at some point, but my Deore m615s were definitely sub-optimal and having a hard time keeping up.
Is there anything I can do except changing out the complete fork? Will bolted skewers be stronger/better than QR?
I've survived my last heavy loaded tour with a lot of crazy descents, 70+kmph at some point, but my Deore m615s were definitely sub-optimal and having a hard time keeping up.
Is there anything I can do except changing out the complete fork? Will bolted skewers be stronger/better than QR?
Basically you bolt the brake disk to the carrier for the 3 planetary gears, but yes; you need a lathe at the least.
If you show the video to someone that does good lathe work (enjoys it); they will sus it out easily and tell you its pretty easy to do, as is evidenced from the prototype.
The mentioned open source ctlr software that needs modding may be another story.
But no doubt j3tch1u and others on this forum will have some pointers?
I do have access to a lathe but no training. will need to hold of until I have some more time to learn.
I have one. I'm very cautious/scared of it: They will eventually catch you and 'wind you up'!
Every lathe should have a sewing machine pedal that cuts and brakes the lathe when you take your foot off it IMHO.
IamIan
100 mW
Chalo
I'm a little confused
???
Justin @ Grin has posted a video , in which he claims the exact opposite of both of your claims about adding regen braking.
Chalo :
1 = "will not reduce total maintenance"
2 = "dramatically reduce the real performance of your brakes"
Justin =
will reduce total maintenance (exactly what OP wanted it to do)
will improve performance of braking to add it to existing brakes.
16:10
Even ignoring what Justin said in the video ..
Every wh of braking that regen braking does is that much wh reduction in brake pads over the same period of time .. and thus a reduction total maintenance over a given period of time .. just due to conservation of energy , I don't see how adding regen braking could do anything other than reduce total maintenance .. make the same brake pads last longer , etc.
????
Sense what was suggested here was adding Regen braking to existing brakes .. how could that do as you suggest and "dramatically reduce the real performance of your brakes" ... ??? seems to me like adding Regen braking should improve braking .. just as OP was looking for.
I'm sorry if I'm just dense and missing something obvious .. but .. I just don't see the basis to support these two claims ??
Chalo
100 TW
Reversing torque on components exacts a maintenance penalty, to assure that things are staying tight. This is greater than the maintenance penalty of replacing pads on brakes that are designed for braking.
Also, brakes designed as brakes work better as brakes than motors that are retrofitted into service as brakes.
Also, brakes designed as brakes work better as brakes than motors that are retrofitted into service as brakes.
Is it really tho? Will a properly tightened screw really come loose that often and even if that is the case, some threadlocker and maybe even a cotter pin on the threaded rod would eliminate this issue. I perform somewhat regular inspections on my bike and tightening a few bolts every couple hundred miles seems more worth than buying new pads every few months.
IamIan
100 mW
Wasn't the reversing torque issue resolved by the ebike motors that started using torque arms to lock it in place ???
In order to know it is a greater maintenance penalty .. ie A > B ... one would have to know what the values of both A and B are ... Would you be willing provide me the basis/source you are using .. ie .. what documented testing that shows the two measured amounts are the values you are claiming them to be ???
I only ask for a source .. because .. my own my own antidotal personal experiences are the opposite B>A ... and thus I would be interested to see the testing and data results you are basing the A>B claim on .. depending on the testing your conclusion is based on , my own antidotal experiences might not be representative overall as a whole to others in other contexts.
- - - - - - -
'better' is a very vague .. too vague for me to know what you are claiming ?? 'better' how ?? in what way ??
In this context .. the comment you replied to .. was a context of adding regen brakes in addition to existing mechanical brakes.
In this context ... How (in what way) are mechanical brakes alone by themselves .. 'better' than the same mechanical brakes combined with additional regen brakes ??
again .. I am sorry if it is an obvious thing I'm missing .. but .. I just do not understand .. I don't see it ???
Maybe I'm naive or something .. but .. it seems to me .. in this context .. adding additional regen brakes .. will result in a combination that is better than the mechanical brakes alone by themselves ever could be .. soo .. you saying the opposite .. Is confuses me , where / in what way you see it that way ???
Chalo
100 TW
You mean Grin, Heinzmann, and Copenhagen Wheel? I've built and serviced all of the above, but never seen one operating out on the street. Out there it seems I only see the 99+ percent of hubs that don't have an integrated torque arm and instead rely on flatted axles to anchor reaction torque. You can superimpose a torque arm or two onto one of those hubs, but it won't keep the axle from budging back and forth and progressively loosening the axle nut, if you constantly reverse the torque direction.
ebike4healthandfitness
100 kW
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Have you seen a wheel using the GRIN v7 torque arm operating out on the street?
@Chalo
As much as I like your contributions to this forum, sometimes I feel like you are stuck in the past, you even still seem to recommend mechanical brakes over hydraulic.
"It's not designed for it" well 90% of what we see on this forum is not the designed for its original purpose, it's called innovation, progression and trying to figure out how we can make things work.
So you are saying with proper torque arms it should be fine?
As much as I like your contributions to this forum, sometimes I feel like you are stuck in the past, you even still seem to recommend mechanical brakes over hydraulic.
"It's not designed for it" well 90% of what we see on this forum is not the designed for its original purpose, it's called innovation, progression and trying to figure out how we can make things work.
So you are saying with proper torque arms it should be fine?
IamIan
100 mW
Soo .. unless I'm missing something.
A = Adding regen braking to existing mechanical brakes .. does NOT "dramatically reduce the real performance of your brakes" .. adding regen braking to existing mechanical brakes is likely to improve the vehicles braking performance.
B = Adding regen braking is likely to reduce the total financial maintenance cost .. for some people it also reduces total maintenance time.
C = It is best for a rider to take preventative measures for the potential for a back and forth torque action.
Caused by alternating between forward drive torque and backward braking torque .. it is possible that such back and forth behavior might eventually cause a bolt to untighten .. if that untightening event happens , it could result in an unsafe operating condition , thus why preventative measures should be applied.
- - - - -
To address this potential back and forth issue .. there are numerous options that a user can apply.
In no particular order (some can be combined and work together) :
1 = Routinely check key fasteners are properly torqued.
1a = a marker line across the two allows a visual inspection in about ~2 seconds.
1b= check the two key nuts at risk to back and forth takes about ~5 seconds with a torque wrench.
2 = Use hub motor design that targets to remove the back and forth effect as much as possible.
see freegren video above 12'50"
motor regen braking torque goes through the same path as the mechanical brakes do (not the 'weak link' nut.)
3 = Use a hub motor designed to compensate/counter-act the back/braking torque effect.
Those with external torque arm to lock position in place.
4 = Use lock washer to keep nut locked in place.
5 = Use lock tight fluid to keep nut locked in place.
6 = Use nylon lock nuts to keep nut locked in place.
7 = Use properly applied double nut to keep nut in place.
8 = Use slotted shaft .. not usually machined to such a tight fit to lock in place .. usually loose enough to only reduce the amount it can shift back and forth.
9 = Use tight cotter pin to tightly lock in place.
A = Adding regen braking to existing mechanical brakes .. does NOT "dramatically reduce the real performance of your brakes" .. adding regen braking to existing mechanical brakes is likely to improve the vehicles braking performance.
B = Adding regen braking is likely to reduce the total financial maintenance cost .. for some people it also reduces total maintenance time.
C = It is best for a rider to take preventative measures for the potential for a back and forth torque action.
Caused by alternating between forward drive torque and backward braking torque .. it is possible that such back and forth behavior might eventually cause a bolt to untighten .. if that untightening event happens , it could result in an unsafe operating condition , thus why preventative measures should be applied.
- - - - -
To address this potential back and forth issue .. there are numerous options that a user can apply.
In no particular order (some can be combined and work together) :
1 = Routinely check key fasteners are properly torqued.
1a = a marker line across the two allows a visual inspection in about ~2 seconds.
1b= check the two key nuts at risk to back and forth takes about ~5 seconds with a torque wrench.
2 = Use hub motor design that targets to remove the back and forth effect as much as possible.
see freegren video above 12'50"
motor regen braking torque goes through the same path as the mechanical brakes do (not the 'weak link' nut.)
3 = Use a hub motor designed to compensate/counter-act the back/braking torque effect.
Those with external torque arm to lock position in place.
4 = Use lock washer to keep nut locked in place.
5 = Use lock tight fluid to keep nut locked in place.
6 = Use nylon lock nuts to keep nut locked in place.
7 = Use properly applied double nut to keep nut in place.
8 = Use slotted shaft .. not usually machined to such a tight fit to lock in place .. usually loose enough to only reduce the amount it can shift back and forth.
9 = Use tight cotter pin to tightly lock in place.
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