Build Options

evglobal19

100 mW
Joined
Apr 3, 2019
Messages
35
cross reference to my other post:
Bought this:
G3.jpg
Striped it down for now to this:
strp.jpg
Wheels are 17" so similar choices are limited to QS, NBpower, and UUMotor.
NB offers a nice kit at 3000W and 5000W. they can be had at 48v, 60v, and 72v
at 300lbs for me and the current frame (probably less, the bike I mean) mostly flat ground. I'm going on the assumption that as a kit the controller is matched properly to the hub motor. I'm looking for suggestions on combinations of the above. This will not be a long distance cruiser tops about 20 mile range. speed - whatever can be had. would like to stay under the 72V due to battery cost but any suggestions are most appreciated.
 
That looks like a sweet, lightweight ride.

What I would do:
-remove the current subframe and build another one that goes to the bottom: This way you'd have lots of space for a big battery and no need to build it in a weird shape.
-Find a way to remove the rubbish front brake, in order to replace it with a disc. I think this is the hardest part of the build, but probably one of the most important ones. I'd change the whole suspension/direction/front wheel alltogether if it were to be mine, it doesn't feel very sturdy.
-Build the battery, preferably 72V and 30Ah minimum if you want good current discharge capability, which is the key here since you don't seem to care much about long range. You didn't really state what kind of power specs you expect so that might need to be adjusted later once you'll be clear on that point.
-For the motor, I think 3000W at least, a QS hub motor will work fine, you'll just have to find a way to attach a disc brake. They do exist with drum brakes but obviously drum brakes are garbage. Attaching the motor to the existing swingarm might be a challenge too. I wonder how this swingarm is made, it kinda looks like both sides can move independantly. In which case that wouldn't be good, you'd have to reinforce it with a transfersal tube to link both firmly, otherwise the torque and weight of the motor might damage everything.
-As for the controller, it will depend on your budget and you ll have plenty of time to figure that out later. Good thing is that you should have enough space to put it in the gas tank or under the seat. I'd go with a good ol' Sabvoton 150A or a similar spec Kelly. That should give you a lot of power. Way, way more than the original gas engine.

You need to be clear on what budget you'll be able to get, because everything will depend on that.
Again, that's a very good basis, it has plenty of potential to become a real awesome, lightweight beast, but that might need some work and some cash. And clear targets.
 
Dui,
thanks for the information and btw, really like the "ninja" build!!!!
so, yes the swing arm is cross braced already made need reinforcing but its there
yes the bottom portion of the frame can be removed and replaced to accommodate anything I suppose. since the bottom subframe is bolted on I can play around with size and shape without the need for welding. It will all be painted later so that gives some flexibility. Still looking at components but the 72v prices are high and the 60V a little more reasonable but, not sure yet....

three vendors have a 17" in the 3-5kw versions. I'm leaning towards the NBPower 5kw kit but also looked into the QS. If you're going to build 3kw and the 5kw is not much more why not? if 72v/32Ah is a minimum it is what it is. the NB hub comes with a 100A sine wave programmable controller but I'll check the Savboton too.

If I go with either kit it has disc brake on hub and suppose could swap in matching front wheel with disc setup too. for budget hmm, I'm more inclined to get good pieces one at a time but always worry about being sure they match. without being sophisticated about the electronics I'm tending to rely on the 'kit' being properly matched. If matching the specs isn't as daunting as I think then any suggestions about what to research is quite helpful. like everyone time patience and research always trumps buying things more than once. I'll post the specs on what I'm considering motor wise and look forward to any and all feedback. ;)
Steve
 
NB Power
5kw kit
48/60/72v 5000w brushless gearless motor
17" rim
100A Sine Wave Programmable controller
twist throttle with 3 speed
electric brake levers
$564 delivered
$885 for 72v/26.1Ah Panasonic cell battery (delivered)
3kw kit
72v/3kw 80A since wave programmable is only $100 less. (Duh)


QS V3 3kw
17" rim
3kw rated 6kw peak
48/60/72v (default)/96
cont. battery current 52A peak 104.2A (@72V)
$219 for Hub - also have kits: Not sure of their prices on these
they can provide a Kelly or Sabvoton controller
electric hydraulic disc brake system

QS V3 4kw $465
cont. battery 55A, peak 111A
suggested Peak phase current 196-245A
disc brake

QS 5kw V2 $459
70A continuous 120A peak
suggested peak phase 280-500A

QS 6kw V2 $492
83A/120-160A
suggested peak 260-550A

QS 8kw $584
110A cont/150-200A peak
phase 300-650A

same as above 8kw kit with Kelly controller $1088
$615 V3 controller $415 only potential problem is 120/70R 17 tire or 3.5" wide rim?? 200mm drop out
 
Lol, I was about to say that's a really clean bike and it's almost a shame to take it apart... then I noticed the year in the photo :) If you can get access to basic fabrication gear then it shoulddn't be much problem to get a 120 section in that swinging arm. It'll look a bit strange but a bigger section wheel from something else should go in the front ok and hopefully come with a disk brake (plus caliper, lever, hoses, etc.). Maybe even a whole front end, that can be a real pain to do sometimes but if your steering bearings are a standard size it can often work out simple. Rolling resistance will go up a bit and tyre prices too but it could come out looking very nice :)

Is the original engine dead? If so it could probably be gutted and a drive added to the output shaft if mid-mounted motors are looking like a more cost effective option.
 
Funny, I bought it from Mike who was the owner of Fat City mopeds for decades.
the 50cc engine is "not working" but Im not sure what you mean about gutting and adding a drive shaft
 
evglobal19 said:
Funny, I bought it from Mike who was the owner of Fat City mopeds for decades.
the 50cc engine is "not working" but Im not sure what you mean about gutting and adding a drive shaft

Stripping out absolutely everything from the engine/gearbox unit except for the output shaft (ie. the one with the sprocket on it) and the bearings that support it. The bearings are likely to be a standard size so could be replaced with sealed units (about $15-20 for pair) and the shaft is fairly likely to have a regular size somewhere on its length, something that could match a timing pulley bore size easily available somewhere like ebay (ie. 20mm, 18mm, etc).

Sorry if that's a distraction btw, I'm in the planning stages of something similar at the mo and a large RC motor looks like the most cost effective option even when overrating the motor by 2 or 3 times. I'm going for an RC speed controller initially (have it here and want to see what it can endure) and then onto vesc but from reading through threads here it looks like the low cost ebike controllers are reliable, manufacturers specs well below what they're actually capable of. Still chain maintenance though, and chain noise plus the noise of a primary drive and screaming motor... hub drive would certainly be the refined option :)
 
no distraction, I'm open to any input (pun intended)
I had thought originally the cheapie was to go for sub $300 was a 72v 3000W bldc motor with a foot to attach to the frame. seller best.sale.for.you on ebay has a pairing of the brushless motor and 50A/80A controller for $289 and free shipping. it's a Kunray MY1020. that and slap an array of 12V/35ah SLA's for $250 and its sub $550 delivered. It would leave the frame a bit empty except for a giant 130lb battery pack!

I would do this to "try" out the combination initially and could even keep it around for something else later but $500-$600 for a spare and another $1800 for this one is getting towards the 'obsessed' side. its an evil slope we start down and I've been this route with sports cars often. Guess have to decide between premium and shade tree version I'm after. that would be about a 4hp (120cc)minibike equivalent which is still double of what it came as in 50CC variety. with a 5kw kit it's only about 6.5hp (200cc)equivalent. going petrol with a 22hp Predator motor for $800 is 16.5kw equivalent but then there is all the messy bits.
 
no distraction, I'm open to any input (pun intended)
I had thought originally the cheapie was to go for sub $300 was a 72v 3000W bldc motor with a foot to attach to the frame. seller best.sale.for.you on ebay has a pairing of the brushless motor and 50A/80A controller for $289 and free shipping. it's a Kunray MY1020. that and slap an array of 12V/35ah SLA's for $250 and its sub $550 delivered. It would leave the frame a bit empty except for a giant 130lb battery pack!

I would do this to "try" out the combination initially and could even keep it around for something else later but $500-$600 for a spare and another $1800 for this one is getting towards the 'obsessed' side. its an evil slope we start down and I've been this route with sports cars often. Guess have to decide between premium and shade tree version I'm after. that would be about a 4hp (120cc)minibike equivalent which is still double of what it came as in 50CC variety. with a 5kw kit it's only about 6.5hp (200cc)equivalent. going petrol with a 22hp Predator motor for $800 is 16.5kw equivalent but then there is all the messy bits.
 
Yeah, when the thirst for horsepower and the creeping feature creature get together things are sure to get expensive fast!

Hadn't come across those Kunray motors, if they're known to be durable then they look like a very good option :) RC motors appear to give more power/price on paper but their continuous ratings are always much lower and gearing down from 30-50000 rpm will be wasteful. On the plus side they're tiny so adding an few extra later should be fairly easy :twisted:

Not sure about lead acid, I was thinking along the same lines at first but it would still cost quite a lot and after digging into it in threads here it seems the amp ratings are deceptive, plenty of burst power but continuous power is nothing like as good as it appears:
https://en.wikipedia.org/wiki/Peukert%27s_law

RC Lipo packs seem to be the best option for testing, not gone through the figures yet but the continuous amps seem to work out cheaper than lead acid, only range would suffer. Had some thoughts on using Li-ion to charge Lipo, might allow a relatively small Li-ion pack for range without stressing them with high discharge, still have to read up on that one.
 
Just thinking that $250 for 72v/35AH pretty cheap to test out the configuration. if all runs well enough then adding the li battery later will feel more deserved. Spending close to $1,000 for lithium batteries then feeling disappointed with the bike overall would have wasted another $750 on top. I'd rather buy and store aside $250 then feel I have $1,000 on the shelf.
 
evglobal19 said:
Just thinking that $250 for 72v/35AH pretty cheap to test out the configuration. if all runs well enough then adding the li battery later will feel more deserved. Spending close to $1,000 for lithium batteries then feeling disappointed with the bike overall would have wasted another $750 on top. I'd rather buy and store aside $250 then feel I have $1,000 on the shelf.

That's kind of what I mean about the Lipo's, I was planning on 4x 12v 15Ah lead acid, about $240 (0.72Kwh), that would have given over 200a burst but it turns out they'd only give me about 10a continuous before their capacity falls off badly (wiki link above). 12Ah lipo comes in at a bit under $200 for only 0.26Kwh but can handle a continuous rated 300A, more than enough to test the heck out of everything else.

Those figures are a bit skewed, the lead acid could be quite a bit cheaper (needed the size and shape) and that 300A (50c) rating looks a little too good to be true on second glance (lipo is a total minefield of fake knockoffs!) but 30c is definitely within that price range, 180A continuous. If those amps are more than enough and even less range is ok for testing then the prices can go a lot lower. I'm basing that on 44-48v btw, 5kw continuous should easily be possible within $150.

EDIT: If anyone has clearer figures for that I'm all ears btw! About to go ahead with them. Thx.

MOER EDIT: Just thought of an example. Say a car battery is 12v 100ah. Starter motors are usually only rated at around 1 to 2kw, battery has 1.2kwh. In theory the starter should be able to crank over for more than half an hour but in reality it would be lucky to get more than 5 continuous minutes before crapping out.
 
stan.distortion said:
MOER EDIT: Just thought of an example. Say a car battery is 12v 100ah. Starter motors are usually only rated at around 1 to 2kw, battery has 1.2kwh. In theory the starter should be able to crank over for more than half an hour but in reality it would be lucky to get more than 5 continuous minutes before crapping out.

Car batteries are rated based on current potential, not capacity. Lead is never worth it...took much weight for the energy they deliver, and their life if quite short except when only 50-60% of rated capacity is used. On top of that Puekerts effect makes true capacity in our use only 50-70% of rated capacity. Lithium batteries are better in all respects (primarily performance, weight, and overall cost), but there are some special considerations to ensure long life.

Forget lead. Lead is dead.
 
evglobal19 said:
three vendors have a 17" in the 3-5kw versions. I'm leaning towards the NBPower 5kw kit but also looked into the QS. If you're going to build 3kw and the 5kw is not much more why not? if 72v/32Ah is a minimum it is what it is. the NB hub comes with a 100A sine wave programmable controller but I'll check the Savboton too.

I would go with a 3KW QS hub motor, if possible Balanced V3 since they are, in my experience at least, the best compromize.
Your machine is lightweight, a 3KW motor shouldn't heat too much and could give you really good performance. That's what I use on my motorbike actually, so it should be no problem with yours.
In my opinion, a 150A battery 350/phase controller should be more than enough. That would give you around 12KW of power, on such a lightweight machine it will be a blast! Trust me, there is no way you could be disappointed with such a setup.
You don't really want to get too crazy with a too powerful motor, because otherwise you'd have to match your battery and controller to be able to deliver that power. Using an underpowered controller or battery might result in frying them.

evglobal19 said:
If I go with either kit it has disc brake on hub and suppose could swap in matching front wheel with disc setup too. for budget hmm, I'm more inclined to get good pieces one at a time but always worry about being sure they match.

If you go for the kind of power I'm describing, then having a good front brake will not be an option. You really need to be able to stop, it can get to high speeds really fast. You could likely reach more than 100km/h and get there in 7-8 seconds, maybe less if you keep the bike light and if you're not a big fatty yourself XD
But that can be done later, in which case you'd just have to tune down the controller, that's the beauty of having a programmable unit.

evglobal19 said:
without being sophisticated about the electronics I'm tending to rely on the 'kit' being properly matched. If matching the specs isn't as daunting as I think then any suggestions about what to research is quite helpful. like everyone time patience and research always trumps buying things more than once. I'll post the specs on what I'm considering motor wise and look forward to any and all feedback. ;)
Steve

Regarding the RC inboard motor setups, I wouldn't go in that direction. Maybe they could give good performance, but I'm not sure they are reliable enough for a daily driver. If you plan on using your ride often then you might want to go for something with enough real road experience. Those hub motors are widely used on litterally hundreds of millions bikes here in China and they work really well. No real need to reinvent the wheel here :)

As for dimensioning the battery, you will need to take into account the power draw:
if you go for a standard lithium battery, then most of these will have a 3C discharge rate. With a 150A controller, that means that you will need a 50Ah battery (150A/3C=50Ah).
So what you want here is to find a battery using cells capable of a high discharge rate. In order to live with a 30Ah battery, then you need to make sure that the cells are capable of 5C continuous discharge at least.
You could probably live with 60V, but if you want a bit more speed and power it would be better to go for 72. I don't know the prices of such batteries where you live but that will be a large part of the total cost, so be prepared. Also, make sure that the BMS you will use is capable of delivering at the very least 150A. Better go for at least 200A if possible, to avoid some unwanted cutoffs, especially when your battery will start aging.

Nowadays, some smart BMSs capable of 300A continuous exist, and they are affordable, so it should not be a big issue (the ANT smart BMS is a good value).

There are various lithium chemistries, none of them is perfect, they all have their drawbacks:
-LiFe has a high discharge rate and they last for a long time, so they will keep their capacity rating for several years, but they are big and heavy. Thay are also less sensitive to deep discharge and overcharge so somewhat safer.
-Li-ion is lightweight and takes up less space, but they will quickly lose their capacity, so if you build a 30Ah battery then the next year it might be no more than 25Ah. So in the end you need to overbuild your battery quite a bit, which gets expensive.
Plus they will die earlier, they can handle way less cycles. They are a bit more risky so you need to use state of the art protection to avoid fires.
-LiPo is the lightest, it has a really high discharge capability, plenty of power, but it is very impractical for a daily driver because it needs to be extremely closely watch during both charge and discharge, plus the cells really don't last for long.
-Lead-Acid: it works fine but it is super heavy and it sags quite a bit. Plus they won't last more than a year. But if you can get them for cheap, then it might be a good option to at least test your setup for a few months, make sure everything works fine, and then upgrade to lithium. It isn't as powerful as a lithium battery, expect to lose around 10-20% of the power. But for testing purpose, it might be a good solution in your case. Just a temporary one and on;y if you can get them for very cheap. In which case, go for seven 12V 20Ah batteries. Expect around 20-25km of range if you drive agressively, maybe 50 if you ride very slowly.

Both LiFe and Li-ion options can work well on your setup, I guess it just comes to whichever you prefer. On my builds I tend to use LiFe because I can live with a bit more weight and I have enough space, but in your case that might be different. I used to run on Lead Acid at the very beginning, it was fine but the beast was very heavy.
 
Dui said:
evglobal19 said:
three vendors have a 17" in the 3-5kw versions. I'm leaning towards the NBPower 5kw kit but also looked into the QS. If you're going to build 3kw and the 5kw is not much more why not? if 72v/32Ah is a minimum it is what it is. the NB hub comes with a 100A sine wave programmable controller but I'll check the Savboton too.

I would go with a 3KW QS hub motor, if possible Balanced V3 since they are, in my experience at least, the best compromize.
Your machine is lightweight, a 3KW motor shouldn't heat too much and could give you really good performance. That's what I use on my motorbike actually, so it should be no problem with yours.
In my opinion, a 150A battery 350/phase controller should be more than enough. That would give you around 12KW of power, on such a lightweight machine it will be a blast! Trust me, there is no way you could be disappointed with such a setup.
You don't really want to get too crazy with a too powerful motor, because otherwise you'd have to match your battery and controller to be able to deliver that power. Using an underpowered controller or battery might result in frying them.

evglobal19 said:
If I go with either kit it has disc brake on hub and suppose could swap in matching front wheel with disc setup too. for budget hmm, I'm more inclined to get good pieces one at a time but always worry about being sure they match.

If you go for the kind of power I'm describing, then having a good front brake will not be an option. You really need to be able to stop, it can get to high speeds really fast. You could likely reach more than 100km/h and get there in 7-8 seconds, maybe less if you keep the bike light and if you're not a big fatty yourself XD
But that can be done later, in which case you'd just have to tune down the controller, that's the beauty of having a programmable unit.

evglobal19 said:
without being sophisticated about the electronics I'm tending to rely on the 'kit' being properly matched. If matching the specs isn't as daunting as I think then any suggestions about what to research is quite helpful. like everyone time patience and research always trumps buying things more than once. I'll post the specs on what I'm considering motor wise and look forward to any and all feedback. ;)
Steve

Regarding the RC inboard motor setups, I wouldn't go in that direction. Maybe they could give good performance, but I'm not sure they are reliable enough for a daily driver. If you plan on using your ride often then you might want to go for something with enough real road experience. Those hub motors are widely used on litterally hundreds of millions bikes here in China and they work really well. No real need to reinvent the wheel here :)

As for dimensioning the battery, you will need to take into account the power draw:
if you go for a standard lithium battery, then most of these will have a 3C discharge rate. With a 150A controller, that means that you will need a 50Ah battery (150A/3C=50Ah).
So what you want here is to find a battery using cells capable of a high discharge rate. In order to live with a 30Ah battery, then you need to make sure that the cells are capable of 5C continuous discharge at least.
You could probably live with 60V, but if you want a bit more speed and power it would be better to go for 72. I don't know the prices of such batteries where you live but that will be a large part of the total cost, so be prepared. Also, make sure that the BMS you will use is capable of delivering at the very least 150A. Better go for at least 200A if possible, to avoid some unwanted cutoffs, especially when your battery will start aging.

Nowadays, some smart BMSs capable of 300A continuous exist, and they are affordable, so it should not be a big issue (the ANT smart BMS is a good value).

There are various lithium chemistries, none of them is perfect, they all have their drawbacks:
-LiFe has a high discharge rate and they last for a long time, so they will keep their capacity rating for several years, but they are big and heavy. Thay are also less sensitive to deep discharge and overcharge so somewhat safer.
-Li-ion is lightweight and takes up less space, but they will quickly lose their capacity, so if you build a 30Ah battery then the next year it might be no more than 25Ah. So in the end you need to overbuild your battery quite a bit, which gets expensive.
Plus they will die earlier, they can handle way less cycles. They are a bit more risky so you need to use state of the art protection to avoid fires.
-LiPo is the lightest, it has a really high discharge capability, plenty of power, but it is very impractical for a daily driver because it needs to be extremely closely watch during both charge and discharge, plus the cells really don't last for long.
-Lead-Acid: it works fine but it is super heavy and it sags quite a bit. Plus they won't last more than a year. But if you can get them for cheap, then it might be a good option to at least test your setup for a few months, make sure everything works fine, and then upgrade to lithium. It isn't as powerful as a lithium battery, expect to lose around 10-20% of the power. But for testing purpose, it might be a good solution in your case. Just a temporary one and on;y if you can get them for very cheap. In which case, go for seven 12V 20Ah batteries. Expect around 20-25km of range if you drive agressively, maybe 50 if you ride very slowly.

Both LiFe and Li-ion options can work well on your setup, I guess it just comes to whichever you prefer. On my builds I tend to use LiFe because I can live with a bit more weight and I have enough space, but in your case that might be different. I used to run on Lead Acid at the very beginning, it was fine but the beast was very heavy.

Dui: Pure Gold.. im taking notes for my upcomming Puch Maxi Project
 
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