Just starting another build...Question

[Old_Dave]

Build number 1 the mid drive went on its first test ride yesterday and all went well, top speed was as expected ;-) Bit of bother with chain but I think that's sorted and may test again tomorrow.... I've a feeling that as most of the time was spent in 6th (14t) a new set with a 12t will be a good idea.

So folding bike number 2 is about to get the treatment, and due to the frame design I've decided that this one will will have a rear hub drive, so the question is what voltage hub, I rather feel like getting a higher speed 20" 250-350w 24v from BMS and over volting it to 36v.

What does the team think ?


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[Deleted member 4366]

I have the 201 rpm 24v Q100 in my Dahon and it;s pretty good with 17 amps. With 12S lipos it's very strong and fast. I've got a feeling that the 328 rpm 36v motor is identical. I think that the difference between the 201 rpm 36v and the other two versions is the 2 stage reduction gears. The 24v one doesn't have them, and I suspect neither does the 328 rpm 36v, though I haven't opened one to see yet. Maybe tomorrow if I have time. A guy on ES tested both the 24v at 36v and the 328 rpm 36v and got identical speeds, so draw your own conclusion. IMHO these are perfect motors for light-weight bikes. I prefer them to the bigger 250w Bafangs. The core runs faster, which makes them smoother and quieter. The Bafangs can run up to 22 amps, but it makes them very noisy at low speed.

When are we going to see some photos and performance data for your GNG drive?

 

[Old_Dave]

Thanks for that info Dave, I'll get the box Brownie out tomorrow and post some piccys.

There's only one major issue with the build and it's all my fault.., lol, but 36 volts worth of SLA in a folder has its problems, but I'll order something that's 9kg lighter tomorrow




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[Deleted member 4366]

I have the 201 rpm 24v Q100 in my Dahon and it;s pretty good with 17 amps. With 12S lipos it's very strong and fast. I've got a feeling that the 328 rpm 36v motor is identical. I think that the difference between the 201 rpm 36v and the other two versions is the 2 stage reduction gears. The 24v one doesn't have them, and I suspect neither does the 328 rpm 36v, though I haven't opened one to see yet. Maybe tomorrow if I have time. A guy on ES tested both the 24v at 36v and the 328 rpm 36v and got identical speeds, so draw your own conclusion. IMHO these are perfect motors for light-weight bikes. I prefer them to the bigger 250w Bafangs. The core runs faster, which makes them smoother and quieter. The Bafangs can run up to 22 amps, but it makes them very noisy at low speed.

When are we going to see some photos and performance data for your GNG drive?

I opened up a 328rpm Q100 today and found that it's the same as the 201 rpm version with two stage gears, unlike the 24v 201 rpm one that has single stage gears. The difference in speed must come from the windings in the stator.

 

[Old_Dave]

Thank you for doing that Dave

So ordering the 24v 328 is OK ( by OK I mean OK 'ish' ) then it gives scope for shunt adjustment and if that's still not pleasing then the 36v route keeping a close eye on the amps ?

 

[Deleted member 4366]

24v 201 rpm or 36v 328 rpm are the choices. Whichever is cheapest. For the 24v one you need the 36v controller and battery, so to avoid confusion, the 36v 328 rpm one would be simpler. The shunt adjustment gives more climbing power and the ability to hold its top speed better. 44v lipos (12S) is needed to make it fly.

 

[Old_Dave]

Sorry to be a PITA Dave but before I press the 'buy' button, you haven't mentioned the 24v 328 ... which in my inexperience would seem to be an option for a 20"


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[Deleted member 4366]

The 24v 328 rpm will have a no-load speed of about 20mph at 24v, which means you have to use a 24v battery. At 36v, it'll try to go 30mph, but won't have enough power for that, so won't be so efficient. I have the 328 rppm 36v one in a 26" wheel, which also want''s to do 30mph. It spens nost of the time at maximum current and over-heats the controller. I think that you'll be happy with the 36v 328 rpm in a 20" wheel. If you decide that you want a bit more speed, you can get some 44v lipos, which gives a nice balance of speed, power, efficiency and durability.

 

[Old_Dave]

Thank you Dave


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[Old_Dave]

36v 328rpm 20" kit ordered ...

 

[Old_Dave]

44v Lipos...

Ok you've got me excited,lol

But did you mean a 36v lipo pack that gives about 44v ish or a build with about 14/15 cells ?

If its the 14/15 then two questions
1. Recommended seller to get the cells and bms from.
2. What charger is adjustable to suit


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[Deleted member 4366]

12S lipos are nominally 44v, but spend most of their time nearer 48v. You can use a 36v controller without problems.

With lipos you need to keep an eye on voltage, so you need a voltmeter on the handlebars and the discipline not to allow the pack go below 44v otherwise you can damage them.

For a lightweight folder a pair of 5000maH 6S packs are a good solution for short distances, or a pair of Zippy 8000maH 6S packes if you want to go further. You need to buy a few connectors and do some soldering to set them up, plus you need an intelligent lipo charger and power supply. Total cost is about £150 for you first set-up, but then additional batteries are cheaper because you' already have chargers etc.

If you want to go down this route, post again and we can give more detail about what's required.

 

[Old_Dave]

Thank you again Dave

Will start with 2 in series and then if the range is pants can add 2 more in parallel, so will get a 4 x 6 charger, electronics & electricky are no problemo as I've a few related certificates (inc 100 yard breast stroke.. ) if its an option then will think about raising the lvc on the controller or a separate automatic circuit rather than have to watch the read out, but I have the necessary displays so when all the bits arrive will modify the 'plan' as required.

Can I assume that hobbyking is a good choice for stuff, or do you have any preferred suppliers ?

 

[Old_Dave]

However ... lol

After a bit of research, I'm put off by the lipo life, may be cheaper for the mid term to build a headway pack with a couple of extra cells ?

 

[Deleted member 4366]

Headways are relatively heavy. I wouldn't be put off by everything you read about lipos. If they were really unsafe, they'd be controlled like fireworks. As long as you're sensible and have a proper charger, the risk is very low. I can't think of any recent examples of lipos catching fire, but I've seen evidence of other types of batteries, including Headways, going up in flames.

To answer your question about Hobbyking: Yes, they're a good source for Zippy and Turnigy lipos, but you have to watch which warehouse you buy them from because you'll pay duty on anything that doesn't come from Europe.

 

[Scimitar]

To answer your question about Hobbyking: Yes, they're a good source for Zippy and Turnigy lipos, but you have to watch which warehouse you buy them from because you'll pay duty on anything that doesn't come from Europe.

Hobbyking now have a UK warehouse, but I've not ordered anything from it yet and when I was poking around I kept getting redirected to the International stock, with suitably high postage costs.

 

[Old_Dave]

Lol... what fire

I was remarking about their short life (rated number of recharge cycles), HobbyKing say

"Zippy: Great value for money. Average Cycle Life* (100+) and minimal voltage sag under load.
TURNIGY Standard: Excellent value, Longer Cycle life* (160+) and very low voltage sag under load.
TUNIGY nano-tech: Unbeatable performance, Longest Cycle Life* (250+) and almost 0 voltage sag under load."


Due to what I want not being in stock in the UK warehouse anyway, I'm waiting for them to come back in before pressing the big button, lol

 

[Deleted member 4366]

Those cycle lives are at max discharge rate of 100 to 200amps. Our ebikes give them a relatively easy time. I think 300 cycles is more like it. Unfortunately they're still the best solution for light-weight high discharge and ability to get intermediate voltages. Headways and A123s are heavy and expensive. I can't think of any light-weight 44v batteries, and 36v batteries don't give the speed. To me the perfect battery for a folder with a small motor is 48v actual for a speed of about 22mph and it needs to be able to sustain 20 amps, which means at least 15aH for a Li-ion battery. A 36v 9aH battery isn't bad if you're happy with about 18mp top speed. Greenbikekit.com do some with Panasonic cells that are nice and light.

 

[Old_Dave]

Thank you for the reasoning ...

So as soon as either there's uk stock of 5.5 ah or 6 ah then I'll order them, or if I get impatient then will pay the extra postage from the eu but won't get involved with extra duty cos I'm bound to get hit enough for the existing stuff from BMS.

Thanks again




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[rpurchon]

Thank you for the reasoning ...

So as soon as either there's uk stock of 5.5 ah or 6 ah then I'll order them, or if I get impatient then will pay the extra postage from the eu but won't get involved with extra duty cos I'm bound to get hit enough for the existing stuff from BMS.

Thanks again




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i have ordered from germany 2 lots of lipos no duty top pay.
if you do order pick the cheap gls shiping apx 6 days. .if you arent in when they arrive they take to the local post office for collection.i got the 15c cheapest ones 5000mah = 75 amp.more than enough.
i have used lipos in rc aircraft and they realy get abused.hot to the touch on landing
crashed a few and bent them [lipo] 45%, stood on them to straighen and they still work fine.
just had a few puff up.even tryed setting the puffed ones on fire connecting the leads toghether but no joy.
if you do decide to go the lipo route get a good charger from giant shark.good place to get connectors and other stuff.
iCharger 106B-plus 250W 6s Balance/Charger
richard