Question about the C5 setting on the KT-LCD3?

[Blunderbuss]

Does setting the C5 value lower make any difference to distance I would get on my battery. Trying out the different values I can feel the changes in the power (torque?) and I have settled on 05 as that gives me the range of pedal assist that works for me; I rarely use the thumb throttle and 99.9% of my biking is off road on farm tracks etc.

On value 05 I get the following pedal assist figures on a fully charged battery (48V 20AH battery, 1000w rear hub motor home built on a low cost Argos Muddy Fox):

1 – 170w
2 – 250w
3 – 380w
4 – 520w
5 – 1200w

Also I have seen two different tables about the C5 setting values the first is an absolute value the second is a division:

Page 26 - https://www.bizobike.com/uploads/5/7/0/9/57094291/handleiding-bizobike-kt-lcd3.pdf

Page 24 - https://880b28d3d003e6b1c176-ee9159906b823979ce618332e73bec87.ssl.cf4.rackcdn.com/other/en_KT-LCD3.pdf

The longest journey I have yet done is 30 miles and I still had about 1/3 power left on the gauge (that was all off road through mud and gravel) so it is more of a curious asking from someone who had not got on a bike for 30 years – and then saw ebikes J

 

[anotherkiwi]

So you have a 35 A controller which you have turned down to 26 A?

Of course if you turn down the maximum current on the controller you might think you should get more range from the battery. But... The important number is the Wh/km you use. If you pedal hard you use less Wh/km and so get more range. If you use the throttle all the time you will use much more and have a shorter range. Modifying C5 will save on Wh/km if you are always zooming around on full assist with a throttle then.

C5 is useful for fine tuning the controller output to fit your riding style: I had my 15 A controller turned down to about 11 A on my hub motor bike for a while because I didn't need any more than 395 W (550W with rider input) to climb the hills on my usual route. I didn't notice any increase in range which was always between 60 and 70 km for a 10.4 Ah 36v battery.

 

[Blunderbuss]

Thank you for response, what you have said makes perfect sense.

I know that if I am ever looking to get more distance from my battery I would be better off losing a couple of stone

 

[Deleted member 4366]

The problem with these motors is that you have to run them fast to get best efficiency. As you reduce the power, the efficiency goes down, which cancels out any saving. Going faster doesn't work either because the air resistance goes up, which cancels out any efficiency saving. These motors are good if you want to go fast with high power and a big battery. If that's not what you want, a geared motor would be a much better solution.

 

[Blunderbuss]

That is very interesting, having done a good few miles i would say that the majority of my speed is under 15mph - I am on farm tracks and bridleways. I have read that the geared motors stress your chain and can cause it to wear out quickly, but I presume i can get "uprated" sprocket and chain to cope.

I can see that having the motor by the peddles will be better for balance - off to do some reading!

 

[Deleted member 4366]

That is very interesting, having done a good few miles i would say that the majority of my speed is under 15mph - I am on farm tracks and bridleways. I have read that the geared motors stress your chain and can cause it to wear out quickly, but I presume i can get "uprated" sprocket and chain to cope.

I can see that having the motor by the peddles will be better for balance - off to do some reading!

Geared motors don't touch the chain. They drive the wheel directly, so can't stress the chain in any way, shape or form.

 

[Blunderbuss]

Could you put up a link to one so i can see what you mean - thanks.

 

[Nealh]

I have read that the geared motors stress your chain and can cause it to wear out quickly, but I presume i can get "uprated" sprocket and chain to cope.
!

You are probably confused by reading to much, a mid mount drive powers via the chain to the rear wheel so this is where you may have read about more wear and stress of the chain gear.
As mentioned freewheel or cassette is mounted directly on to the hub motor like a D/D hub and drive is indirect, you drive the hub unlike a mid drive which is direct and the drive drives the gears and chain.

 

[Deleted member 4366]

Could you put up a link to one so i can see what you mean - thanks.

https://bmsbattery.com/search?controller=search&orderby=position&orderway=desc&search_query=q128&submit_search=

 

[Blunderbuss]

Thanks guys - i see what you are describing, a couple of questions!

Is it a fixed gear inside the hub, so there is a permanent reduction and you lose top end for better low speed power?

If I have a 1000W gearless, do I need the same wattage in a geared version?

 

[Deleted member 4366]

You can have any speed you want, but, generally, you get more torque. Direct drive motors would be OK (apart from the weight), but they always choose the fast ones instead of slow ones. Speed has a big effect on efficiency. You need to choose a motor that has a maximum speed such that your modal speed is about 75%of it, e.g. if your modal speed is 15 mph, you want one with a ma speed of 20 mph. The DD motors that you see on Ebay and in the cheap ready-made bikes normally have max speeds of around 30 mph (36v) and 40 mph (48v).

 

[Blunderbuss]

Really appreciate your help - I now understand (i also found one of your previous threads from May 20th 2015 which helped!)

 

[anotherkiwi]

If I have a 1000W gearless, do I need the same wattage in a geared version?

There is a difference between the rating stamped on a motor, which is a consumer protection guarantee that the manufacturer is not over rating its motors, and the wattage that motor can really produce. Most 250 W geared hub motors are capable of 750 W constant and over on the ES forum you have reports showing that the nylon clutch gearing in those starts to fail at around the 1500 W mark. Any 350-500 W geared hub motor will produce +1000 W without risk of failure - unless you manage to stall it by being incredibly silly.

 

[Blunderbuss]

I Like the sound of a 350 - 500W geared hub, given that i mostly use my current gearless under 500W (with the occasional burst of full power for a big grin on my face), do you have any suggested suppliers? they seem to be a lot rarer than the gearless ones.

 

[anotherkiwi]

https://bmsbattery.com/

http://wooshbikes.co.uk/cart/#/category/uid-6/rear-hub-drive-conversion-kits

https://www.amazon.co.uk/YOSE-POWER/pages/9709887031

in no particular order

 

[Blunderbuss]

Thank you

 

[Deleted member 4366]

Don't get hung up on power ratings. They're more or less meaningless and don't have much bearing on how much power they produce. The Woosh 48v kit will give plenty of poke. If you're sub-80kg, most 36v geared motors should be able to give you all the power you need.

 

[Blunderbuss]

I am a little over 80KG! and already have the 20Ah 48V battery which is only 3 months old, so the Yose 48V 350W looks very tempting.

https://www.amazon.co.uk/Conversion-Freewheel-Brushless-Retrofit-Electric/dp/B0752NKLSB/ref=lp_9709887031_1_10?srs=9709887031&ie=UTF8&qid=1520946101&sr=8-10

 

[Deleted member 4366]

I am a little over 80KG! and already have the 20Ah 48V battery which is only 3 months old, so the Yose 48V 350W looks very tempting.

https://www.amazon.co.uk/Conversion-Freewheel-Brushless-Retrofit-Electric/dp/B0752NKLSB/ref=lp_9709887031_1_10?srs=9709887031&ie=UTF8&qid=1520946101&sr=8-10

I didn't know they did a 48v one. That will be perfect because it has the KT controller.

 

[Nealh]

http://www.pedelecs.co.uk/forum/threads/yosepower-hub-kits.30061/

48V kit £15 cheaper if you get it from Elifeshop in #5 in above thread.