40 mile round trip commute - 20mph - help please :)

[R0881E]

Hi, I have been googling for electric bike info and have been impressed with the knowledge on this site.

I used to cycle 10 miles to work and could average 20mph on my road bike , but I am no longer this fit.

I am now looking to cycle 20 miles to work , and then another 20 back. Ideally I would like to make it in approximately an hour so looking to be able to hit over 20mph. I would like fitness at the same time so manual effort is something that I actively seek, though I am aware that I probably won't wish to cycle hard for 2 hours each day.

I am happy with the option suggested by d8veh in other threads (Q128C at 36v) with a 48v battery as this looks like it will suit my speed nicely.

Despite literally days of research I am still unsure on some things.

1) BMS Battery appear to be the only realistic place to get this from?
2) I would love to have a battery that only required charging once per day. Is this feasible or should I get a smaller one and charge after each trip? (I am also trying to gauge cost given that the charge cycles will be doubled and presumably life expectancy halved if I do it this way. Alternatively, if I try to make 40 miles then I also wish to not charge / discharge fully to improve battery which means that I may effectively require 50 miles range, or even greater once it begins to fade).
3) Is the 36V running on the 48V battery going to cause any issues with overheating or will it be ok?
4) I am also aware that I shouldn't labour the motor at a low RPM. How does this work if I am stuck in slower traffic for instance? Is it geared and therefore coping ok if I am only doing 15mph instead of 20mph plus for a prolonged distance? Or will it just overheat? What is the best strategy if I ever hit a problem such as this? (Or do I just turn off the assistance).
5) Which other parts do I need to buy from the site? I am looking at buying a donor hybrid of some kind. I want probably 28mm tires and a flat bar, but I don't want MTB style as it will just reduce speed, particularly if I have electrical issues 4 miles into a 20 mile commute. I would like to use pedal assist and not a throttle.
6) Do I need a cycle analyst (or cheaper alternative?) if I wish to adjust my wattage assistance on the fly. Happy with setting something up for low, medium, high assist if cheap and easy.

Thanks for anybody willing to take the time to answer all of my questions.

 

[Deleted member 4366]

Unless it's a long straight road with no hills or wind, or you're very light, you'll struggle to average 20 mph over 20 miles. 20 mph needs about 200w to 250w for an average person pedalling steadily. 25 mph is up to about 400w assistance. If you use a big battery, it will probably slow you down further, so I think a 12Ah battery recharged at work would be the best solution. You could probably make the journey two ways if you don't exceed 20 mph, but that will take longer.
3. no
4. Low speed with low power is no problem. you only overheat if you give full power for a long time when the motor is held at a low speed, like when climbing long severe hills.
5. A torque arm
6. No. The PAS setting in the

 

[R0881E]

Unless it's a long straight road with no hills or wind, or you're very light, you'll struggle to average 20 mph over 20 miles. 20 mph needs about 200w to 250w for an average person pedalling steadily. 25 mph is up to about 400w assistance. If you use a big battery, it will probably slow you down further, so I think a 12Ah battery recharged at work would be the best solution. You could probably make the journey two ways if you don't exceed 20 mph, but that will take longer.
3. no
4. Low speed with low power is no problem. you only overheat if you give full power for a long time when the motor is held at a low speed, like when climbing long severe hills.
5. A torque arm
6. No. The PAS setting in the

Thanks for your reply

I am unsure if #6 was cut off mid sentence?

Are you saying that I can average 20mph with 250w assistance? Or that I won't be able to average 20mph even if I use the hub with battery?

I was assuming that it was feasible from your previous responses such as here.. http://www.pedelecs.co.uk/forum/threads/whats-the-q128c-like-at-low-speeds.28717/#post-394269

Sorry if I misunderstood

 

[soundwave]

 

[R0881E]

View attachment 21190

Thanks for that Soundwave, that is the pace that I am looking for. Is that on your haibike ?

 

[soundwave]

 

[Deleted member 4366]

No. 6 was cut off. The power is adjustable through the LCD.

The Q128c at 48v can average 20 mph as long as you're not too heavy andyou don't have traffic problems or extreme hills. You should be able to easily reach 24 mph, but you need to think about battery consumption.

I would think that it would trounce Sounwave's bike over the same journey with the same rider because it gives at least 30% more power, and it has a similar maximum speed. I can imagine that the Q128 would match it without pedalling.

 

[awol]

How about a 36v Bafang CST 500w and a 48v 30ah battery and an S12S controller, would maybe get both ways on a single charge. The CST motors don't get mentioned much anymore but they are solid beasts with huge torque and athough it would be heavy and more expensive, I would imagine it would do what R0881E is after.

 

[R0881E]

Thanks, that is helpful.

I am indeed trying to ascertain the correct battery life. I know that people say to buy the biggest that you can afford but there would be no point having a battery that is just short of the round trip as I will be lugging the excess around which isn't economical.
I am also trying to decide on battery composition and where to purchase from.

I weigh 12.5 stone but it will go down once I cycle

I can only see the cassette option and shipping with the wheel built costs a fortune. I wonder whether it is better to have that done upon arrival though I don't know how much an LBS would charge.


So it looks like;

Q128C-135mm 500W CST Rear Driving EBike Hub Motor Wheel
S12S 500W Torque Simulation Sine Wave Controller
S-LCD5 LCD Meter for S-Series Controlers
PAS--Pulse Padel Assistant Sensor With 12 PCS Magnets
+ donor bike
+ battery TBC (12ah+)

I would like some kind of brake sensor too just in case the PAS sensor failed (is that possible)? Perhaps I am worrying over nothing there and a PAS sensor is sufficient for cut out?

 

[R0881E]

How about a 36v Bafang CST 500w and a 48v 30ah battery and an S12S controller, would maybe get both ways on a single charge. The CST motors don't get mentioned much anymore but they are solid beasts with huge torque and athough it would be heavy and more expensive, I would imagine it would do what R0881E is after.

Hmm, I will take a look now. I think that reliability is a biggish factor for me but I don't know which wins out of these two. (At least the Q128 is cheap enough to easily replace if it blows up).

I did also note that the Bafang is a bit bigger and more obvious which isn't great given that it is 500W.

Would there be any benefit over just hooking a 30ah battery up with the Q128C?

I am not being negative of your suggestion, just trying to work out the benefits

Yet more googling ahead now

 

[Steve A]

What no stop for coffee n cake!

 

[Artstu]

Just here to trump SW's photo.

 

[Nealh]

An alternative kit to consider is a Bafang BBS01B 250W.
I have an original BBS01 although now on it's 2nd controller it propels me approx. 13 st on my MTB on the road at up to 24mph when getting to A 2 B, road conditions need to be fairly windless and flat though.
mfj197 uses one on a hybrid commute bike and did some running reviews a couple of years ago they are archived on here somewhere.

 

[Deleted member 4366]

An alternative kit to consider is a Bafang BBS01B 250W.
I have an original BBS01 although now on it's 2nd controller it propels me approx. 13 st on my MTB on the road at up to 24mph when getting to A 2 B, road conditions need to be fairly windless and flat though.
mfj197 uses one on a hybrid commute bike and did some running reviews a couple of years ago they are archived on here somewhere.

Can you average 20mph over 20 miles though? It's easy to do for a couple of miles, but on a long journey, you'd need to sustain that 24 mph for long periods to average 20 mph. Crank drives can't be run at maximum power for as long as a hub-motor because the motor is smaller, more insulated and doesn't get as much air-flow.

The choice of motor comes down to whether you want to get the speed by efficiency or whether you want something that's more like an electric motorcycle. When you go to big batteries and motors, it's more difficult to convince people that you're riding an electrically assisted bicycle.

The q128c can easily manage a modal speed of 20 mph with bursts up to 24 mph when conditions suit, but it'll be down to 15 mph on hills. That's with a 14amp controller and a 13st rider. I estimate a range of about 25 miles from a 48v 12Ah battery when ridden like that. The S12S gives double the power at about 28 amps. That will make it faster up the hills and give a modal speed of about 22-24 mph, but range would be down to about 15 miles if you rode with that additional power. I think that the S12S is overkill. It's more suited to fat people that don't want to pedal. The highest I'd go for a 12st rider would be the 17amp sine wave controller from PSWPower.

 

[Woosh]

he may kill a Q128C with the S12S controller at 48V.

 

[R0881E]

Thanks for all the advice, I am still reading

The PSWPower sine wave controller (17amp) says 350W max though. Is that not an issue?

It has very contradictory info:

Applicatoin: Max. 36V/48V 350W

Fit bafang 8FUN 350W sensor motor AKM 500W sensor motor QQ 500W sensor motor

If I purchased this could I still fit the other parts from BMS or would I need to buy the PAS sensor etc from PSWPower too?

Sorry, this is really confusing.

 

[Deleted member 4366]

250w, 350w, 500w, 1000w, etc, don't mean anything. What's important is amps and volts.

 

[R0881E]

Thanks d8veh,

I know that I shouldn't be spoon fed but I really don't wish to mess this up.

Is this all ok before I purchase? Any issues with this battery suggestion? And also, does anybody know which charger would be suitable as I believe a slow charger which can be stopped at 90% is a worthwhile investment (and I will ideally want two if I plan to charge both ways).

From BMS:

Q128C Rear 36V 201RPM
https://bmsbattery.com/ebike-kit/768-q128c-135mm-500w-rear-driving-ebike-hub-motor-ebike-kit.html#/213-rpm-201/42-voltage-36v

48V14.5Ah Case-08 Bottle Panasonic Battery Pack No Controller with a USB Charger
https://bmsbattery.com/ebike-battery/819-48v116ah-case-08-bottle-panasonic-battery-pack-battery.html#/27-ac_voltage-200264vac

From PSWPower:

36V/48V 350W 6Mosfets 17A Brushless DC Sine Wave Controller
http://www.pswpower.com/peng/iview.asp?KeyID=dtpic-2016-3F-39N8.50CQE
+
KT-LCD6 display
Lamp & Switch ($6 so why not)
Left Throttle (may not install)
Wuxing Brake (don't think I will purchase given that PAS sensor will solve that issue)
Speed Sensor
Dual Hall PAS Sensor

 

[LeighPing]

I take my hat off to anyone that can spend as much as 3 hours a day, with work in between, in the saddle. With the best will in the world, that's roughly how it'll be when you factor in packing and getting dressed for the bike, the weather and road conditions, traffic, punctures.. I wish you the best of luck.

 

[R0881E]

I take my hat off to anyone that can spend as much as 3 hours a day, with work in between, in the saddle. With the best will in the world, that's roughly how it'll be when you factor in packing and getting dressed for the bike, the weather and road conditions, traffic, punctures.. I wish you the best of luck.

I don't have to cycle every day since I have a car and 200cc scooter. But I would like to do it at least twice per week