Power Assist to behave like a turbo-charger or cruise control?

Mike leroy

Active Member
In my case, I need power assist to behave like a turbo-charger, not cruise control. I would like to use power assist to function like a transmission, rather than energy conservation. Match torque to RPM to optimize power. I was told transmission-like functionality is not possible.

My option is to turn pedal assist off (PAL 0). I will use the throttle as a turbo charger in the few, short, extremely steep sections.

To my way of thinking, throttles are better than pedal-only systems. At the very least, a throttle enables you to optimize the tradeoff between speed and battery consumption to find the best balance.
  • How to configure PALs to correspond to hill steepness optimize the entire power system, rather than just battery consumption?
  • Is it wasteful to use power assist in a high gear?

The BBS02 allows nine (firmware update) levels of assist to be configured. Each assist level specifies the ratio of leg/motor power, not wattage. Wattage is not a parameter because the controller software factors cadence into the algorithm.

Both torque and gear shift sensors will be available for BBS02 or BBS03 from lectriccycles.com in the near future. Only a controller replacement is necessary. Additional sensors improve gear shifting, but make power level configuration even less possible.

My main route is 2700m or 1.7 miles and 600 foot elevation change. My trip is entirely up or down a canyon, not rolling hills:
  1. 10% grade for 400m
  2. 02% grade for 400m - power unnecessary.
  3. 18% grade for 250m
  4. 10% grade for 200m
  5. 05% grade for 500m
  6. 02% grade for 1000m - power unnecessary.

What is the steepest you can climb?
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J.R.

Well-Known Member
Hi Mike, you may get more interaction if you put quantifiers in more bicycling terms. How much total incline, climb over what distance? You could breakout and include total decline. I ride some very serious, very long hills. I'm talking miles not meters. That's what kills battery power, miles + climb!
 

Mike leroy

Active Member
Hi Mike, you may get more interaction if you put quantifiers in more bicycling terms. How much total incline, climb over what distance? You could breakout and include total decline. I ride some very serious, very long hills. I'm talking miles not meters. That's what kills battery power, miles + climb!
I do not own a bike. I run this 1.7 mile, 600 foot elevation gain, route to store. I carry back 15 to 35 pounds of groceries. I started doing the run for physical therapy from a martial arts sparring accident that split my knee meniscus in half.

Now, I love being car-independent, as much as possible. Running is my primary pastime. I only envision myself using the bike for transportation. I am sure I would ride more if I had a bike, but I see so much anger on the road when running, that I seriously doubt it. I am talking real confrontation! On weekends, hundreds of cyclists in my area. Perhaps, a thousand or more on race days.

I can only justify the eBike for Running neighborhood errands, so I am not as exhausted and to save time. I could easily take the bus back for the 1 mile steep section that averages 10% grade, but I never do.

I find it just as easy to make a strong argument in favor, as against a bike or eBike. So, it probably seems that meters or yards is nothing to a serious cyclist. The 18% grade is so intimidating to me, even though I run it very fast, that I would have to push 50 pounds of food up the hill. I would be better off running/walking.

I am actually more attracted to the idea and technology, than anything.


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Mike leroy

Active Member
Hi Mike, you may get more interaction if you put quantifiers in more bicycling terms. How much total incline, climb over what distance? You could breakout and include total decline. I ride some very serious, very long hills. I'm talking miles not meters. That's what kills battery power, miles + climb!
What is your eBike, in terms of battery, controller and motor?
How much incline and distance on your daily ride?
How much wear and tear do your long rides put on the electrical system?
 

Mike leroy

Active Member
Hi Mike, you may get more interaction if you put quantifiers in more bicycling terms. How much total incline, climb over what distance? You could breakout and include total decline. I ride some very serious, very long hills. I'm talking miles not meters. That's what kills battery power, miles + climb!

Someone left this comment in Court's review

Mike
August 25, 2014 at 11:45 pm ·
Hello

I also fitted a 48V 20A BBS02 motor with a 48V 13ah LiPo bottle type battery to my bike this summer which I bought from China for about 700€ altogether. It doesn’t say how many Watts on the motor, but 48 x 20 gives 960W I think. I fitted it to 700C wheel “city” bike to which I’ve fitted 2.3 inch MTB tyres to as I ride on a lot of dirt tracks and the other tyres were just too scarey! I think the kit is really easy to fit. I changed the 48T chainring for a 38T ring as I wanted help climbing hills over top speed. I have a seven speed 32T-11T cassette on the back. It will hit about 32 kph on the flat without pedalling with this gearing. With the 48T chainring it would hit 50+ kph. I ride mostly on level 4 of 9 and mostly just use the pedal assist. I always pedal.

If you abuse the throttle on levels 5-9 (even if you are pedalling) the battery starts to suffer. Using it as I do, sometimes coming home after 35km it’s still only dropped one bar on the battery meter.

I do live in a fairly flat area so probably 70% of this distance is fairly flat. The most i’ve done at one go was 60km and I still had over half the battery left. I intend to get a Watt meter in order to get a more accurate measurement of this.

The motor has a considerable amount of torque for hills and makes riding a real pleasure. I’ve done about 800km this summer so far. The brakes come with micro switches which kill power to the motor. I gently apply my left brake when changing gear (without actually braking). This gives a smooth gear change. You don’t really need to do this on the lower power levels unless the chain is under a lot of tension, but on the higher levels the gears can really crunch if you’re not careful.

Wouldn’t want to snap my chain when far from home. I’m sure that if you did this often on the higher power levels you could soon do this!

In first gear on level 9, if you hold the handlebars and give it full power (standing next to the bike) it literally flies into the air! Smiles from ear to ear! Probably not good for the chain/cassette though! I’m really happy I bought this kit.

It would be nice to have a 48V 20Ah battery which matches the power of the motor.
 

Randy

New Member
Mike, do you know if the cadence sensor provides any programming info to the controler (750 W 8Fun with 48 V)? Or is it just to turn on or off the power to the motor if the pedals are turning or not?
 

DWEBiker

Active Member
I find myself using the throttle in a sequence . 1. Pedal 2. Throttle 3. Coast , rinse repeat . Granted its pretty flat where i ride.
On the hills i try to pedal as much as i can to help the motor. I don't ride long distances either only 10-15 miles per day.
I am happy with the throttle.
To my way of thinking, throttles are better than pedal-only systems. At the very least, a throttle enables you to optimize the tradeoff between speed and battery consumption to find the best balance.
 

Ann M.

Well-Known Member
Cadence sensors are pretty simplistic, @Randy --go/no go with a certain amount of preprogrammed delay for the power cut out. So all of the modifying comes via the Bafang console which talks to the controller. Those kits can be ordered from different sources with a sensor that allows a brief power cutout during shifting to create a smoother ride and no chain jam. Now a true torque sensor is a different beast, usually a combination of both some sort of analog strain gauge along with a Hall effect sensor to chat with the controller
 

Thomas Jaszewski

Well-Known Member
Sadly no torque sensing with this motor. All USA resellers have programed the controller at specific PAS levels. there are 3 choice, 3. 5 0r 9 levels. They are available by accessing the controller by way of the console connection. No information is available from the console other than PAS levels. One vendor has incorporated a Gearsensor which senses the shift and momentarily cuts the motor. The same effect can be achieved by taping the installed kit bike lever, and additional handlebar mounted button, or the Gearsensor.