DIY stage 8: Continuous improvements...

[andyh2]

I've just sorted out fitting my Controller, Throttle, Pedelec sensor and 3 position switch to regulate power (from Frank to replace my original tongxin controller). As far as I can tell the throttle can overide the pedelec sensor, but is still subject to the limit set by the 3 position power switch.

I do have an overall on switch, but it's in the battery bag so not something to use on the go. It does mean when stopped I can turn off battery power and not have continuous low level current going into controller when not being used (as noted by Dan elsewhere). It would be possible to place this switch at the handlebar, but would mean additional wire from battery bag to bar and back.

The no.1 setting on the switch really is low level so I wouldn't imagine it's using much power at all. It's useful to be able to choose not to have full power coming in when 'trickling' along in traffic or undertaking slow manouvres. I'm not sure its input goes down to zero on this setting once its maximum assist speed has been reached though as happens with setting number 3.

I really like the pedelec mode and the choice of power settings as I don't like holding a throttle on. Just need to remember when freewheeling to begin pedaling a bit earlier to bring power in when I want it. And it's nice to have the throttle overide if I need to.

I'd be interested to know if the cadence affects the power output and if so at what cadence gives max output or if it just operates as an on switch once continuous pedaling is above a set low cadence.

 

[cirrus18]

Simply use the throttle to override the pedelec signal, that's it

True, but that's not the point. I have already noticed that the throttle overrides the pedelec but I want to be able to switch the pedelec off altogether.
I also find it annoying having to fiddle-about adjusting the throttle all the time.

With the setup at the moment, throttle and pedelec, once you start pedalling you get motor assistance whether you wanted not. This is what I don't want to happen as I only want the assistance when climbing hills.

I want to be able to get fit by pedalling most of the time, but without getting exhausted climbing our many Cornish hills.

Ideas anybody?

 

[daniel.weck]

I see. Have you tried the bypass connector coming out of the controller ? (it's two short male/female wires) I don't remember what it did when I tried. I think it disables the pedal sensor...

If that's what it does, you could add a switch to your handlebar or somewhere near enough your hands.

 

[NRG]

This is what I need to do to my Chinese based kit. The pedelec is all or nothing, great for a long hill climb as the throttle can cause my wrist to ache but its not need all the time or when the throttle is a better choice. Unfortunately it means wiring a switch into the pedelec sensor wire and running it to the handle bars...I will need to search for a miniature water proof switch and some sort of housing to accommodate it.

 

[daniel.weck]

These "all or nothing" pedal assist sensors (or rather: controllers) are a nuisance. Might as well unplug them all the time.

 

[daniel.weck]

Frank's setup is a so-called "intelligent" pedal sensor, so the motor speed varies proportionally to the pedal cadence. It means that you have to drop a gear or two when going uphill, which pretty much matches what you would normally do anyway, however that's the opposite behavior of a "real" pedelec (a crank motor with torque sensor requires a slower cadence and more pressure).

 

[daniel.weck]

Cycle Analyst log

Although the battery had plenty of juice left, I decided it was time for a charge cycle (I like not to run below 80% capacity, to increase the life of the LiFePo4 cells). Obviously, I took note of the Cycle Analyst statistics before resetting it. Here's the report:

• total ride: 1h - 20km (50% moderate hills, otherwise flats and descents)
• average speed: 20 km/h (max 40km/h)
• capacity consumed: 4.5Ah (battery is rated at 10Ah @ 1C)
• average consumption: 170W/h - 8Wh/km
• peak ampere: 11A when climbing hills, 15A shown in CA (?) => 370-400W max power
• controller + shunt temperature (inside bag): 30˚C (outdoor: 5-10˚C)
• voltmeter before charge: 41/42V (more than CA's indicated 39.2V)
• voltmeter after charge: 45.4V (41-42V displayed by the CA)

The LEDs on the Ping battery's BMS are constant red, sometimes they blink when the cells are passing balancing current...for a few minutes it's a nice prelude to the Christmas tree !

 

[NRG]

I've been looking at the Cycle Analyst as an early xmas present but I'm not too sure about the shunt resistor they use in cct, do you know what the value is? Even something as low as 0.1R will drop 2v at 20amp and on my 24v bike that's just too much....which could also be why your CA volts read lower than the battery volts....

 

[daniel.weck]

I've been looking at the Cycle Analyst as an early xmas present but I'm not too sure about the shunt resistor they use in cct, do you know what the value is? Even something as low as 0.1R will drop 2v at 20amp and on my 24v bike that's just too much....which could also be why your CA volts read lower than the battery volts....

I think the manual explains how it's built, but you're probably right about the voltage drop I observe between the voltmeter and the CA. See here:

http://www.pedelecs.co.uk/forum/electric-bicycles/5050-cycle-analyst-v2-1-a.html?highlight=cycle+analyst#post63850

Cheers, Dan

 

[NRG]

They talkabout milliOhm but don't say what the shunt value is...10milliOhm would be a 0.2v drop @20amps so much better....

 

[daniel.weck]

Although the battery had plenty of juice left, I decided it was time for a charge cycle (I like not to run below 80% capacity, to increase the life of the LiFePo4 cells). Obviously, I took note of the Cycle Analyst statistics before resetting it. Here's the report:

• total ride: 1h - 20km (50% moderate hills, otherwise flats and descents)
• average speed: 20 km/h (max 40km/h)
• capacity consumed: 4.5Ah (battery is rated at 10Ah @ 1C)
• average consumption: 170W/h - 8Wh/km
• peak ampere: 11A when climbing hills, 15A shown in CA (?) => 370-400W max power
• controller + shunt temperature (inside bag): 30˚C (outdoor: 5-10˚C)
• voltmeter before charge: 41/42V (more than CA's indicated 39.2V)
• voltmeter after charge: 45.4V (41-42V displayed by the CA)

The LEDs on the Ping battery's BMS are constant red, sometimes they blink when the cells are passing balancing current...for a few minutes it's a nice prelude to the Christmas tree !

Interesting stats the morning after the charge (short trip to town). I think that the Cycle Analyst stops logging data when slowing down to a standstill at traffic lights, so I don't know how much this skews the average speed and total distance...(off to read the manual now )

• total ride: 24mn - 8.3km (50% moderate hills, otherwise flats and descents)
• average speed: 21 km/h (max 50km/h)
• capacity consumed: 2Ah (battery is rated at 10Ah @ 1C)
• average consumption: 78W/h - 9Wh/km
• peak ampere: 11A when climbing hills, 15A shown in CA (?) => 370-400W max power
• minimum voltage (sag under load): 37V
• remaining voltage: 40.1V (39.6V displayed by the CA)
• controller + shunt temperature (inside bag): 30˚C (outdoor: 5-10˚C)

 

[jerrysimon]

Must admit Dan that little unit gives out some useful info. It might be worth me getting one as my E-Brompton project progresses.

Still awaiting a few parts including the Brompton!

This cycle to work scheme has been a complete joke

Regards

Jerry

 

[daniel.weck]

The Cycle Analyst is expensive (> 100 GBP), but then it is quite unique. The way I saw it is that I would have purchased a computer anyway, probably 30 GBP. I would then have bought a power meter for 30 GBP (see here: http://www.pedelecs.co.uk/forum/electric-bicycles/4821-watts-up-vs-turnigy-power-meter-analyser.html#post60953 ). But then I would have to manually correlate the time/distance information with the Ampere/Volt/Watt logs. The CA does this automatically and it saves the logged data when the battery is disconnected, which in itself is worth the extra 40 GBP
Make sure you get the latest hardware and firmware version (2.11) as it offers an interface for external logging, suitable for hooking-up to this kind of toy: http://www.pedelecs.co.uk/forum/electric-bicycles/4821-watts-up-vs-turnigy-power-meter-analyser-4.html#post64611 (in fact, Justin the creator of the CA is looking into it himself, according to posts on Endless-Sphere)

Re. Cycle To Work Scheme: thumbs-down...

 

[cirrus18]

These "all or nothing" pedal assist sensors (or rather: controllers) are a nuisance. Might as well unplug them all the time.

I'll also don't like using a three position switch as the settings are just too coarse and its an all or nothing situation, hardly ever exactly what you want.

Frank has come up with a solution though and I have just ordered from him one of his 11 position switches, which will give one a finer control over the speed. Each step changes the speed by 2.5 km per hour. A much better idea.
11 Level switch with battery indicator 36v cruise control function

27.00 Euro including shipping

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I have also ordered from Maplin's a miniature switch, to switch the pedelec on and off.
They also have a waterproof cover which will waterproof the moving toggle and it will then be a fairly easy task to make a waterproof container to mount the switch in.

Sub-Min Toggle switch A
FH00A £2.29
FREE Standard UK delivery on all orders - Hurry must end soon

Sub-Miniature Toggle Switches : Toggle Switches : Maplin

Sub-Miniature Waterproof Toggle Switch Cover
only £1.99 FREE Standard UK delivery on all orders - Hurry must end soon

Sub-Miniature Waterproof Toggle Switch Cover : Toggle Switches : Maplin on

 

[daniel.weck]

Thanks Cirrus !

Well, I saw the 11-level switch, but I didn't think it would suit my riding style. I like the simplicity of the 3 power levels when I pedal in traffic and have to make quick decisions, plus, the switch is tactile (no need to look, just a very intuitive thumb flick).

The trigger is instant from the highest level to the lowest one (and vice-versa): I wouldn't like to have to press "plus" or "minus" several times. As for the cruise control, well the Cycle Analyst provides this feature already, but I'm not so keen on this either as I don't use my bicycle as a moped.

That being said, I would love to hear your experience with this switch ! Do you know where to connect it ? Does it go between the PAS (or throttle) and the controller ?

Regards, Dan

 

[cirrus18]

Thanks Cirrus !

Well, I saw the 11-level switch, but I didn't think it would suit my riding style.

I can't answer your questions yet Dan as I don't expect delivery of it until next week.

I agree with your comments about adjusting the control is not intuitive but I find that using pedelec in traffic is rather frightening, hence the switch to switch it off.
I think the pedelec system needs a bit of redesigning and perhaps there are controllers out there that do a better job.

I don't have much traffic to cycle through but when I do I make sure that I switch the pedelec off.

I also don't use my bike as a moped. I pedal most of the time, to get fit, and only use the motor when climbing hills.

For me, it's most disconcerting to have the pedelec switching in, giving me a kick up the backside, when in traffic and stopped, only wanting to pedal forward a couple of feet and having to make a hasty grab at the brakes as the motor starts.
It's far too sensitive and should be designed so that the pedelec only starts to work above a certain speed, say 4 mph. This would eliminate the problem.

The lowest setting on my controller will give me a speed, on level ground, of 9.8 mph, so you can see that this kicking in and trying to accelerate me to this speed is most disconcerting.
I am hoping that the 11 position switch would give me a better/smoother range.

I also think that the 11 position switch could be better designed to make it more user-friendly. Fiddling around to trying to press the + - buttons is definitely not the way to go. In my opinion a better way would be for the control not to be a switch but more like a linear volume control. The switch itself should be a three position toggle switch, up/down for the + - functions, sprung loaded so it always remains in the middle position. The middle position remembers the last + - setting.

 

[daniel.weck]

For me, it's most disconcerting to have the pedelec switching in, giving me a kick up the backside, when in traffic and stopped, only wanting to pedal forward a couple of feet and having to make a hasty grab at the brakes as the motor starts.

I see what you mean. It happened to me a couple of time, but more because cars start to drive-off and then suddenly stop, just as I begin to gather momentum (and the motor kicks-in). Otherwise, the first power level works for me when I'm in slow-moving traffic. The ability to override with the thumb throttle is great, that's my favorite feature ! (to quickly get out of the way)

Regarding the crank-mounted torque sensor: I'm now waiting to hear back from an electronics engineer to see if such unit can be connected to a generic controller, rather than the proprietary one they normally come with. I'm not in a rush (I'd better not be)

 

[daniel.weck]

I'm running with a 15A blade fuse at the moment. Although the Cycle Analyst registers a 15A peak, I observe 11A max when climbing hills, so I'm not too worried about melting the fuse half-way through a steep climb (I carry spare fuses anyway: 15A, 20A, 25A, 30A )

I'm running the second charge cycle (since I installed the Cycle Analyst). I haven't done many miles due to the weather. Here are the stats:

• total ride: 1h - 20km (50% moderate hills, otherwise flats and descents, quite windy)
• average speed: 20 km/h (max 50km/h)
• capacity consumed: 4.72Ah (Ping LiFePo4 battery is rated at 10Ah @ 1C)
• average consumption: 178W/h - 9Wh/km
• peak ampere: 11A when climbing hills, 15A shown in CA (?) => 370-400W max power, 36V min (voltage drop/sag)
• controller + shunt temperature (new location: inside bag with even more insulation than before): 32˚C (outdoor: 10˚C)
• volts before charge: 39.1V (given by CA, not voltmeter)
• volts after charge: ? (charging...)

Cheers, Dan

 

[daniel.weck]

Since I now make more extensive use of the rack-sack with its mini pannier-bags, I decided to move the controller to the back, near the battery (before, the water-proof frame bag was mounted externally). I've also stopped using the aluminium battery case because it was adding a lot of bulk in the rack bag, and I realized that the battery was protected-enough already with copious amounts of padding. I now use the CD alloy case to safely store the battery at home (i.e. to avoid knocking on the semi-exposed cells by accident).

 

[daniel.weck]

I've also moved from the Touring bag to the new C-Bag...but that's another Brompton-specific story and it doesn't make any difference to the electrics / component layout. Note: you can just about see the dual temperature display along the vertical handlebar stem. It's not an ideal location (because it's hard to read), but I couldn't find any other neat place for it.