cycleanalyst DP vs DPS speed precision

[bowlofsalad]

Hello,

I was looking to get a CA DP(cycleanalyst direct plug in), but I ended up with a CA DPS ('s' stands for speedo) version. Modifying the CA to work as a DP version is simple enough, but since I have the choice, I am wondering which is truly more accurate? I think speed accuracy for the CA is of significant importance; I am certain I'll use the device to modify certain throttle settings and such.
I like to think that the only difference that makes no difference is no difference. Surely one is more accurate than another. I've never set up the CA before, I know that in the other non-ebike computers I've set up, the computer asked for information concerning the wheel diameter and things of that nature. I am unsure if this is a type of setting that can be found in the CA.

So, which is more accurate and reliable, CA DP or CA DPS?

Thanks for reading.

In case someone is going to ask, I have a direct drive hub.

 

[Alastor]

Hey man ,

The CA's are the same except the fact that one of them have speedometer.About accuracy now i did a test ride with my bike and a friends KTM with a new digital speed meter and the CA was showing the speed correctly.
In the DPS you have the option of putting a lot of magnets so the CA can be more accurate on its readings.So if you ask me its the most sophisticated speedometer i ever owned.Just because of its extra features.

My motor is also Direct Drive.

Also i believe that the CA's with a shunt will be better not in the speedometer reading but for the rest of the power readings you get out of your CA ,Whours , volts etc etc.

 

[ambroseliao]

I've had CA Standalones where the speedometer cable has broken through no fault of Grin Tech so the CA DP Would be more reliable.

 

[bowlofsalad]

I've had CA Standalones where the speedometer cable has broken through no fault of Grin Tech so the CA DP Would be more reliable.

How do you mean the cable broke? Can you elaborate, please?

Hey man ,

The CA's are the same except the fact that one of them have speedometer.About accuracy now i did a test ride with my bike and a friends KTM with a new digital speed meter and the CA was showing the speed correctly.
In the DPS you have the option of putting a lot of magnets so the CA can be more accurate on its readings.So if you ask me its the most sophisticated speedometer i ever owned.Just because of its extra features.

Is it possible your friend's digital speed meter wasn't calibrated correctly?

I've never heard of using multiple spoke magnets before now. I am sure the CA is sophisticated, but that alone doesn't spell out accuracy. Many sampling points makes sense to increase accuracy. I don't know how many 'poles' my mxus hub has, but I am sure it's far more than 1 or 4. I am guessing the hub has at least 8 poles inside. I assume you are suggesting that since you can place as many poles as you have spokes, you could attain a higher sample average?

Looking around, spoke magnets aren't exactly free.

 

[ambroseliao]

The speedo wire broke. CA was fine. The speedo wires are very thin and easy to break.

 

[John in CR]

I'd check to see whether the the DPS's speed wire can be connected into the controller like a normal DP. I'd think it can. As far as accuracy, I've had speed sensors similar to the stand alone's type freak out at high speed. The difference between the 2 is a magnet and a hall sensor connected to the wheel and frame, so as long as you get the pulses accuracy is determined by the accuracy of your tire size. The DP piggybacks on hall pulses coming from the motor, so the pulses are less likely to be disturbed unlike an external magnet and sensor. It's accuracy is dependent upon accurate setup in the CA settings, and accuracy of the actual tire size.

I'd say the accuracy is the same and is pretty darn accurate, though the actual circumference of a tire can vary slightly with inflation, load, and even speed.

John

 

[Ariane]

Hi,

I used a CA-HC with a speed cable from many years and I never broke the speedo wires even a on my old electric dirt bike (harsh still of riding) and I'm still using it since then.

The only problem that I have over the years is this one, the sensor as a tendency of popping out, you can easy fix this by putting some hot glue to it.

In the worse case scenario if you break this wire you can fix it in about a minute or two good day!
Black Arrow

 

[bowlofsalad]

The speedo wire broke. CA was fine. The speedo wires are very thin and easy to break.

I am sorry, that is still difficult for me to understand. How do you mean the wire broke?
Here are some examples of what could be possible. The wire was cut. The wire pulled from from the solder.

I'd check to see whether the the DPS's speed wire can be connected into the controller like a normal DP. I'd think it can. As far as accuracy, I've had speed sensors similar to the stand alone's type freak out at high speed. The difference between the 2 is a magnet and a hall sensor connected to the wheel and frame, so as long as you get the pulses accuracy is determined by the accuracy of your tire size. The DP piggybacks on hall pulses coming from the motor, so the pulses are less likely to be disturbed unlike an external magnet and sensor. It's accuracy is dependent upon accurate setup in the CA settings, and accuracy of the actual tire size.

I'd say the accuracy is the same and is pretty darn accurate, though the actual circumference of a tire can vary slightly with inflation, load, and even speed.

John

Thanks for the response. I am not sure I understand what you mean by 'connected into the controller like a nomral dp'. http://postimg.org/image/yfqovz42f/ Here is a picture of the inside of my CA DPS. You can see a letter G with a black wire, to it's left there is a white wire, you can't see it fully, but the white wire is labeled 'sp'. At the very top of the picture, there is a yellow wire, all that is needed to turn the CA DPS into a DP is to cut the yellow wire and solder it to the SP spot after removing the black and white wires that are there.

Also, I am not sure I perfectly understand all of what you said. It reads like they both should be the same, but the DP version might be less likely to have any errors? I almost want to say you are saying the DP style would be more accurate, does the DP version not rely upon information relating to the tire diameter and such?

 

[richmpdx]

Both just detect rpm and both should accurately measure rpm. And therefore to convert rpm to speed (velocity), the tire circumference is needed to calculate distance traveled in a revolution. So both kinds should be equally accurate, assuming accurate information about tire size is used.

Rich

 

[ambroseliao]

The speedo wire broke. CA was fine. The speedo wires are very thin and easy to break.

I am sorry, that is still difficult for me to understand. How do you mean the wire broke?
Here are some examples of what could be possible. The wire was cut. The wire pulled from from the solder.

Simple. The speedometer stopped working because of a break in the wire from the sensor. I believe i stressed it when my fork got twisted around and pulled the speedo sensor wires. I didn't troubleshoot it. I used my spare CA DPS and then sold the bad one as-is.

 

[Alastor]

The speedo wire broke. CA was fine. The speedo wires are very thin and easy to break.

I am sorry, that is still difficult for me to understand. How do you mean the wire broke?
Here are some examples of what could be possible. The wire was cut. The wire pulled from from the solder.

Simple. The speedometer stopped working because of a break in the wire from the sensor. I believe i stressed it when my fork got twisted around and pulled the speedo sensor wires. I didn't troubleshoot it. I used my spare CA DPS and then sold the bad one as-is.

Man for your own sake mount it on your rear wheel next time it will never twist or brake if you adjust the wire the right way.6 months now in a downhill ebike and speedometer works fine.And think that my sensor gets to mad , water , dust , sand and all of this again and again and again in every ride.

 

[bowlofsalad]

The conclusion that I came to is, at low speeds, a higher pole count will be better. My direct drive hub motor has 23 poles, compared to one or two magnets I'd use externally, DP is likely to be an all around better choice for myself. I think at higher speeds, there would be little difference.