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"Thinking Outside the Four-Wheeled Box" ebikes.ca |
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The Cycle Analyst (formerly called DrainBrain) is the first digital dashboard and battery monitor originally designed around the specific needs of electric bicycles. However, the flexible setup configurations, wide feature range, and affordable price have led it to widespread appeal in a range of other EV applications. From the dashboards of MIT's solar car, to record breaking electric motorbikes, to small trains, powered wheelchairs, and even sailboats and airplanes, the Cycle Analyst has become the e-meter of choice for keeping track of the vehicle's battery usage and performance characteristics.
Once connected to the vehicle's power bus, the Cycle Analyst calculates and shows the following information:
Furthermore, the Cycle Analyst has the ability to over-ride the user's throttle and regulate the power delivered to the motor, turning an otherwise dumb ebike into an intelligent device with a user programmable speed limit, current limit, and low voltage cutout.
There are currently 4 standard versions of the Cycle Analyst being produced to accommodate different vehicle setups. All models have the same circuitry and code, and all of them have speedometer functionality. However, additional wiring is required by the end user to take advantage of the speed and current limiting features on the Stand Alone and High Current models.
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Stand Alone Model: Stand Alone Model (CA-SA): The stand-alone Cycle Analyst comes pre-calibrated to a molded shunt resistor capable of handling 45 amps continuous and up to 100 amps peak. It is designed to be compatible with virtually all types of Personal Electric Vehicles (PEVs). A pair of pigtail leads on either side of the shunt simply connect between the vehicle's battery pack and motor controller. Speed is detected via a spoke magnet and sensor cable. |
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Direct Plug-in Model (CA-DP): This unit is designed to plug directly into a motor controller to get the appropriate signals, resulting in a tidy installation with minimal wiring. Most motor controllers have an internal current sensing shunt resistor that can be used for measuring current, as well as a hall sensor signal that can be used to detect the wheel speed in direct drive hub motors. The CA-DP is terminated with a 6-pin plug that connects directly to the modified Crystalyte, Infineon, and eZee Controllers that we have at www.ebikes.ca. |
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Direct Plug-in with Speedo (CA-DPS): This is a variation of the CA-DP device for ebike setups that can't use the hall signals in the motor controller for the speed sensing. This would include DC motor systems which don't have hall sensors, geared motor setups like the eZee kits where the motor RPM does not match the wheel RPM, and mid-drive arrangements where the motor powers through the bicycle drive chain. It uses a separate speedometer sensor and spoke magnet like the Stand Alone device to pick the speed from your wheel. |
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High Current Model (CA-HC): For larger vehicles that draw in the 100's of amps, a high current model is available that can be connected to a user-supplied shunt in the 0.1 to 1 mOhm range. The two sense leads that go across the shunt are terminated with a ring connector. The vehicle speed is detected with a spoke magnet and sensor as with the Stand Alone model. |
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Large Screen High Current Model (CA-HC-LS) We also have for sale an OEM version of the Cycle Analyst designed for use in larger electric vehicles such as scooters, motorcycles, and cars. This model has a display screen that is twice the size as our regular version so that it is easily readable at a glance (LCD specs here). It's designed primarily to mount behind existing dashboards, and as such is not supplied with any enclosure, just the bare LCD and circuitboard. Please note this when purchasing, they are generally NOT suitable for bicycles unless you want to take on making an enclsoure. These units are also modified to operate up to 200V. |
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High Amperage Shunt We offer a large 0.25 mOhm shunt resistor to use with the High Current Cycle Analyst devices for those who do not already have a suitable shunt in their system. This device will work for recording up to 200-300A continuous currents, and up to 800A peak. |
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TTL -> USB Converter We make a molded cable that has an integrated circuiboard for converting the serial data output signal into a USB format, as the majority of modern laptops no longer have a serial port. When pluggd into a computer, the cable is recognized as a virtual COM port, and data from the CA can then be viewed or logged with a program like hyperterminal. The Prolific RS232 driver can be downloaded here. Please note that this device does not come with any user friendly software, and is intended at the moment for computer-savvy DIY types who are familiar with handling raw RS232 data. |
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CA-DP Extension Cable We have a 2 foot extension cable that is terminated with a 6 pin male connector at one end and a mating female connector on the other. This can be useful for some recumbent or stretched vehicles with the stock 5 foot cable lenth is insufficient for reaching between the display and the controller. |
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SD Memory Card Logger We are working on a data logging solution that will store the information stream from the Cycle Analyst and GPS unit directly to a small solid state memory card. Then you can simply plug the card into a computer afterwords to study the data, rather than having to have a small laptop with the vehicle while riding. Expected availability is sometime in July 2010. In the meantime, DIY customers can use a Logomatic device from SparkFun electronics, as explained here, and on the forum here. |
The regular Cycle Analyst units are available from JVBike in Vancouver, EVTech in Texas, BobTech in Germany, Electro Ride LLC in California, Power In Motion in Calgary, and several other outfits around the globe, such as OnBike in the UK, EMTB in Australia, and BinBike in Belgium. Thunderstruck-EV and Electric Motorsport both have the high current and 200V models in stock coupled with an appropriate shunt for larger vehicle applications.
Alternatively, you can buy Cycle Analysts directly from our online store.
For anything else, such as 200V units, OEM boards, volume orders, or other custom requests, please contact us directly.
| Voltage: | 15-100V standard. 20-200V for CA-HC-LS, and by custom order |
| Quiescent Current: | 7mA |
| Current Range: | + - 200 mV/Rshunt. So for instance, with a 2mOhm sense resistor, the maximum current is 100 amps. With a 0.5 mOhm sense resistor, up to 400 amps, and so forth |
| Current Resolution: | 0.01 A in low range mode, 0.1A in high range mode |
| Current Accuracy: | Temperature coefficient and accuracy depend on the shunt and calibration. With the pre-calibrated Stand-Alone model, it is within 2% +- 0.04A. |
| Speed Range: | Up to 600 kph or mph. There is an upper limit of about 1kHz for the speed sensor input, which correlates to a very fast moving vehicle indeed. |
| Wheel Size: | There are no restrictions on the allowable wheel circumference within the range of 0 to 9999 mm. |
| Distance: | Trip distance is capped at 1999 km or miles. Odometer distance rolls over after 99,999 km or mi. |
| Amp-Hours and Watt Hours: | Both forwards and negative amp-hours are limited to 1999 Ah per trip, while the watt-hours can go up to 19999 Wh. |
Current Two Button V2.2 User's Guide
Manuel Utilisateur, version 2.1, en Français, traduit par C. Bayard, merci beaucoup!
Old V2.1 User's Guide Applies to devices with V2.1 and 2.11 firmware, May 2009 - Jan 2010
Cycle Analyst V2.0 User's Guide Applies to devices sold between June 2007 to April 2009
Original DrainBrain User's Guide For the original "DrainBrain" from way back in the day (2005-2007).
The installation of the Stand Alone unit is straightforward. The molded shunt is attached inline with the battery pack's discharge leads. The easiest way to accomplish this is by terminating the shunt leads with the same style of connector that joins the battery pack to the controller, and then the CA unit can be inserted and removed from the system at will. If there is an ON/OFF switch in the system, it should be connected on the battery side of the shunt so that the CA powers down when vehicle is turned off.
The speedometer sensor is attached to the fork of the vehicle with a pair of zip-ties, and a small magnet screws on a wheel spoke to detect rotation.
For the Direct Plug-in Cycle Analyst, installation is as simple as plugging it into the motor controller if it already has the 6-lead CA connector. All the Crystalyte, eZee, and Infineon controllers at our shop have this attachment, as do many 3rd party controllers supplied by other vendors. Note though that some controllers (such as the Cyclone-USA and some eZee Bicycle [not kit] controllers) have a similar looking 6-pin connector, but it is not a Cycle Analyst port.
When the CA-DP is purchased from us along with a motor controller, it is pre-calibrated to the particular shunt resistance of that controller. If the unit is purchased alone, it is set by default for a 1.000 mOhm shunt, and you will need to calibrate it to the shunt resistance within your controller for the amps and watts readings to be accurate. As well, the #Poles variable in the advanced setup menu needs to be set to the number of hall effect transitions per wheel. The Crystalyte 400 series have 8 poles, the 500 series have 12 poles, Nine Continent style hubs have 23.
The High Current model is like the Stand Alone version but without a molded shunt, so that you can attach it to high amperage sense resistors. The blue wires and with a ring terminal go to the (-) side of the sense resistor, while the white wire goes to the (+) side of the shunt. The remaining red wire is connected to the positive leads of the battery pack.
By default, this unit is supplied in the High Range mode (resolution of 0.1 A instead of 0.01A, and display readings in kW instead of watts) and the shunt is set to 0.500 mOhm.
In order to take advantage of the speed limit, current limit, and low voltage cutout, the Cycle Analyst needs to be wired in such a way that the Throttle Over-Ride output is able to take charge of the motor controller when one of the limits is surpassed. This is already accomplished in our CA-DP and DPS models when connected to any motor controllers which have the 6-pin Cycle Analyst connector, so no additional wiring is required beyond plugging the two devices together. We don't recommend attempting to use the direct-plug devices with 3rd party controllers unless you savvy with electronics and have no problem understanding the following details:
The over-ride output is an analog voltage that can range from 5V down to 0V. When it detects that a limit is exceeded, the voltage begins to ramp down from its resting point (set by ItermMax), until power to the motor is reduced and the limit (speed, current, or voltage) is no longer exceeded.
The actual output is derived from an op-amp on the circuit board, and it is capable of both sinking and sourcing current. In the original Cycle Analyst boards (identified by a lack of label on the PCB) this output was wired directly from the op-amp, so it was quite stiff, but also made the board vulnerable to damage if the Throttle Over-Ride was accidentally wired incorrectly to a voltage source. In PCB revision 7 (labelled DB2 Rev7b), the output line was modified to include a 1k resistor (R6) to protect the silicone. This however means that the Over-Ride line can only source or sink small currents, and if more than a mA needs to be drawn from the output, then resistor R6 should either be reduced in value to a couple hundred ohms, or possibly shorted out entirely.
In most setups, the user typically has a throttle signal that varies from close to 0 or 1V when it is off, up to 4-5 V when the throttle is fully engaged. For proper operation of the Cycle Analyst limitting features, the signal for the motor controller should be the lower of these two voltages. An easy way to achieve this without even opening the controller is with a diode and current limiting resistor on the throttle line as shown in the following schematic:
In cases where the controller circuitboard is readily accessible, then you will often find that there is a series resistor already on the PCB and the throttle over-ride should ideally tap in just after this point, and then an additional resistor is not required.
With the Stand Alone and High Current versions, you will need to drill a hole through the enclosure and feed a wire to the Th pad on the CA circuit in order to access the over-ride signal.
The response time and stability of the limiting features can be adjusted by changing the gain values in the advanced setup menu. Each one is implemented as a Proportional / Integral (PI) controller. Gain settings that are too high will lead to oscillations about the set point, while gain settings that are too low may cause large overshoots and time lags before the values have stabilized.
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Cycle Analyst tap points for 20A Crystalyte controllers |
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Cycle Analyst tap points for old style 35 and 40A Controllers |
No, the data output in Version 2.1 and 2.2 Cycle Analyst devices is a 0-5V serial data stream transmitted at 9600 baud. In order to read this information to a PC or laptop, it is necessary to either make or purchase a small RS232 level shifting circuit to interface with the computer serial port. Basic instructions on how to do this are included in the user manual. We also make a TTL->USB converter cable that can solder to the Tx and Gnd pads and allows you to read the data through a USB port. It is also possible to log the data to an external memory card rather than having to carry a small computer on the vehicle, click here for details.
The backlight can be turned off by shorting the two pins leading to the backlighting LED. It would be possible to insert a switch across these leads so that you could have ON/OFF control of the light if desired.
As well, the backlight can be dimmed by putting a resistor or potentiometer in parallel with the backlighting LED. A range of 0-1000 ohms will provide a good adjustment span.
Yes, the Stand Alone unit uses a 5' cable between the shunt and the display box. If a longer span is required, then an additional length of 4-conductor cable can be spliced inline. The Direct Plug-in version needs a 6-conductor extension.
If the speedometer sensor cable is also insufficiently long to reach the wheel, then that can be extended with a simple 2-conductor wire.
Yes. You can install an inline connector if you wish for these two items to separate.
If an external device draws current from the 5V bus, then the data will not save properly on power down. If only a few (2-3) mA of current are required, then it would be possible to tap into the controlled 5V supply which goes to the LCD screen, through the pad labeled 5V*
Set the wheel circumference to 1666 mm, and the display units in Km. Then the speed indicator will display in 10's of RPMs, so for instance 34.5 kph would be 345 RPM.
In principle yes, all of the Cycle Analyst devices are internally identical, and it is only the wiring and some setup parameters that are changed between the various units. So you could take a CA-DP device, snip off the 6-pin connector, and then wire it up to a large shunt to make a CA-HC. Similarly, if you have a CA-SA but want DP functionality, then you could in principle replace the shunt with a 6 conductor cable terminated with the right connector.
Ideally, you will have some other current reference and then you can compare the readings on the CA with the known readings of another amp or amp-hour meter. So if the Cycle Analyst says 27 amps while a reference shows 19 amps, then the CA's RShunt value needs to be increased by 27/19 = 42% higher. By default it is set to 1.000 mOhm, in which case the correct value for RShunt would be 1.42 mOhm. If you don't have another current reference, then you can get a decent calibration value based on the current limit of the controller. Look at your continuous amperage draw (second screen) while riding low speeds at full throttle. If the CA says 53 amps while your motor controller is limitted to 20 amps, then your best guess for RShunt is 53/20 = 2.65 mOhm.
The exact value of RShunt can vary quite a bit from controller to controller even from the same manufacturer and batch. The 6 mosfet Infineon controllers are typically between 5-6 mOhm, the 12 mosfet controllers are more often between 2.5-3.5 mOhm. Crystalyte controllers can range from 1.1 mOhm to about 2.6 mOhm. The eZee controllers are usually between 1.3 - 1.6 mOhm.
We get asked this a lot, but as far as we know no one is going around ripping Cycle Analysts's off the handlebars of parked ebikes. Trust us on this. It's a specialty device that is hard wired to the bicycle (someone would need to gut the the cables to get it off), with no black market value at all since no one would have a clue what to do with it.
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Yes, in general we aer open to OEM sales of this unit and love to work with entrepreneurs who are advancing the state of personal EV's. However, bear in mind that this is an accessory that is manufactured by hand in North America. It is not available in the 10000 piece lot for a few dollars apiece to throw on imported Chinese scooters.
For OEM customers purchasing in volume, there is a limitted amount of customization that can be done to the firmware and display screens to more ideally suite the application. For instance we have done this for both the Stokemonkey and the M55 ebike. The cost for customizations to the firmware starts at $1000.
Unfortunately, the inrush current at these high voltages the moment that the Cycle Analyst was powered on could sometimes damage a resistor (R9) on the LCD circuitboard that is in series with the backlighting LED. The nominal 270 ohm resistor then ends up becoming in the 10's of kOhm. If this has happened, simply soldering a 1/4 watt replacement resistor that is between 300-600 ohms across the pads of R9 will solve the problem and restore full functionality up to the rated 100V. This unfortunately affected a number of units in late 2008 / early 2009 when the LCD manufacturer changed brands of resistor.
If you are running at 72V or higher and have this issue where the display fades or goes blank, please send us an email and we will sort the situation for you.
With Stand Alone CA units shipped prior to June 2007, the capacitor used to filter the signal from the speedometer pickup was not always adequate at eliminating switch bounce from the magnet sensor. This could cause brief periodic speed glitches in the +100 km/hr range. Simply repositioning the magnet would generally cause the problem to go away, but if it continues then capacitor C6 on the back of the circuitboard should be increased from 1nF up to 30-100 nF.
For the CA-DP devices, sometimes the hall signal coming from the controller will produce spurious glitches that will provide a false MaxS reading.
If the speed is always showing 0, then there are a few things to check. First is to make sure that the magnet is passing adequately close to the sensor. The gap should be under 2mm, and sometimes just moving the magnet up or down relative to the sensor will find a location where it
If this is not the source of the problem, then it is possible that the speedometer sensor cable has been torn. The cables are pretty thin and we have seen numerous instances where cable ties have been overzealously tightened to the point that the copper wire was sheared. When the wiring is sound, you should measure an open circuit across the speedometer pickup pads when there is no magnet present and a short circuit when the magnet is nearby.
With Direct Plug-in units, right after letting go of the throttle you may see an initial current which gradually settles to zero over the course of a few seconds or even tens of seconds. This is due to thermoelectric voltages produced by the interface between the material of the shunt resistor and the copper/solder PCB traces, and cannot be avoided.
If there is a steady offset current that persists, it is possible to reset the zero offset by performing the "zero amps" operation in the advanced setup menu.
The minimum allowable shunt resistance in the Low Range mode is 0.728 mOhm. If you have a lower shunt resistance than this, set the unit in High Range mode for operation down to 0.0728 mOhm.
Check to see if the Ground, (-) Shunt, or (+) Shunt lines or solder joints are broken. If any of these lines are open circuited and not connected to the shunt resistor, then the indicated current can swing wildly to one extreme or the other.
The units in the version numbering refer to major redesigns of the circuitboard and microchip. The first decimal digit is incremented when there are new features added, and the 2nd digit is incremented with bug fixes and/or minor tweaks.