MAC motor temperature sensor - best way to read

Hi all,

I've been running a MAC motor for a few months now on my trike with a cheap Chinese controller + SW900 LCD, 36v 26A, and I haven't been concerned at all about climbing hills due to the relatively low power output. Yesterday I wired up a no-name, non-programmable 72v 40A controller to it and have been having a blast while I wait for a programmable controller to come in. Since I can't limit the amps with what's on it now and I live in a hilly area, I thought to ask - how best can I read the temperature sensor preinstalled in this motor? I'm guessing I could hook a volt meter up, but I'd have no frame of reference for what they mean.

What have others done with regards to temperature sensors?

Hook up the volt meter, it's easy to read. .01 v per degree C. Sitting at rest, in my office right now, it reads .22 volts (22 degrees C).

If it reaches 1.00 volts, the motor is just hot enough to boil water -- you might want to slow down.

normally these are 10k thermistors, meaning they change their resistance with temperature.
a cycle analyst v3 can directly read it, and do a LOT more.

something like that could work as well: https://www.aliexpress.com/item/2pcs-lot-T110-Digital-Display-NTC-10K-3435-Thermometer-Temperature-Meter-with-Probe-Detect-Range-50C/32810194809.html?ws_ab_test=searchweb0_0,searchweb201602_2_10152_10065_10151_10344_10068_10345_10342_10547_10343_10340_10341_10548_10541_10084_10083_10304_10307_10177_5640015_10302_10060_10155_10154_10056_10055_10539_10538_5370015_10537_10312_10536_10059_10313_10314_10534_10533_100031_10103_10073_10102_5720015_10142_10107-10177,searchweb201603_30,ppcSwitch_4&btsid=1eecafa4-651c-4c70-b5d4-1860e076d67a&algo_expid=8618370e-bbc6-4109-9583-9e65bf5541a9-14&algo_pvid=8618370e-bbc6-4109-9583-9e65bf5541a9

izeman said:

normally these are 10k thermistors, meaning they change their resistance with temperature.
a cycle analyst v3 can directly read it, and do a LOT more.

something like that could work as well: https://www.aliexpress.com/item/2pcs-lot-T110-Digital-Display-NTC-10K-3435-Thermometer-Temperature-Meter-with-Probe-Detect-Range-50C/32810194809.html?ws_ab_test=searchweb0_0,searchweb201602_2_10152_10065_10151_10344_10068_10345_10342_10547_10343_10340_10341_10548_10541_10084_10083_10304_10307_10177_5640015_10302_10060_10155_10154_10056_10055_10539_10538_5370015_10537_10312_10536_10059_10313_10314_10534_10533_100031_10103_10073_10102_5720015_10142_10107-10177,searchweb201603_30,ppcSwitch_4&btsid=1eecafa4-651c-4c70-b5d4-1860e076d67a&algo_expid=8618370e-bbc6-4109-9583-9e65bf5541a9-14&algo_pvid=8618370e-bbc6-4109-9583-9e65bf5541a9

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The new Mac motors have linear temperature sensors not thermistors. Like I said, they're simple -- .01 V per degree C. Not complicated at all.

I highly recommend using a cycle analyst, though. It makes all the information you could want instantly available. Make sure you go through the procedure detailed in the users manual for handling a MAC type temperature sensor. (removing a pull-up resistor from the CA and adding a pull down resistor, etc. That's the set-up I have on my bike right now.

I'll see about getting a small, battery-powered volt meter as a temporary solution, and add a cycle analyst to my wish list, to be purchased along with a ton of other things in a moment of poor self-control. Thanks all!

Where are the temp sensors located on the new MAC motors?

Does anybody have a picture?

My MAC is running OK but my temperature readings on my Cycle Analyst jump all over the place of my rear wheel moves. When it is sitting still, the temps are constant and accurate. As the temperature goes over 100C the CA does start to roll back the power but the actual readings on the display are all over the place unless I stop and then they are accurate without changing.

I have changed motors...luckily I have two, and the problem went away so to me that means it is in the motor and not the CA.

Any suggestions on how to troulbeshoot this problem would be appreciated...if I knew what the temp sensors looked like that would be a big start. Nothing appears to be loose when I visually inspected the motor. Haven't pulled the cover that contains the sun gear yet...are the temp sensors on the planetary gear side of the motor or the opposite side?

Thanks for any help.

The temp sensors are NOT on the side where the gears are. The sensor is touching the windings to get the relevant temperature.
If it was loose or would never work. Fluctuating values indicate some other issues. Maybe wiring to the CA or similar?!

nevermind

Has anybody run a 12T MAC on more than 58.8v...if yes, what voltage and how well did it work?

I am currently running a 14s battery and I know at some voltage the eddy current and hysteresis losses are going to become significant. I just have no experience or "feel" for what rpm and/or voltage that occurs with my 12T MAC.

Since MAC gives a lot of data on 36v and 48v, I would believe that those voltages are not a problem and stretching it to 58.8v (fully charged 14s battery) should be relatively acceptable.

Anybody have experience at voltages above 58.8...what are your no load full throttle power consumptions...just another good reason to have a Cycle Analyst. My 12T on 58.8v pulls 90 watts at full throttle with no load i.e. the rear wheel off the ground.

i do. 63V 15s li-ion. and i use FOC with 45A. so rpm goes REALLY high.
eddy current losses also depend on you lamination's thickness. thinner is better. old MACs have 0.5mm newer ones 0.35mm.
no load power loss is about 200W with my situation. so around 3A @63V.

izeman said:

The temp sensors are NOT on the side where the gears are. The sensor is touching the windings to get the relevant temperature.
If it was loose or would never work. Fluctuating values indicate some other issues. Maybe wiring to the CA or similar?!

Click to expand...

Thanks izeman....still troubleshooting my temp readings.

If anybody has ANY ideas, please chime in .

My 8T MAC was bought from EM3ev about a month ago. It is supposed to have the 10K Thermistor for a temp sensor. When I initially turn my battery on, I get a reading of 63C even though the bike has been sitting in a garage that is 25C overnight. When I lift the rear wheel off of the ground and apply full throttle, my CA3-DPS reads 26C, 25C, 27C...sort of bounces around in that area. Took the bike out for a ride and the temp never changed from what it was reading in the garage with full throttle applied...i.e. 25C-27C yet the outside temp was 30C and I was running the bike pretty hard for about 10 miles. When the wheel comes to a stop, I get a reading of minus 13C or some other odd reading that occasionally changes and when I apply throttle I get the 25C-27C reading again. So that is one problem I am trying to resolve...any ideas are appreciated. 8T MAC, Infineon 12 FET IRFB3077 controller, and CA3 are all brand new and from EM3ev.

Problem #2 that may be related or may not...max speed I can get with a 13s battery is about 26 mph on perfectly flat ground. Running a 686 mm OD tire and have verified my speedometer with a GPS. With my conditions, the Grin Tech Motor Simulator says I should be doing a little over 30 mph. I have checked and rechecked every connection and reset the CA a couple times as well as tried multiple settings and no changes for the temp readings or the speed. I have the 10K thermistor selected in the CA3 and Threshold and max temps set to 90-130. ANY help or ideas why I can't get the 30 mph the 8T MAC should do and/or if the two problems are related would be appreciated.

Besides the weird temp readings and the lack of top speed, everything functions perfectly.

I am about to pull the wheel off and open the motor to see if I can find a loose/broken wire or temp sensor.

Thank You for any assistance that anyone can provide. Is there another thread that would be better for me to post this dilemma? Thanks again.

My 8T MAC was bought from EM3ev about a month ago. It is supposed to have the 10K Thermistor for a temp sensor.

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Does it have the 6th pin in the hall sensor connector? Also, what does the CA3 report for voltage in the temperature setup?

max speed I can get with a 13s battery is about 26 mph on perfectly flat ground. Running a 686 mm OD tire and have verified my speedometer with a GPS. With my conditions, the Grin Tech Motor Simulator says I should be doing a little over 30 mph.

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I'm running 14s but regularly topped 32 mph with a 9x 4110 controller (even faster with the Baserunner). In your case, I wonder if there's a limit set on either the CA3 or the controller (the 12 FET should be 40A, but you never know).

I posted an update on the "MAC motor worth it?" thread with photos. Turns out that I didn't have temp or speed sensors on the PCB, and the gray and white wires were snipped short inside the stator. Since I'm not confident with soldering, I joined the yellow thermistor wire to the speed sensor wire inside the CA3 and re-purposed a brake sensor for wheel speed. I call it the "CA3-WPS".

Well I solved my speed issue by using a jumper in the three position switch three pin plug to the controller so now I get 30-31 mph on a 48v battery. Shorted the black and green wires in the three position switch three pin plug on the Infineon controller.

Temp readings...I have a white wire in the six pin motor plug that connects to the controller but the corresponding slot on the controller plug is empty. I just found out the white wire carries the temp signal. So no way for the signal to get to the controller and be passed along to the CA.

Waiting for a response from EM3ev but I hope they will provide a wire I can use to insert in the controller six pin connector to transmit the temp signal on down the line.

Bullfrog said:

Waiting for a response from EM3ev but I hope they will provide a wire I can use to insert in the controller six pin connector to transmit the temp signal on down the line.

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A dirty but workable solution would be to cut the wire at the Molex block, take any old multi-wire cable, splice the temp wire, steal an unused ground wire from the controller and splice, then make a 2-pin JST plug at the other end to plug into the CA3. I feel like a crash course in JST connector-making is mandated when buying the CA

I am hoping EM3ev will offer a solution at no charge.

Thanks for all the info and suggestions .

Hi !
Update on this topic.
I have GMAC 8T.
Is this the cable I have to use for reading motor temperature on the CA3 ?
https://ebikes.ca/thermcable.html?qty=1

Jil said:

Hi !
Update on this topic.
I have GMAC 8T.
Is this the cable I have to use for reading motor temperature on the CA3 ?
https://ebikes.ca/thermcable.html?qty=1

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I am 90% sure that is it...I'd send Grin Tech an email and make 100% sure .

:thumb: