10k thermistor how to?

Hi folks.

I bought a 10k ntc thermistor from ebay. How do I go about hooking it up and get a reading from it. I understand you can use a cycle analyst to power and display it but that cant be the only way.

Is there a panel display or egadjet I can use instead.

Hoping not to have to buy a £100 panel to display a £1 temp gauge.

Thanks in advance.

Matt.

An easy route is to not use a 10K NTC thermistor, but instead to use an LM35 temp sensor chip (datasheet).

You hook up Gnd and +5 volt (typically from your hall power connections) and you can read the temperature directly with a $10 DMM or panel voltage display. It reads 0v = 0degC with 10mv/degC scaling e.g. 100degC = 0v + 100 x 10mv/degC = 1.00v

This device is what EM3EV delivers pre-installed in MAC motors - annoying to use with a CA V3, but very easy to use with a simple meter.

You may find it simpler to just buy a cooking thermometer such as this (thanks to Doc Bass!):


Uncrimp the SS tube and slip it off the sensor bead.

Wow thats what I call an answer. Thanks very much.

To ebay!...

Thanks teklektik (and drbass).

Once you go to the trouble of taking the motor apart, it's not a bad idea to epoxy-in both...a 10K thermistor, and also an LM35. You don't have to use either one of them right away, but they are both there if you ever want to use them.

As stated, the LM35 can read out temps from a $5 digital screen from a voltmeter. 0.60V = 60 degrees Celcius. This is the optional sensor that cell_man installs in the MAC geared motors that are popular. the benfit of the 10K thermistor is that it opens up a wide variety of options if you get a Cycle analyst in the future.

The most useful feature (IMHO) is the CA's ability to "roll back" the amp cap temporarily when the motor is starting to get hot...so you can pay attention to having fun, instead of constantly watching a screen. As long as I'm on the subject, I am reminded that the V3 CA has THREE temp sensor inputs...one each for the motor, controller, and battery pack. Justin L-E is a really smart guy, and the more I learn, the more I realize just how incredibly clever he is.

$6.90 from Ebay (there are better deals than this, the link is just a quick Google to show proof)
http://www.amazon.com/SMAKN-4-0-30v-Digital-Display-Voltmeter/dp/B00B689UGA

spinningmagnets, the voltage panel you linked to is 4-30v but surley I would need a panel that measures from 0v?

I have a panel on my bike for battery voltage but only reads 15-120v

So this panel has three wires, How would I go about hooking up a three wire voltmeter? http://www.ebay.co.uk/itm/DC-0V-30V-Mini-Red-Digital-Voltmeter-Tester-Three-Wire-/271274325508?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item3f2935b604

I cant find any panels that read from 0v that have only two wires. Is this right?

Thanks

I bought some of these. Havent received it yet. http://www.ebay.com/itm/190978964743?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
Planning on adding one into my controller.

littleskull99 said:

So this panel has three wires, How would I go about hooking up a three wire voltmeter? http://www.ebay.co.uk/itm/DC-0V-30V-Mini-Red-Digital-Voltmeter-Tester-Three-Wire-/271274325508?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item3f2935b604

I cant find any panels that read from 0v that have only two wires. Is this right?

Thanks

Click to expand...

You won't find a 2 wire voltmeter that reads from 0V because one power wire needs to supply power for the volt meter.
With the 3 wire ones you wire black wire to ground, red wire to your power supply (within spec.. 4.5 to 30V for that meter), and white wire will be used to read voltage from whatever its connected to.

On the note of temperature measurements, I just found this BBQ thermometer at Goodwill, and it is going to serve the purpose of motor and/or controller and/or battery temperature monitoring. I'm hoping I can use each sensor in it's fork independently, switching manually between them, but am doubtful that will work.
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=12500&p=848849#p848608

If I am going to use the CA3, is this the kind of thermistor I want?

http://www.amazon.com/100-Temperatu...9020&sr=8-1-fkmr0&keywords=NCT+10K+Thermistor

Also, what gauge/type of wire would I use to run to the thermistor(s), assuming typical DD hub temps?

I think you are confusing the voltage the meter needs to function, its power power source with the range of voltage it can display. As well as the signal from the thermistor to give it the information to display a voltage it needs a power source to power it up which is your 4.5-30 etc.

3 wires, positive and negative from the power source to operate the meter and the third is from the temp sensor telling it what to display.

teslanv said:

If I am going to use the CA3, is this the kind of thermistor I want?

http://www.amazon.com/100-Temperatu...9020&sr=8-1-fkmr0&keywords=NCT+10K+Thermistor

Also, what gauge/type of wire would I use to run to the thermistor(s), assuming typical DD hub temps?

Click to expand...

http://www.ebikes.ca/ca3-therm.html
This one is made by the maker of the CA3.

teslanv said:

If I am going to use the CA3, is this the kind of thermistor I want?

http://www.amazon.com/100-Temperatu...9020&sr=8-1-fkmr0&keywords=NCT+10K+Thermistor

Also, what gauge/type of wire would I use to run to the thermistor(s), assuming typical DD hub temps?

Click to expand...

That has a B rating of 3950... which is about perfect for the CAV3 iirc (telektek wrote it)

cal3thousand said:

That has a B rating of 3950... which is about perfect for the CAV3 iirc (telektek wrote it)

Click to expand...

Great! How about wire size/insulation?

That is up to your preference. They don't carry any real current, so most anything you can find and fit will work.

I recently reused the innards of a Cat 5 ethernet cable

Hey SPinning MAgnets,

I was searching for info on how to connect the Themistor from a MAC to a V3 CA and came across this comment of yours:

The most useful feature (IMHO) is the CA's ability to "roll back" the amp cap temporarily when the motor is starting to get hot...so you can pay attention to having fun, instead of constantly watching a screen. As long as I'm on the subject, I am reminded that the V3 CA has THREE temp sensor inputs...one each for the motor, controller, and battery pack. Justin L-E is a really smart guy, and the more I learn, the more I realize just how incredibly clever he is.

Curious, I can't see three inputs for temp on the CA circuit diagram. Am I missing something here,

In any case,

This from EM3ev re the thermistor on a new generation MAC: "The temperature sensor produces a DC Voltage referenced to the hall sensor gnd and proportional to the temperature, 0.5V = 50degC, 1V = 100degC."

Do I take a GND from the hall wiring and connect to the CA and then scale to get the correct voltage range?

Appreciate any insights, Cheers and Happy NEw Year!

I misunderstood the three inputs, that is not correct. I seem to remember there was a post about how to hook up two probes to one input, and the CA V3 would only see the hottest reading (obviously the cooler probe would not be an issue). Plus...I was drunk.

I'd go with something like this



http://www.amazon.com/Qooltek-Thermometer-thermostat-thermometer-Refrigerator/dp/B00PQ2GJNY/ref=sr_1_8?ie=UTF8&qid=1452361263&sr=8-8&keywords=temperature+sensor+aquarium

eee291 said:

I'd go with something like this

http://www.amazon.com/Qooltek-Thermometer-thermostat-thermometer-Refrigerator/dp/B00PQ2GJNY/ref=sr_1_8?ie=UTF8&qid=1452361263&sr=8-8&keywords=temperature+sensor+aquarium

Click to expand...

I've used these before, bought 5 of them off of eBay to monitor the temperature of my battery during the winter. They are junk! Eventually, they all broke. What would happen was certain segments of the display would stop lighting up even when I changed the battery. This made it impossible to tell what temperature the thing was trying to display. Also, the sensor wires are extremely thin and would break off at the PCB. I'd always have to put hot glue all over the wires inside of the housing to keep them from breaking off.

My new BBQ thermometer hasn't had a single problem.