Balmar MC614 temp sensor

[Jd1]

Has anyone figured out what Balmar uses as the actual temperature sensor in the MC614 temperature wiring harnesses? I have had the second failure of the sensor now due to vibration. Instead of buying the entire wiring harness, I would like to get the appropriate sensor and repair the two units I have (and maybe incorporate more support to avoid vibration taking out the wire)

[john61ct]

http://shop.pkys.com/Balmar-MC-TS-B-...or_p_1733.html

MC-TS-A for the Alt

MCTS-B is the battery*temperature sensor

[Jd1]

John, thanks for the link but what I was trying to ask for is the actual sensor bit, the semiconductor that is inside the battery lug that does the actual sensing of the temperature so that I can make up my own cable. It helps that the semiconductor is likely less than 1/10th of the price of the cable assembly but more important is the fact that it will allow me to incorporate some stiffeners that prevent failure of the solder joint where the wire harness is soldered onto the leads from the semiconductor. RTD, is in a metal can, has 3 leads with one lead clipped off. So far I have been unable to extract the metal can out from the lug.

[Frankly]

I have a older small case 100A Balmar and 612 regulator. Switch the alt temp sensor input manually with a toggle switch. My guess is that the Balmar alt sensor is really a switch (probably normally open that closes around 200 F). You can buy such switches from supplier such as Digikey but when you start messing with a good heat conducting potting/ lugs ect your time must be cheap considering replacement is less than $40.

As to better mousetrap, my experience is Balmar is pretty good quality. Might consider a sensor loop on the alt so that flex is kept away from the connections or maybe need new motor mounts. My field wire/ connector has been vibrating away for over 12 years and ain't broke yet.

[Jd1]

Originally Posted by Frankly

My guess is that the Balmar alt sensor is really a switch (probably normally open that closes around 200 F). You can buy such switches from supplier such as Digikey but when you start messing with a good heat conducting potting/ lugs ect your time must be cheap considering replacement is less than $40.

As to better mousetrap, my experience is Balmar is pretty good quality. Might consider a sensor loop on the alt so that flex is kept away from the connections or maybe need new motor mounts. My field wire/ connector has been vibrating away for over 12 years and ain't broke yet.

The sensor is definitively a 'sensor' and not just a switch. The MC614 reports alternator temperature. I have tried another way of reducing flex now but am not sure if that will do the trick.
Sure I could just fork over $40 plus another $30 for freight to Canada but it is never good to use solder alone in a device that vibrates which is why I would like to improve on the Balmar design.

[Jd1]

Just to close this thread out, the sensor is an LM235H which is fairly dear at around $10 USD. I will be using a plastic package substitute at just under $1 and I hope that will work out OK. If it doesn't work out I can upgrade to the original metal package that Balmer uses. In any case, I hope to correct the perceived issues of how the Balmar wiring harness is assembled.

[gauvins]

Originally Posted by Jd1

Just to close this thread out, the sensor is an LM235H which is fairly dear at around $10 USD. I will be using a plastic package substitute at just under $1 and I hope that will work out OK. If it doesn't work out I can upgrade to the original metal package that Balmer uses. In any case, I hope to correct the perceived issues of how the Balmar wiring harness is assembled.

Interesting.

Could you explain how you'll do it such that a klutz like me could learn how to do it? (Solder the sensor to a lug?)

Would the same apply to their alternator temperature sensor?

[Jd1]

Originally Posted by gauvins

Interesting.

Could you explain how you'll do it such that a klutz like me could learn how to do it? (Solder the sensor to a lug?)

Would the same apply to their alternator temperature sensor?

Unfortunately it's been a while and things are a bit rusty but here is my 2 cents:


First, you need to honestly examine your abilities of making this device vs buying it. Quite honestly, unless you are set up for this kind of work, it's not worth doing this yourself! You can only solder the device leads and not the sensor itself - it has to be mounted in something.



AFAIK the same sensor device is used for both units.


The sensors are 3 wire devices with one wire not used. You will have to get the product sheet yourself to figure out which leads go where.


The sensor has to be mounted in a sheath of some kind to be able to attach it to either the battery terminal or the alternator stud that is provided for the temperature sensor. In my case this was made with copper tubing with the end doubled up (tube in tube) and squished flat. The flat area is drilled to accept the appropriate stud.

The tube needs to be closely fitted to the sensor for best accuracy and I ended up adjusting the tube diameter to suit.


The sensor gets it's leads attached (soldered) to the signal wires, the joints are sealed with heat shrink tubing, the entire assembly is slid into the tube and potted in the tube.
The entire temperature probe assembly, up to but not including the flat contact area is protected with heat shrink tubing which also acts as strain relief on the wire to the assembly.


In a nut shell, that is it ..... again, think long and careful before you tackle this

[deluxe68]

Originally Posted by Jd1

Unfortunately it's been a while and things are a bit rusty but here is my 2 cents:


First, you need to honestly examine your abilities of making this device vs buying it. Quite honestly, unless you are set up for this kind of work, it's not worth doing this yourself! You can only solder the device leads and not the sensor itself - it has to be mounted in something.



AFAIK the same sensor device is used for both units.


The sensors are 3 wire devices with one wire not used. You will have to get the product sheet yourself to figure out which leads go where.


The sensor has to be mounted in a sheath of some kind to be able to attach it to either the battery terminal or the alternator stud that is provided for the temperature sensor. In my case this was made with copper tubing with the end doubled up (tube in tube) and squished flat. The flat area is drilled to accept the appropriate stud.

The tube needs to be closely fitted to the sensor for best accuracy and I ended up adjusting the tube diameter to suit.


The sensor gets it's leads attached (soldered) to the signal wires, the joints are sealed with heat shrink tubing, the entire assembly is slid into the tube and potted in the tube.
The entire temperature probe assembly, up to but not including the flat contact area is protected with heat shrink tubing which also acts as strain relief on the wire to the assembly.


In a nut shell, that is it ..... again, think long and careful before you tackle this

The sensor is not a simple resistor device as i thought it was, it is actually an IC chip. Per the product documentation it is sensitive to ESD. It would not be my first design choice for a sensor in this type of environment. I saw no mention of vibration testing in the data. No wonder it does not hold up, who could have foreseen that a diesel engine would vibrate.

http://www.ti.com/lit/ds/symlink/lm135.pdf

11.4 Electrostatic Discharge Caution
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates.

[Jd1]

Originally Posted by deluxe68

The sensor is not a simple resistor device as i thought it was, it is actually an IC chip. Per the product documentation it is sensitive to ESD. It would not be my first design choice for a sensor in this type of environment. I saw no mention of vibration testing in the data. No wonder it does not hold up, who could have foreseen that a diesel engine would vibrate.

Virtually anything is ESD sensitive these days. What do you think is in your alternator regulator .... integrated circuits. In any case, it's not an issue.
My issue was not with the device itself but how Balmar assembled it. When my sensor failed it was not the sensor itself but poor workmanship/design on the assembly. The sensor itself was just fine.

If I felt I could trust a replacement Balmar sensor I would have just purchased it. My sensor could have just been the one assembled first thing Monday morning or last thing Friday just before shift end but I thought I could do better.

[deluxe68]

Originally Posted by Jd1

Virtually anything is ESD sensitive these days. What do you think is in your alternator regulator .... integrated circuits. In any case, it's not an issue.
My issue was not with the device itself but how Balmar assembled it. When my sensor failed it was not the sensor itself but poor workmanship/design on the assembly. The sensor itself was just fine.

If I felt I could trust a replacement Balmar sensor I would have just purchased it. My sensor could have just been the one assembled first thing Monday morning or last thing Friday just before shift end but I thought I could do better.

1. Resistive temperature sensors are not ESD sensitive, at least not compared to integrated circuits.
2. I have a 614 regulator, I assume the person who installed it took the proper precautions.
3. You did not say precisely what the failure was beyond vibration. Did the wiring separate from the sensor?
4. ESD damage can be an issue in the long run. There is a reason for the warnings manufacturers put in the installation instructions.

[Jd1]

Originally Posted by deluxe68

1. Resistive temperature sensors are not ESD sensitive, at least not compared to integrated circuits.
2. I have a 614 regulator, I assume the person who installed it took the proper precautions.
3. You did not say precisely what the failure was beyond vibration. Did the wiring separate from the sensor?
4. ESD damage can be an issue in the long run. There is a reason for the warnings manufacturers put in the installation instructions.

<sigh> ... Please read the entire thread and please note who says what.



The sensor is not resistive


The failure was the attachment of the wire leads to the sensor leads


I won't comment on your number 4 other than to say that ESD is not a problem as long as you know what you are doing ... which is a paramount issue in this entire thread.

[pdxsailordiver]

Originally Posted by Jd1

Just to close this thread out, the sensor is an LM235H which is fairly dear at around $10 USD. I will be using a plastic package substitute at just under $1 and I hope that will work out OK. If it doesn't work out I can upgrade to the original metal package that Balmer uses. In any case, I hope to correct the perceived issues of how the Balmar wiring harness is assembled.

Jd1
Thank you, this is a project I have wanted to look into. Price of Balmar cable is stupid, I knew it had to be an off the shelf sensor.
Now all I need todo is build it.
Tim

[deluxe68]

Originally Posted by Jd1

<sigh> ... Please read the entire thread and please note who says what.



The sensor is not resistive


The failure was the attachment of the wire leads to the sensor leads


I won't comment on your number 4 other than to say that ESD is not a problem as long as you know what you are doing ... which is a paramount issue in this entire thread.

I did not see in your first post anything about how the sensor failed. Good to see that you know what you are doing.

[gauvins]

Originally Posted by Jd1

think long and careful before you tackle this

Well, I need three sensors (2 alternators, 1 battery). So there's a significant economic incentive, and there's the learning opportunity. So I'll try.

I think I'll use a battery cable copper lug, stuffed with aluminum foil to improve thermal conductivity to the sensor. A dab of expoxy resin to encapsulate the sensor. Crimped butt connectors and heat shrink tubing to take care of the cable. I assume that an amateur sensor will help in determining if a battery is cool or just about to boil. Even if the reading is off by a few degrees.

My question is - how to test this contraption for accuracy?