Solenoid Getting Hotter than I imagine, remote fuse box dissconnect on UTV

Discussion in 'General Electronics Chat' started by smoman, Aug 19, 2016.

  1. smoman

    Thread Starter New Member

    Aug 19, 2016
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    Howdy all,

    Glad I found this forum. I am an EE and befuddled a bit. I have a brand new UTV that has the battery in the back of the machine. So I ran a main to the front from the battery to a solenoid that is triggered by the KEY. The 4awg goes from battery to 100a thermal, to solenoid, to fuse block, then to the devices.

    I was using a 150amp continuous (generic) duty solenoid with 12v trigger 4 post. I am very OCD wiring and everything is soldered and ground very well. I have a few LED light bars connected to the fuse panel only. BUT this problem is happening when there is zero draw (all lights are off). I came back from maiden voyage and checked all my wiring and the solenoid was a metal housing one...and was very hot to touch...hotter than what I thought was normal. I know that the 12v generates heat due to keeping the circuit closed...so warm is ok...hot is not. I figured I had a bad solenoid or a real cheap one!

    So I purchased a new one (The White-Rodgers 120-105711 12V DC Solenoid features SPNO terminal, and continuous duty cycling with contact rating of 100 Amps and an inrush of 400 Amps. Temperature range: -20 degrees to +120 degrees F. Water resistant and dust resistant. Coil resistance 16 ohms.)

    This one is 100amp continuous too and very well made. I wired it all up and and made sure all was good. I took the fam for a ride and came back, it was hot to the touch! I did not have any draw or the lights on! I got my temp gun and shot it...it was showing 145f on the gun down low by the double small posts that take 12v to close the circuit when the key is on.

    I did not have any draw on the solenoid! I just took out the volt meter and tested the voltage across the solenoid that triggers it from the key switch and it was 14.3volts. This solenoid is 12v...could the extra 2v being causing all the heat? I am wired to the T and testing this will all hooked up but nothing on accessory wise to make the solenoid heat up like this. Is this normal? The specs say 120f max?

    Long winded but I like to show the whole picture because I have tried all I know from years of wiring.

    Thank you for the help!
    Steve
     
  2. BR-549

    Well-Known Member

    Sep 22, 2013
    2,007
    395
    Draw us a labeled picture. A print. You know, a schematic.
     
  3. KeepItSimpleStupid

    Well-Known Member

    Mar 4, 2014
    1,150
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    Get a frame of reference. I'll pick a 5-7W night light bulb. You would not want to grab it. So, I would say it's probably normal.

    You could reduce this significantly because it can run at 75% of the coil voltage and power is proportional to V^2 with a special solenoid driver. The application may or may not be appropriate.

    I've designed a couple for various reasons primarily because the coil did not have a continuous rating.

    In one case, I had to excite the shutter slowly because it was too close for comfort to a 1 mm thick lens, at $1000.00 USD and it was cycled on for about 2 minutes and off for about 30 seconds during the working day. It got a break for lunch.
     
  4. smoman

    Thread Starter New Member

    Aug 19, 2016
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    Here you are...rough but not around visio right now. I will need to have this solenoid excited while driving the whole time...2 hour ride it may be closed with no draw from accessories.

    [​IMG]

    Steve
     
  5. BR-549

    Well-Known Member

    Sep 22, 2013
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    After reading the sheet on the solenoid, maybe you should try the 14 volt model.
     
  6. smoman

    Thread Starter New Member

    Aug 19, 2016
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    I am wondering if they even make a 14v 100amp solenoid continuous duty...or do I drop that voltage from the key switch power?

    Steve
     
  7. smoman

    Thread Starter New Member

    Aug 19, 2016
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    White Rodgers 120-107112 Solenoid, SPNO, 14 VDC Isolated Coil

    I know most chips and leds have +- but I woudl assume the solenoid would too...but I cant narrow it down to anything but 14.5 volts instead of 12v

    Steve
     
  8. BR-549

    Well-Known Member

    Sep 22, 2013
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    395
    It's down at the bottom of page.

    Look at the coil resistance between the two.
     
  9. smoman

    Thread Starter New Member

    Aug 19, 2016
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    Are you thinking the 14v and higher resistance (26ohm compared to 16) will alleviate most of the heat in your opinion

    Steve
     
  10. smoman

    Thread Starter New Member

    Aug 19, 2016
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    Just saw this:
    NOTE
    : CAUTION must be used in coil selection for use in 12 volt
    systems where battery charging may expose coil to continuous,
    higher-than-rated voltage. 14 volt coils are recommende
     
  11. BR-549

    Well-Known Member

    Sep 22, 2013
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    395
    Google is your friend.
     
    smoman likes this.
  12. smoman

    Thread Starter New Member

    Aug 19, 2016
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    So I got the White Rodgers 14v DC constant cycle solenoid. Installed it as normal and it does not seem to get as hot fast but I gunned it at 122deg with no load and just key switch turned on. WTH, maybe I am worrying for no reason?

    I have the two small lugs key switched to engage coil (14.3v from keyed power).

    The other lug has main in and winch on same post, winch is pass through from battery...but no draw untill its solenoid is engaged with winch.

    Other large post is to the fuse panel I installed (no draw until dash switches are turned on)

    This is on a 2016 kawasaki mule UTV.

    Scratching my head

    Steve
     
  13. smoman

    Thread Starter New Member

    Aug 19, 2016
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  14. tcmtech

    Well-Known Member

    Nov 4, 2013
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    1,678
    Yes you are. Take your OCD meds and report back next week. :rolleyes:

    In human touch terms 120 - 145 F is hot but in electrical device terms it's completely normal similar to how your vehicle's engine isn't working in its proper range until it gets to 180 - 200+ F.
     
  15. smoman

    Thread Starter New Member

    Aug 19, 2016
    9
    0
    Thats what I wanted to hear! Thanks for the response!
    Steve
     
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