Page 1 of 6 1 2 3 ... LastLast
Results 1 to 10 of 51

Thread: New Fan Fail relay

  1. #1
    Senior Member Bitsyncmaster's Avatar
    Join Date:  May 2011

    Location:  Leonardtown, MD

    Posts:    7,097

    My VIN:    03572

    New Fan Fail relay

    I've got one of my new REV C relays working and want to get any comments on the operation I have decided to program into the software.

    I designed a new fan fail unit because I found the fuses and fuses holders were producing a lot of heat. The condition is more pronounced when running OEM high current fans. It does not seem to cause failures since a lot of users run my original fan fail with their OEM fans.

    To reduce the heating, I designed solid state fuses within the unit. That circuit is a MOSFET and the driver circuitry on each fan output that I can turn on or off when my software detects an over current condition. If I had another pin available, this new fan fail could eliminate the fan relay by connecting that fan relay signal circuit to the fan fail unit. But Iíve found most owners do not want to do wiring changes to the stock harness.

    I have eliminated the fan current compare failure. I decided to show a failure (flashing the fan fail light) for either fan drawing less than 4 amps or more than 15 amps. I have set the electronic fuse to open each fan circuit if 18 amps is exceeded. The electronic fuse is reset when power (the fan relay shuts power off) to the fan fail is removed. I set the stagger fan turn on to 2 seconds. Let me know if you can think of any reason to change those values I chose. As with the first unit, once they get potted, there is no way to reprogram the software. So sorry that I can not update older REV units to this new fuseless design.


    The bad:

    1) If you loose the ground connection on the fan fail sockets, your fans will turn off.
    2) Higher cost, more components and more time to assemble.

    The good:

    1) Runs cooler. Should have no heat problems even running OEM fans..
    2) Electronic fuses precisely cut off excessive current much faster than any fuse for the bad fan.
    3) Can stagger the fans turning on. Not able to stagger turn off because power from fan relay cuts power to fans.
    4) Less problems for me potting the units without the fuse sockets.
    5) Single flashing sequence shows you one fan has a problem, less than 4 amps, (electronic fuse could be tripped) or more than 15 amps
    6) Double flash sequence shows both fans have the problem shown in #5.
    7) Works down to 8.8 volts from fan relay. If you have my LED AC panel, I turn the green fan running LED off below 8.8 volts.
    Dave M vin 03572
    http://dm-eng.weebly.com/

  2. #2
    Senior Member Morpheus's Avatar
    Join Date:  May 2011

    Location:  Orlando, FL

    Posts:    1,174

    My VIN:    1098

    Club(s):   (DCF)

    I really love how you keep making improvements on your products, Dave!

    Once I am done with my exhaust project, I will be sorting out my electrics. You will be hearing from me soon!
    Brandon S.

    2014 Honda Civic EX
    2016 Toyota Tacoma SR5 V6


  3. #3
    Senior Member
    Join Date:  May 2011

    Location:  Burnsville MN-Moving to Kalispell MT. in June 20111

    Posts:    769

    My VIN:    2691

    Dave

    How come Houston hasn't hired you?

  4. #4
    Senior Member BABIS's Avatar
    Join Date:  Sep 2012

    Posts:    460

    My VIN:    4502

    great news! all the values seem to be very appropriate..
    VIN 4502

  5. #5
    Senior Member Bitsyncmaster's Avatar
    Join Date:  May 2011

    Location:  Leonardtown, MD

    Posts:    7,097

    My VIN:    03572

    Quote Originally Posted by BABIS View Post
    great news! all the values seem to be very appropriate..
    Thanks for your thoughts. I chose 4 amps for the low value just in case someone develops a super efficient motor design. Our low current fans are now around 7 or 8 amps each.

    OEM fans seem to run 9.5 to 13.5 amps each but my original fans were closer to 15 amps each. We want the fan fail light to give the owners an early warning of a fan nearing a problem so I figured to fuse the fans a little above the 15 amp warning light.

    Two second fan on sequence should let the engine idle ECU recover from the alternator load easily.
    Dave M vin 03572
    http://dm-eng.weebly.com/

  6. #6
    Senior Member DMC5180's Avatar
    Join Date:  May 2011

    Location:  Reedsburg, WI

    Posts:    3,773

    My VIN:    5180

    Club(s):   (DMWC) (DCUK)

    I wonder if the, essentially continuous, running of the OEM high current fans is a contributing factor to heat being generated in the previous version as opposed to cycling with the A/C clutch.
    DENNIS

    VIN 5180, Frame 3652, STAGE I, DM-eng Solid State Solutions (RPM Rly, Dm.Lt.Mod., Fan Fail Mod. , FAN Rly, HS.Rly) , HID sealed beam style headlights, SPAX user since 2009, Eibach springs, Mid-State Club Adj. Rear LCA's, DPNW poly-sway bar kit, DMCEU LCA Stabilizer link kit, DMCMW Illuminated door sills, Aussie Illuminated SS Shifter plate, GENUINE MOMO EVO Steering wheel, DELOREANA Extended View Side Mirrors w/ Heaters, DELOREANA LED Door Lights.

  7. #7
    Senior Member Bitsyncmaster's Avatar
    Join Date:  May 2011

    Location:  Leonardtown, MD

    Posts:    7,097

    My VIN:    03572

    Quote Originally Posted by DMC5180 View Post
    I wonder if the, essentially continuous, running of the OEM high current fans is a contributing factor to heat being generated in the previous version as opposed to cycling with the A/C clutch.
    On a hot summer day I don't think your AC will cycle anyway. I know mine will only cycle on a cool day if the sun is not shining.

    But yes, running the fans or any electric loads will generate more heat in the relay compartment. It's just a matter of watts generated and the thermal conductance of the relay compartment.
    Dave M vin 03572
    http://dm-eng.weebly.com/

  8. #8
    Senior Member DMC5180's Avatar
    Join Date:  May 2011

    Location:  Reedsburg, WI

    Posts:    3,773

    My VIN:    5180

    Club(s):   (DMWC) (DCUK)

    Do I understand this correctly, This new multi-function FAN FAIL RELAY combines the stagger start and 20 second delay off features of your current FAN RELAY essentially eliminating the need for it?
    DENNIS

    VIN 5180, Frame 3652, STAGE I, DM-eng Solid State Solutions (RPM Rly, Dm.Lt.Mod., Fan Fail Mod. , FAN Rly, HS.Rly) , HID sealed beam style headlights, SPAX user since 2009, Eibach springs, Mid-State Club Adj. Rear LCA's, DPNW poly-sway bar kit, DMCEU LCA Stabilizer link kit, DMCMW Illuminated door sills, Aussie Illuminated SS Shifter plate, GENUINE MOMO EVO Steering wheel, DELOREANA Extended View Side Mirrors w/ Heaters, DELOREANA LED Door Lights.

  9. #9
    Senior Member Bitsyncmaster's Avatar
    Join Date:  May 2011

    Location:  Leonardtown, MD

    Posts:    7,097

    My VIN:    03572

    Quote Originally Posted by DMC5180 View Post
    Do I understand this correctly, This new multi-function FAN FAIL RELAY combines the stagger start and 20 second delay off features of your current FAN RELAY essentially eliminating the need for it?
    It could do that if I had another pin (the fan relay signal pin) and the relays sockets were rewired. But as it stands now, the unit is plug and play and uses the fan relay to turn power on and off to the fan fail. So you can use a standard fan relay or my solid state fan relay. With my fan relay that adds the one second delay from the fan starting and holds the 20 seconds of running.
    Dave M vin 03572
    http://dm-eng.weebly.com/

  10. #10
    Senior Member DMC5180's Avatar
    Join Date:  May 2011

    Location:  Reedsburg, WI

    Posts:    3,773

    My VIN:    5180

    Club(s):   (DMWC) (DCUK)

    Quote Originally Posted by Bitsyncmaster View Post
    It could do that if I had another pin (the fan relay signal pin) and the relays sockets were rewired. But as it stands now, the unit is plug and play and uses the fan relay to turn power on and off to the fan fail. So you can use a standard fan relay or my solid state fan relay. With my fan relay that adds the one second delay from the fan starting and holds the 20 seconds of running.
    I get it now, your FAN RELAY delays power to the FAN FAIL 1 second from when the A/C clutch engages. Your New FAN FAIL splits the delayed the power input between the fans with a 2 second stagger for both to be ON. Now you have a total of 3 seconds of transition time to full power load on the charging circuit.
    DENNIS

    VIN 5180, Frame 3652, STAGE I, DM-eng Solid State Solutions (RPM Rly, Dm.Lt.Mod., Fan Fail Mod. , FAN Rly, HS.Rly) , HID sealed beam style headlights, SPAX user since 2009, Eibach springs, Mid-State Club Adj. Rear LCA's, DPNW poly-sway bar kit, DMCEU LCA Stabilizer link kit, DMCMW Illuminated door sills, Aussie Illuminated SS Shifter plate, GENUINE MOMO EVO Steering wheel, DELOREANA Extended View Side Mirrors w/ Heaters, DELOREANA LED Door Lights.

Page 1 of 6 1 2 3 ... LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •