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Selectable 2wd/4wd Front Diff Controller

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I am making a selectable gizmo for @Vintage Motors 2003 Rancher 350. As soon as I get this project done I intend to make one for @MoeBwonKinobi as well. So since I cannot find an old thread here showing how I make them, this will be a howto thread of sorts. I'll try to document part numbers of components required best that I can.

 

This controller idea stemmed from @jeepwm69's information, his 2wd/4wd Selectable Front Diff using OEM parts thread is linked here. Everything required for the conversion is in Jeep's thread:

 

 

Here are some pics of a completed controller I made in the past:

 

gizmo-0.png

 

gizmo-1.png

 

gizmo-2.png

 

gizmo-3.png

 

This is rant about the "why for?".... I'm just pasting this from an old file I found on my laptop:

 

Quote

This is a selectable 2WD/4WD front diff actuator solenoid control gizmo designed for all 2000-2006 Honda Rancher TRX350 4x4 models after performing a 2004-2007 Rancher TRX400 AT bolt-in selectable front diff conversion. This gizmo also works on all 1998-2001 Honda Foreman TRX450 4x4 models after performing a 2002-2004 Foreman TRX450 bolt-in selectable front diff conversion.

 

The idea for this gizmo stemmed from the fact that after a OEM Honda selectable 2WD/4WD front differential, driveshaft, selectable switch assembly and 4WD indicator light are swapped into those two early models there is no OEM option available to intelligently control that feature. Those early full-time 4WD Honda ATV models have electrical systems that are incapable of allowing the later model ECMs to be swapped with the early ECMs. So despite the fact that those conversions use 100% bolt-in OEM Honda parts that are readily available and cheap, there is no intelligent solution available for controlling them. This gizmo solves that control dilemma very neatly and adds a few useful features that the later model Honda ECMs could not.

 

Most notable among those features is a Texas Instruments fixed 5 volts DC, 5 amps capacity, low drop out LM1084 voltage regulator which supplies a much lower signaling voltage through the Honda selectable 2WD/4WD handlebar switch (5 volts vs the nominal 14.5 volts Honda feeds them with). The current load seen by that selectable switch is further reduced by using a PCB mounted 5 volts DC relay having only a 40 milliamp coil to switch B+ supply voltage to a second, ST Microelectronics (or TI)  adjustable output, 5 amps capacity, low drop out LD1585CV voltage regulator which engages and holds the selectable front diff actuator solenoid coil when the operator selects 4WD mode. Those two voltage regulators provide for the least possible voltage and current loads seen by both the selectable mode switch and by the front differential actuator coil, which together extends the service life of each of those two major components exponentially.

 

Testing was performed on the front diff actuator solenoid engagement coil by supplying various voltages beginning from 5 volts minimum, up to the nominal battery/charging system (in increments of 1 volt from 5V to 14.5V) voltage to that coil. Honda provides 14.5 volts to that coil with its later model ECMs and I felt that might be an excessive, unnecessarily high figure. That testing session confirmed that actuator engagement functions are completed every bit as surely and crisply when supplied with 5 volts, as it does when supplied with 14.5 volts. So it was time to do the math using Ohms law as a guide to help choose a reasonable, safe but sure supply voltage while lowering the current consumption through that coil to minimize the heating of those windings, thereby greatly extending the component's service life.

 

This spec for the actuator coil is quoted from the Rancher 400AT factory service manual:

Clutch resistance: 5.1 - 5.8 ohms (@68 °F)

This link was used to predict gross clutch coil currents and power consumption at various coil voltages, using the worst-case coil resistance spec of 5.1 ohms for comparison purposes:

https://www.rapidtables.com/calc/electric/watt-volt-amp-calculator.html

 

Calculated results (rounded off):

 

At 14.5 volts = 41.22 watts - 2.84 amps

At 12 volts = 28.23 watts - 2.35 amps

At 11 volts = 23.7 watts - 2.15 amps

At 10 volts = 19.6 watts - 1.96 amps

At 9 volts = 15.88 watts - 1.76 amps

At 8 volts = 12.54 watts - 1.56 amps

At 7 volts = 9.6 watts - 1.37 amps

At 6 volts = 7.05 watts - 1.17 amps

At 5 volts = 4.9 watts - 0.98 amps

 

With those questions answered a coil supply voltage was chosen to initially be adjusted to supply 9 volts. This figure is near the middle of the testing range. And keeping the voltage drop minimal (from 14.5 volts supply to 9 volts output) through the adjustable LDO voltage regulator also helps to minimize heat production that must be sunk away from that regulator chip, thereby guaranteeing a long, stress-free service life for that chip. The 9 volt supply voltage figure reduces wattage by more than 50% and removes more than 1 amp of heat producing current from that coil as compared to the factory Honda ECM solution.

 

Other notable features include an onboard Green LED which indicates that the gizmo is powered on and is supplying 5 volts through the selectable switch. The 4WD indicator light circuit for the dash is supplied with 14.5 volts, so that the factory usage of standard replacement light bulbs is retained. Access for the voltage readjustment trimpot is provided by a single expandable neoprene rubber plug located in the center of the clear plastic enclosure cover, which includes a corrosion resistant brass screw. The waterproof momentary switch which activates the onboard voltmeter is mounted externally on the heatsink and can be relocated to either side by moving its two mounting screws to the installers choice of thread tapped holes. The gizmo and its harness connectors are 100% waterproof and the entire gizmo is submersible.

 

 

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A heat sink is cut to a 2.625" length from 1.5" x 1" 6066-T6 aluminum bar stock. The heatsink also serves as a frame mount for the controller using two bolts, and as a mount for the waterproof switch after drilling and thread tapping the aluminum block.

 

The waterproof enclosure with a clear cover that I use can be purchased on ebay. It measures 3.875" long x 2.625" wide x 1.875" deep.

 

The double-sided with tinned-holes Proto board that I use can also be found on eBay. It measures 50 mm x 70 mm square. I cut two of the corners off so it fits inside the enclosure neatly, and then 5 holes are drilled in it for attachment to the enclosure and heatsink.

 

enclosure-heatsink.png

 

I live off-grid with solar power, so tomorrow after our snowstorm passes I'll start my portable welder up and plug my drill press in to it for drilling and tapping all of the holes in the aluminum heatsink. Stay tuned...

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Hi Vintage,

 

Good to see you hanging out with us!

Yeah, I'm living out on a deadend private one lane road in the middle of the woods, 1.25 miles from the nearest neighbor who has utilities. I've been 100% off-grid since 2010, bought my remote raw land on purpose so I could retire and live out my remaining years the way I wanted to experience them. It's a wonderful, natural lifestyle I've created for myself. The local community consists of tough, hardship-hardened responsible and co-operative folks and I've made many awesome friends who are every bit as principled and hard-nosed as I am! HaHa... :)

Some in my family think I'm nuts for choosing to live out of the usury system, I'm broke and poor but I'm wealthy as ! when it comes to comparing my unlimited freedoms and opportunities against their lives of slavery though. I have discovered and come home to the community I should have been born in, few people can honestly say that about themselves.... I'm buried in work, way behind on projects and preps this year though, so it's the most challenging times now I've ever experienced. With a bit more patience we'll get this thing done!!!!

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No pics today... I didn't get to the point that I wanted to today because I have misplaced my boxes of #4-40 and #6-32 screws and spent too much time trying to find where I left them. Still made decent progress though... I found enough screws to complete the gizmo by sorting through random bags of screws, so there'll be pics of progress tomorrow!

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22 hours ago, retro said:

Hi Vintage,

 

Good to see you hanging out with us!

Yeah, I'm living out on a deadend private one lane road in the middle of the woods, 1.25 miles from the nearest neighbor who has utilities. I've been 100% off-grid since 2010, bought my remote raw land on purpose so I could retire and live out my remaining years the way I wanted to experience them. It's a wonderful, natural lifestyle I've created for myself. The local community consists of tough, hardship-hardened responsible and co-operative folks and I've made many awesome friends who are every bit as principled and hard-nosed as I am! HaHa... 🙂

Some in my family think I'm nuts for choosing to live out of the usury system, I'm broke and poor but I'm wealthy as ! when it comes to comparing my unlimited freedoms and opportunities against their lives of slavery though. I have discovered and come home to the community I should have been born in, few people can honestly say that about themselves.... I'm buried in work, way behind on projects and preps this year though, so it's the most challenging times now I've ever experienced. With a bit more patience we'll get this thing done!!!!

Retro, 

Living off grid like that is quite the accomplishment, my hat’s off to you!
I’d like to have a place like that. 
I can’t remember, aren’t you in Michigan?

 

 


 

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Yeah, I'm in the northwestern upper peninsula of STATE OF MICHIGAN corporation.

 

3 minutes ago, Vintage Motors said:

I’d like to have a place like that.

 

Anyone can... it takes determination is all... go for it!

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19 minutes ago, retro said:

Yeah, I'm in the northwestern upper peninsula of STATE OF MICHIGAN corporation.

 

 

Anyone can... it takes determination is all... go for it!

I make frequent trips to the U.P. In the summer to ride the dirt bike trails. 
it’s one of my favorite places on earth. 

Vintage


 

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If you ever visit the Keweenaw Bay area look me up Vintage!!

 

Got pics today... the enclosure and heatsink are prepped and I am now laying out and soldering parts onto the Proto board.

 

Here is a pic showing the heatsink and enclosure after drilling and tapping for enclosure box attachment screws. The heatsink was wetsanded smooth and shiny to maximize heat transfer from the two voltage regulators that will attach to the aluminum surface. The enclosure was drilled for mounting and a square hole/window was cut where the two regulators must mate with the heatsink. Ten holes were then drilled in the bottom of the enclosure for the wiring harnesses. The plastic enclosure box was roughed up with sandpaper in the areas where there will be glue & sealer for waterproofing the box/heatsink assembly.

 

enclosure-heatsink-preps.png

 

This pic shows how the heatsink will be mated with the bottom of the enclosure box. There are three mounting location options - the center or at either end of the heatsink - for the waterproof momentary switch. I'll ship this with the switch located in the center location (as on my Rancher), but one of those other two locations may be handy if the gizmo is mounted to the ATV any differently than is intended by this build. Options are good.... Also in this view are the two offset 1/4" bolts that will mount the gizmo to the '03 Rancher frame. I'll hang a pic of that frame mount location later on when we are talking about the gizmo installation details.

 

enclosure-heatsink-preps-back.png

 

This is the offset holes drill template that will be provided for center punching and drilling the Rancher frame for the gizmo installation. More later about that....

 

drill-template.png

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Well, I've been busy with real life stuff, so I haven't gotten very much done lately. I did drill and tap holes to mount the two voltage regulators onto the heatsink though. Then I glued the heatsink onto the enclosure using two different sealers, 3M automotive weatherstrip adhesive was used to glue those two pieces together and Ultra Black gasket maker was used around the square window and the screw holes to insure that the enclosure is waterproof. I am currently laying the components out on the proto board and soldering them down. This project should proceed a bit faster now that most of the fabricating, drilling and thread tapping is done.

 

layout.png

 

 

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I'm gonna drop the electrical parts list here so I don't have to do it later. You can download the datasheets for the two voltage regulators and the relay from their Mouser product page which contains circuit diagrams for each. Assembling the circuits is pretty straighforward, if ya have any questions just holler! Some of the common parts (resistors, tantalum caps, Green LED, trimpot etc.) I am listing here are from my parts bins and may not be the same brands that are linked, but links are provided to help you find what is needed for this project. You can substitute parts with other brands if you find them cheaper.

 

(Qty 1) Texas Instruments LM1084-5.0, 5 volts fixed, 5 amps max, Positive Low Drop Out (LDO) voltage regulator - TO220 package.
https://www.mouser.com/ProductDetail/926-LM1084IT50NOPB

 

(Qty 1) STMicroelectronics LD1084V, Positive LDO Voltage Regulator, Input: 2.85-30v 5.0 Amps max, Output: 1.25v to 28v - Adjustable, TO220 package.
https://www.mouser.com/ProductDetail/511-LD1084V

 

(Qty 2) TO-220 package Thermal Mounting kits for electrically isolating the two Positive LDO voltage regulators from the heatsink (which is negative grounded).

https://www.mouser.com/ProductDetail/Aavid/4880G?qs=qnsgj6q%2FbLwjD6IEIUy7Dw%3D%3D

 

(Qty 1) Omron PCB mount Relay 5v - 40ma coil, 10 amps max.
https://www.mouser.com/ProductDetail/653-G5Q-1A4-EUDC5

 

(Qty 1) Nichicon Aluminum Electrolytic Filter Capacitor - Radial 25volts 4700uF.
https://www.mouser.com/ProductDetail/647-UVK1E472MHD

 

(Qty 4) Solid Tantalum Capacitors - 10uF 35volts 10%.
https://www.mouser.com/ProductDetail/Vishay-Sprague/173D106X9035X?qs=g6kuvf6BGQiYSkThjpWIrg%3D%3D

 

(Qty 1) 5k ohms PCB mount Trimmer Pot for LD1084V voltage adjust.
https://www.mouser.com/ProductDetail/Bourns/3306P-1-502?qs=UmpSLsh52mUkrrqMRol37A%3D%3D

 

(Qty 1) Diode to protect the LD1084V regulator from flyback voltage that is generated by the 4WD electromagnetic actuator coil when switching 4WD off. Just about any 2 amp or 3 amp, 100v or higher diode will work. Something like this one should be more than adequate.
https://www.mouser.com/ProductDetail/Comchip-Technology/1N5402-G?qs=2qJf6qQ4IOJpLjLRvRLbhA%3D%3D

 

(Qty 1) 120 ohms, 1/8 watt or 1/4 watt resistor for the ADJ leg of the LD1084V. Your choice, whatever you find cheap.. Here's one for a dime.

https://www.mouser.com/ProductDetail/KOA-Speer/CF1-4CT52R121J?qs=sGAEpiMZZMsPqMdJzcrNwlGlqEwMEaeo57seUsQNj%2BM%3D

 

(Qty 1) 150 ohm 1/8 watt or 1/4 watt resistor to limit current (20ma) through the 3mm Green LED. Your choice, whatever you find cheap. Here's one for a dime.

https://www.mouser.com/ProductDetail/KOA-Speer/CF1-4CT52R151J?qs=sGAEpiMZZMsPqMdJzcrNwmPqJH5y3wndhhXO3hLxQXg%3D

 

(Qty 1) Green LED (ebay).
https://www.ebay.com/itm/125613263819

 

(Qty 1) Digital LED Voltmeter (cheap on eBay).
https://www.ebay.com/itm/114554572995

 

(Qty 1) Waterproof Microswitch (cheap on eBay).
https://www.ebay.com/itm/232106831039

 

(Qty 4) 2-pin Waterproof wiring harness connector plugs similar to these type - 4 2-pin connector sets are needed - solder them together yourself (eBay or Amazon).
https://www.ebay.com/itm/175385646315

 

All of the parts linked above that are available from Mouser in a Project shopping cart:

https://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=6bbdcca783

 

 

 

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Update for this non-updated thread.... :classic_blush:

 

I am taking this project on a road trip with me since I can't clear any time to finish it up at home. Will resume this after I get settled in while visiting my daughter and grand daughter, so maybe in little more than a week from now? I'm sorry for the delays...

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