Electric steering motor

[Northof53]

Has anyone tried installing an electric steering system out of a different vehicle? I see some swaps in other vehicles and wonder if anyone has tried it. I’m planning on giving it a go for there is lots of room behind the dash to install it.

[JimC]

I'm very much interested in this for both my 37 and my 708.

[Northof53]

Well I just got my steering motor and will post info as I go. I’d like to post a video but don’t know how

[Rdinatal]

What is the charging system?

While there's a lot of 24v steering out there I don't think the stock 25a charging system will work.

[Northof53]

I have the stock generator so will soon find out, have it mounted under the dash and will be suppling power to it today. Will have to wait on a 24 to 12 volt reducer of some sort for the keyed wire.

Mounted on brace from firewall to dash

IMG_5897.jpeg (156.17 KiB) Viewed 22745 times

Mounted and out of sight when the cover is on

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[Northof53]

I found this, not sure if it applies to the motor I’m using.
Most electric power steering systems use a three-phase electric motor powered by a pulse width modulated DC voltage. The motor is brushless and has an operating voltage range of 9 to 16 volts. If it is a heavy draw on the generator then which it might be then rabbit hole here I come.

[Northof53]

Well I got it installed and just put a battery in the cab for now. First opinion it is awesome. Can drive with one hand no problem and if I unhook it I'm back to Armstrong steering just like before. I have a question for someone. I’m able to buy a 75 amp 24 volts one wire alternator which should be easy to install and alleviate my problem of to small generator. Question is it looks like there is only one wire coming off the box after the generator that goes thru the firewall to power every circuit. Am I correct with that thinking? So for all the guys who already converted there trucks to 12 volt this is a good modification. The cost of the EPS was only $70 C.

[John Mc]

I can't remember the amperage of the 24V alternator in my M37.

If you are going to install a 75A alternator, yo will most likely need heavier gauge wiring. You may also need more belts than the single belt found on a stock M37 ??

[Northof53]

My plan is to run about a 10 gauge wire to starter then a 10 gauge wire to a master fuse that will splice into the wire that goes into the cab. I’m thinking there is next to nothing to power if the headlights are off. I’m definitely not an expert on wiring but if I put a 30 amp fuse to protect everything and that doesn’t burn out. I’m running a separate wire right from the one battery to the steering that will be protected with a fuse so none of the old wiring will be used for it. I will hook up a relay to the key to activate the steering. Will let you know how it goes.

[just me]

Tapping power off one battery in a dual battery setup is very bad practice. It will greatly reduce battery life. There are white papers on it online.
There are 4 general options for military truck multi voltage systems.
1: Convert the truck and/or accessories to all be one voltage
2: Use a buck converter to produce the lower voltage from the 24V system.
3: Add an auxiliary charging system and battery for the lower voltage devices.
4: Convert the vehicle to 12V and use a boost converter for the 24V systems
There is a 5th option but I haven't seen it available in a while and it was very expensive. There were alternators that output 12&24V to run dual voltage systems. (Still required separate batteries. )

[Northof53]

I was told that but the little I use it I’ll just put up with it and see how long it lasts.When the day comes that I’m going to put a new paint job on it I’ll strip it all down and convert it to 12 volt and completely redo the wiring.

[John Mc]

The comment by just me is correct: it's bad for batteries connected in series to be subject to unequal loads. Since the charging system only "sees" a single 24 volt battery, one of your 12 V batteries will be chronically undercharged, and the other overcharged. The one that is undercharged will be subject to sulfation, over time lowering it's capacity and shortening it's life. The one that is overcharged can see it's electrolyte boiled off or other damage. (It can also out-gas corrosive fumes).

Buck converters are inexpensive. You can find 30 amp units for about $20 on Amazon.

Another option: there are battery equalizers (also known as battery balancers) that can balance batteries connected in series to make up for unequal loads.

[Northof53]

Looked up the buck converter and will do that thanks. In the meantime I swapped out the generator for the 24 volt alternator and wired it in. Have a 15 amp breaker protecting the original wiring going thru the firewall. Also the wire running from the battery compartment has a 30 amp breaker on it. I looked up the car that I got the electric steering from and the largest fuse in the panel was a 30 amp. So with that said a 40 amp buck converter should be big enough? Then I installed a relay to the key to turn the EPS on. After all that I took the truck for a tour and was it ever enjoyable driving. Went down some rutted up roads with only one hand on the steering wheel. I’ll get that buck converter and install it in the battery compartment which I think should work. As they say education is hard but it’s fun learning new stuff

[just me]

My compact car (FIAT) fuses the electric steering box at 70 amps.
I would go as high as I can afford on the converter just to keep from stressing it. In this application efficiency isn't a factor, so going oversized doesn't matter.

[Northof53]

I did I got a 80 amp one. I have a 30 amp breaker on the line and so far it hasn’t tripped.