awefulspeller
Posts: 87
Joined: Sat Aug 10, 2013 6:59 pm

Disable Power Steering

Sun Jan 01, 2017 12:41 pm

Yep. Long shot I know.

Anyone know how to disable power steering? I would imagine that costs tons of energy and you would probably considerably extend the amount of distance you could travel if power steering was disabled.

I always liked the feel of driving a car without power steering anyways.

WattsUp
Posts: 2113
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Location: SF Bay Area, CA

Re: Disable Power Steering

Sun Jan 01, 2017 1:23 pm

Why would it cost tons of energy? Most of the time, the car is not steering very much.

Turning on the headlights likely dwarfs anything used by something like power steering.
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amped
Posts: 60
Joined: Thu Aug 11, 2016 3:31 pm

Re: Disable Power Steering

Sun Jan 01, 2017 5:35 pm

Power steering in ICE vehicles pump fluid continuously even when assist isn't needed so there might be a significant mpg loss there. With the electric power assist operating only as needed, I doubt the energy cost per mile amounts to much.

If you're going to extremes to squeeze out more range, consider disabling the DC-DC converter that powers the 12v systems and replace the OEM 12v battery with something more amenable to deep cycling, and with more amp-h capacity, that can be recharged at home/work/wherever. Depending upon what 12v systems you're typically using, this might yield a slight increase in range. This would be analogous to an alternator deletion in an ICE vehicle, which can increase fuel economy upwards of 10%, IIRC. However, the DC-DC converter is a lot more efficient so I'm guessing you'd only see a few % difference in Wh/mi. I'm also not sure how feasible this would be - are there sophisticated fail-safes in the FFE to prevent the car from operating with a "bad" DC-DC converter?

If you're typically driving at higher speeds, maybe consider some aero mods....or slow down:-)

fbitz777
Posts: 172
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Location: Wexford, PA

Re: Disable Power Steering

Sun Jan 01, 2017 8:44 pm

My Mini Cooper has electric assist for steering and I am sure it's pretty common use with ICE cars these days.

As for the FFE have you tried turning the steering wheel at a standstill while power is off? I can tell you it's not possible (or I am not strong enough)
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EVA
Posts: 874
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Location: Chicago Area

Re: Disable Power Steering

Sun Jan 01, 2017 10:13 pm

I am always truly amazed at Watts Up answers to everything. I'll give you a huge bunch of credit and say you knew this.
Meanwhile, EPAS system is only consumed energy when the steering wheel is turned.
EPAS = Electric Power Assist Steering

From this incredibly detailed and long article:
A comparative study of power consumption of electric power steering system
https://www.researchgate.net/publicatio ... ing_system
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EVA
Posts: 874
Joined: Tue Aug 06, 2013 9:10 pm
Location: Chicago Area

Re: Disable Power Steering

Sun Jan 01, 2017 10:20 pm

And now to answer your question awefulspeller. The answer from that paper is crystal clear, the answer is nope, it uses a tiny amount of electricity compared to other things in the car. I could answer the question for you, or make you read this research paper:
https://www.researchgate.net/publicatio ... ing_system

Since I have a bit of experience reading research papers - I'll save you the trouble. The power steering electric motor uses tiny amounts of electricity for very short periods of time. It only uses electricity when you try to steer the car - running down the road with no turning input costs zero energy. When you are turning, the motor uses at most 0.6 amps for tenths of a second at a time.

The research paper talks about a control (PID) algorithm that could reduce that electricity use even more. It is a simple solution that only requires programming, not a new motor or hardware.

And like another person said, try to turn the steering wheel with the car not moving and there is no power steering. It is incredibly hard to do.

A far better path would be to use something like an old Volkswagen Beetle heater - one that ran on propane - to heat the interior of the car. But they wouldn't do something like that, it creates some level of pollution. And actually another way to heat the battery when it is cold outside. That uses far more energy than anything else.
2014 Platinum White FFE (Turning in mid Dec. 2016 25,000 miles)
2013 Ingot Silver FFE
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2014 Tesla Model S 85

EVA
Posts: 874
Joined: Tue Aug 06, 2013 9:10 pm
Location: Chicago Area

Re: Disable Power Steering

Sun Jan 01, 2017 10:23 pm

2014 Platinum White FFE (Turning in mid Dec. 2016 25,000 miles)
2013 Ingot Silver FFE
2012 Titanium ICE Focus
2014 Tesla Model S 85

michael
Posts: 1113
Joined: Sun Sep 22, 2013 9:55 am
Location: Los Angeles, CA

Re: Disable Power Steering

Mon Jan 02, 2017 12:39 pm

As stated above, the most wasteful device on the FFE is the heater. Nothing you can do (disabling power steering, streamlining, pumping up tires to 100 PSI, etc) would touch the advantage of a heat pump vs the resistive heater. Worse, it comes into play when it's cold outside and battery performance is already diminished.

Those of us from the old days who drove cars without power steering know that it requires very little effort to steer when the car is in motion. Only when it's stopped (like pulling out of a parallel parking space) does it require brute force. When I was learning to drive, we were taught to let the car roll even a few inches rather than being completely stopped, and the effort dropped tremendously.

And yes, modern electric power steering solves the energy waste issue of old fashioned hydraulic power steering.
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WattsUp
Posts: 2113
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Location: SF Bay Area, CA

Re: Disable Power Steering

Mon Jan 02, 2017 2:16 pm

EVA wrote:I am always truly amazed at Watts Up answers to everything. I'll give you a huge bunch of credit and say you knew this.
Haha... thanks EVA.

I knew that electronic power steering was way more efficient than hydraulic power steering (and is even used in ICE cars as it can meaningfully improve MPG), but many kudos to you too for finding the articles.
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