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Discussion Starter #1 (Edited)
Designing my EV I have concluded that power steering s*cks.

No power steering is not an option for a modern car;
Hydraulic power steering driven by a pump and belt from the main motor wastes too much energy;
A 12V electric pump (from e.g. the MR2) requires a 1000W DC-DC system (and as far as DC-DC systems go they are either expensive or unreliable).

As per Bart Simpson: Damned if you do; damned if you don't.

My conclusion: I need a 280-320V (main pack voltage) hydraulic pump that only engages at low speed and when steering (can such a pump be triggered by the torque sensor?) Preferably controlling the power steering pump is not an on/off issue but a gradual thing.

Problem #1: I can't find a high voltage power steering pump
Problem #2: Do I really want an additional 1kW DC controller for the PS pump instead of a switch?

Alternative: replace the current hydraulic PS system by an electric system from e.g. a Kia Cee'd or something other Korean (= affordable). [But wouldn't that also require 1kW 12V DC?]

Your thoughts would be highly appreciated.
 

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Hi Raymond,
I have an electric PS in my Renault Clio electrique ( no DIY ). It is only fused 20A, meaning it cannot draw more than 250W. I think it comes from Pierburg, but I can check the manual later. More important than PS is brake assist, at least in modern cars. Do you have a solution for that?
One day I disengaged both PS and PB to save some energy, but even with the nice regen braking from my Clio, I felt unsave without PB.

Groeten,
Olaf, working in Echt (Limburg, NL)
PS: I have a Clio PB-pump as spare for sale.....
 

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Solution is to not try to run the 12V PS pump from the DC-DC converter. Use a small accessories battery to provide the current on demand and a smaller DC-DC converter to top up the battery.

Unless you spend all your time parking the car the pump will be off, or on standby, most of the time giving the battery time to recharge.

If you have a pack voltage pump then you will have all the problems of switching high voltage DC to deal with.
However, if you really want one then you could adapt a small forklift pump motor from, say, a 72V forklift. I think some of them have steering pumps separate to the main hydraulic pump.
 
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