Solid State version of SPDT Switch

I need a component that mimics as closely as possible a single-pole double-throw switch as it relates to DC.
It will not be understood right now, but the normally open and normally closed contacts will be connected to the positive and negative poles of a battery or battery pack. There will never be a complete circuit or current flow. The criteria are that between the active contact and the common, the DC resistance must be less than 1 ohm, preferably less than 0.5 ohm.
Cost is a consideration. The less, the better.
Isolation between the NO and NC contacts, as far as DC, should be high, up to 200 volts at low amperage and up to12 volts at 1,000 amps.
Low power drain to operate the switch is a consideration also. As in a battery-powered device that one can carry in a pocket, with a variable-frequency square-wave oscillator that will alternate between the NO and NC contacts being connected to the common.
I have looked into solid state changeover relays, etc., but found they seem to be designed for AC signals and have a high DC resistance.
Any ideas? Thanks much for your time.
ps - This is a not-for-profit and open source endeavor. Will reveal all details when coplete. Very much of use to anyone. I just want to make it s simple and cheap as possible.

Two Power FETs. To help you, post a diagram that would work if you used a SPDT relay. After seeing the open circuit voltages and direction of current flow, converting from the relay to FETs will be obvious. Your description is not.

The 200 volts and 1000 amps rating is problematic for a battery-powered pocket sized device. We need more info.

Lol, even cable which is rated to 1000A won't be pocket sized.

A 1000A cable will need to have a cross-sectional area of 500mm² which is a diameter of 25.23mm, just under an inch.

Even with a 0.5 ohm switch resistance, the voltage drop @ 1000 amps would be 500 volts.
Like the previous posters have mentioned, the description/specifications don't make much sense.

Switching 1000 amps at a high frequency has problems, that is a pretty high current and inductive voltage spikes will explode any solid state switching device you use. Make sure that you keep the leads short, like milimetres short.

MikeMl said:

Two Power FETs. To help you, post a diagram that would work if you used a SPDT relay. After seeing the open circuit voltages and direction of current flow, converting from the relay to FETs will be obvious. Your description is not.

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Imagine this. You have a battery or battery pack and two alligator clip test leads, and an output. One end of each alligator clip lead is connected to the output. One at a time, one of the alligator clip is connected to one pole of the battery or battery pack. One pole only at a time is connected to the output. There is never any current flow. I know this may be impossible to understand at the moment, but all will be made clear in time.
Again, there must be less than 1 ohm DC resistance between the output (common) and the normally-open or normally-closed lead when one of these connected to the common. Like an analog SPDT switch with a battery's poles connected to the normally-open and normally-closed leads.
At no time is there ever current flow or a complete circuit.
Again, thanks for your time.

Sorry but your spec's don't make any sense.

A 1 Ohm contact resistance is huge at 1000A, it will mean a voltage of 1kV and a power dissipation of 1MW.

Are you sure you didn't mean 1000mA or 1A?

Even then the voltage drop is 1V which is significant a lower voltages.

Hero999 said:

Sorry but your spec's don't make any sense.

A 1 Ohm contact resistance is huge at 1000A, it will mean a voltage of 1kV and a power dissipation of 1MW.

Are you sure you didn't mean 1000mA or 1A?

Even then the voltage drop is 1V which is significant a lower voltages.

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There is no current flow or complete circuit. I mean that if one put a meter across the active contact (NO or NC) and the common, it would show less than one ohm DC resistance.

What do you mean?

Why dod you say this?

grizzle said:

, as far as DC, should be high, up to 200 volts at low amperage and up to12 volts at 1,000 amps.

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If there is no current flow at any time, you don't need the battery, or the battery pack, or the test leads, or the relay. The one ohm resistance is meaningless without a current.

Hero999 said:

What do you mean?

Why dod you say this?

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Those are the maximum parameters that I have found to be of use.

mneary said:

If there is no current flow at any time, you don't need the battery, or the battery pack, or the test leads, or the relay. The one ohm resistance is meaningless without a current.

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I don't want to start an argument, I am only asking for advice.
This is not a commercial application btw, although it well could be. It is going to be open source.

Grizzle;
I for one would LOVE to provide you with helpful advice.... and trust me more than one would also help.
However, your requirements are a little vague and confusing.

I'm enclosing a small schematic showing what I am guesssing you require. One is for a ground referred load (N-chann fet), the other for a battery referred load (P-chan fet).

Of course, the actual fet part number will depend on the the actual maximum voltage and current required

grizzle said:

Those are the maximum parameters that I have found to be of use.

Click to expand...

As I said before, 1000A is too higher current to switch without a huge thyristor or an array of MOSFETs.

Here's the highest current MOSFET I could find.
INTERNATIONAL RECTIFIER|IRF1324S-7PPBF|MOSFET, N D2-PAK/7 | Farnell United Kingdom

https://www.electro-tech-online.com/custompdfs/2010/02/28247.pdf

You'll need to solder three in parallel between two pieces of thick copper bus bar. The piece with the drain terminal will need a large heatsink and a fan or water cooling to get rid of 266.67W of heat.

That MOSFET is grossly inadequate because the OP needs a 200V rating.

It looks like a thyristor is the only solution then you need to find a way to turn it off.

It's a thousand amp, 200V switch that's part of a secret battery powered device that can be concealed in one's clothing.

I'm guessing it's a single-use device. With a major portion of a megawatt involved, the survival of the operator and those around him is not to be expected.

I'm not sure we want to know what it is. I am sure we shouldn't be assisting.

Hero999 said:

As I said before, 1000A is too higher current to switch without a huge thyristor or an array of MOSFETs.

Here's the highest current MOSFET I could find.
INTERNATIONAL RECTIFIER|IRF1324S-7PPBF|MOSFET, N D2-PAK/7 | Farnell United Kingdom

https://www.electro-tech-online.com/custompdfs/2010/02/28247-1.pdf

You'll need to solder three in parallel between two pieces of thick copper bus bar. The piece with the drain terminal will need a large heatsink and a fan or water cooling to get rid of 266.67W of heat.

Click to expand...

You still do not understand. There is no current flow, no complete circuit. Visualize a SPDT switch, a changeover switch. The poles of a battery or battery pack is connected to the NO (normally open) and NC (normally closed) contacts.

mneary said:

It's a thousand amp, 200V switch that's part of a secret battery powered device that can be concealed in one's clothing.

I'm guessing it's a single-use device. With a major portion of a megawatt involved, the survival of the operator and those around him is not to be expected.

I'm not sure we want to know what it is. I am sure we shouldn't be assisting.

Click to expand...

The thousand amp device is not the wearable device. The wearable device uses up to 16 A23 batteries, which are 12 volts and are slightly smaller than AA batteries. The thousand amp device, of course, can not be worn on one's person. OKs?