Ideal diode used as relay?

jall

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Hi. Have someone here experience using a "Ideal Diode" commanded as a relay?
I want to use it as a commanded switch (instead a contactor) since it has ideal performance for high current (more than 200 Amps and a incredible low loss due to the ultralow internal resistance (0.4 miliOhms).
I plan to command the module through the ground pin, and The mosfet should switch off.
The great adventage over the contactor is that the mosfet module has not "internal current" when activated (any contactor has several amps lost just to keep the contacts in ON position).
I have ordered a pair of modules to ALIX, but it will take some weeks to arrive...
So, any previous experience will be wellcome
 

efficientPV

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Just what have you ordered? Everyone should be switching FET. If you ordered (0.4 miliOhms), you paid too much for the pleasure.
 

RCinFLA

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It is MOSFET switch that has circuitry to turn on MOSFET like a diode forward current conduction.

0.4 milliohms with 200 amps is 16 watts of heating, requiring a fairly good sized heat sink.
 

Bud Martin

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It is MOSFET switch that has circuitry to turn on MOSFET like a diode forward current conduction.

0.4 milliohms with 200 amps is 16 watts of heating, requiring a fairly good sized heat sink.
Yep, I do not know why OP call it 'Ideal Diode'.
 

jall

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jall

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It is MOSFET switch that has circuitry to turn on MOSFET like a diode forward current conduction.

0.4 milliohms with 200 amps is 16 watts of heating, requiring a fairly good sized heat sink.
this is hundreds times less that using a normal diode (even if using schottky diodes that are the lowest loosing diodes). In adition, a contactor has not much lower contact resistance....
 

Bud Martin

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MOSFET: N- channel IPT015N10N5

It is MOSFET as indicated, no new technology there. The body diode of the MOSFET is used as blocking diode, the MOSFET is used as switch (Pin 1 is the Gate pin).
The module may be using 300A rating MOSFET but the way the module is made, it is using PCB copper plane as heatsinnk and that is why it shows: it is a false claim of 300A handling module.
Module operating voltage: 5-75v
Conduction pressure drop: 0.02v
Standby current: about 0.0004A
The board can be loaded for a long period of time: 25A
Instantaneous starting current: 50A
Small volume limits heat dissipation, under natural conditions without heat sink room temperature 30 degrees measured below data.
Operating voltage 20V current 13.5A continuous half hour thermal imaging shows maximum temperature 41 degrees.
Operating voltage 48V current 7.5a continuous half hour thermal imaging shows maximum temperature 36 degrees.
Because the hand load meter can only test 380W at most, it cannot continue to test more power.
As a rule of thumb, this plate should have no problem loading 500W 20A under natural cooling conditions.
 
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jall

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MOSFET: IPT015N10N5

It is MOSFET as indicated, no new technology there. The body diode of the MOSFET is used as blocking diode.
The module may be using 300A rating MOSFET but the way the module is made, it is using PCB copper plane as heatsinnk and that is why it shows: it is a false claim of 300A handling module.
Module operating voltage: 5-75v
Conduction pressure drop: 0.02v
Standby current: about 0.0004A
The board can be loaded for a long period of time: 25A
Instantaneous starting current: 50A
Small volume limits heat dissipation, under natural conditions without heat sink room temperature 30 degrees measured below data.
Operating voltage 20V current 13.5A continuous half hour thermal imaging shows maximum temperature 41 degrees.
Operating voltage 48V current 7.5a continuous half hour thermal imaging shows maximum temperature 36 degrees.
Because the hand load meter can only test 380W at most, it cannot continue to test more power.
As a rule of thumb, this plate should have no problem loading 500W 20A under natural cooling conditions.
thanks.
The original question was: Will it be acting as a relay if the ground wire is just disconnected?
 

Bud Martin

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thanks.
The original question was: Will it be acting as a relay if the ground wire is just disconnected?
The Gate pin is driven by IC U1, base on wiring diagram, the Ground pin is the control pin and it is Active Lo logic, so if ground is not connected then the MOSFET will be off but the body diode will still let the current to flow from Vin (Source/Anode of Body Diode)) to Vout (Drain/Cathode of Body Diode).
 
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jall

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The Gate pin is driven by IC U1, base on wiring diagram, the Ground pin is the control pin and it is Active Lo logic, so if ground is not connected then the MOSFET will be off but the body diode will still let the current to flow from Vin (Source/Anode of Body Diode)) to Vout (Drain/Cathode of Body Diode).
you are absolutelly right. I should have seen that , but I ignored the "protection diode" path since the protection function is not needed here.... :cry:
 

sunshine

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I think these are the tiny brothers of what you are getting??
15A 400W MOS FET Trigger Switch Drive Module

They work well at 10% of their rated amps as a relay with only the trigger V connected with any v above the - input. At 10 amps you get smoke machine....the mosfets are tiny and there is no way you can add a heatsink.

So be prepared to not accept the stated amperage. Test first!
 

Bzzzt

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Whoops! Made irrelevant comments. Deleted to save confusion.
 
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jall

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I think these are the tiny brothers of what you are getting??
15A 400W MOS FET Trigger Switch Drive Module

They work well at 10% of their rated amps as a relay with only the trigger V connected with any v above the - input. At 10 amps you get smoke machine....the mosfets are tiny and there is no way you can add a heatsink.

So be prepared to not accept the stated amperage. Test first!
the problem is that most of the available products control just the negative side (ground path) (as almost all the BMS do) and although it is posible using it, I would prefer to control the positive side and make a common ground system (just for simplicity and safety)
 

JMc

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The other important issue is the failure mode — usually ON. Consider a mechanical contactor, coil power ~ 4W and little chance of it failing as a closed switch.
 

jall

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The other important issue is the failure mode — usually ON. Consider a mechanical contactor, coil power ~ 4W and little chance of it failing as a closed switch.
It is true, but 99,9% of the BMS in the market are subject to the same failure in "on" state
 

Bzzzt

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Sorry, this isn't a proper reply to your question but how about 'just' using MOSFETs and skipping their control circuitry? If you have a control signal to drive the gates you should be able to make up a simple PCB containing a MOSFET and possibly a protection diode. The great thing is that they are easily paralleable to reach your target capacity. I am currently using Vishay SQJ407EJs as a high side, low voltage cutoff (at very modest currents).
 

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jall

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Sorry, this isn't a proper reply to your question but how about 'just' using MOSFETs and skipping their control circuitry? If you have a control signal to drive the gates you should be able to make up a simple PCB containing a MOSFET and possibly a protection diode. The great thing is that they are easily paralleable to reach your target capacity. I am currently using Vishay SQJ407EJs as a high side, low voltage cutoff (at very modest currents).
The problem is as I already mentioned, to switch the positive side of the circuit. The MOSFETs are quite good to cut the negative side since in such position they are easily drived to saturation (and therefore in to the ultra-low resistance state we want). But doing it in the positive branch is not so easy due to the imposibility to push the transistor to saturation. The "control circuitry" makes the necesary voltage boosting to the gate´s signal to solve this problem. In the "ideal diode" modules such control driver is already included, and therefore it should work fine even in the positive wire. The problem is the protection diode internally built ...
 

Bzzzt

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The problem is as I already mentioned, to switch the positive side of the circuit. The MOSFETs are quite good to cut the negative side since in such position they are easily drived to saturation (and therefore in to the ultra-low resistance state we want). But doing it in the positive branch is not so easy due to the imposibility to push the transistor to saturation. The "control circuitry" makes the necesary voltage boosting to the gate´s signal to solve this problem. In the "ideal diode" modules such control driver is already included, and therefore it should work fine even in the positive wire. The problem is the protection diode internally built ...
Yup, I hear you. If you need to protect against reverse currents this will fail, similar to the melting Victron BPs I imagine.

In my case I had to use some additional circuitry to get a solid 0 (on) to 13V (off) signal to control the PNP MOSFETs. If you have a BMS that can pull this off for you then the solution becomes much simpler.
 
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