Make a relay switch? Like a mosfet high amp.

[Jake Johnson]

Hey guys,
I'm new here and don't know really anything about making electronics, but I know about basic electronics.
I want to make my own sort of mosfet. I have made box mods in the past and I want something that could handle more amps or less of a drop in power and so I could use a normal momentarily switch.
I want it to be very safe, I need it to handle 4.5v tops and 150-200 amps (i would be extremely shocked if I usd over 100amps). it would be 5 seconds at a time max, mostly 1-3 seconds at a time. I want to use just a normal

I feel like this would be a pretty easy task for y'all.


Yes I vape. I know and use ohms law, don't want batts blowing up in my face.

This is the wiring diagram I'm going for if anyone knows anything that could work like that. If I have to wire it differently that's fine too.

Any help would be great thanks guys!

 

[dorke]

"I want to make my own sort of mosfet"...
Well if you can do that ,there is nothing stopping you from making your own space-shuttle

A 200A circuit is never easy...in fact it is also extremely dangerous!

So, in plain words you wont to build a 4.5V/200A DC controllable switch?

 

[Jake Johnson]

"I want to make my own sort of mosfet"...
Well if you can do that ,there is nothing stopping you from making your own space-shuttle

A 200A circuit is never easy...in fact it is also extremely dangerous!

So, in plain words you wont to build a 4.5V/200A DC controllable switch?

What about a car starter Solenoid? Same principle, just bigger. 12v up to 600 amps and its smaller then a tennis ball. You probably drive a car every day and okay so I can't make one. Anything I can buy? That's not as big as a car starter solenoid.

 

[Jake Johnson]

What about a car starter Solenoid? Same principle, just bigger. 12v up to 600 amps and its smaller then a tennis ball. You probably drive a car every day and okay so I can't make one. Anything I can buy? That's not as big as a car starter solenoid.

IRLB3034PBF MOSFET has those ratings they are just so tiny.

 

[dorke]

Well a 12V car Solenoid is not what you need(it needs 12V to operate).
You need a solid-state relay (SSR)
What is it you actually need to switch (voltage range and Max. current)?

 

[Jake Johnson]

Well a 12V car Solenoid is not what you need(it needs 12V to operate).
You need a solid-state relay (SSR)
What is it you actually need to switch (voltage range and Max. current)?

4.2V-3.7V and 84 amps

 

[dorke]

o.k
Is it a Lithium battery bank that you need to connect/disconnect from a load?
What side of the connection + or - ,do you need to switch?

 

[AnalogKid]

At 84 A, the circuit path (battery connectors, power connector, MOSFET, and wire) will dissipate 7 W for every 0.001 ohm if series resistance. The FET mentioned above as an Rds of 0.002 ohm max at Vgs = 4.5 V. Impressive, but that's still 14 W in a TO-220 package. It will survive a few 3-second hits without a heatsink, but eventually those thermal shocks will add up to doom.

ak

 

[Tha fios agaibh]

Sounds like you need a high power SCR or thyristor

 

[AnalogKid]

At 84 A, Vf would be at least 1.5 V based on Digi-Key's inventory, so power dissipation in an SCR would be in the 130 to 200 W range and it would cost $60..

ak

 

[dorke]

Sounds like you need a high power SCR or thyristor

The main reason an SCR isn't a choice is it will drop about 1.5V of the battery's 3.7V...
nor is a Darlington one from the same reason .
We won't even get to the power dissipation issue

The way to go is with a low RDS-on power Mosfet like the BSC009NE2LS5I
RDSonMAX(@VGS=4.5V) is 0.00135 ohm.
It should have a proper heat-sink,at 84A the voltage drop would be about 0.1V

 

[Tha fios agaibh]

The main reason an SCR isn't a choice is it will drop about 1.5V of the battery's 3.7V...
nor is a Darlington one from the same reason .
We won't even get to the power dissipation issue

The way to go is with a low RDS-on power Mosfet like the BSC009NE2LS5I
RDSonMAX(@VGS=4.5V) is 0.00135 ohm.
It should have a proper heat-sink,at 84A the voltage drop would be about 0.1V

Thanks Dorke, that's a big vd considering a 3.7v source.