# DIY 150Amp power full bridge rectifier help ..#1

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#### quitenoob

Joined Mar 27, 2022
262
WARNING: Playing with high amps is not recommended and can lead to fatal injuries. Proceed with caution.

I need to make high quality/performance rectifiers to convert high current AC to high current DC. I'd like to avoid store bought for now as I can't afford the reputable branded ones and am also wanting to learn how to do it.

For this 150 amps rectifier I have in mind now the VAC input will be about 3.65 and the current will be about 125 amps. But I'd like to oversize the rectifier a bit so that I can go up to 140amps in case needed.

As diodes I am thinking along the lines of these components

Would those work? If not please recommend a suitable component that does not require a second day job (i.e affordable)

To smoothen out the ripple I have been told to use a capacitor but am soo new to the field I have no idea where to start. What type of capacitor(s) should I get here?

Any ideas are welcome.

i've edited the OP to use an internal link to the component I am thinking of rather than an external one.

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#### Ian0

Joined Aug 7, 2020
8,424
You want 3.65V at 150A - why not use a battery?

Joined Jul 18, 2013
27,660
I would use something sturdy such as stud mount etc. You can get them with stud anode or cathode for ease of making a bridge.
Also the link you gave are high speed, do you need this feature for the application.?
Or look at the stud style used in alternators.

#### LowQCab

Joined Nov 6, 2012
3,458
You want to work with a Voltage of 3.65-Volts .......
The Diodes You have suggested have a nominal "Forward-Voltage-Drop' of approximately 1-Volt,
( this will vary slightly depending on Temperature and Current ),
1-Volt X 150-Amps = 150-Watts EACH of Heat that is wasted, and must be dissipated.
So, You will be wasting 600-Watts of Power.

This is probably not something that You were aware of.
There are solutions to this dilemma, but they are not cheap.

Please explain what You are trying to accomplish with this project so
that a workable solution can be discussed.
( Schematic-diagrams, or at least Block-diagrams,
and a full explanation would help immensely )
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#### twinsemi

Joined Apr 13, 2022
1
Currents like you describe along with low voltages are the name of the game in arc welding. Those companies have been dealing with these kind of issues for a hundred years. Maybe there are some ideas if you search for that kind of stuff??

#### quitenoob

Joined Mar 27, 2022
262
You want 3.65V at 150A - why not use a battery?
You may have missed

You want to work with a Voltage of 3.65-Volts .......
The Diodes You have suggested have a nominal "Forward-Voltage-Drop' of approximately 1-Volt,
( this will vary slightly depending on Temperature and Current ),
1-Volt X 150-Amps = 150-Watts EACH of Heat that is wasted, and must be dissipated.
So, You will be wasting 600-Watts of Power.

This is probably not something that You were aware of.
There are solutions to this dilemma, but they are not cheap.

Please explain what You are trying to accomplish with this project so
that a workable solution can be discussed.
( Schematic-diagrams, or at least Block-diagrams,
and a full explanation would help immensely )
.
.
.
yes, thank you for warning me.

but how to proceed?

I would use something sturdy such as stud mount etc. You can get them with stud anode or cathode for ease of making a bridge.
Also the link you gave are high speed, do you need this feature for the application.?
Or look at the stud style used in alternators.
This will be used in a power transformer setup using the mainland Europe grid. So I will be going for 50 hertz

#### LowQCab

Joined Nov 6, 2012
3,458
I just realized and re-read part of your previous post with the cobbled-up Transformer.
I didn't know this was a follow-up post.

Quit messing around before You burn-down your house.
A reasonably efficient Charger can be made from just 4 used MOTs ( Microwave Oven Transformers ).
( 2 of them will be used to make a half-assed Output-Choke sort of a thing )
Try to get 2-pairs that have roughly the same sized Iron-Cores so that they will share the Load mostly equally.
After You accomplish this task, and get the Secondary-Windings removed in 2 of them,
and remove ALL Windings in the other 2 Cores,
and remove the Magnetic "Shunts" from all the Cores,
then post back here for further instructions.

2- of the MOT Transformers must have .........
perfect, undamaged, pristine, Primary-Windings, that are completely intact and unmolested by any sharp tool.
2- of the MOT Transformers will be left with just bare-Iron-Cores.

You will be able to get around ~1000-Watts of power without fear of
burning down your House before You even connect a Battery.
This will be roughly 200-Amps at ~5-Volts.
You should also have some 200-Amp rated Wire for making the Secondary-Windings, ( #2-AWG ) ( 6.54mm ).

The Bridge-Rectifier will require a massive Heat-Sink, which will be quite expensive,
unless You are capable of building a relatively simple Bread-Board project with
5- expensive High-Power-MOSFETs and a few other small parts.
This will create much higher efficiency in your finished project and
reduce the Heat-Dissipation down to easily manageable levels of maybe ~30-Watts or so.

This project is going to cost You, at the very least, around ~\$150.oo in parts,
and if done in a respectable manner, about twice that much.

It's not going to work for less.
I suggest that You set your goals down to something like ~20-Amps-Max if You need it to be cheaper.
~20-Amps will still work just fine, but it will require 10-times the required Charging time of 200-Amps.
But it has the advantage of increasing your Battery's Life-Expectancy, by not abusing so much,
and seriously reduces the chances of burning your House down.
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#### quitenoob

Joined Mar 27, 2022
262
the dark side I sense in him.. why the anger?

But anyway I will try to absorb what you told me. and thank you non the less for your contribution.

#### quitenoob

Joined Mar 27, 2022
262
@LowQCab please do not take my strict behavior as disrespect. On the contrary!. I have maximum respect for your, and other contributions. I need to stay focused though so now you know why.

#### LowQCab

Joined Nov 6, 2012
3,458
Certainly, I'm not angry, I wouldn't have replied if I was angry.
It can be frustrating though, to watch someone burn time and money and resources to create something
that might actually burn their House down, and still never function the way they imagine.
Learning from your mistakes is just fine, but when it gets expensive, and/or, dangerous,
it's a much better plan to learn from other peoples mistakes.

MOTs are dirt cheap, and can be made to work quite acceptably,
but the rest of the Charging-Circuit is going to cost actual Money.
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#### quitenoob

Joined Mar 27, 2022
262
the rest of the Charging-Circuit is going to cost actual Money.
Thanks bro for picking this up with a light heart.
I am in luck though, Money is one thing I have in abundance. Also time seems to be in my fafor. Although sometimes my doughtier/family drag me down to a halt.
But it's like they say. You can't be with them but also can't be without them.

#### quitenoob

Joined Mar 27, 2022
262
Yes I know I keep saying I can't afford the reputable branded stuff elsewhere.

I stick to that.

#### strantor

Joined Oct 3, 2010
6,690
I am in luck though, Money is one thing I have in abundance. Also time seems to be in my fafor.
An enviable position! I've had money and I've had time, but never have I had both at once. In fact it is a thing I have given much thought on how to achieve. Maybe you will share your secret? So far the only solution I have come up with is to be born to wealthy parents, and I was delivered before I knew to choose that option.

Anyway, you have now been advised by more than one person in more than one thread, to go the trodden path of microwave oven transformers (commonly referred to as MOTs). Are you willing to follow the path or are you committed to your idea of the iron powder core? It is fine if you are, and I do and will continue to applaud your outside-the-box thinking, but if you stick to that, you will not get much help. Nobody has done this before that I know, therefore nobody will be qualified to advise you. You are very green to be blazing trails like this. Anyway, given what I know (which isn't exhaustive) about transformers, I think your 30-something percent efficiency is probably about as good as it's going to get. I strongly recommend using a MOT.

If you would like some inspiration as to how these MOTs can be used to generate high current/low voltage output there are many examples already on the internet. My own example I think is pretty unique, but I am biased in the matter.

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