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DIY 150 amps rectifier

brandnewb

brandnewb

Going for serious. starting as newb
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WARNING: High amp applications are not recommended and can lead to fatal injuries. Proceed with caution.

Does one have suggestions on what diodes to get for a DIY single phase full bridge rectifier? I currently have a rectifier that is rated at 100 amps but those on paper stats are slapped on there by our friends from the east and I can already tell that when passing 100 amps through it it gets really hot really fast.

Also can one recommend capactitator(s) to use in a 150 amps rectifier setup?
 
Diodes have a conduction voltage drop. It has a logarithmic increase in voltage drop with increasing current.

With 100 amps you may have 1 to 2 volts drop across diode depending on diode.

Heating of diode will be voltage drop times current passing through it.

You need a significant heat sink on diode.

Other important parameter is its reverse voltage breakdown.
 
yes thank you for added info.

May I please intice you to try suggesting components that might work?
I am willing to try a few and determine in the field that they are not suitable if the purchase did not break the bank / require a second day job.

The point I am trying to make is that I will not hate one for a suggestion that did not work out perfectly or worse. Currently I have no idea what so ever and having at least some idea is better than nothing
 
These high current diode's are pretty expensive. And you're going to need 4 of them.

Expect to pay 25-30 euro / each, or 90-100 euro for a bridge rectifier.

Better try to get some overstock ones, or salvage them from somewhere

Also
- They get hot.. VERY hot. You're going to need a massive heatsink with probably forced cooling. 150A, at a forwarding voltage of 1.5V (with a bridge rectifier, power passes 2 diodes) you're looking in to 225 watts of heat generated.

- You're going to need massive capacitors if you need something which looks more like DC.
General guideline is 1000uF for each amp, so you're looking into 150.000 uF at least.

Better go for switching regulators. These currents are hard to handle with regular lineair electronics. With a switched design
- You can rectify at the primary side, thus much less losses in the diodes, and much smaller ones needed
- Much higher frequency on the output, thus smoothing capacitors can be much smaller
- Much more efficient: Less transformer losses
- Much less inrush current: A regular transformer for these kinds of power is going to need additional electronics to startup, or will trip any breaker.
 
Select the search parameters you want:

Discrete Semiconductor Products | Diodes - Bridge Rectifiers | DigiKey

Discrete Semiconductor Products - Diodes - Bridge Rectifiers are in stock at Digikey. Order Now! Discrete Semiconductor Products ship same day
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Diodes have a voltage drop, so 150A x (about 1 V) x 2 (two diodes in series) is 300W dissipated.

MOSFET can be used for synchronous rectification, a couple milliohms so maybe 0.3V drop, less if multiple in parallel. Downside is needs control circuit, and if every two both on simultaneously connecting power to ground they burn up. But MOSFET synchronous rectification is common in switchers and inverters for the efficiency.

en.wikipedia.org

Active rectification - Wikipedia

en.wikipedia.org en.wikipedia.org

For AC powered 48V battery charger, KISS and used diodes with fan-cooled heatsink.
For high efficiency PV or battery inverter, consider the more complex and efficient approach.
For wind turbine, hmm, already got moving air any time power is high?
 
Make it a synchronous rectifier instead of bridge rectifier. No diode drop this way :)
 
Where are you located? I have big diodes and heatsinks and capacitors that I am willing to make a deal on. If you have system particulars I can see what I have.
 
The post is a bit older, but I want to add, if you are going to use this to convert AC from the grid or solar keep in mind that using just a rectifier and caps, all the load comes from the tops of the sinewave (because of the caps) for small loads this is not an issue, but for 150Amps it is. It will give a lot of polution on the net.
Also keep in mind the dc voltage will be higher and keep in mind touching DC is more dangerous aa AC voltage (if you touch it)
 
PDJ said:
The post is a bit older, but I want to add, if you are going to use this to convert AC from the grid or solar
Click to expand...
My threads are never too old to reply to!

This will be used to rectify AC generated by a wind turbine generator to charge LifePO4 batteries.
In a related project that I'd like to master before I start using my generator that is no way near completion yet I am now in the process of optimizing a DIY transformer to be able to charge said batteries at 140 amps. Or when using a BMS at 125 amps.

I have in the meantime gotten myself some diodes but for the life of me I do not know how to hook them up. hold on I will get the specs.
 
PDJ said:
The post is a bit older, but I want to add, if you are going to use this to convert AC from the grid or solar keep in mind that using just a rectifier and caps, all the load comes from the tops of the sinewave (because of the caps) for small loads this is not an issue, but for 150Amps it is. It will give a lot of polution on the net.
Also keep in mind the dc voltage will be higher and keep in mind touching DC is more dangerous aa AC voltage (if you touch it)
Click to expand...
Should I be worried about polluting the grid? I mean it's not that our government is treating us well and I have even less good words available about our grid masters.
However, I do not want to become a problem for my peers. Imagine my horror if I end up accidentally tripping the breakers.. at my neighbor's house!!!!!!
 
brandnewb said:
Should I be worried about polluting the grid? I mean it's not that our government is treating us well and I have even less good words available about our grid masters.
However, I do not want to become a problem for my peers. Imagine my horror if I end up accidentally tripping the breakers.. at my neighbor's house!!!!!!
Click to expand...
I'm bound to the same goverment and probally a differnt grid master (Amsterdam is Liander it is?)
The 150A you are talking about, is that directly from the grid or is it after a transformer? If it from the grid directly, you probably have 3 phases, that's a bit easier, but 150A you will have a special meter and you will pay alot more if you do not have "perfect" load. If you want to use it for low voltage, a switching power supply with power correction will save a lot of problems and has a higher efficiency also if you use them for your turbines the efficiency will be beter (fpc does require some frequency stability)
 
I saw your other post, now I think I know what you want to do.
You want to mak a transformer and charge your lifepo4 cells, right?
That will not work and you'll end with ruined cells. Going from AC to DC you need to take peak voltage so from 3,6VAC to DC you end up at 5V. , but the voltage on the grid will change and will reflect the output voltage. If your transformer is outputting 3.6VAC @230V, it will be 3.75VAC @240V (about 5,3VDC). For LifePo4 0,1V extra is allready a big deal, and 0,6V is the difference between optimal charge voltage and a dead battery. Also you need to limit the charge current, you can't do it like this. So if that's what you want to do, really don't do that..
 
Well, in that case. Can we just simply charge at a 3.5VDC high amp level to allow for some grid swings (there is a variac in between though)
The topping off to 3.65VDC will be done in a controlled manner using a CC/CV
 
The curent limit has to be done in almost the complete charge cycle, and in the low end SOC (where you want to use your charger) the current limit is most important.
You can have some sort of a current limit with the length of wire you are using (3.5V @140A the cable loss will have a huge impact)
But this is all theoretical, all the spices etc. on the grid will be absorbed by your battery, on a sunny day the grid can be at almost 250VAC, but in the winter it could be 210VAC in both conditions your charger should work and it should not destroy your battery.
If you would ask me, I wouldn't do it like this.
I think you are making a big battery tester here to find the limits of your battery.
If you want to make a cheap charger, I think you should try to find some Aliexpress stuff but even then you need to be very careful.
 
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