Right. If the loads are just heaters then a simple PWM controller avoids all the voltage conversion.

What are the loads?

 

Right. If the loads are just heaters then a simple PWM controller avoids all the voltage conversion.

What are the loads?

The loads are 12v charge controllers. All 4 will have identical constant power draw while switched on.

 

The loads are 12v charge controllers.

If you are charging 12V batteries then don't you need more than 12V input?

 

If you are charging 12V batteries then don't you need more than 12V input?

Around 12-15v

 

This thread will definitely go places.

 

The loads are 12v charge controllers. All 4 will have identical constant power draw while switched on.

I'm still trying to get a handle on what the LOADS are. Can I assume that the loads are batteries, given there is a charge controller in the path?

If so, it seems unlikely that they will all have identical, constant power draw.

The minimum input voltage of a charge controller is almost certainly higher than the battery being charged. What battery chemistry are they?

 

Motor-generator! Get a 48V DC motor, couple it to an ambulance alternator or four.

 

What is a circuit?

Please check these.

What is a pcb?

Please check these.

What is a circuit of switching power?

Please check these.

 

Once again, while the rest of the system design is probably well within the TS current skill set, the actual switcher supply module to step 48 volts down to 12 will be less expensive purchased from an honest and competent source.
Another choice could be four similar devices sized to each handle a quarter of the load, each one charging one battery bank each. That would also provide improved reliability, thru redundancy.

 

I don’t need a diploma to do things. Don’t waste your life standing behind a piece of paper. If you want to learn/do something you will. A piece of paper isn’t going to tell me what I can and can’t do.

The TS will not be the first, nor the last to express a haughty spirt, only to end up on the rocks of misfortune. We shall see.

 

without paper, you will need to spend lots of time and paper.
and ... and everyone knows that time equals paper...

 

I don’t need a diploma to do things.

No, because you are asking people with diplomas and decades of experience to do it for you.

This is probably a half year long project for someone with the right experience.

 

Thanks for all the help…… So much negatively minded people chiming in.. Saying things like go to school for 24 months before you draw a single trace… I didn’t ask anyone to do it for me, I asked how I should do it.

 

didn’t ask anyone to do it for me, I asked how I should do it

What do you think? We can write a paragraph or two and that will be enough for you to complete the project?

In reality you are asking for about $100,000 worth if consulting.

The loads are 12v charge controllers. All 4 will have identical constant power draw while switched on.

Really? Where does the 25A go after the battery is fully charged?

 

What do you think? We can write a paragraph or two and that will be enough for you to complete the project?

In reality you are asking for about $100,000 worth if consulting.

Really? Where does the 25A go after the battery is fully charged?

$100,000 hahaha now there’s a price to it too… this is hilarious.
$100k and 24 months of school. The best.

Obviously the charge controllers will stop drawing current once the batteries that they’re wired to are at the correct voltages….

 

HOW??? I suggested that the HOW will be to purchase the bare switcher modules and do the rest. I can drop an engine into a car that did not have that kind of engine before. BUT I can't design a high performance engine for a FUNNY CAR. But I could probably put one into that funny car.
My point being that some things are a whole lot more demanding than other things. I don't do brain surgery either. Nor do I design optimized switcher supplies, which are almost as complex, but not so messy when you goof up.

 

that time equals paper...

need to buy mosfets by the hundredweight prototyping those things.

$100,000 hahaha now there’s a price to it too… this is hilarious.

A lot of people here with a lot of experience are expressing their opinions, and you are not listening. Designing is time consuming, challenging, and expensive on one front or another. By all means have a go, but be prepared for the path being rockier than you seem to appreciate.

I too have dealt with trying to control high power loads from a solar source, and my recommendation is that you convert your solar to AC mains (240V in my case), as high powered AC converters are readily available, then run your loads on standard off-line products. I gave up on DC power delivery - too expensive, and too much copper to transport it.

 

this is no simple undertaking. it requires designing suitable controller, sizing parts (lots of math), choosing correct solution for cooling, busbars etc. yes, bus bars...you are not going to run 150A through a PCB. if you ever tried designing PCB for 10A and any continuous duty, you would begin to have an idea of what you are getting into. which is why suggestions included scaling it down and building smaller version first and 10A unit is a good choice.

at 1800W and 90% efficiency losses will be 200W. and that is if you can get to 90%. i would be quite impressed to see someone just starting and making this work at any efficiency... doing 65% would mean 1000W of heat losses and lots of blown parts.

 

I ws not addressing the balance of the design:Interconnect and control. My suggestion was only about the switch-mode converter. Probably the TS is quite able to handle the rest.
I do suggest having four converters to go from 48 volts to 12 volts, because it will be easier, and it will allow the use of more commonly available packages, AND it will prevent a fault happening to leave the other segments still operational. It will also probably cost a bit less.

 

Thanks for all the help…… So much negatively minded people chiming in.. Saying things like go to school for 24 months before you draw a single trace… I didn’t ask anyone to do it for me, I asked how I should do it.

I for one NEVER said that. It is true that you can learn by reading and by experience. It will take longer to acquire thr requiste skills and that is what I was referring to. You see it as negativity, but I see it as a necessary dose of harsh reality. It's what you get when every kid in school or on a team gets a crummy little trophy for participation.