Smps Car Battery Charger

[CHACALPOWERS]

Hi dears. This is my battery charger (SMPS), light, small and strong.
I like it so much, this is a 30A version, but, there are 60A and 90A too.
All comments are wellcome.

Thanks.

CHACALPOWERS

 

[EWorkshop1708]

VERY Nice!!!!

I like how you re-used a computer PSU case.

What did you do to make this charger? What kind of transformer did you use to get the 12V+ output?

Schematics?

 

[luka]

Hi

Does it have current limiting? More pictures please

 

[CHACALPOWERS]

Thanks by comments

Hello SMPS builders

I'm your fan, because I learn so much with all you. Than you very much.
The battery charger/power supply don't have a current limiter, only a input fuse to prevent overload or short circuit, ok?

The PWM card work with SG3524, 2SC954/2SA733 buffers, IRFP264 mosfets in the output and the output transformer was build with 3 PC power supply output transformer (together) Ae = 3,6cm2 and no load the input current is only 0,04A (40mA).

I will post some schematics in the future for you.

Here a pic of the SMPS rear side.

Thanks

CHACALPOWERS

 

[luka]

Hi

3 cores for 30A version? Or was that for some other?

 

[Eva]

Why are you not including current limiting? This yields an extremely easy to blow circuit.

 

[CHACALPOWERS]

cores & current limit

HI luka
Yes, 3 PC power supply cores for 30A version only.

Hi Eva, I'm your fan, ok?
When I built the SMPS my time very short, but I want install a current limiter shutdown based in the next version. About this, what the best way to action the shutdown in the SG3524 (your suggestion)?

Thanks

Chacalpowers

 

[Eva]

Method 1:

Replace SG3524 by SG3525A and use the shutdown pin to terminate each cycle in case current rises above a certain threshold. This requires some "slope compensation" for stable operation into limiting.


Method 2:

Use a shunt to sense output current and one or two op-amps with suitable frequency compensation to reduce target output voltage or duty cycle in order to keep current below the limit.

And so...

 

[luka]

Hi

Why you need 3 cores for 30A? I have 25A output with one core only

 

[CHACALPOWERS]

cores

Hi luka

I don't know "why" but my cores are "EI33' , Ae=1,2cm2 aprox. X 3 = 3.6cm2.
74Khz switching, 2 X IRFP264. (115VAC version).

Regards

Chacalpowers

 

[luka]

Hi

I used the same as it was in before, it was 230w supply before...now a bit over 300w, all the same power components as before, same settings, all the same, just the feedback was changed and output things

 

[CHACALPOWERS]

Hi luka

I will try to change somethings here and after I talk about, ok?

Thanks

CHACALPOWERS

 

[megajocke]

Method 1:

Replace SG3524 by SG3525A and use the shutdown pin to terminate each cycle in case current rises above a certain threshold. This requires some "slope compensation" for stable operation into limiting.


Method 2:

Use a shunt to sense output current and one or two op-amps with suitable frequency compensation to reduce target output voltage or duty cycle in order to keep current below the limit.

And so...

Eva, won't pulse-by-pulse current limiting tend to reinforce any imbalance on the balancing capacitor? The half period with the lower transformer voltage gets longer conduction time, decreasing its voltage even more for the next cycle and so on.

(http://www.fairchildsemi.com/an/AN/AN-7531.pdf)

 

[luka]

Hi

Sure, at least try and see what happens

 

[CHACALPOWERS]

current limiter and others

Hi

In the Rod Elliott page there is a good SWITCHMODE PSU PROTECTION
http://sound.westhost.com/project108.htm

I think build this, any other idea or schematics?

Regards
CHACALPOWERS

 

[CHACALPOWERS]

CORES x AMPS

Hi luka

Take a look in this page, four cores = 40A, it's wrong?

Regards

CHACALPOWERS

 

[luka]

Hi

What page? saying that core is limited by output current is wrong, you have to look at power that you transfer with the core.

20A @ 5v, would be more or less the same for core if you would have 10A @10V or 5A @20v

 

[CHACALPOWERS]

Excuse me

Hi luka

Excuse me AND MY BAD ENGLISH . I lost the page. Here it's. I understand your explanation.

http://ludens.cl/Electron/PS40/PS40.html

Thanks

CHACALPOWERS

 

[luka]

Hi

Yea yea, this page has 4 cores because it has lot more power then normal PC supply has... if you read all of it, you will find out why he used 4 and not only one

 

[MatthewS]

Re: current limiter and others

Hi

In the Rod Elliott page there is a good SWITCHMODE PSU PROTECTION
http://sound.westhost.com/project108.htm

I think build this, any other idea or schematics?

Regards
CHACALPOWERS

A simple panel mount circuit breaker? drill a hole and attach two wires. It's a great 'afterthought' type of solution.

- Matt