Simple DiY 40a PSU / Ac-Dc converter

Thread Starter

bigjoncoop

Joined Feb 1, 2019
129
Hey guys,

I need to get anywhere between 12v to 24v DC @ ~40amps. All the power supplies I can find are $100+ ....

I need this to power a large 1500w CC/CV boost converter to charge a large lithium ion battery pack which will be going thru its BMS.

I've been keeping my eyes open for even a used server power supply etc... But again haven't found anything under $100 but normally a lot more.

I don't know how clean the DC needs to be going into the boost converter but...

I wasn't sure if it would be as simple as going through a transformer or bridge rectifier then into a large coil and some capacitors and what not. Or maybe modding a smaller psu to handle the current

Just trying to save money on this project since I'm already got too much into it.

Thanks
 

Irving

Joined Jan 30, 2016
1,018

SamR

Joined Mar 19, 2019
2,590
SMPSs get a bad rap but every critical computer runs on one. Maybe not as suitable for a research-grade electronics lab when looking for a mV or uV supply but I use them to supply my HF XCVRs and Amps. Suitable and value-priced depending on use. Plus there is a LOT of them available surplus for a very good price.
 

Irving

Joined Jan 30, 2016
1,018
SMPSs get a bad rap but every critical computer runs on one. Maybe not as suitable for a research-grade electronics lab when looking for a mV or uV supply but I use them to supply my HF XCVRs and Amps. Suitable and value-priced depending on use. Plus there is a LOT of them available surplus for a very good price.
I use a modified SMPS for a variable 0-50v, 25A bench 'lab' supply. It is a little noisy on the output but the 80 - 120kHz switching is easy to clean up with an LC filter (much easier than if it were 100Hz hum from a linear regulator).
 

SamR

Joined Mar 19, 2019
2,590
Yup, I just ran into a situation where I needed a 3rd PSU and thinking I might just have to do a conversion job on one of the junk computer SMPSs I have to fill the bill. But I also have a couple of dish tubs full of wall warts to chose from. LOL
 

Irving

Joined Jan 30, 2016
1,018
You can never have too many PSU! I picked up a useful 4-channel linear bench supply on eBay for £90 ($120) (Instek PS4303) - used and ch2 voltmeter is a little flakey (probably a dry joint, it is 20y old after all!).

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