Repurpose 600W Boost Converter as bench PSU? - Page 1
Forum section: electronics / beginners

author: thejoggingmat
author_rank: Regular Contributor
timestamp: August 10, 2015, 03:20:36 pm
content: I was wondering if one of these:http://www.ebay.com.sg/itm/331346833095?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AITWould be able to be repurposed as a bench PSU?I was thinking of using one of those coupled with a ~12-24v ~10-20A mains transformer, and replacing the miniature 10turn pots with equivalent value external ones (big enough to adjust with knobs). Slap on a voltmeter & ammeter as well. Afterwhich I would enclose everything in a nice aluminum enclosure.This is just one of those many whacky lightbulbs that suddenly lit up when I'm in the shower/bus/train. But would it work in real life?

author: tszaboo
author_rank: Super Contributor
timestamp: August 10, 2015, 03:29:33 pm
content: A bench PSU goes down to 0V. This is a boost converter, so your output voltage is always higher than your input.A bench PSU also has current limit, which should be fast acting.Last of all, a bench PSU should be safe, isolated, and you should bet your life on it's safety. Because in fact you will when working with the powered device.

author: rickselectricalprojects
author_rank: Regular Contributor
timestamp: August 14, 2015, 01:13:09 am
content: I doubt that that could safely and reliably do 600 watts and as NANDBlog pointed out that is a boost converter and even step down converters don't go all the way down to 0vGet one of these:http://m.ebay.com.au/itm/Hot-30V-5A-Variable-DC-Power-Supply-Digital-Display-Lab-Grade-Adjustable-AU-/400965963373?nav=SEARCH$70aud 30v 5a. It should do the trick and if you want to spend a bit more they have 10a versionsI hope this helps

author: wraper
author_rank: Unknown
timestamp: August 14, 2015, 01:23:15 am
content: Quote from: rickselectricalprojects on August 14, 2015, 01:13:09 amNO, DON'T GET THESE!!!They are worthless junk. If running at full current, it will be a miracle if they last more than an hour. Often with counterfeit parts inside, especially pass transistors which are mounted on the plate which cannot even be called a heatsink and cooled by noisy fan. Also usually lack constant current regulation, only have cut off, which you even cannot set normally. Even transformer often is dangerous.

author: rickselectricalprojects
author_rank: Regular Contributor
timestamp: August 14, 2015, 01:28:52 am
content: Quote from: wraper on August 14, 2015, 01:23:15 amThank you for letting me know, i was looking to buy one.Thanks for saving me $70

author: wraper
author_rank: Unknown
timestamp: August 14, 2015, 01:38:31 am
content: If going to get something that actually works and is not too expensive, go for Korad. If want something like on the link you posted and what have at least some level of quality, Mastech is a bare minimum.

author: rickselectricalprojects
author_rank: Regular Contributor
timestamp: August 14, 2015, 02:03:43 am
content: Quote from: wraper on August 14, 2015, 01:38:31 amThanks, I'll look at korads

author: rx8pilot
author_rank: Super Contributor
timestamp: August 14, 2015, 02:05:03 am
content: Quote from: thejoggingmat on August 10, 2015, 03:20:36 pmHa! I know a guy that got those from eBay with big plans. I saw it and examined it - TOTAL PIECE OF SHIT! I did not waste a second of my time evaluating electronically since it failed the visual test so miserably. Poor quality at every level of design and workmanship. They claim 95% efficiency! Not a chance they are even close to that.Now that this thread is up, I may try to test one and see how long it takes to catch on fire. How much noise and ripple it has, dynamic response, etc.

author: thejoggingmat
author_rank: Regular Contributor
timestamp: August 14, 2015, 02:36:08 am
content: Quote from: wraper on August 14, 2015, 01:23:15 amWow, I fully expected they were built to a price, but I'm sure they arenotthat bad, are they?I was looking at Julian Ilett's videos, and he reviewed it & they didn't seem so bad.I'll buy a real bench PSU when my part-time photography/videography/web design cashflow picks up, but in the meantime I would want to build something to a price and only use for low power applications.I ordered 2 B3603 modules (https://www.eevblog.com/forum/reviews/b3603-dcdc-buck-converter-mini-review-and-how-the-set-key-could-be-fatal/) (they look dandy enough, and apparently the ST Microcontroller is hackable too) to play around. The max transformer I can get (other than ATX PSUs) is a 30VA 24V one, so I need something that can step up an ATX PSU to only around 100W, ~30V to let the B3603 buck it.

author: thejoggingmat
author_rank: Regular Contributor
timestamp: August 14, 2015, 02:43:08 am
content: Quote from: rickselectricalprojects on August 14, 2015, 02:03:43 amI just found a basic KORAD model from a DaveRant:http://www.ebay.com.sg/itm/KORAD-KD3005D-Precision-Variable-Adjustable-30V-5A-DC-Linear-Power-Supply-Di-/121638762387?hash=item1c523c3793...Aaaand its ~S$250+++++ after shipping. Thats way too much what I can spend now.

author: thejoggingmat
author_rank: Regular Contributor
timestamp: August 14, 2015, 02:46:27 am
content: Quote from: rx8pilot on August 14, 2015, 02:05:03 amI'd estimate around 60-75% efficiency. I haven't ordered one, but if I did I would run it on less than 200W with an active cooled heatsink.

author: wraper
author_rank: Unknown
timestamp: August 14, 2015, 11:15:40 am
content: Quote from: thejoggingmat on August 14, 2015, 02:43:08 amBecause of that global shipping program shit. Though (normal) Lab PSUs are heavy and very expensive to ship anyway. So usually it is better to find what is available more locally so cheaper to ship.