Power-One MAP80-4001 : I need advice, ready to buy on eBay  - Page 1
Forum section: electronics / projects

author: montreuilg@sympatico.ca
author_rank: Newbie
timestamp: September 05, 2016, 05:17:47 pm
content: I found a power supply at at good price i think, 39US$.I want to use this unit and develop it as a bench power unit with two variable outputs, voltage and current.What do you think?I will use it for low voltage electronics and sbcs projects mainly, all beyond 12 volts and 2 amps max 99% of the time.Thanks,_gabriel

author: uncle_bob
author_rank: Unknown
timestamp: September 05, 2016, 10:09:02 pm
content: HiI think that if you shop a little, you can find a perfectly good bench supply for almost the same price. It will have nice features like knobs / switches and meters. The cost of adding all that to the bulk supply will add up ....You are pretty much guaranteed to never find a good deal on this sort of thing on a "buy it now" sale. It is not uncommon to see them listing prices that are 10X to 100X above the auction price. You have to wait for an auction and resist the urge to bid crazy numbers. It may take a while to win an auction at a good price. It also will take you a while to get all the parts and fabricate all the sheet metal to make a decent bench supply .....Bob

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: September 05, 2016, 10:21:16 pm
content: Where in Canada are you?

author: uncle_bob
author_rank: Unknown
timestamp: September 05, 2016, 10:51:28 pm
content: Quote from: Alex Eisenhut on September 05, 2016, 10:21:16 pmHiI'm guessing you are referring to the OP. These days I'm mostly (but not always) on the south side of the Canada / US border ...Bob

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: September 05, 2016, 11:36:10 pm
content: Quote from: uncle_bob on September 05, 2016, 10:51:28 pmOh yes, asking the OP. I have a nice Power One linear supply lying around unused for over a year, time to donate it.

author: uncle_bob
author_rank: Unknown
timestamp: September 06, 2016, 12:19:15 am
content: Quote from: Alex Eisenhut on September 05, 2016, 11:36:10 pmHiOk, in that case I can pretty much guess the answer. He's in Halifax and you are in Vancouver. It *always* works that wayThe odds of him being in Oshawa and you being in Hamilton are statistically pretty good. It never works out that way.Bob

author: montreuilg@sympatico.ca
author_rank: Newbie
timestamp: September 06, 2016, 05:44:07 am
content: Quote from: Alex Eisenhut on September 05, 2016, 10:21:16 pmOn the south shore of Montréal, QC._gabriel

author: montreuilg@sympatico.ca
author_rank: Newbie
timestamp: September 06, 2016, 05:56:08 am
content: Quote from: uncle_bob on September 05, 2016, 10:09:02 pmHi,It's true I only spent a few hours looking for exactly what you mention, i.e., a complete, functional unit. I will keep looking for it of course, but I haven't seen a 0-24v, 2-3a, variable volt. & curr. on dual output unit at such a low price. I would not be here wasting everybody's time_gabriel

author: uncle_bob
author_rank: Unknown
timestamp: September 06, 2016, 11:31:19 am
content: HiThe problem with searching for almost anything is that junk tends to hang around and the good stuff sells quickly. That is especially true of surplus test gear. A quick search will convince you that prices are high and you will act accordingly. You could *easily* spend three months or more watching for a deal on just about any sort of test gear. I tend to watch for it all the time and then make a "need" decision when I find something.A few things that I would *think* you would want on a bench supply:1) Adjustable output down to zero volts2) Adjustable current limit down to zero current3) Metering (at least for current)4) An enclosure to keep stuff from falling into it5) Switches and fuses to make it practical and safeAll of that is missing on the MAP80 devices. They *do* have the nice feature of multiple outputs. I would suggest that once you get past +/-12 and +5, the extra outputs are nice, but not essential.I would *assume* (a nasty word since I don't really have a clue) that you would have a list something like the one above. You at least need 4 and 5. The device is very dangerous without. You probably also will find that it's current limit is not very bench compatible. By the time you get it up to a reasonable level, you will be a lot closer to $100 than to $40 for the entire project.Bob

author: montreuilg@sympatico.ca
author_rank: Newbie
timestamp: September 06, 2016, 04:27:02 pm
content: Quote from: uncle_bob on September 06, 2016, 11:31:19 amAgreed, 98% of the time it will be on my desk, and used for mainly for learning about small electronics and micro-controllers. The remaining 2% will be useful around the house (lighting, car/bike mechanics).I am a just a software guy slowly coming back to the source, be patient I usually get it after 64 tries... I can be stubborn ;-)Thanks again,_gabrielps: did you mean any small unit like this one?http://www.ebay.com/itm/30V-5A-EU-220V-DC-Power-Supply-Adjustable-VariableDual-LED-Digital-Lab-Grade-CE/401149708932?_trksid=p2047675.c100623.m-1&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D38806%26meid%3D1d0d5347972249deb15f0695a5d43b6f%26pid%3D100623%26rk%3D5%26rkt%3D6%26sd%3D302046204778

author: nctnico
author_rank: Super Contributor
timestamp: September 06, 2016, 10:11:59 pm
content: Quote from: montreuilg@sympatico.ca on September 05, 2016, 05:17:47 pmThe MAP-80 is a DC switching power supply intended for fixed output voltages. You can't make it into a variable power supply unless you add regulators. Current limiting is also a nice-to-have on a power supply. The 30V/5A supply you linked to on Ebay is probably also a switching power supply but one which has been designed to be variable and have current limiting. I wouldn't be sure about built quality though especially when it comes to safety and leakage current.

author: montreuilg@sympatico.ca
author_rank: Newbie
timestamp: September 06, 2016, 10:25:44 pm
content: Quote from: nctnico on September 06, 2016, 10:11:59 pmThat is the reason why i am asking if it is crap or not. My prime intention is to buy a good fanless and stable psu, and add the features i want._gabriel

author: uncle_bob
author_rank: Unknown
timestamp: September 06, 2016, 10:31:41 pm
content: Quote from: montreuilg@sympatico.ca on September 06, 2016, 10:25:44 pmHiIn terms of a switcher for running a PC, it is fine. In terms of a bench supply, it's crap. You will have to add a set of external regulators to it to clean it up. While you are at it, you can put big heatsinks on them and get variable outputs. That's a lot of work.Bob

author: montreuilg@sympatico.ca
author_rank: Newbie
timestamp: September 07, 2016, 12:41:11 am
content: Quote from: uncle_bob on September 06, 2016, 10:31:41 pmNow sir, that was the kind of information/commitment i was looking for.Thanks again,_gabriel

author: bitseeker
author_rank: Super Contributor
timestamp: September 07, 2016, 02:10:38 am
content: Hi Gabriel,Welcome to the forum! Definitely keep on the look out for a real bench supply. It can take a while. I've watched eBay for as much as a year to get a particular piece of test gear at a good price. As Bob indicated, the good deals don't stick around, so you must be vigilant. A couple of times I've missed out by only a few minutes and the item had only been listed for a few hours before I saw it.Also, don't let analog meters deter you. Those old power supplies are still great to have and usually cost less than ones with digital displays (LED, VFD, LCD, etc.). Many of mine are analog. Unless you get a supply with external sensing, the onboard display will just be for letting you know that things are generally in the right ballpark anyway. Use a DMM for accurate measurements and measure at the device.Oh, and you may want to change your displayed user name to something other than an email address. Spam harvesting bots love collecting email addresses.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: September 07, 2016, 02:25:22 am
content: Quote from: montreuilg@sympatico.ca on September 06, 2016, 05:44:07 amMontreal here. Well, I have one of thesehttp://www.ebay.ca/itm/INTERNATIONAL-POWER-IHBAA-40W-5VDC-3AMPS-W-OVP-12VDC-1AMP-POWER-SUPPLY-UNIT-/311676391936?hash=item48915c5200:g:NqkAAOSwZjJU38Qnbut it has a fan. It's also not adjustable, more like trimmable.... I thought you were a kid I could donate the supply to, but you have a house with a car and a bike...