High Current 12V | 13.8V DC Power Supply - Page 1
Forum section: electronics / projects

author: requim
author_rank: Regular Contributor
timestamp: October 31, 2011, 07:54:56 am
content: I'm thinking that I want to try building a high current 12V or 13.8V DC power supply (100+ amps) so I can power car stereo equipment with it. I've looked around a little bit and found a couple of schematics, but haven't really found anything that I like. Any suggestions?

author: Simon
author_rank: Unknown
timestamp: October 31, 2011, 07:57:43 am
content: that is a lot of current, You be best buying an off the shelf SMPS maybe a few beefy computer PSU's ?

author: requim
author_rank: Regular Contributor
timestamp: October 31, 2011, 08:50:04 am
content: It is alot of current, and the idea did cross my mind. Here are a couple of the links/schematics I saw for building one:http://sound.westhost.com/project77.htmhttp://www.aaroncake.net/circuits/supply2.aspThe other thing I'd like is to find a nice professional looking case (19" rackmount?) and mount an LCD or something to display current, voltage, etc.

author: requim
author_rank: Regular Contributor
timestamp: October 31, 2011, 09:02:47 am
content: Here's a silly question. I could buy a couple of old server hot swappable power supplies since those are very reliable and quite inexpensive and very compact. Would I be able to put them in series (or is it parallel?) to get up to 2400 watts ( 200 amps)?

author: Unknown
author_rank: Unknown
timestamp: October 31, 2011, 11:34:15 am
content: Does the stereo equipment actually draw 200A or are these marketing amps (ILS power)?

author: Psi
author_rank: Super Contributor
timestamp: October 31, 2011, 12:32:39 pm
content: yeah, i think you'll find the average current is probably more like 10-20A.In which case a 10-20A power supply float charging a battery or large capacitor would probably work fine.

author: hacklordsniper
author_rank: Frequent Contributor
timestamp: October 31, 2011, 12:35:56 pm
content: Quote from: alm on October 31, 2011, 11:34:15 amI also consider author is mixing power draw and PMPO

author: Simon
author_rank: Unknown
timestamp: October 31, 2011, 12:48:24 pm
content: yes I was about to start work when I posted and was wondering the same thing, 1+ KW of audio power is not something you would actually want unless your trying to blow your house down. A few watts of power can be heard all over a house, what are you doing with it ?200A out of a car will kill most car systems it would drain the battery fast and be 3X the typical max alternator output

author: requim
author_rank: Regular Contributor
timestamp: October 31, 2011, 01:57:14 pm
content: At the moment the only thing I plan on hooking up to it is an amp that uses two 30 amp fuses on it. When I purchased the amplifier years ago I had intended to purchase one or two more which would have easily put me over 100 amps I only want to hook it up to test it outside of the car. If you would like to see the owners manual for the specific amp I am talking about here it is:http://vault.alpine-usa.com/products/documents/PDX-4.150.PDFHowever I was only using the car stereo equipment as an example. I may also like to use it to connect DC powered computers at a later point in time. Google does this inside their many data centers and I think it would be nice to have a high amperage dc power source that I can use for multiple devices if I want.Is it possible to take two server hot swappable supplies and use them for a combined 2400 watt supply (200 amp)? An easy way to do this would be to just take the power supply hotswap cage along with the two power supplies and then use the external leads on the cage to run the necessary jacks and circuitry.

author: hacklordsniper
author_rank: Frequent Contributor
timestamp: October 31, 2011, 03:54:54 pm
content: Why would you paralell server power supplies, you could use every one for itself powering a part of the equipment. Paralleling can be done but not so simple.

author: Simon
author_rank: Unknown
timestamp: October 31, 2011, 05:27:55 pm
content: if you have more than one amp then power them seperately, it will work out easier and cheaper in the long run. You can parallel psu's but need to make sure they support it first

author: sonicj
author_rank: Frequent Contributor
timestamp: October 31, 2011, 09:07:56 pm
content: when i worked in car audio we used large Astron power supplies in parallel for our demo room. i think they were 50A x 2 or 3. also had a battery on float as a buffer which helped a bunch.-sj

author: NiHaoMike
author_rank: Super Contributor
timestamp: October 31, 2011, 10:36:33 pm
content: Quote from: Simon on October 31, 2011, 12:48:24 pm1kW peak might be overkill for music (at home at least) but would add a lot of realism to movies. 1kW RMS for more than a few seconds would be insane.There's actually a DSP trick of starting bass notes really high power for a few cycles and then dropping off in a controlled manner to give the illusion of more powerful bass with less average power usage.

author: Achilles
author_rank: Regular Contributor
timestamp: October 31, 2011, 10:54:02 pm
content: As far as I have seen that, above 50A it gets quite expensive. We had a winch for a Balloon which was operated at a 12V car winch that consumed up to 150A (with very low load on it). We bought an 380V winch because that solution has been much less expensive........So if you really want to blast your brain out of your head it may get expensive (transformer, capacitors).......well, but I think there are People around here with more experience in high energy circuits....if you really put together that beast I wanna see (hear) it

author: Chet T16
author_rank: Frequent Contributor
timestamp: October 31, 2011, 11:19:23 pm
content: One of the brothers used to have a sound system in his car that would hit over 150dB...I'd love to know how much power that was taking. It had 12 amplifiers, 2 big batteries and some big caps.

author: requim
author_rank: Regular Contributor
timestamp: November 01, 2011, 04:30:35 am
content: Subwoofers generally can suck up a lot of amperage. For the rest of the speakers you can get by relatively lightly. Just depends on how many channels you want. Dual subs gets even crazier. You can easily throw 500 - 1000 watts RMS a piece to a pair of subs. In fact good THX home theatre subs will do about that. So using up the amperage isn't that difficult.But as I said, my main objective isn't to build a wicked car stereo sound system but to have a large 12 - 13.8 or 14.4 volt DC power supply so I can power computers and other gear off of. If I went with a redundant system, then I have uptime as a benefit and if I go with more power then I can power more equipment.Is the general concensus that I should just follow one of the two designs I posted earlier or does anyone have suggestions or ideas? I'm just looking for a project to work on once i finish fixing the various devices I have laying around here.

author: hacklordsniper
author_rank: Frequent Contributor
timestamp: November 01, 2011, 05:11:59 am
content: Do you necessarily want to build one or would you buy too?

author: requim
author_rank: Regular Contributor
timestamp: November 01, 2011, 08:03:13 am
content: I suppose it depends on the price as well as what I think my chances of success are if I build it myself. I would definitely need help with the design, since I'm just learning this stuff. I've got most of the basic gear and am watching the MIT opencourseware for the 6.002 class. It's probably a bit too ambitious for a first project, but at the moment I'm just working on trying to repair broken electronics gear.I saw the reference in an earlier post about batteries and it got me thinking perhaps I could repurpose one of my APC 3000VA rackmount UPS units for the job. Not sure how feasible it would be, but it would give me plenty of existing parts/material to work with. The only thing I'd need to do to it cosmetically is create a new bezel.

author: Unknown
author_rank: Unknown
timestamp: November 01, 2011, 11:54:41 am
content: I think DIY is unlikely to be cheaper in this case since you're likely to need a fair amount of expensive parts like switching transistors and transformers. It's also something that's likely to destroy a fair amount of parts during testing, especially if you're doing it for the first time.Note that a 3000VA UPS is not usually rated for 3000VA continuously, it's only expected to run until the battery runs down, and then recharge at a much slower rate.