86% Efficient AC-DC ATX supply

**auto_robotics** · 10-06-2004, 10:40 PM

I've been trying to avoid the sine wave inverter + ATX supply route because of 1) inefficiency and 2) cost. I think I just found a good way around the efficiency problem ...

I just came across the Antec Phantom 350 ($155):
http://www.antec.com/us/productDetails.php?ProdID=24350
with 86% efficiency at full load.

Now combine that with the Samlex 600W sine wave inverter ($279) I was looking at:
http://www.samlexamerica.com/product...roductsID=7016
with 85% efficiency, and I get 73.1% overall!

Considering the Keypower 250W seems to be the only available 12V input higher wattage DC-DC supply and it's only 65% efficient, DC-AC-DC wins here.

Only issue is the $434 vs. $2XX something the Keypower costs.

I thought people would like to hear about this. Anybody with any better finds?

BTW, I need the higher wattage for some engineering experiments I'm planning on running, so please, no cries of OPUS!

**mushin** · 10-06-2004, 11:34 PM

OPUS! Opus solves EVERYTHING!
j/k

There's an interesting thread going on about skipping the DC-DC or DC-AC-DC altogether and using cheaply acquired deep cycle batteries instead. You'll still need to isolate your charging system, but it may be worth a look.

**hcker2000** · 10-06-2004, 11:43 PM

Yea if you got the cash to waste on that junk u were talking about just buy an opus.

**Ricky327** · 10-06-2004, 11:56 PM

And OPUS says :

High Efficiency power supply (extended battery life).

I wonder whats the exact figure...I hate it when they cant say the damn figure.

Can we say that if a PSU is 100% efficient and can run the PC for 120mins. Lets say OPUS is 85% efficient and a DC-AC-DC is only 75%. The OPUS can run the PC for 102mins and the DC-AC-DC can run for 90mins, now thats only 12mins more running power...wow big deal

Thats why I can never understand the DC-AC-DC efficiency bashing...or am I missing something here?

So anyone know the exact figure for the OPUS?

**auto_robotics** · 10-07-2004, 12:07 AM

Oh, I have no doubt that the venerable OPUS is still the way to go for <150W apps, but that's not me.

From OPUS's site:
http://www.opussolutions.com/modules...=article&sid=6
The supply is 90% efficient. So that kicks ***, but again, not for higher wattage apps.

My power supply is isolated out the wazoo. I just installed an auxiliary Optima D34/78 for the computer and a Hellroaring isolator and surge protector between the two batteries. Still need to power the computer though, so that's my current project.

Thanks for the replies. I would love to hear about any DC-DC supplies with >250W watts and high efficiency (70%+). I've found some, but those are always 24/48V input and to convert to that, you lose still more efficiency. At that rate my poor ol' Camry will be using most of its engine power to run the computer.

**mushin** · 10-07-2004, 12:08 AM

I recall my opus advertising 95% when I got it (last year). Not an exact figure, but it's ballpark. I always thought the extra efficiency was a nice bonus to lesson the strain on the alternater, never so that my batter will last longer... car batteries aren't designed for deep discharging, and I don't run the computer with the ignition off.

edit: duh, of course even if you have a nice isolated 12V power, you still need a unregulated DC PSU

Bad me! Though at that point, you just need to get 5V and 3.3V... Well, short of making your own, I havn't seen any DC-DC units greater than 250W. Good luck on you system, sounds like you've got quite a setup going there.

**Ricky327** · 10-07-2004, 12:14 AM

95% sounds alot better to compare with

But really I dont think DC-AC-DC solution is that really bad the way people described it.

Sure DC-DC is an ideal

**Ricky327** · 10-07-2004, 12:16 AM

Look for MrP's PSU design, not sure about the exact power output or efficiency but it does look promising if you need more power.

**Tony S** · 11-22-2004, 10:29 AM

Opus at 90% efficient? It's possible because of the low wattages, but with all the problems people are starting to have I doubt that figure. I'm beginning to think the Opus has been out long enough that we're now seeing it's useable life expectancy... or the techy term MTBF. I think that MTBF is getting shorter.

**MrPerfectionest** · 11-22-2004, 12:27 PM

Really at this point in the game there just isnt a very economical high powered solution because in general it doesn't make sense to need this kind of power in a car for every day purposes.

I am curious what you are experimenting with that you need such high power.

Secondly, is a build your own option out of the question?

I have designs (mentioned by Ricky327) that I am kicking around but generally if 250-300W is required then in small quantities it is still going to cost in closer to $100 just for the parts.