Thread: OPUS 150w keeps killing my battery. Need help!

Originally Posted by EuroFan

Hey,

I have a custom pc in the trunk of my vw passat. I have the OPUS 150w PS correctly connected between the PS and the Mobo. I have the RED wire (12v battery) powered from the factory radio's harness which in VWs, gives power even with the key off, so I use the radio spot in factory fuse box as a computer fuse now. Then I have the YELLOW wire (trigger) running to a switch, which gets its power from being tapped off a cigarette lighter. The BLACK (ground) wire taps into the cigarette lighter ground.

Anyway, when I flip my switch to turn off the feed to the yellow wire, the computer shuts down as expected "Windows is shutting down" follows by the mobo turning off and the OPUS status light blinking once every 3 seconds.

Here's the problem. When I don't drive my car for a couple of days, it won't start! I would boost it with a power pack I have in the trunk, drive around for a long while, then when I would turn it off the car still wouldn't start the next time. In order to diagnose the origin of the problem, I unplugged the OPUS compeltely from the car and every since the I've had ZERO problems starting the car.

Does anyone know how I can cure this problem? The whole point of buying the Opus was to be able to have windows shut down normally when I turned off the acc. switch. I also thought the Opus was supposed to protect your battery from dying. I thoguht about just wiring both the yellow and red wires up to my switch, but that would defeat the purpose of having the opus in the first place because as soon as I'd turn the switch to the off position, the computer would abruptly shut down, which is something I obviously don't want.

Thanks for any help you can offer!!!

Eric

YOu should have the red wire going to the possitive terminal on the battery, the black going to the neg. the yellow should go to anything that has a 12v during cranking and as well as running.

The way you've got it set up should work.

If the opus is faulty then it may just require replacing. If you are draining the battery and nothing is switched on then you could have a short circuit, this problem could lead to your car not only being drained of battery, but also being surrounded by firemen next time you return.

I;d get a multimeter and see if there is any voltage going through areas that you didn't expect it to be.

First off,

I would suggest you power your opus (red wire) off your cig-lighter plug. That is also constant on and your HU power wire is rated for 10A draw, your opus will want 15A at times. (blown fuse). And the yellow can connect to the red wire off the hu harness which is the ignition on wire. Ground just go crazy.

And then I would measure the current draw at both wires.

Originally Posted by samc

First off,

I would suggest you power your opus (red wire) off your cig-lighter plug. That is also constant on and your HU power wire is rated for 10A draw, your opus will want 15A at times. (blown fuse). And the yellow can connect to the red wire off the hu harness which is the ignition on wire. Ground just go crazy.

And then I would measure the current draw at both wires.

Why would someone NOT follow the OPUS instruction and hooked it right the the battery?

i would not recommend connecting the Ground cable directly to the battery ..

Do you have a lot of USB devices? I'm pretty sure that the 150W opus doesn't cut power to the USB stuff when it's shut down, that could be draining your battery.

Originally Posted by Mogwai

i would not recommend connecting the Ground cable directly to the battery ..

HELLO...YOU ARE SUPPOSED TOO!

Originally Posted by bosstone74

HELLO...YOU ARE SUPPOSED TOO!

Mine isn't.

To be compliant with the ATX specification, the Opus 150W ALWAYS powers the +5VSB rail. Depending on your specific motherboard and peripherals, you may be consuming upwards of 5W here -- more than enough to drain your battery in just a few days. You can override this behavior with a relay and a few diodes. Search the forums.

Also, though unrelated to your power drain issue, you should consider a more appropriate power and grounding strategy for your Opus. It is unlikely that your cigarette lighter power circuit can provide adequate power and ground. As specified by Opus, you should run a dedicated 12G or larger circuit (fused) from the battery. You should use a 12G or larger ground wire running back to the battery ground or to the nearest GOOD ground point (bare metal with a bolt). Your turn-on circuit sounds fine.

Good luck.