OPUS 150 low battery shut down

**archimense** · 08-11-2004, 01:52 AM

I just wanted to clear something up about the OPUS 150 since I came home after a week of vacation to a dead battery.

The OPUS 150 will shutdown the computer if your battery drops to 11V for more than 10 seconds(according to manual). A known problem with the OPUS is that it still provides power to the motherboard even when the computer is shut off.

What this means is that even if your computer is shut off, or shuts down because of low battery, the motherboard will still continue to draw minimal power, and ALL USB devices will still be powered that are connected to the computer.

This is what happened to me, my 5 USB devices drained my car battery even though the computer was shut down.

Feel free to confirm or deny my observations.

**Avalerion** · 08-11-2004, 02:12 AM

As far as I know, Hibernate or Shut Down will not use any power. Standby will use minimal power, therefore draining the battery. I have not let my car sit for more than 12 hours, so I cannot confirm these ideas. I typically use Hibernate.

**matty_g** · 08-11-2004, 02:54 AM

Yeah it must still give power as my gps stays powered even when off, as it now looks like I have an extra alarm LED in the back window all the time!!!!

**DjBac** · 08-11-2004, 05:58 AM

Do you have your USB devices on a self-powered USB hub?

**matty_g** · 08-11-2004, 06:29 AM

No straight into the port on the machine!!

**STIdev** · 08-11-2004, 06:54 AM

The Opus provides standby power even when the CPU is in hibernate mode. Some motherboards have CMOS settings that allow you to turn this off. Mine does not. If you are going to leve your car for any length of time I suggest having a power switch to turn off the CPU completely.

**stimps** · 08-11-2004, 07:19 AM

put a latch in relay on the infeed power wire to the power supply, that latches on when the pc is on. When it shuts down, it will cut its own power, totally. Off will be OFF. no power drain.
connect the relay's power wire to the 12v yellow hdd wire for an easy source of "on" signal/power.

Hope that makes sense.

**archimense** · 08-11-2004, 01:53 PM

Originally Posted by stimps

put a latch in relay on the infeed power wire to the power supply, that latches on when the pc is on. When it shuts down, it will cut its own power, totally. Off will be OFF. no power drain.
connect the relay's power wire to the 12v yellow hdd wire for an easy source of "on" signal/power.

Hope that makes sense.

This thread gives a bunch of info on how to isolate power supplies, so when the computer and ACC are off the power supply is completely disconnected.

Looking for a creative solution: USB bus still powered after CPU is off

The main reason I started this thread was to dispel any ideas that the OPUS 150 disconnected all power to the PC when it was off.

**rando** · 08-11-2004, 02:05 PM

Correct. The Opus ALWAYS supplies current to the 5VSB rail anytime its hooked up to the power source.

**rando** · 08-11-2004, 02:06 PM

Originally Posted by stimps

put a latch in relay on the infeed power wire to the power supply, that latches on when the pc is on. When it shuts down, it will cut its own power, totally. Off will be OFF. no power drain.
connect the relay's power wire to the 12v yellow hdd wire for an easy source of "on" signal/power.

Hope that makes sense.

Based on experience, this causes the Opus startup to fail intermittently. Apparently it needs to see the +12v line go high before the ACC line. In any case, the link two posts up explains what I did to resolve the problem.