laptop standby -> hibernate on battery doesn't work

dazman2 · 10-05-2008, 06:16 AM

I'm preparing a toshiba satellite P20 for a carputer however I have an annoying power management issue.

I set my computer to standby after 1 minute and hibernate after 3 minutes when running on battery. The computer goes into standby fine, but the problem is it never hibernates. If I set it to just go straight into hibernation it works fine. If I use the standby then hibernate settings when running on AC power, the computer successfully wakes from standby and then hibernates. The battery on the laptop is a bit cactus (I'm guessing it holds a charge for at least 5 mins though) Its the only thing that I can think of that might be causing the problem. Should I replace my battery? Has anybody else experienced a similar problem? What gets me is I'm sure that the battery has enough juice to do what I'm asking. Its not in great shape, but it has enough. Its almost like XP is confused that there's not enough power to wake from standby and hibernate.

FusionFanatic · 10-05-2008, 11:31 AM

why are you telling it to go into standby for 2 minutes? just set it to go directly into hibernation.

dazman2 · 10-05-2008, 07:24 PM

The times are just for testing. I want the computer to be in standby mode for a certain period of time after I switch my ignition off.. why, because it resumes almost instanly, as opposed to several seconds resuming from hibernate. This will cover the scenario where I'm in and out of my car frequently. Hibernation will be for when the car sits for a longer period.

FusionFanatic · 10-05-2008, 08:01 PM

ok, that's understandable...

I suspect you are right about the battery being too weak to hold a charge long enough to remain in standby. however, XP isn't getting "confused", the computer will automatically shutdown once the battery reaches a certain level. you can disable this in the power management control panel, but then the computer will remain on until the battery is completely dead, resulting in a sudden loss of power (which can cause serious data corruption issues). you could buy a new battery, but considering the high price of replacement batteries, it may not be your best option.

what will you be using to power/control your laptop? if you buy a nice DC-DC regulator like one of the Carnetix units then you won't even need a battery in the laptop at all, plus it has a built-in startup/shutdown controller so you don't have to mess with unreliable windows power settings. the regulators are expensive (about $100) but it's not much more than you would pay for a new laptop battery.

as for the in-and-out frequently scenario, I think a better option is to use an override switch to keep the PC running while you're in a store, etc. no need to have the PC go into standby only to boot up again a few minutes later. you simply wire a switch to the power supply to interrupt or override the automatic ignition switch control.

dazman2 · 10-05-2008, 08:42 PM

My plan is to just to use the laptop DC power adaptor which I already have and wire it so that its powered when the ignition comes on. I'd then rely on Windows power management/shutcontrol for shutdown. For startup, I've already rigged an external momentary switch.. I'll probaly extend this at some point at some point with something like W3BMA5T3R's laptop auto power on module. I chose this setup for a) cost and b) it avoids drain on the car battery. Something like carnetix may be the way to go though...

As for the laptop battery, it still amazes me that it can survive in standby for almost 24 hrs, yet not move from standby to hibernate after a few minutes. Anyway, I think I have a few options.. I might forget about standby altogether and leaveit powered on (running on battery) when I'm in and out of the car frequently and set it to just hibernate after a certain period.

FusionFanatic · 10-05-2008, 09:43 PM

I used a laptop auto adapter to power my old carPC system (Dell Inspiron 8000). it got extremely hot; so hot it would burn your hand. I ended up removing it from it's plastic case and mounted it in an old ATX PSU case (with exhaust fan to keep it cool). inside the PSU case I added a relay to cut power to cut power when the car was off. I used the REM wire from my amp to trigger the relay. I wired a simple pushbutton switch in the dashboard to startup/shutdown the PC. it worked fine, and I used it like that for months, but I can tell you from personal experience that pressing a button to start it up gets pretty old. I eventually stopped turning it on most days and just used my regular head unit without the PC.

when I decided that I wanted to move up to a "full carputer" setup (where the computer handles all audio/video, -no head unit), I wanted a more powerful and less space-consuming computer than my prehistoric laptop

if I had kept the laptop then I would have definitely went with a Carnetix power supply. if you don't want to upgrade to a carnetix unit then you could always add the uSDC standalone startup/shutdown controller

It comes down to what you want out of your carputer. if you're just using it as a cool novelty then your setup will be fine. but if you want the carputer to take over all head unit functions then you're gonna want reliable automatic startup/shutdown control.

whatever you decide to do; good luck with your carPC project.

dazman2 · 10-05-2008, 11:16 PM

Thanks FusionFanatic. I'll keep an eye on the heat of the power adaptor. Its my first project, so I'm learning as I go in many ways. My goal is for a reliable system, not something half baked. Perhaps using a laptop in itself is half baked.. but I'll give it a try

The machine has decent specs and the LCD is dead, so it seems to be begging to be used. My plans are pretty similar to your v1.0 project, except I'll be buying a bezel rather than making my own. The HU will be retained for amplification and access to steering wheel controls, but will be hidden it in the glove box.

Anyway, I'm sure that as many before me have found out, once I try things out, my plans my change

Thanks a lot for the advice.

NSFW · 10-06-2008, 05:12 AM

I built my system around a laptop and I'm very happy with it. I have zero regrets - except maybe regretting that I didn't replace my battery sooner.

It wasn't as dead as yours but it wasn't a holding much charge either. I see lots of upside to building around a laptop, and no downside. There is nothing half-baked about it. Perhaps I would feel differently if I wanted to upgrade the video card, but I'm perfectly happy as-is.

I'm using an inverter for power right now and it is working fine. It gets warm but not hot, so I have no worries. However I bought a 12v power supply from epowersupply.us (they make them for many brands/models, have a look) and I will switch to that next weekend if time allows.

Mine is configured to sleep for half an hour, then hibernate. It works like it should.

dazman2 · 10-06-2008, 08:05 AM

Good to hear... I'm pretty sure its going to work ok. I can see upsides to using a laptop too.

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