Epia M10000 + PW70a + car startup

**SuperSonic** · 11-26-2003, 05:16 PM

Hi,

I've been reading this forum for some days now and I'm not entirely sure about some things.

Here's what I have now :
-Epia M10000
-Laptop HD 80Gb
-PW70a
-home built shutdown controller (from design off yahoo groups dashpc - detects acc line going up OR down and thus sends ATX pulse, no more no less)
-Xenarc clone TFT 7inch screen (powered seperately, not on the PW70)

When I hook everything up, I get the known sympthons:
-My 12V line is not regulated (but that's no problem : no 12V devices)
-My PC reboots while starting the car (it is a diesel engine BTW, only restarts when starting, not when pre-heating, car is 2 years old so battery is fine, cranking takes about 2 sec max.)
-Pc runs fine with engine running/not running (but again reboots while starting)

I'm dying to use the standby function of the Eipa, gets up and running in 2 sec, so I put the PC in standby automatically when turning the car off. When I start the engine again however, the PW70a goes safety and resets the PC thus ruining the chance to resume the OS that was in suspend-to-RAM mode.

I've seen the posts about the tank circuits. I'd gladly make one but I'm in doubt about what the correct solution to my problem is. The thing I'd go for is the diode and capacitor circuit (MBR3045/MBR6045 + 22000uF-25V Cap) since it won't be a hassle to buid. I'm not very keen on an extra (small) battery solution, nor about x Farad caps (too big) unless I have no other choice. The winning question off course is : will that solve my problem? I know too little of electronics to assure myself about the good solution. Help?

My car seems to drop to about 10V minimum while cranking (but that's just a simple multimeter value ).

When I would add the tank circuit, would that be responsible for battery drain on itself, next to the PC taking a standby voltage to keep the RAM under power?

Considering that the car is pretty new, I drive it pretty much every day, can I solve this myself? Or do I really have to forget about it all and get an Opus? I just would like to make it work as I have it now.

Thanks for helping out !

**SuperSonic** · 11-26-2003, 06:13 PM

Ok so I looked trough the board again (but non specificaly on tank circuits), and I bumped onto this :

12-24V adjustable 5A regulator

This seems to be able to solve my problem am I correct?

If it is I guess I'd have to go fetch one of those things at a local electronics shop they should be able to get something like that easily no? Does someone know of a manufacturer of those types of devices in Europe?

However same question will this drain any battery while in standby mode on carpc?

**telekineticfool** · 11-26-2003, 06:24 PM

I use hibernate for mine...slightly longer boot times, but I believe it shuts more stuff down and doesn't have as much power draw...I'm gonna check, but I think standby continues to draw 5V to keep the ram active.

Edit: Good article about power states: http://informationweek.com/story/IWK20020927S0028
Windows Standby, depending on the OS version, is an S3 state...meaning it still needs a trickle current to keep the ram active. So in theory, given enough time, you could empty your battery...however, Opus would shut power off completely before that happened. Hibernate is S4...which means the computer is completely shut down, but copied the RAM to memory first. I've got 512 megs of ram, and it only takes me less than 15 seconds from boot to play.

**DodgeCummins** · 11-26-2003, 08:01 PM

Hibernate saves it all to disk, and completely removes power. Standby saves to ram, so if power is interrupted...you are done.

Use Hibernate.

**Ricky327** · 11-26-2003, 09:01 PM

Forget the capacitor, even a 1F can only hold your PC on for less than half a second. If you want to crank for 4 seconds you need something like 10F.

I dont know where this capacitor tank circuit came from...it obviously cannot work for PC.

**PTCruiser** · 11-27-2003, 05:32 AM

Suspend to ram is maintened only by 5V stby...

You can use a linear regulator to feed the 5Vstby on your mainboard.

I have also a mpdh-810 DC-DC 120W.
My PC reboots while starting the car...

But if it was on Suspend to Ram, I crnak the car then I start my pc => 2 second boot! (The 5Vstby is alway here even when starting the car)

note you epia neeed 12V (rs232 ctrl...)

**SuperSonic** · 11-27-2003, 03:21 PM

I had the same idea about the capacitor didn't think it would work. What I need is a regulated and undervoltage-safe 12V supply to the PW70.

Just like the one posted above ...

Anyone know how they are designed or where I can find scematics of it maybe?
I know sproggy supplies used to work this way, so it can't be too hard to figure out a schematic for this?
Damn I wish I knew more about electronics then basics and soldering