Ignition Voltage Gap kills everything

tempgp · 01-11-2008, 03:45 PM

Hey all
I'm having problem with ignition voltage gap. If my comp is on and then i'm starting the car (voltage drops to 9v) everything gets frozen and i have to reboot. Does any one know the easy way round this problem?

Thanks!

MatrixPC · 01-11-2008, 06:37 PM

A beefier capacity battery will help, but not much if the PSU isn't capable of handling low voltage for a short time.

pokki · 01-11-2008, 06:38 PM

Quote:

Does any one know the easy way round this problem?

Don't turn you pc on until after your car is started.

As for actual solution to the problem - any of the following should work if executed corrently:
- Look for a powersupply that works under cranking
- Secondary battery
- A huge *** capaciator (likely not an econmonical solution)

However before doing any of the above - I'd check your wiring. To small a wire and/or poor grounds creates voltage drop. Combine that with voltage drop while cranking and you are likely to go below your powersupplies minimum voltage limit.

tempgp · 01-12-2008, 02:36 AM

well so far i tried Diode + 12,000 mili Farads Capacitor... I cant really change PSU, since its not changable in my Monitor and All IN one embeded board.

I'm thinking about UPS, but the once on the market got some potential problem

So i might end up building my own custom UPS to meet my requirements BUT i dont want build custom things any more, unlesss some omne else would wanna use it besides me (cost repreciation)

I'f i dont find good comercially avalible UPS (so fart found one but as i mentioned dont like it) I'm thinkingh about mini controller that can be programeed any way you want + the ona that would have at least 24hours battery + 30min Startup Batteru ... um 25AH maybe? um no 40AH (damn thats like 6 Batery blocks, too much space) any way something like that, i'm just starting my recerch... thats why I asked on forum to make sure that there is no something similar offrered...

PS: Sorry for my spelling, just came out of the party

DarquePervert · 01-12-2008, 09:24 AM

One option not mentioned: A tank circuit.

It might be easier to offer up solutions if we knew what your system was comprised of...

tempgp · 01-12-2008, 12:08 PM

A tank circuit - what is that, I never heard of it?

Ssytem:
8" Monitor OEM ~1.3A
Comp = 15W @12V
Cameras = 1.5A
GPRS = 0.3A
Wi-Fi = 0.8 A

And who knows what else can I add in the future. Oh I forgot Radio + USB hubs, I dont know their power usage

DarquePervert · 01-13-2008, 07:34 AM

Quote: Originally Posted by tempgp

A tank circuit - what is that, I never heard of it?

Time to make use of the infamous search function.
I'm also certain there's a writeup on them in the FAQ Emporium.

I've never needed to use or make one, so I'm certainly not the expert.

greatwhite · 01-13-2008, 08:06 AM

I think darque was refering to how your system is powered and what the components are (ie; dsatx, opus, etc)

Are you using an inverter or a dc-dc power solution?

Most dc-dc's survive crank if your battery is healthy.

Inverters are a "hit and miss" proposition with cranking...................

tempgp · 01-13-2008, 11:18 AM

ok will google "tank circuit"
as to what power supply im using,, well all powersuplies are build in and technically designed for cars 12v (which seams not be a true statement) I can try to use DC-DC poresupply to tweak it and put in the middle beween my equipment aand car bus.... will that work?

greatwhite · 01-13-2008, 11:41 AM

Quote: Originally Posted by tempgp

ok will google "tank circuit"
as to what power supply im using,, well all powersuplies are build in and technically designed for cars 12v (which seams not be a true statement) I can try to use DC-DC poresupply to tweak it and put in the middle beween my equipment aand car bus.... will that work?

You don't need to google, use the seach feature in the blue bar at the top of this page.

As to the rest, I don't know where to start with that..........................

Methinks you need to do a bit more research.

Good luck with your project.

tempgp · 01-13-2008, 12:23 PM

well i guess will se what i can find

h3rk · 01-13-2008, 04:22 PM

I'm not sure, but it seems like, since your embedded computer has it's own internal power supply, you've just hooked it to the vehicle's positive. Perhaps a 12V DC-DC regulator from carnetix would be the best/easiest fix.

Ok, enough with the suspense: What computer are you using?

DroStar · 01-13-2008, 05:29 PM

Where are you measuring the 9V from? 9V seems low for cranking voltage. Measure voltage at the battery while cranking. If that is above 10V (which it should be if your car is starting without problem) then you need better wiring and grounding to your CarPC. You could do a quick test by temporarily wiring up your CarPC power supply directly to the battery, both power and ground (do not ground to chassis), and if it helps.