how long will the carputer run on the car's battery?

**blackcar** · 07-24-2006, 03:15 AM

Just curious
how long will the carputer run on the car's battery??
I was thinking of add a security feature, but it will require the carputer to be on full time, not just sleep mode?

I'm guessing 12-24 hrs???

**psyrex** · 07-24-2006, 03:17 AM

Depends on:
1) How much power your computer draws.
2) How much power your battery supplies.

Provide those two numbers and you just answered your own question.

**blackcar** · 07-24-2006, 03:29 AM

using a laptop
power supply output is 16V 4.5amps

battery is 660cold cranking

**ODYSSEY** · 07-24-2006, 03:31 AM

Well I suggest not trying to find out, unless you have a deep cycle battery.

**2k1Toaster** · 07-24-2006, 05:21 AM

Get a second Deep Cycle battery and run it that way. Have the battery act like the wall plug in XP, so when the battery goes bye bye, then the laptop's battery kicks in for another 4hours kind of thing. When laptop battery is below 2%, then shutoff. You'll get a bit from that. I assume this is overnight security, so that should be sufficient.

But if this is a camera thing, then more power. If you want wifi to upload it to your homepc so if they do steral your car, they don't take your proof too, more power. You get the idea.

**GuessWhosBack** · 07-24-2006, 05:41 AM

is this to have a camera in your car, recording the goings on in, and out of the vehicle?

thats what I intend on doing, plus the alarm, so the alarm will scare them away, but not till they've already been recorded

**sama** · 07-24-2006, 05:49 AM

if you don't want to get a second deep cycle battery, split charger, etc, you can get an M2-ATX which will provide you with ample 12v power (10A I think) and will also monitor the battery level to shut down if it goes under 11.2v (or some figure close to that). you also get 3.3v and 5v should you need it for anything else.

of course a second batter is the most effective solution to your problem since it provides you redundancy/isolation for starting your engine, and gives you longer times of supply. It may be a little more costly however and may require a little more work to do.

**shizzzon** · 07-24-2006, 11:36 PM

for computers, power draw is low.

the voltage u say is 16v with a max output of 4.5A. That means at full tilt, you would be seeing a draw of 72w or on 12v battery equaling 6A.

If considering getting a 2nd battery, do what is suggested, get a deep cycle, they are made to discharge for very long periods of time and be discharged FAR lower than a standard lead acid can.
I would suggest getting an Isolator or Solenoid relay so the battery's charge does not share itself with the stock battery, the life expectancy will be lower if that happens.

Next- to find a good battery, look at reserve time specs on batteries. These are low current discharges labeled by minutes before battery dies. However, most Reserve specs are done at 25A which is way higher than what u need.

I would suggest to go here- http://www.lifelinebatteries.com/marinebatteries.php

There batteries are very nice and if ordered direct through them, you should get em cheaper than buying from any of their retailers.

Their GPL-4DL is considered a Group 4 battery able to do 8A of constant output at 1375 min straight. That's roughly 1 full day as 1440 min equals one day.

Group 4 batteries are roughly around $300 through this company i believe but there is one option for a battery and how to find which battery to get.

**vxcarpc** · 07-25-2006, 12:25 AM

I killed a Champion Heavy duty battery perminantly with my carpc by leaving it on by accident overnight. Killed the battery hard.. Wouldn't hold charge the next day and this was a brand new battery about 3 weeks old.

I've been searching for a voltage cutoff ciruit or maybe some software for windows that will detect the voltage that the power supply is drawing and if it falls below a certain voltage from the battery it will cut off the computer or shut it down in a timely mannor instead of just cutting voltage to the pc all together.

**Henk Bos** · 07-25-2006, 03:31 AM

Also have a look at Optima batteries. I have a red top as main and a deep charge yellow top for all the goodies. Will test later this week how long my car pc will last.