time to a dead car battery?

**chuckctv** · 08-20-2004, 10:57 PM

How many users have experimented with the time a car battery will power the carpc (understanding equipment differences) untill it wont start a car. I have not yet... ( ineed a spare battery first, i work nearly everyday and nee my truck). But anyway lets see a running laptop pulls roughly 2 amps and has a 3-5 amp battery installed, thusly giving us 1.5 - 2.5 hours of continus usage(remembering that 2.5 hrs of continus usage is a new battery only). But it stands to reason that a 500amp car battery (or batter a 200amp lawnmower battery) would last 2 days of continus use, assuming the screen stays on constantly{which it wouldnt}. So technically if you add a diode between your vehicle battery and you second (lawnmower small) battery you would charge it but your carpc would not pull from the main car battery, and if you use your car/truck at least once a day if just to start it for 10mins. .you should never need to shut down at all under any condition, although the screen will kill the battery in a few hours, so i recommend turning it off. and if you use items like CF Harddrives and maybe even laptop size harddrives (minimum power devices) may get 2 days of power until you restart your vehicle).

I have done no experimenting as of yet, still in the planning/biulding stages myself, if anyone has tryed or has any new/other knowledge on the matter then please post. I have much more ideas for my carpc like autoalarm system, and other things, so I need a way to keep running 24/7.... I use my truck everyday any way its off at its longest time maybe 12 hours (afterwork/sleep). I did consider an idea of battery monitoring and conecting to a autostart alarm relay box, for charging the battery purpose as a last resort.

fewwwww!!!!

Chuck

**stevieg** · 08-21-2004, 05:21 PM

I regulary use my Opus-connected car PC for 2-3 hours at a time using WLAN in the house with the car switched off, without any problems

**god_of_cpu** · 08-21-2004, 05:30 PM

You don't need to experiment with this at all, the battery will tell you exactly how long it will last under load, just look at the amp hour rating of and calculate the time based on how many amps your computer draws.

http://www.1st-optima-batteries.com/amp_hours.asp

**stevieg** · 08-21-2004, 05:31 PM

Originally Posted by god_of_cpu

You don't need to experiment with this at all, the battery will tell you exactly how long it will last under load, just look at the amp hour rating of and calculate the time based on how many amps your computer draws.

http://www.1st-optima-batteries.com/amp_hours.asp

Woudl it not depend on the condition of the battery too?

**MikeXP** · 08-22-2004, 07:44 AM

stevieg, how many watts is your opus?

**Gibson99** · 08-24-2004, 02:13 PM

my old camryamp would go up to 4 hrs on an approx 700cca diehard battery.... and that was with the 300w sub and entire stereo going, plus whatever else gets turned on in the car when the key is in ACC position. i used to leave the stereo on all the time while i was working on the car.

oh and did i mention camryamp used an inverter and 145w desktop at p/s, and 100% desktop components?

check the link in my sig.

**stevieg** · 08-24-2004, 03:15 PM

Originally Posted by MikeXP

stevieg, how many watts is your opus?

150W

**cheerio** · 08-24-2004, 03:31 PM

It depends on YOUR battery, the temperature and the AMP load. Optima YELLOW TOP deep cycle battery D34 has 120 minutes reserve capacity @ 20 AMPS in 80degrees F and the D31A has 155 minutes at the same characteristics. These are at full charge of course.

And i wanted to do a 2 battery setup too, but a your altinator has to be able to handle the AMP load to charge both batterys whiel your componets are being used as well. Soemone in this forum told me to search for tank cirutcts to do what your talking about(the dioad). BUT i was also read that you will loose 1 volt?? Now that i dunno if its true, just stating what i was told.

**stevieg** · 08-24-2004, 03:47 PM

Originally Posted by cheerio

It depends on YOUR battery, the temperature and the AMP load. Optima YELLOW TOP deep cycle battery D34 has 120 minutes reserve capacity @ 20 AMPS in 80degrees F and the D31A has 155 minutes at the same characteristics. These are at full charge of course.

And i wanted to do a 2 battery setup too, but a your altinator has to be able to handle the AMP load to charge both batterys whiel your componets are being used as well. Soemone in this forum told me to search for tank cirutcts to do what your talking about(the dioad). BUT i was also read that you will loose 1 volt?? Now that i dunno if its true, just stating what i was told.

Agreed. My old car had a crap battery and didn't last very long at all. I've recently got a brand new car and the new battery with it allows a much longer time.