time to a dead car battery?

**chuckctv** · 08-20-2004, 10:21 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

**RogerWilco** · 08-20-2004, 10:25 PM

how bout dual alternators one to the seperate battery in trunk for battery, and 500 cca isnt xactly that much you could prolly find

better.
http://www.dcbattery.com/optima_yellow.html
http://www.dcbattery.com/optima_red.html
It'd prolly cost 360$ for a new 180 alt and a spare optima battery.
of course it depends on your vehicle

In your BIOS you can make HDs stop spinning after a certain amount of time, so they wont over heat if you use laptop 2.5s, you can put the computer into standby, and most monitors into powersaving mode.

**RogerWilco** · 08-20-2004, 10:47 PM

also, i dont really believe you'd want to go with dual alternator and batteries, unless your planning on high subs and amps also, unless you really have the spare cash.

**john1701** · 08-20-2004, 10:51 PM

I keep seeing specs that I can run my pc on my car battery for a long time.
Real time before I need a jump? just over 4 hours. Tested it myself watching Lord of the Rings 3. System just shutdown.
I have 800cca battery, running 350w inverter that runs my carputer.

**chuckctv** · 08-20-2004, 11:07 PM

power inverters (especially 350watts)actualy pull alot more power then your system is really pulling, so yes i can believe it killed you battery , but if you only got 4 hours then you need a new battery or need to check your alt unit. Because I run a laptop 9 hours a day for work in my truck on a 300 watt power inverter, and i have forgot about it once in the evening and went out their 5 hours later (bedtime) and the truck started just fine. but i also forgot it over night once and the next morning the truck was not dead, but it almost didnt start very sluggish. now at the same time i used to have a different laptop for work and it was just a 12volt cig-lighter plug (plug straight into laptop) , i left it on one night -all night (now mind you the screen was closed;assumed screen turned off

, and the next morning the truck started fine and the laptop was still on and going. I have a 900 ccamp autozone gold battery(1 year old). So I know theirs a way here. BTW their is no need for the second alternator. Just a diode off your main battery terminal to a second battery will charge the second battery with out and power pull coming from the first battery.

Chuck