I'm Stranded! Dead battery

**justintime** · 09-29-2005, 01:33 PM

Ran the Carputer for about 1 hour, engine off, without realizing. (garage at home).

My battery is dead. I didn't think 1 hour of this would kill it. I will try to get it jumpstarted, we'll see. Any hopes?

**numbers** · 09-29-2005, 02:12 PM

Any hopes for what?

Don't just jump it and let the car charge it back up. Find a battery charger and do it the right way.

**justintime** · 09-29-2005, 02:16 PM

I waited 10 mins, and then it started. Doesn't appear to have problems anymore.

Wht the heck didn't the Opus shutdown the Carputer for me, assuming it detected low voltage. I thought it had a protection for that?!

**numbers** · 09-29-2005, 02:28 PM

I don't know much about the opus, but any voltage protection I've ever seen shuts down before deep discharging the battery, yet still not always in enough time to be able to start the car. When my inverter alarm goes off I must shut everything off and wait ten minutes before I can start the engine. If I let the inverter power itself off due to low voltage, I cannot start the engine back up at all. I would expect the opus to do a better job, but I wouldn't have a clue. No mass produced product will be able to work well in every car right out of the box. It takes a lot more juice to start some engines than it does to start others, and therefore the low voltage limit is much higher for some than for others. It would be most ideal to be able to set the voltage protection manually so that you can fine tune it to meet your car's needs. I don't know if you can with the opus or not.

**justintime** · 09-29-2005, 02:30 PM

Originally Posted by numbers

Any hopes for what?

Don't just jump it and let the car charge it back up. Find a battery charger and do it the right way.

I just re-read this comment of yours. Am I screwing up the battery by just starting the engine and letting it charge the battery up? I drove for ~ 20 minutes.

**greenman100** · 09-29-2005, 02:34 PM

Originally Posted by justintime

I just re-read this comment of yours. Am I screwing up the battery by just starting the engine and letting it charge the battery up? I drove for ~ 20 minutes.

no.

**numbers** · 09-29-2005, 02:41 PM

Originally Posted by justintime

I just re-read this comment of yours. Am I screwing up the battery by just starting the engine and letting it charge the battery up? I drove for ~ 20 minutes.

Not exactly, but YES YOU ARE SCREWING UP THE ALTERNATOR. The battery doesn't really like to be charged so rapidly from such a discharged state, but it's the alternator that really hates it. I wouldn't worry about doing it just once, but if you let your alternator charge a dead battery several times, you are really asking for trouble. It puts a very big strain on it, and it will fail if you do it too much.

**greenman100** · 09-29-2005, 03:12 PM

Originally Posted by numbers

Not exactly, but YES YOU ARE SCREWING UP THE ALTERNATOR. The battery doesn't really like to be charged so rapidly from such a discharged state, but it's the alternator that really hates it. I wouldn't worry about doing it just once, but if you let your alternator charge a dead battery several times, you are really asking for trouble. It puts a very big strain on it, and it will fail if you do it too much.

My alternator is rated for 135 amps. I have a fusible link rated for the same. If iI'm overlaoding the alternator, why isn't the fuse blowing?

If you're putting 135 amps into a car battery, it's boiling away the electrolyte very fast.

**dmurray14** · 09-29-2005, 03:43 PM

Wow, your battery must be weak. I've had my computer running outside for over 3 hours while I did stuff on it inside through VNC, and the car started right up...

**numbers** · 09-29-2005, 06:12 PM

Originally Posted by greenman100

My alternator is rated for 135 amps. I have a fusible link rated for the same. If iI'm overlaoding the alternator, why isn't the fuse blowing?

If you're putting 135 amps into a car battery, it's boiling away the electrolyte very fast.

Sounds like you are having some trouble with doubt, eh? I didn't write the book; I just try to make sure everyone knows what it says. 135 is pretty hefty. I don't know for sure whether you'd have to worry about it or not. Still, I don't recommend that you test your luck unless your doubt is very serious. If your doubt is only mild, google will cure it. ;-)