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Discussion Starter #1
If the light under my hood measures .7 ohms and the battery is about 12.39 volts, how long can I leave the light on at a car show without doing damage to my battery?

It's a brand new Optima Red Top battery and I don't want to kill it right away.

I got some of those white LEDs that have practically no draw, but until I get them I'll be using my hood light.

I used to know how to figure these things out...
 

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Discussion Starter #3
That wouldn't light my engine compartment up very good, then...

Guess I should have mentioned that the car show is until 9pm.



<font size=-1>[ This Message was edited by: 89Trooper on 2/9/06 8:44am ]</font>
 

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I ran a 22" Television from a power inverter for over 8 hours or more (may have been more like 12, don't remember we had a power outage) from my Optima Red Top (brand new,) after that it sat for about 3 months, then we put the engine in my car, started her up for the first time, cranked for a good minute total getting the timing/fuel mix right, then it fired right up, no problems.

Ran totally on battery power for a good 10 minutes too when my alt belt snapped. Shut it down cause it was overheating, got the belt replaced, fired right back up. You can't beat those Optimas with a stick.


<font size=-1>[ This Message was edited by: thekingofazle on 2/9/06 2:03pm ]</font>
 

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I agree that you should be more than fine with just the under-hood light on. A little bit of info on light bulbs too... you said it measured .7 ohms... a light bulb's 'resistance' goes WAY up once the light is on, the extreme heat in the filament makes it a not-so-good conductor. So a little 5 watt bulb may measure less than an ohm when it's off, but will be closer to 30 ohms once the bulb is lit.
 

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Discussion Starter #8
That's true, E=IR, I=17, then P=IE, P=204!

Never thought about that before...
 
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