Random battery question..

Chairokey

Chairokey

New member
Just to save gas I thought I'd ask this question.. I frequently find myself listening to my radio at the lake and every hour or so I'll let my jeep run for about 15 mins to charge the battery.. There's a guy parked a little ways down who's doing the same thing only he started his truck, gave it some gas for about 20 seconds and shut it down.. I know nothing about batteries, am I wasting 15 min worth of gas??
 
I'm not sure, but short of running a dual battery setup, I'd consider buying a second battery or a battery charger. It may cost more upfront, but both options have a better long term upside.
 
I do the same thing as the guy in the truck. We go to the beach a lot and about every hour I crank my Jeep for about 20 to 30 seconds. I've done this with every vehicle I've owned and never had any issue. I do the same if I'm washing mine and my wife's or working in the yard.
 
I have to admit that the electrical aspect is my weakest knowledge point of a vehicle. Is 20 seconds enough to re-charge a battery? It doesnt seem like that would be nearly enough :thinking:
 
StrizzyChris said:
I have to admit that the electrical aspect is my weakest knowledge point of a vehicle. Is 20 seconds enough to re-charge a battery? It doesnt seem like that would be nearly enough :thinking:
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I agree, but if mikes been doing it for a while I suppose I'm going to take his word for it. Besides, I choose not to listen to my radio when there's no one around to give me a jump :p
 
Considering you are supposed to run your vehicle for AT LEAST 20 minutes after your battery dies and you have been jumped just to get the charge high enough to be able to start the car again later, I highly doubt 20 seconds is enough. The physics of charging a battery that large in 20 seconds of engine rev-ing is impossible. The only reason his battery didn't die was because it had the capacity to run that long, not because he ran the car for 20 seconds every hour.
 
ichthus said:
I'm not sure, but short of running a dual battery setup, I'd consider buying a second battery or a battery charger. It may cost more upfront, but both options have a better long term upside.
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Or, buy a cheap, battery powered boombox.... Way more uses than a secondary battery and when it dies, you're not stranded. Everyone is overthinking the actual problem at hand here... Haha.
 
As long as your only listening to a AM or Fm station and not a cd or iPod the drain on the battery is minimal. I have left my radio on all night by accident and it cranked the next morning
 
I carry a meter with my tools. If my battery is voltage is questionable I just check it. Meters are cheap. Maybe consider getting one for your rig.
 
Chairokey said:
There's a guy parked a little ways down who's doing the same thing only he started his truck, gave it some gas for about 20 seconds and shut it down.. I know nothing about batteries, am I wasting 15 min worth of gas??
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More energy is consumed starting the vehicle than can ever be regenerated in 20 seconds. He gets away with it cause his battery is in good shape. Try it with an older battery and you will have a dead battery pretty quick.
 
How can a boom box have more uses than a spare battery? One provides a few hours of music... The other could power any number of camping items, a power converter, winch, air compressor, fridge, his Jeep, or be used for welding, holding his beach towel in place, etc...
 
I played music for hours at the lake in the wife's car and No problem with the battery and she has a 13 speaker stereo.
 
ichthus said:
How can a boom box have more uses than a spare battery? One provides a few hours of music... The other could power any number of camping items, a power converter, winch, air compressor, fridge, his Jeep, or be used for welding, holding his beach towel in place, etc...
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Haha, because a portable boombox would be used around the house too, not just out on the trail, for outside chores, painting, bbq's, car washing, holding his car-drying towel in place, etc... And I challenge you to plug a winch into a stand-alone car battery... Let me know how that works for you.
 
It could be that I was more thrown by your use of such a vintage term: boom box. I may have grown up in a time when it was cool to walk the streets with a big silver boxy, tape-playing, noise maker sitting on your shoulder....but I've long since adapted to iPods. Simple speakers with a build in dock can handle all the away-from-home duties. Around the house, just one nice centralized stereo takes care of my music.
 
ichthus said:
It could be that I was more thrown by your use of such a vintage term: boom box. I may have grown up in a time when it was cool to walk the streets with a big silver boxy, tape-playing, noise maker sitting on your shoulder....but I've long since adapted to iPods. Simple speakers with a build in dock can handle all the away-from-home duties. Around the house, just one nice centralized stereo takes care of my music.
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What do they call portable stereos now? I'm just using the term "boom box" to refer to a highly portable music playing device. Whether that's a dock with speakers, or my personal favorite choice, the heavy duty construction site boom box-type. Mine has an ipod port and a waterproof compartment to keep the ipod in... I still call them boom boxes, even if they aren't silver and don't come with an Adidas sweat suit anymore.
 
Chairokey said:
Just to save gas I thought I'd ask this question.. I frequently find myself listening to my radio at the lake and every hour or so I'll let my jeep run for about 15 mins to charge the battery.. There's a guy parked a little ways down who's doing the same thing only he started his truck, gave it some gas for about 20 seconds and shut it down.. I know nothing about batteries, am I wasting 15 min worth of gas??
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Indefatigable said:
More energy is consumed starting the vehicle than can ever be regenerated in 20 seconds. He gets away with it cause his battery is in good shape. Try it with an older battery and you will have a dead battery pretty quick.
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I believe that the 20 second start and run is just verifing he has a good battery, no way it's charging enough to charge a run down battery.
If it starts hard/slowly, it time to let her run, slightly above idle, for 5 or 10 minutes.


Prime8 said:
I still call them boom boxes, even if they aren't silver and don't come with an Adidas sweat suit anymore.
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BoomBox.jpg

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Drawing from my Submarine days for this... (and that seems like forever ago)

If you draw 1 amp for 1 hour out of your battery you burned 1 amp hr. to put that much energy back into your battery you have to put back in 1 amp hr. now you can do this by 2 amps for .5 hr or 4 amps for .25 hrs and so on.

I do not know what the draw of just a stereo or CD player is. I would guess that just the radio is probably .5 to 1 amps and a CD player is 2 to 3 amps. I really have no idea what the output of the alternators are... you would think being an electrician I would pay more attention to that sort of thing :thinking:.

Factor in the draw for starting the rig and I do not think that running for 20 Seconds will restore a battery to full charge. But running for 15 or 20 mins would be a waste of gas if you have a good battery.
 
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