I'd like to power my laptop for many hours while it's inside my Civic and with the car shut off (to save power/fuel). The laptop charger part says
AC 100V 1.5A 50-60hz
DC 19V 3.42A

I came across a DC power inverter in a friend's home. To be exact, it was .

Section One. Questions about DC power inverters
1. If the inverter can be used either ON or OFF, which is better?
2. Will using it greatly decrease a battery's life?
3. If the battery becomes depleted due to using a DC inverter, would starting the car and using the car as normal bring back the battery to full capacity again? Is it that simple?

Section Two. Any other alternative products?
Is there some other product I can buy that will do a better job than a DC inverter? What I mean to say is: The battery under the hood is meant to power my car. Is there some battery that is used particularly to power an appliance when away from home? Is there some battery (or some power source) I could place on an empty passenger seat, and have the car's battery used only to power the car?


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UPDATE: Space and weight are no problem. What I prioritize is price and battery life (length of battery life divided by price).

 

technically its the alternator that powers your car not the battery. unless you strap multiple solar panels to the roof an inverter is your only viable option. or maybe some spare batteries or an external battery.

 

The stock battery, if in good condition, can power a laptop for a few hours with the car off, but not all day. If you run the battery down too far you will need to jump-start the car. You can put a larger battery in the trunk and either use that as the only battery (also for starting the engine) or as a two-battery system commonly used in RV's.

Switching to a computer such as a tablet or netbook that uses less power in the first place would make it possible to run longer on any given battery.

 

Thanks for your responses, itburnswhenIP and mk378.

If I get another battery, I presume that I could buy any vehicle battery (it doesn't have to be a battery that would power my Civic). Would you folks have any suggestions as to what type of vehicle battery to get?

We have a battery charger at home, so we are open to buying any type of battery.

On the other hand, I suppose there's an advantage to buying a battery that's compatible with my Civic. And that would be this: After a battery is depleted due to powering up the appliance (laptop or tablet), I could switch the batteries around, putting the depleted battery into my car's battery compartment, and powering my appliance with the battery that was powering the car.

FYI, some DC power inverters automatically shut off before the battery becomes too depleted to start up a car. So, no jump-starting needed.

 

you would actually have the second battery wired to the altornator so it charges while you drive.also lead acid car batteries give off toxic fumes so if its going in the trunk or cabin you would need a speciality sealed battery or sealed battery box. you would want a deep cycle battery if its going to constantly be depleted. or look into something like this Duracell Powerpack 600 | Portable Generator | Duracell

 

First of all, you would need a really clean inverter to power a laptop. Because they are digital equipment, they are very sensitive to power fluctuations and dirty power which most inverters supply. If you go that route spend the money and get a really good one.
The bad part is that few inverters with that power work long without the car running.

Your best bet is to buy a DC adapter for your laptop. They will plug in directly to the 12V outlet and you aren't trying to power 2 items off the battery.

 

itburns, thanks for warning me about the health risks of having the car battery in the car's cabin.

TiggerDX, would the car need to be running for the DC adapter to work? Or it it just like hooking up an inverter, in the sense that the battery gets depleted at the same rate?
UPDATE: I initially thought your advice was about using the cigarette lighter. But now, I don't think the cigarette lighter hole was what you had in mind.

 

It's exactly what I mean. An inverter draws a significant amount of power in an effort to turn DC into AC. Then you have a convertor inline on your power cord to turn it back into DC.
Skip the middle man, and power the laptop straight from DC. It plugs into any 12 volt outlet and will run 10 times longer than it would using an inverter with the key off.
I would imagine you could power a laptop off your car battery for several days if it's a good battery. I have an HP laptop, 17" screen that will run 6-8 hours on its own battery.
I think it would run much longer on a car battery.

 

Tigger, I'm trying to understand you.
Do you mean:
1. plugging something into the cigarette lighter hole?
2. the other end of this device will be an AC outlet? And then I plug my laptop's "power-brick" into it?
3. we're talking about just one device? The "convertor inline on my power cord" is the power-brick that came along with my laptop purchase, yes?


UPDATE: Are you talking about a product like this: ( )? One end of the product plugs into the car's cigarette lighter hole. The other end plugs directly into a laptop.

UPDATE 2: I think the product I linked to was what you hand in mind. I'd like to find a universal 12V DC adapter. Universal means that I can select the output wattage, and I can change the tips. I'd like a universal adapter so that I don't have to buy another DC adapter if I get another laptop (or another laptop brand).

 

You got it.

This one is very light weight

Something like this is great as it works on airplanes as well.

You are bypassing the power cord that came with the laptop in favor of a direct connection.