Car Battery Question

[FordVanMike]

I would like to use a Car Battery to power my laptop computer when I am on a camping trip. Is it possible to buy a car battery and some type of converter so that I can charge my laptop anywhere I go?

What type of converter should I get?
How many hours of power can I get from one battery?

[shorod]

Welcome to the forum!

You have a lot of questions that cannot be answered without knowing more about the products in question. For example, how much voltage and current does your laptop power converter require? If it requires more than 12 volts, you will need a DC-to-DC converter to step up the voltage. Then determining the converter will require knowing how much current the laptop requires.

The easier approach would be to pick up a properly rated inverter which will run off the 12V battery then inverter the DC to AC to give you a pseudo-sine wave that your regular laptop charger will connect to. Selecting the right one again depends on what the power draw of your laptop converter is when operating. Knowing how many hours of operation this setup will yield though requires knowing how much current the inverter draws when powering your laptop as well as the amp-hour capacity of the battery. Also, the current draw of the setup will vary depending on if you are powering your laptop or just charging it.

-Rod

[RahX]

Small inverters can be ha for around 50$ and a good battery should power your laptop for 3 hours easily.

[jdmccright]

I'd suggest buying a marine/deep cycle battery for this application, and even further a gel or glass mat matrix to combat vibration if you intend on lugging the battery around (frickin' heavy...not recommended for long hikes). They're more more expensive, but also more tolerant of deep discharges than conventional car batteries.

I'd also suggest buying a marine battery switch so that you can mount the battery in your car and have it charge while you are driving. You'd be able to switch between the two when you want to run the car's electrics (including the inverter) from the marine battery while keeping the car battery charged and untouched. With this, you might want to invest in a higher output alternator for your vehicle if available.

I don't have any info on capacities and current draws, but we can estimate. Using my relatively new Acer AspireOne netbook as an example, its battery is rated at ~2 Amp-hr. This gives my computer about 2 hours of work time, resulting in a discharge rate of ~ 1 Amp per hr. A typical larege marine battery holds approximately 100 Amp-hr of useable power (this may vary depending on how well the inverter you use can cope with falling voltage...it may shut down below a certain voltage and leave unused power in the battery). So, using simple theory, you could achieve 100 hours of runtime on one battery charge.

I will note that there is power loss from the inverter itself and a laptop plugged into a charger will not not run in low-power mode unless you configure it correctly. Nevertheless, that's alot of computer time.

Hope this helps!

[FordVanMike]

thanks for the replies everyone.

when I have the battery, where do I plug in the inverter/converter?

is there a spot on the top of the battery where I can plug it in?

just in case I confused anyone, I won't actually be using the battery in my vehicle. I will just be carrying the battery with me.

[jdmccright]

Marine batteries are just like car ones...they have two big posts on the top or side. Can't plug anything into them. You'll need to wire up a car power adapter to it.

Just had a thought...why don't you just use a car battery jump starter pack. They are smaller, made for recharging, usually have a handle and a 12V power port built in? The inverter would plug right into the 12V outlet on the pack. They may not give you the runtime of a real car battery but it'll be alot easier to tote/lug. Found one for $120 with 18 Amp-hr of capacity. Other smaller ones also offer USB charging and an air compressor. I think this is the easiest route for you to go. And if you can shove a solar panel in there somewhere, you'd get even more out of it.

Hope this helps!

[MagicRat]

For the price of a deep cycle battery and inverter, you can just buy a compact generator. Around here, 900 to 1200 watt gasoline powered generators go for $100 to $200.

It would be more versatile and useful in the long run, imo.

[AutoService101]

All you need is a power invertor, it plugs right into your cig lighter (if you have a power outlet that's even better). I have a 150 watt invertor that has two plug in's. I use it in my 94 Ford Ranger and have plugged my laptop in it for long road trips and had a cell phone plugged in it at the same time and worked great. They have larger watt invertors for more money. I think I got mine for $40 through Micro center. You can chack there (online) or Tiger dierect (amazon.com to). Don't go buy a new car battery that makes no sense!! Waste of money!

Of course the vehicle needs to be running for the invertor to work, LOL -- When looking on those web sites find yourself a long lasting battery for your laptop, believe they make some that go from 6 to 8 hours, buy a couple so you have back ups and charge them while driving (assuming your 4x4ing??). Either way why buy a battery that you will drain down and damage over time and only use a few times???

[shorod]

Since you won't be using this in a car, the suggestion of using a portable jump start pack is an excellent one. You can even find some with inverters built in for around $100, such as this one.

-Rod