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I was thinking of upgrading my battery on my laptop + as that has seemed to hit a bound I thought of buying a reasonable average car battery, charging it full up and using it with a inverter so I can run my laptop for many hours on end..

Has anyone had any experience or would recommend another method that isnt a generator or kinds as i need a stored power method.

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closed as off topic by studiohack Jan 8 '12 at 16:23

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up vote 1 down vote accepted

Do not buy a car battery. Been there, done that.

Car batteries are not sealed, and they give of poisonous gasses as they are used. Furthermore, they are meant for cranking a few hundred amps for a short period of time. They are not meant to be deep-cycled. That is, if you discharge them and recharge them, they will only last about 3 or 4 charges before they are useless to you.

I used to carry around a car jump starter battery. These are the kind that contain a sealed lead-acid battery. They usually have accessory jacks on them, which you can plug in a small 100W inverter and run your laptop on all day. My last battery would run my laptop and 4 routers (don't ask) for 14+ hours. These are perfectly safe. However, the one I had didn't have removable alligator clips, and I was always worried they would come in contact with each other in my backpack and weld themselves together and blow up the batttery.

I have since switched to one of those xPal/Energizer batteries that run your laptop/camcorder/cellphone for a few hours. However, my laptop is power hungry and their biggest battery only runs my laptop for 45 minutes.

In short, go with the car jump starter if you can. Best to find one with detachable, or at least coverable, clips.

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I should also note that I used to run my UPS off of a car battery in my basement. It worked well, but I'm sure I was killing myself with gasses in the process. – Brad Sep 11 '10 at 16:57
Sounds very interesting, well in that case I think i might go with a marine deep cycle battery hopefully it wont release poisionous gas and die out like you mentioned after a few recharges? – Ben Sep 12 '10 at 15:42
personaly I wanted to get my laptop running for as long as possible and the idea was to extend the cells in my laptop as much as possible but after that i figured, why not a battery? , a car battery ( or marine deep cycle ) – Ben Sep 12 '10 at 15:43
The battery doesn't push 800 amps, that's it capacity. It's analogous to the fact that your home electrical outlet may be rated for 15 amps but your toaster (shouldn't) draw 15 amps. – Dennis Williamson Sep 12 '10 at 19:49
Dennis, your car battery is designed to supply hundreds of amps of current at 12V for a short period of time. It isn't uncommon to require 200A to start a car. I mentioned it because despite capacity, the battery's plate configuration is in such a way that it is less capable of providing lower amounts of current over long periods of time, vs. high amounts of current over a short time (like what is needed to start your vehicle). – Brad Sep 13 '10 at 1:40

If you don't understand Amps, Volts and Ohms and what they are in relation to each other and how they can affect sensitive equipment, DO NOT DO ANYTHING WITH POWER outside the product specifications as you will probably hurt yourself and your equipment. Car batteries are dangerous. You can't just hook up any type of battery to any type of equipment. The voltage and the amperage have to be precise or something will break and even possibly explode. This is a bad bad idea.

EDIT: and you don't need an inverter. Car batteries are DC and laptops take DC. The adapter that your laptop plug has on it is an inverter. What you need is something to control the voltage, but keep in mind that car batteries run at about 800amps and you probably only need about 4.5 amps for your laptop.

If you insist on this option look at batteries for kids cars as they are sealed. You might need to run some in series and then you'll be closer to the correct amperage.

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+1 for "no inverter needed" – chronos Sep 11 '10 at 18:17
If no inverter, how do you plug it in? DC computer batteries transform AC to DC. Is there another way to plug the computer in? – Xavierjazz Sep 11 '10 at 22:21
if wanted to plug it in he wouldn't need the battery solution. He would still need a charging system for the batteries, yes, but he wouldn't need his own inverter, just the one that is built into the battery charger. – MaQleod Sep 12 '10 at 0:02
You don't need an inverter if you have a proper DC voltage converter for your laptop. It is way more efficient to just step the 12V up to 20V or whatever is needed by your laptop. However, inverters are cheaper, and then you can use them for other things as well. – Brad Sep 13 '10 at 1:41

If you want Lead or similar (car battery), you can take a look at buying a UPS.

Apart from this, I cant really think of anything that meets your criteria

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Thing is would a UPS power a laptop for that long? – Ben Sep 11 '10 at 16:28
Depends how powerful the UPS you buy is. It certainly shouldn't be weaker than a car battery considering they use similar batteries. – William Hilsum Sep 11 '10 at 16:35

I don't see why it wouldn't work. It seems a lot of heavy carrying back and forth although you could have a battery recharger. I have no idea how long the battery would be able to last on each charge.

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If you do it, use a deep-cycle marine or RV battery.

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Cheers for the help but why would I choose this over a standard battery and will it die out after a few recharges like the person below said ? – Ben Sep 12 '10 at 15:41
@Ben: A deep-cycle battery is designed to be discharged more deeply than a standard battery and will last through many charging cycles. – Dennis Williamson Sep 12 '10 at 19:47

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