Running a Laptop in a Car?

edessex

Solid State Member
Messages
11
Hopefully an easy one here... I want to be able to power my laptop from a vehicle. The laptop takes 19.5v.

Do I:

a) buy a power pack that runs off a 12v lighter socket, or

b) buy an inverter to convert 12v DC to what is effectively mains power?

What would the Pro's & Con's be of each?

Sent from my GT-I9100P using Tapatalk
 
I'd get an inverter, to be honest. Much more versatile, should you need it for anything else. Probably also boat loads cheaper.
 
There isn't too much in the price really. I can get the 12v lighter socket chargers really cheap from China, but we all know what the quality is like!

If I use an inverter, will I need to keep the engine running?

Sent from my GT-I9100P using Tapatalk
 
You won't need to keep the engine running but, if the engine isn't running, then, of course, you will be running your battery down.

Make sure the inverter is large enough to power the laptop (power = volts x amps). If your laptop uses 2.5A @ 19.5V then you need at least a 50W inverter. A bigger inverter would be a waste and may use more power and run your battery down faster.

Less expensive inverters produce a MSW (Modified Sine Wave) while more expensive inverters produce a PSW (Pure Sine Wave). Some people report that their devices run hotter with an MSW. I've used MSW inverters in my RV for years and haven't had any problems.
 
There isn't too much in the price really. I can get the 12v lighter socket chargers really cheap from China, but we all know what the quality is like!

I think you just answered your own question there. ;)

If I use an inverter, will I need to keep the engine running?
You won't need to keep the engine running but, if the engine isn't running, then, of course, you will be running your battery down.

Depends on how your 12v socket is wired. Some newer cars kill the juice to the 12v sockets when they aren't on or aren't in the AUX key position. You'll need to check with your manufacturer/model of your car.

Make sure the inverter is large enough to power the laptop (power = volts x amps). If your laptop uses 2.5A @ 19.5V then you need at least a 50W inverter. A bigger inverter would be a waste and may use more power and run your battery down faster.

A 150-200W should do swell. A little headroom if you'd ever need it for another device, and not overkill. Also, OP, please do not go overkill here either and try to run something that will fry your 12v socket wiring. You don't want to be drawing more current than the vehicle's wiring can handle. I've seen wire damage occur when the fuse didn't properly blow on a 12v socket. It's not pretty.

If you need a higher wattage, you'll want an inverter that is wire direct to the battery with properly gauged wiring.

Less expensive inverters produce a MSW (Modified Sine Wave) while more expensive inverters produce a PSW (Pure Sine Wave). Some people report that their devices run hotter with an MSW. I've used MSW inverters in my RV for years and haven't had any problems.

Once again, you get what you pay for. I wouldn't be running a $500-$1000 laptop on a $5 inverter. Probably a little exaggerated, but you get the point.

On a related note to this whole ordeal, may I suggest a separate deep cycle marine battery to use with the inverter? If you're running the vehicle, great. You don't need to worry about battery drain. But if you want to be parked with the vehicle off for more than 30-60 minutes, I would go with an auxiliary battery. Back when I was doing car shows with my '84 Camaro, I had dual monitors setup, along with my PS2, and speakers/sub system and it ran for 3-4+ hours on a charge. I'm sure it would have kept going, but I didn't need to run it any longer. I'd imagine a laptop drawing that little bit of current would run for substantially longer.
 
Regardless of how the vehicle is wired from the factory, a socket could be wired directly to the battery. With inverters, you want to keep the wire run from the battery to the inverter as short as possible (definitely fused). If the inverter is in an inconvenient place due to short leads to the battery, it's better to use an extension cord on the AC side.

As far as risking a $500 laptop with a $5 inverter, I doubt the inverter would damage the laptop itself. It's more likely that it might take out the power adapter for the laptop.
 
It's a £20 laptop, but thats besides the point! Lol.

I can get the Chinese power packs for much less than a small inverter, but I was looking at high street ones that cost about the same as a small inverter.

My worries with a power pack is it overheating, and any possible overload issues with the lighter socket itself.

My worries with the inverter is unnecessary power drain, jacking 12v to 240v to 19.5v.

I am starting to consider fitting a small leasure battery...

Sent from my GT-I9100P using Tapatalk
 
Regardless of how the vehicle is wired from the factory, a socket could be wired directly to the battery.

Correct. But I'm not going to be rewiring a brand new vehicle and voiding any warranties to make this happen, if that's the case.

With inverters, you want to keep the wire run from the battery to the inverter as short as possible (definitely fused). If the inverter is in an inconvenient place due to short leads to the battery, it's better to use an extension cord on the AC side.

I agree that it should be a fused line, regardless of how it's terminated to the inverter. I disagree, however with the rest of what you have said. If you're creating a permanent home for the inverter, find the location you want for your inverter, then run the correct gauge wiring for the distance.

As far as risking a $500 laptop with a $5 inverter, I doubt the inverter would damage the laptop itself. It's more likely that it might take out the power adapter for the laptop.

Damaging the power adapter can damage the laptop. Either way, why risk it? If it's something you're going to be using in the long term, don't skimp--buy something of quality.

Edit due to OP response:
It's a £20 laptop, but thats besides the point! Lol.

Well then, I guess you don't have anything to worry about!

I can get the Chinese power packs for much less than a small inverter, but I was looking at high street ones that cost about the same as a small inverter.

Go for it if you want. I guess I'm just pretty safety conscious. Lol!

My worries with a power pack is it overheating, and any possible overload issues with the lighter socket itself.

That would be my worry as well, especially with a cheap off-brand.

My worries with the inverter is unnecessary power drain, jacking 12v to 240v to 19.5v

I'm not sure you'll have a lot of drain. I'll check into it, but it shouldn't be too excessive.
 
Last edited:
I was looking at 1500w inverters (£35) as they seem pretty common, but if I only need a little one there are some 200w ones (under £10).

Sent from my GT-I9100P using Tapatalk

---------- Post added at 05:37 PM ---------- Previous post was at 05:34 PM ----------

Thats one of the 1500w ones:

http://pages.ebay.com/link/?nav=item.view&id=271204309787&alt=web

If I go down the inverter route it will be hard wired in, not via a lighter socket or battery clips...

Sent from my GT-I9100P using Tapatalk

---------- Post added at 05:38 PM ---------- Previous post was at 05:37 PM ----------

Sorry if that was a double post, having phone issues!

Sent from my GT-I9100P using Tapatalk
 
Back
Top Bottom