Choosing a power inverter for your laptop
My Point...Exactly
Hi All - The power inverter for Laptop GPS is a pretty important component of the system and I thought the subject deserved its own thread (hope you agree).

I travel via airplane allot - so equipment with a small/light footprint is important to me, as I typically carry on my bags. I also have to rely on the car auxiliary power port/cig lighter. Choosing a power inverter can be confusing...Here's a primer I made up to help my customers (mobile sales reps) choose the best device...

When choosing an inverter, make sure it’s properly rated for your laptop. Check your laptop’s power requirement specification in the manual and then choose a model that has a continuous power rating that exceeds your computer's requirement. A good rule of thumb is to choose one that exceeds the requirement by about 20%.

For example: If your laptop uses 60 watts of power, then you should look for a power supply that provides 20% more or a minimum of 72 watts of continuous power.

Make sure the supply is rated for ‘Continuous’ power – some models will highlight their unit’s ‘surge capacity’ on the front of the package, and bury continuous power supplied in the specifications on the back. Inverters will only operate at their surge capacity for a limited amount of time – and then will shut down to reset (often after getting very hot), and that’s not what you want. Generally, most laptops in use by the mobile sales rep will do fine with an inverter that provides at least 90 watts of continuous power.

Consider what other devices you’ll want to power and charge while you’re on the road – your MP3 player or your cell phone perhaps. Some inverter units incorporate additional USB sockets to power additional equipment.

If you do plan to power additional devices off your inverter, add the wattage of all devices – again, add at least 20%, and size the inverter accordingly.

If you travel in rental cars, I suggest getting an inverter that plugs into the cigarette lighter or accessory socket with a cable. In some vehicles, space can be tight around the socket, and an inverter with a fixed plug can be difficult to insert at times. Choosing a model with a cable allows you to more easily position it in tight spaces.

Finally – make sure your inverter has ‘low battery’ and ‘overload’ shut-off protection – so you don’t kill the car battery if you leave your equipment running too long with the engine off – or damage the inverter if you overload it.
Marvin Hlavac

Excellent tips! Thanks for sharing them with us, Keith!

I'm using a 400 Watt inverter. That's much more powerful than I need for my 12" HP tx 2000 laptop, but at least it doesn't get hot at all. Before I got my new laptop, I used a plain old desktop PC (sitting on the floor behind the driver seat), and a 15" (and later even 17") LCD monitor. The 400 Watt inverter was always very hot, but now, with the new laptop, it is just warm.
1,500 watt here

I can run my system on a 200 watt inverter, but just barely.
Marvin Hlavac
Yeah, but your setup consists of a laptop with an external LCD monitor, a printer, scanner, etc, etc ... What else do you need household power in your 18-wheeler for?
Microwave, sweeper, apartment size refrigerator, curling iron, hair dryer, etc. The last 2 are for when my wife rides with me, of course.
Hi, new guy here, with a Del Vostro 1500 and S&T 2008 w/GPS.

Any reason I would use an inverter instead of Dell's adapter that plugs into the cig lighter? Or are inverters for running more than the basic setup that I have?

My Point...Exactly
Hi PetalumaLoco -

No problem using factory issue car charger/inverter. Not all laptops come with a charger. If at some point you decide you want to charge a cell phone, PDA or MP3 player at the same time as your notebook is plugged, then you might consider getting a new inverter with more capacity.
Ok, that sounds reasonable. One thing is a converter can be less expensive than Dell's power adapter, I think Dell's start at about $65.

I mainly got S&T for a x-country trip by Amtrak, to track progress of the train as we go, and to be alert to trackside highlights that may be posted in travel journals or maps. I'm just blown away what technology you can get for just 65 bucks today.

It would be doubly cool if I could get tracking to work with Google Earth. I read a thread here about using Google Earth+, with it's larger caching, with S&T's GPS but interest seemed to peter out from the posters.

My Point...Exactly
Oh - Ok - I thought you already had the Dell inverter. You can do cheaper than $65. Here's a model (Amazon -at bottom) for half that at amazon - and there's less expensive. Just make sure it's continuous power rating meets your laptop's requirements. And if you use it in a car, you'll want low battery and overload shutoff protection.

You know, I've never traveled by train - do they have 12V power connections at the seat like some aircraft do? If so, look for an inverter that will allow you to plug into the seat too.

If you're new to Streets and Trips - check out the 'find nearby places' button for your travels, as well as the 'search on live search' when you've got an internet connection. 'Find nearby places' let's you search around a point and along a route - unfortunately you can't search along railroad tracks (I just tried) - but when traveling on the road, it's often very useful to search for a restaurant or something that's no more than a half mile or so off your route of travel.

Also - check out the 'import data wizard'. If you've got a list of sites to see along your route, you can plot them on your map - assigning your own pushpins. There's allot to Streets and Trips - you should have fun.
Hey, that Duracell looks pretty slick, thanks.

Trains have good ol' 120vac, the trick is the older coaches have maybe 3 per car, the newer ones have an outlet at every seat row. It's a good idea to have a surge protector though. We're booked in a Roomette, a small sleeping room, with 2 seats during the day, and they have an outlet no matter how old the car. We're free to roam the train, I'd like to spend some time in the observation car.

If you want an idea of what it's like, go here
for some 3D views of the inside of Amtrak cars.

I'll check out Import Data, that's a good idea.

As far as net access on the train, it's pretty slim, usually only when in a larger station and then you're not there very long, only a matter of minutes. I'm not going to do a wireless service, that can get expensive and I'd only use it for the trip, I don't want an annual subscription for a 2 week vacation.
I brought a Xantrex 1kW Inverter for 80 bucks at Sam's club back in 2005, I have it installed in the trunk of my car.

Not the prettiest installation, but who cares? it's the trunk.

I also have a 300 watt samplex sine-wave inverter that I'll carry with me to a different vehicle or sometimes I'll plug it up to run the tv when we lose power :]

http://www.donrowe.com is a good place to buy inverters, their prices are pretty good.

the biggest inverter they sell is rated for 8kW :O
Ken in Regina
Here's the unit I have, from Canadian Tire.

If the link doesn't work, go to www.canadiantire.ca and put 11-1869-2 into the Quick Search box.

It's really nice and slim. It has a USB connector so you can charge things that only charge from a USB connection. I had occasion to use mine quite a bit on our recent three week trip. My car charger for our cell phones started to act up part way through and we could not depend on it to keep our cell phones charged. So I plugged in the inverter, plugged the 120VAC cell phone charger into the inverter and we were back in business.

It has an on/off switch on it. If your 12V outlet is switched by the ignition, it will turn off automatically whenever you turn off the ignition. It will not turn back on automatically when the ignition is switched back on, so you have to remember to turn it on. This is a good safety feature so I didn't mind.

It has both a cigar lighter cable and alligator clips in the box. You can connect either cable to the unit, depending on how you want to mount and use it.

The inverter runs a little hot, especially if you manage to cover it up so the air can't flow through it properly. I love the size of it and it's really cheap (Cdn$39.99) for such a well thought out item. If 175W is enough for you, this is a very nice unit.

I just purchased the one that Ken gave the link to (from Canadian Tire) and this week it's on sale for $23.99 i'll test it out tomorrow and i'll let you guys know how it went.

On my laptop power adapter it says 120W output and the power inverter is rated 130W of continues power, but i know that my laptop only takes 120W when it's booting up and normally when it runs it's in the 60 to 90W range.

The inverter worked great ... even when i discharged the battery in the laptop and then plugged it in, it was running at 120W for about 45 minutes straight without shutting down or resetting (although it did get pretty hot so be careful where you put it or when you grab it, they do mention this part in the manual) and the small size is great for traveling, i would recommend this for anyone that is picky about size.
You generally get what you pay for and if you want the best go here:


Ours says 'Made in Canada'.
I have a Sony VAIO VGN-NS10J laptop and a 150W continuous Silverline power inverter. I tested it while the car had its engine on, but we were not moving. The laptop's power symbol flashed, but never began charging. I wonder whether the inverter isn't powerful enough, or is it because the car isn't moving?

Does the vehicle have to be moving to make the inverter power the laptop?
laptopgpsworld.com About