Recommend a Car Power Inverter

August 13, 2009 8:26 AM

I'm looking for recommendations for a power inverter for use in a car on a road trip.

The wife and I will be going on a lengthy road trip, and we'd like to be able to keep various gadgets powered en route. The biggest use will be for a laptop, but we may also need to charge some small electronic devices (a camera, a Nintendo DS, etc).

I'm having a real hard time weeding through all the marketing and specs for what is out there. Wattage ratings seem to vary from as low as 50 to as high as 2500, with prices similarly all over the place.

So, I'm looking for advice -- hopefully to answer the following questions:

1. What wattage do you really need for a laptop and a few small battery charging devices? How realistic are the ratings?

2. Is there a significant difference in performance in more expensive models?

3. Is overheating a concern? Are some models better at preventing this than others?

4. Any specific models that are notably good? Notably bad?

Size is a bit of an issue as well, so I'd really like to find the smallest and most reliable inverter I can to meet my needs.

posted by tocts to Technology (5 answers total)

I have had many inverters over the years. They have ranged from really sixteen dollars to one in the camper that is two grand. To find one that will suit your needs, you will need to add up the wattage of everything you will be powering at one time. The label on your chargers should tell you this. If it only shows you amps, you can do volts X amps to get the wattage. Then narrow down your search for one a little bit larger than you need. Laptop chargers generally vary from 65 to 150 watts. My latest one I picked up at Costco. It's small, but to does make more noise then some I have had. It gets warm too. It was still well worth it. It also has a usb charging port.

Anything over about 150 watts will require it's own 15 amp fuse. So keep that in mind when you are shopping around. I have an issue in my car with that. If I plug the 90 watt charger for the laptop in, I blow the fuse.
posted by Climber at 9:12 AM on August 13, 2009

I have successfully used something like this with a Macbook Pro and cell phone charger (though not at the same time) with no problems:

http://www.invertersrus.com/inv75w.html

As long as what you are using is less than 75 watts at one time, you should be fine. It might even be prudent to get a larger one (such as 150 watt) for a few more bucks just to be safe.
posted by bengarland at 9:24 AM on August 13, 2009

David Pogue wrote about this one on the New York Times website.
posted by exhilaration at 10:20 AM on August 13, 2009

Anytime you're going over a couple of hundred watts you should run a dedicated power outlet that is connected directly through the firewall to the battery using suitable gauge electrical wire, otherwise you risk glitches and power problems with the inverter and the equipment. The stormtrack.org forum has some discussion about this in their equipment section, since those guys run a lot of gear in their vehicles. If you can't do this, just keep the connected equipment to a minimum at any given time.
posted by crapmatic at 11:10 AM on August 13, 2009

Response by poster: I highly doubt we're going to be going over a couple hundred watts -- probably not even much over 100 (I'll have to check the power brick on the laptop when I get home). The main concern I have is whether the lower wattage units are actually able to supply what they claim, and whether there are quality differences or reasons to buy the higher rated ones.

I've heard anecdotal evidence of fuse problems and inverters burning out, so to speak, but don't really have any hard data, so, anything that anyone can provide in that regard would be useful. Some of these links so far are looking like a good starting place.
posted by tocts at 1:09 PM on August 13, 2009