Car charger or car adapter cable for Thinkpad w541

[venexiano]

Dear all,
this summer I am planning to do some long road trips in Europe on a comfortable car, I am not driving so I will bring with me some work to do on my thinkpad w541. I already have 2 batteries but here we are speaking about 6-7 hours driving per day so I d like to have a car charger or car adapter for thinkpad w541 which allows me if not to slowly charge my laptop at least to keep the battery level constant or slowly discharging. Any option? An adapter cable that goes from my Lenovo AC adapter to the car outlet would be best.

thanks
V.

[hellosailor]

Try iGo, Kensington, or Targus. If they don't have a specific charger, the usual web search should turn one up. Or perhaps as a last resort Lenovo makes one.(G)

A direct DC-to-DC converter is more efficient, but if all else fails you can buy a small (200 watt?) DC-to-AC inverter, plug that into the car's 12v system, and plug your usual AC adapter into that. The loss of efficiency won't be an issue with a car moving at highway speeds, and those inverters are cheap and easy to find. (If you need to run off 120VAC, you may find it easier to buy in the US.)

Splurge a little, buy a name brand with a warranty, the cheap stuff is just that: Cheap. Not rated for continuous duty, etc.

[UMPC2024]

I know it's not summer anymore, but here's a 65W DC travel adapter. From the review it says it doesn't work with a W540....
http://shop.lenovo.com/SEUILibrary/cont ... de=0B47481

And as hellosailor said, a power inverter (http://www.homedepot.com/p/BLACK-DECKER ... /205431825) would work as well.

[ddamerjian]

Unfortunately I discovered a while ago when I got this laptop that such an adapter doeskin exist like for previous models. I only revisited this now hoping that someone including lenovo came up with one but still not, looks like the power consumption may be too much to handle. For instance even my power inverter that I have usef for many years with all sorts of devices turns off immediately when I try to use it with this laptop, I am sure they make one that will work, but my point is that this thing draws a lot of power and precludes a DC to AC adapter, too bad, very inconvenient.

[TankPad]

Unfortunately I discovered a while ago when I got this laptop that such an adapter doeskin exist like for previous models. I only revisited this now hoping that someone including lenovo came up with one but still not, looks like the power consumption may be too much to handle. For instance even my power inverter that I have usef for many years with all sorts of devices turns off immediately when I try to use it with this laptop, I am sure they make one that will work, but my point is that this thing draws a lot of power and precludes a DC to AC adapter, too bad, very inconvenient.

Little bit of an old thread so I'm not sure how useful this will be but something like this is what you'd need.
http://www.maplin.co.uk/p/15-24v-laptop ... tips-a33hu

The W521 comes with a 170W / 8.5 Amp charger so that makes it a little more difficult to get a converter that'll work. It's best to get a 12V to 20V step up instead of using a typical 220V inverter type deal with the standard charger. The one listed above is good for 7.5 Amps so it will work but it'll be a little slower than the standard 8.5A charger. I'm not sure what exactly the threshold is but if you go for one of the lower ones like the Lenovo one linked above then the laptop will just refuse to charge. I believe the W521 won't charge with the 90W/4.5A charger so you'd want to target a bit higher than that.

If you're are in any way technical, you could assemble one pretty cheaply from components that are easily available online. That would be my preferred option.

[hellosailor]

A very useful gizmo, $20 in the US, is the Kill-a-Watt. You plug it into a wall socket, plug any AC device into it, and you can view the actual line voltage, frequency, instantaneous amperage being pulled, and accumulated wattage pulled over time.
From my W530 experience I would bet you can see the computers don't need all the power unless you are trying to do photorendering or other intense tasks, while charging, and running the drive spindles. More typically a 90w supply will allow you to work, or charge, just not everything at once. That can do very nicely for many users. Kill-a-Watt takes the guesswork out.