What will charge my 13 inch MacBook when free camping

Hi Barry,

I have a 15 inch Macbook Pro and on a recent camping trip it actually drained my battery very quickly. It surprised me as I was using a 300 W inverter simlar to this

http://www.bcf.com.au/online-store/products/Battery-Link-300W-Inverter.aspx?pid=129188&menuFrom=380102#Description

I had it plugged into the 12v socket in the vehicle while I was importing some photo's with my camera and it was beeping at me so I whacked it straight onto the battery with the clamps and it was fine but after 20 mins or so had completely drained my battery. I've used this before for just general charging when the appliance is off and never had any issues. I didn't expect it to drain so quickly when it was on. I wouldn't trust the can type and get something like mine. Charge it when the laptop is off but don't use it when it's plugged in unless you run the vehicle. Maybe I was doing something wrong. I didn't think such a small appliance could drain a battery so quickly!

Cheers

Barry,
Have a look on eBay and you can get cigarette lighter adaptor for about $35. The MacBooks are 16.5v DC and by using an inverter you are going from 12v DC to 240v AC and then back to 16.5v - no wonderit is draining your battery. A cigarette adaptor simply ups the voltage to 16.5 volts and is much more compact
Cheers
Andy

G'day Barry22
As mentioned, the dc to dc converter is an efficient use of the 12v to the 16.5v you require. Good prices too.

Just a word about inverters, some appliances and switchmode chargers in modern stuff don't like cheap inverters which output a modified square wave. It isn't modified sine wave as claimed.
Sometimes this rubbish wave form will not allow the switchmode appliance to begin switching and so uses heaps of battery with the inverter trying to keep the power up to it or it burns out the appliance.
Always do a quick connect and check to see if the appliance runs correctly. If not don't keep trying.

Regards
Ross M

I have a 17" MBP and charge it using a 300W inverter that is connected to our 105AH aux battery. I usually find that running the inverter for an hour a night to charge it doesn't pose any problems re excess battery drain. It leaves enough to run the fridge overnight anyway. Wouldn't be able to do this for a few nights in a row though. Having said that, I usually try and charge it when on the move, running the power supply lead through to the back where I store the Mac. We only use an ordinary old modified square wave inverter and the mac power supply doesn't seem to mind. Same with all my video camera batteries.

Pat

I'm guessing you have the magnetic power socket. If so, maybe this 12V power adaptor is what you need (No first hand experience though):
Macbook adaptor on Ebay

I run mine on a dc-dc "Auto Laptop Power Supply" I got it from Jarcar for $70.
You can adjust the Voltage to suit the application, it fits most netbooks and small laptops. Be mindful that the voltage and polarity of the tips are different from one to the other computer so best to take it in with you.

Craig

Check out this place:
http://www.battery-charger.com.au/laptop_auto(dc)_adapter/apple/anb014c28.htm#