[gilthethrill]

Hello from Canada

Could anyone tell me if there is a product that I can buy
that will plug into my boats cigarette adapter outlet
or 12 volt system to charge my G4 14" iBook battery?
I have an inverter that plugs directly into the cigarette
outlet and I can just plug in the AC charger that came
with the laptop but this uses more power than what is required
to actually charge the computer.

Thanks,
Gil

[cyberhusky]

Hello

I don't know of any dealer in Canada, but in Germany you can have this power adapter from Gravis

http://shop.gravis.de/Application/Articl...ID=2004306

[gilthethrill]

Thanks for your reply.
I did some searching and found the Kensington Lightweight, Slim line 70 Watt DC Mac Notebook and iPod power Adapter. Up to 60% smaller and 70% lighter than other DC chargers for easy portability
70 Watts easily powers and charges Apple iPods, PowerBooks, iBooks
Turns any cigarette lighter or Empower port into a Mac or iPod power source
Includes tips for use with Apple notebooks and iPods with docking connector
Incredibly lightweight power supply - less than 10 oz.
http://us.kensington.com/html/6328.html

Take care.
Gil

[Peter Smith]

I'm a long-time Mac-head but a complete novice at onboard use: we're just starting out with a new boat, cruising in NC, and I've equipped my iBook G3 with GPSNavX and a GlobalSat GPS sensor with USB connection. The last item, power supply, seems to be the hardest to solve. Is there any reason I can't run the iBook from two 12-Volt batteries in series, producing 24 volts? If there is a problem, it must be the need for a power-input plug; is there anywhere I can purchase a coaxial plug that will fit my iBook and can be wired to two 12-Volt marine batteries in series? (If this IS possible, surely it would be simpler than using a cig-lighter outlet, an inverter, and the iBook's 120-to-24 volt adapter, or using the expensive 12-volt-to-24-volt adapters available from Germany?)
Any advice will be much appreciated!
Peter Smith

[cyberhusky]

I would go for the 12V to 24V cigarette lighter cable.
It's an energy equation, with the 12 to 24V method only using some energy, but if you use an inverter you do go from 12V to 110V (or 220V Europe) and back again to 24V. The latter uses much more energy and you will loose energy too, by heat generated by the inverter.

Last time we did have to inverters on board: one generated 120 Watts and the other 150 Watts (both 220V): only my iBook G4 and an external 8" TFT were connected to the 150W converter. Though there were no problems with the generated power, both devices did work perfectly for several hours a day, but when outside temprature climb to 30 degrees Celsius, the 150 Watts inverter just switched off because it got too hot, after 2 hours. The other 120W inverter just made it, though it dissipated a lot of heat too.

Now I use the Networx 12V to 24V car adapter, which won't get too hot and works perfectly for many hours. It is connected via a cigarette light adapter, a second adapter give the power supply for the above mentioned 8" TFT monitor.

Regards,

Manou

[Peter Smith]

Dear Manou,
Many thanks for your message responding to my query. I do know about Kensington's cig-lighter adapter ($80 here in the US), and I do agree it's better than using an inverter plus adapter. But my question was really this: Why can't I simply put two 12-volt batteries in series, thus generating 24 volts, and let that be the power-supply to my iBook (and so to my GPSNavX navigation display)? That ought to be the simplest solution of all; but I'm afraid it's hard to find a coaxial plug that will fit my G3 iBook.
yours,
Peter Smith

[cyberhusky]

Dear Peter,

putting up 2 12V batteries in series, is the lowest energy loss of all 3 possibilities (2x12V in series, 12V to 24V car adapter, 12V to 220V (110V) inverter). Even if you do build your own cable, I think the 24V the iBook needs aren't really 24V but 23.x or 24.x something.
I'm no electronic engineer but I was told when my Amiga One computer PSU went bust and I replaced it with a 700 W PSU the computer didn't work properly because it only needs 100-200 W and modern PC PSU (700 W and more) can't deliver the right voltage at these low level power usage.
The voltage differs by 1 decimal but that's enough that the CPU won't get it's 3.1 or 3.2 V of charge!

I think these adapters available today are very small and filled with electronics so that the right volatge is available. If they were done the old way we would have a big box with a lot of copper wire weighting several pounds.

But I could be wrong here, as I'm no engineer.
OTOH if you only do have 2 batteries on your boat, draining power from both of them simultaneously will give you 2 used batteries with probably at a worst situation not enough power to start your engine. On most sailing boats 1 battery ist just used for this (though you can switch them)

So I still would go for the car adapter either from Networx (apparently it isn't available any more from neither Gravis nor Networx) or Kensington. The one from Kensington seems to be the same as the one from Networx.
The Kensington adapter can be seen here:
http://reseller.kensington.com/html/4502.html


And if there should be problems still take an inverter with me.

Regards,

Manou

[iBook-FR]

I have used an older kensington 12V airline/car adapter for several years with G4 iBooks with great success. I hooked up an ampmeter as well just to see and the charger draws almost exactly 1A@13V which is very good (it draws about 1.8 A if the battery is in need of a charge. ) I don't think they have the new magnetic plug yet though for the latest macbooks.

AC Inverters are not a very good choice because they waste about 50% of the power they transform.

One other trick to save power: If I am sailing in clear water and not navigating a tight passage, I just close the computer and wake it up when I want to see where I am. I asked the GPSNavX guys to modify the route function so the route is continuous even if there is no new data for an hour or so. (They kindly did the modification) In this way I can easliy navigate a full day on just one battery charge. I have a SIRF III usb dongle that I use sometimes and I remains powered up even with the Mac sleeping so you don't need to wait for a new fix.

[escapade2]

Low-cost inverters (120 AC to 12 v DC) are all "modified sein wave"; actually square wave (a true sein-wave inverter costs as much as a lap-top). Low-cost 120v AC to 12v DC interters cause many transformers to overheat and fail. In 10 years of live-aboard I must have fried 6-10 charging devices for small elecrical appliances, power tools and etc.
So an inverter is a poor choice for powering a DC appliance (like a laptop) IF there is a way of getting the 12-14 volt boat power to the correct voltage of the device to be used (not to mention the power loss from going from 12 DC to 120 AC and back again to whatever DC you need).

Q: Has anyone tried the "Megsafe Airline Power Adaptor" sold by Apple for the new Macbook and Macbook Pro?
It looks compact and is cheeper than ones mentioned above, but I can't find actuall specs on it.
Do the converters mentioned above plug to a Macbook?
CAUTION: If yoiu are trying to wire directly from boat batteries to an appliance be aware that voltage will run as high as 14v with the engine running and 13.1v with a fresh charge on your house bank. If that's beyond the specs for the device you can lose an expensive device. If a $50 adaptor regulates the voltage you are money ahead to get one.

[lldoza]

Can get 12 V power adapter from LIND electronics. Works fine ....
Now I need one for my new MacBook. So I can actually sell you mine for G4 if I need to get another base unit. Linda M

[JoMeKe]

Our yard is also highly recommending the Lind power supply. He feels that it is good at filtering out extraneous electronic noise and providing a good consistent power supply. His question is what voltage the MacBook actually demands. Supposedly many computers don't actually run at 12v, but more like 14-16 volts. I can't find any answer on Apple's site. Does anyone know?

And anyone else using Lind's unit? if so, how is it working?

Thanks