October 14, 2006 11:00
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
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