[RBJ]

Here's one for the Alpha techies.

In the course of sorting out my I-Book to use on board I purchased a car adaptor from the Apple store.

If I left the battery in the I-Book it would continue to power the computer and not charge. If I removed the battery I could run the I-Book using the adaptor. When I added my extension lead the I-Book would not run at all.

On checking the adaptor closely I noticed that the input voltage was quoted as 13.5 volts. This seems high to me. On my boat with two brand new fully charged batteries I reckon about 12.7-12.8 volts maximum is the best I am going to get.

Any thoughts on this? Is 13.5 volts standard for car adaptors? I'm also going to get a car charger for my Pod with a view to using it on the boat and don't want the same problem.

My Nokia mobile phone charger works fine onboard using the same socket.

I tested adaptor in my car and it works as expected.

Roger

[davidbains]

I run an I Book on my trimaran and have done for three years.
Using the Powerbook G4 Auto adaptor to convert 12 to 24 volts.
It does work via the "cigar lighter" and charges the battery while
running Maxsea on OS9.
It's rated to work from 12 to 18volts but uses 5 amps which really
knocks down the ship's battery voltage, but it still works.
I have other electrical items such as an Icom radio, a GME CD player,
and a Magellan GPS which are all more sensitive to less than 12 volts.
This is a problem, especially with items primarily designed for autos
where the alternator is constantly running. On a yacht I feel it's
important to use deep cycle batteries and a solar panel helps to
keep the voltage from dropping too much.
Even so the IBook certainly isn't left on all the time. I often close it
to sleep. but on reopening it doesn't always display all the
updated data, and may have to be restarted.
I have a sheltered chart table and the multi doesn't heel much so the
I Book stays put and the screen can always be viewed. It is much
brighter at night, which helps on night entrances at large scale.
My regular crew says it's "much better than radar", and radar is even
more power hungry.
David.

[Copprhead]

If you get only 12.8V with fully charged batteries, there is something wrong. Reasons might be:

• 1.) Batteries not really fully charged (maybe the charge regulator stops charging too early?)
  2.) Batteries old/broken
  3.) Cables too long or not thick enough
  [/list:u]
  3.) applies also to your extension cord, it might be too thin. We have the same problem with our fridge. With extension cord the fridge only runs with really full batteries, then the voltage gets too low and the fridge stops voluntarily to protect the battery from deep discharge.

[bobetter]

If you get only 12.8V with fully charged batteries, there is something wrong.

applies also to your extension cord, it might be too thin. We have the same problem with our fridge. With extension cord the fridge only runs with really full batteries, then the voltage gets too low and the fridge stops voluntarily to protect the battery from deep discharge.

Actually, if the motor is not running (no alternator) then a reading of 12.8volt IS a charged battery. The gauge of you extension cord will affect the voltage drop to your Mac. The car adaptor is designed for a car which usually has the engine running (hence an alternator putting out charging voltage >13 volts). There are numerous adaptors out there (DC-DC convertors) which are more appropriate for boat use, check out the iGo products.

[bobetter]

anticipating a flurry of opinions re: state of charge

from the Exide page
http://www.exideworld.com/faq/faq_marine.html

NOTE:
Standard "flooded" lead acid batteries state of charge (SOC) is as follows:

12.6=100%, 12.4=75%, 12.2=50%, 12.0=25%, 11.7=0%.

Sealed AGM or Gel VRLA batteries have a state of charge (SOC) as follows:

12.8=100%, 12.6=75%, 12.4=50%, 12.0=25%, 11.8=0%

[jagasail]

I've used an iGo Juice for several year's with success. It's stated input voltage is 11.75-16 VDC, which will handle most stuations with a house bank unless it get's drawn way down. The Juice keeps my iBook, Palm, iPod, and cell phone charged (with the right adapter for each). I orginally bought the Juice because I used to travel a lot and got tired of hauling all the different power adapters along.

[adjuvantjfoster]

I've used an iGo Juice for several year's with success. It's stated input voltage is 11.75-16 VDC, which will handle most stuations with a house bank unless it get's drawn way down. The Juice keeps my iBook, Palm, iPod, and cell phone charged (with the right adapter for each). I orginally bought the Juice because I used to travel a lot and got tired of hauling all the different power adapters along.

OK, I seem to be failing an IQ test here..... Where did you find that stated input voltage informatin?....(sigh)...

The iGo product pages refer to automobile and aircraft use. This seems to imply that an engine with a battery charging alternator will be providing battery charging level of votage.

Will the iGo Juice 70 provide a proper level of DC voltage output as the battery voltage level in a boat, with no attached charging alternator, fall from the fully charged voltage to some lesser voltage.

from the Exide page
http://www.exideworld.com/faq/faq_marine.html

NOTE:
Standard "flooded" lead acid batteries state of charge (SOC) is as follows:

12.6=100%, 12.4=75%, 12.2=50%, 12.0=25%, 11.7=0%.

Sealed AGM or Gel VRLA batteries have a state of charge (SOC) as follows:

12.8=100%, 12.6=75%, 12.4=50%, 12.0=25%, 11.8=0%

I guess my concern is whether the iJuice 70 will deliver adequate voltage to ithe iBook G4 when the battery voltage has fallen to 12.0 volts, the 25% charge level of typical marine use flooded or gel batteries.

The iGo data sheets I found on line at <http://www.igo.> seem to ignore providing output DC voltage information.

What are your thoughts on this?

John

[jagasail]

John,
Can't answer your other questions but I read the 'stated voltage' right off the label on the "Juice" power supply. I've run it off my house batteries, but I have a huge house bank and have yet to run it down below 12v with my ibook on.

Scot

[bobetter]

I have many times run my various Pwr Books from an iGo adapter off a house bank that is running at <11volts. While the computer battery will obviously not charge, the power supply still operates. Don't know what the threshold is on the lo side for the iGo, and I don't really wanna find out ;>), but I would think that it would be as much a current limitation as anything, remember, as the voltage drops, the current the iGo is pulling will increase and at some point some protective device will go.