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Beliyaal

macrumors member
Original poster
Feb 14, 2008
53
19
What do you think about this battery from Batterygeek?

Specs:
130 Wh
16 or 19 volts output
1.7 lbs

This should give 4.5 times the normal operating time. Should be possible to watch demanding movies for about 7 hours, or do less demanding things for 18 hours.

I'm not sure if the voltage is too high or within limits. The Air magsafe seems to output 14.5 volts.
 

NC MacGuy

macrumors 603
Feb 9, 2005
6,233
0
The good side of the grass.
This looks rather interesting. In theory it should work fine but sure would like to see one in action or hear from someone who's actually used one. At $300 it's not a cheap option but worth it if it gets an extra 6-8 hours of usage.
 

BWhaler

macrumors 68040
Jan 8, 2003
3,789
6,249
Apple has not licensed the Magsafe connector, so I would be very, very reluctant to use this product.
 

Beliyaal

macrumors member
Original poster
Feb 14, 2008
53
19
Apple has not licensed the Magsafe connector, so I would be very, very reluctant to use this product.

Why do you say that? It doesn't seem very complicated to provide a direct current to a couple of connectors. Should be very hard to get wrong.
 

stpchien

macrumors newbie
Feb 3, 2008
5
0
I called for more information and was told that they're working on a connector tip that's sized correctly for the MacBook Air, which should be available in late March. (The existing MacBook and MacBook Pro tips are too thick for the Air's profile.)

Has anyone had experience with these batteries for other computers?
 

t4cgirl

macrumors member
Feb 22, 2008
33
0
I understand there isn't gonna be much news on this front until Battery Geek gets their MBA connector out, but I, too anxiously await this product.

I found one review that claimed, secondhand, that one of BG's batteries powered a MBA for 9 hours. Plugging their battery in with a MacBook connector sounds brave (and probably doesn't let the laptop sit evenly on the table/tray table.)

http://www.macintouch.com/reviews/macbookair/

Entrepreneur Mike Lee sells Kensington and iGo battery packs with custom-made MagSafe cables, harvested from Apple power supplies. And, MacInTouch reader Gershom Martin has informed us of a vendor named Battery Geek that sells external battery packs with MagSafe-compatible cables. Mr Martin reports the BG 15-21-130 powered MacBook Air in a 9-hour plane flight with power to spare.

If I can add 2 pounds to the travel weight and have 9 extra hours of work on my laptop, that's fine with me. Sounds like more work and much less weight than a MBP with an extra battery.
 

Eraserhead

macrumors G4
Nov 3, 2005
10,434
12,250
UK
I would expect a few hours, it shouldn't be considerably longer than a normal battery.
 

SunshinegotaMac

macrumors newbie
Feb 23, 2008
17
0
SF
For long flights - seatguru.com. Find out which seats are wired. Go on line and make sure you're in that row. That's what works for me. But then I'm talking 14 hour flights.
 

rroback

macrumors member
Jun 29, 2007
77
0
I've got a lot of experience building battery packs, all sorts of round, and flat lithium cells, and conventional cells ( nickel-based). I had an old slightly broken magsafe adaptor for my mbp, that i cut and used to run some tests. The powersupply is quite complex, appearing to have a low 'resting voltage" and upon contact with the laptop, brings the voltage up to a correct charging level. I'm a little uneasy building a battery pack, because I don't know what sort of circuitry lies between the magsafe, and the laptop battery. If you can present the laptop with a range of voltage, I could certainly build a range of pack options that would work, but I don't want to risk my mbp to find out. What my bladding is suggesting is that you wait to get some decent reviews about any of these battery units, before testing them on your own laptop! A poorly made unit could potentially be quite disastrous.

As an aside, doing some rough calculations, assuming a 16v input is required, I should be able to build a 1lb battery unit that should double the air's capacity. I'm not sure if using lithium-polymer packs would be commercially viable, but it certainly would be a nice setup for me!
 
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