Looking for external laptop battery

[megalomania]

I have an old laptop I never use because it has no battery, just an AC adapter. A replacement battery would cost at least $150 assuming I can even find one since this is a Keynote laptop, not exactly a common brand.

I was at Best Buy a fey days ago and I saw they had an external rechargeable lithium ion universal battery that plugs into a laptop (or any portable electronic device) to provide power. Unfortunatly this too costs $150.

I was just wondering if anyone happens to know of a much cheaper solution. Something rechargeable that can be connected to the laptops AC adapter is fine. Bulk not an option. I found a device on Ebay that is quite cheap that consists of a rechargeable battery pack and a replacement AC adapter unit. These are 10.4V to 12V though; my system is a 10.2V

I also found this nifty item on Ebay:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=64472&item=6782059108&rd=1
I don't know if this would work on a laptop though. It runs power through a cigarette lighter connector. Would it be possible to get a lighter adapter, connect it to my laptops AC adapter, and then plug it into this thing?

[megalomania]

I have an old laptop I never use because it has no battery, just an AC adapter. A replacement battery would cost at least $150 assuming I can even find one since this is a Keynote laptop, not exactly a common brand.

I was at Best Buy a fey days ago and I saw they had an external rechargeable lithium ion universal battery that plugs into a laptop (or any portable electronic device) to provide power. Unfortunatly this too costs $150.

I was just wondering if anyone happens to know of a much cheaper solution. Something rechargeable that can be connected to the laptops AC adapter is fine. Bulk not an option. I found a device on Ebay that is quite cheap that consists of a rechargeable battery pack and a replacement AC adapter unit. These are 10.4V to 12V though; my system is a 10.2V

I also found this nifty item on Ebay:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=64472&item=6782059108&rd=1
I don't know if this would work on a laptop though. It runs power through a cigarette lighter connector. Would it be possible to get a lighter adapter, connect it to my laptops AC adapter, and then plug it into this thing?

[xyz]

You could always use the 10.4V supply with a resistor wired in series to get the voltage down to 10.2V before the computer is supplied with power (if you know the current used by the laptop then use V=IR to calculate the value of the resistor). That is if a 0.2v difference even matters in the first place?

[xyz]

You could always use the 10.4V supply with a resistor wired in series to get the voltage down to 10.2V before the computer is supplied with power (if you know the current used by the laptop then use V=IR to calculate the value of the resistor). That is if a 0.2v difference even matters in the first place?

[Jacks Complete]

0.2 volts is likely to be an issue in a laptop, which would normally rely on the exact PSU supplied from the factory. Laptops are generally about the most sensitive thing you can find re: batteries and power supplies. A sealed battery with finger protection, etc. will *never* get a voltage spike, so they will save 50p on that bit of the circuit. It won't be ESD protected, either.

You could use an inverter, but you need one that offers "true sine wave" so the transformer gives a nice ripple-free output.

[Jacks Complete]

0.2 volts is likely to be an issue in a laptop, which would normally rely on the exact PSU supplied from the factory. Laptops are generally about the most sensitive thing you can find re: batteries and power supplies. A sealed battery with finger protection, etc. will *never* get a voltage spike, so they will save 50p on that bit of the circuit. It won't be ESD protected, either.

You could use an inverter, but you need one that offers "true sine wave" so the transformer gives a nice ripple-free output.

[linfieldfc]

This may or may not be of interest, it is a link concerning the rebuiling of laptop batteries:

http://laptops.engadget.com/entry/1234000927048426/

[linfieldfc]

This may or may not be of interest, it is a link concerning the rebuiling of laptop batteries:

http://laptops.engadget.com/entry/1234000927048426/