Nokia 5800 - Trying to build a portable battery pack, anybody with this knowledge help?

Cruise

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HomeTown: Los angeles
Posts: 6

Trying to build a portable battery pack, anybody with this knowledge help?

« on: September 17, 2009, 09:23:54 PM »

I didn't wanna spend a buttload on a portable battery charge that wasn't going to charge very much either, so I started looking into the specifications needed to build this thing but won't fry the 5800. I actually don't know what is necessary since I'm not electrical engineer, but I was thinking of grabbing this battery pack from Radioshack and gutting a DC-8 wall charger to get the connector that goes into the 5800.

http://www.radioshack.com/product/index.jsp?productId=2062253

Wiring the positives and negatives together, I'm pretty sure this thing will work right out of the bat. However, if I stick 4 1.2V 2300mAh batteries into the pack, will it exceed the charge load for the phone? Will it fry?


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Cellular-Decay

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HomeTown: Kapolei, Hawaii, USA
Posts: 188

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Re: Trying to build a portable battery pack, anybody with this knowledge help?

« Reply #1 on: September 18, 2009, 07:06:11 AM »

I would not recommend charging your phone using direct drive from a battery pack.

Either use fewer batteries and a boost regulator, or more batteries and a drop regulator.

The latter would be the simplest and cheapest, since very inexpensive linear regulators are readily available at Radio Shack. I have built charging packs using those running off of 6xAA batteries for several portable devices.

The disadvantage is that linear regulators are not the most efficient, and can generate a good deal of heat while operating. Also, it's a rather large unit due to the number of batteries.

The better option would be to use only 2 or 3 batteries and a boost regulator. Small, efficient boost regulators are harder to find, and will cost more, but you end up with a smaller, cooler charging pack.