What Do You Look For In Rechargable Batteries?


Shikaku posted on Feb 4 2006 at 05:03 PM said:
Fiendicus_Prime posted on Feb 4 2006 at 11:44 AM said:
I doubt they are really 1.5V since they are still NiMH chemistry, but I could be wrong.
My understanding is that all NiMH batteries start at about 1.4V at full charge, rapidly drop to 1.2V and stay there until they are nearly depleted, when the voltage drops off. It's only the capacity which differs between different NiMH batteries.

If they *were* truly 1.5V they would be better, since they have a greater capacity (1.5V * 2.5 Ah = 3.75 Wh [Watt hours] versus 1.2V * 2.5 = 3 Wh), in addition the GP2X seems to use power more efficiently at that voltage as explained in the post you quoted.

That said these sound like they would be as good as any other batteries, at least!

How can I test this myself? I think I will go today and buy them, test them out, and see if they really are 1.5V (and of course how well they work in the GP2X)

EDIT: Damn asshats..

http://www.tigerdirect.com/applications/Se...p?EdpNo=1168668

Click on the picture: it says 1.2V ON THE BATTERY, yet it says 1.5V in the description...

Time to find out how to hook up 3 batteries into it xd

You can use as many batteries as you want in sets of 2, as long as the batteries are wired in parallell Like this:
-battery-battery+
-battery-battery+
-battery-battery+
- 3 volts +
With 3 times the MA rating
But NEVER (-battery-battery-battery-battery+) that's a 6 volt battery
 
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4.5 volts might be safe, someone should find the voltage regulator chip on the gp2x and lookup the datasheet to find what range it can accept. If using NiMH cells, those max out at roughly 1.4 volts, so it'd "only" be 4.2 volts in that case.
 
I'd be careful about putting 4.5v to the GP2X without researching the voltage reg specs. I've read on a few forums that people experimenting with AC/DC wall adapters used 4.5v to get rid of the "flicker" in the screen, but then ended up with a unit that couldn't use batteries at all, cause all the components got out of tolerance and needed the 4.5v just to run at all. I'd stick to 3.5v or less.

I'm thinking of making my own mod to use "2 sets" of AA batteries in parallel to have 2.4v@5000mAh. 9 hours of continuous movie playback without any firmware fixes... Think about after they fix the firmware....

I'm guessing (from working with PCs for so long) that the voltage this thing needs is 3.3v. I say that because most computer parts, e.g Ram, CPU, USB, etc., run on 3.3v. If you go to high, the voltage regulator might be able to handle it at first, but it will wear out the components faster. Go for more amps at 3-3.3v.

-Kensupen
 
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