Battery question (with pics/diagram)

deviouskoopa · Post by **deviouskoopa** » Wed Jan 14, 2009 11:38 pm

Is there any reason I can't (or shouldn't) use this battery? Idk if 14.8V is workable or not... I have 2 that belong to my old Gateway tablet that's broken (I would only use 1 probably, since it's 5200 mAh and 8 cells).
http://www.skyline-eng.com/index.cfm?fu ... ct_ID=5398

deviouskoopa · Post by **deviouskoopa** » Thu Jan 15, 2009 12:42 pm

Anyone? .......

jjhammerstein · Post by **jjhammerstein** » Thu Jan 15, 2009 12:42 pm

deviouskoopa wrote:Is there any reason I can't (or shouldn't) use this battery? Idk if 14.8V is workable or not... I have 2 that belong to my old Gateway tablet that's broken (I would only use 1 probably, since it's 5200 mAh and 8 cells).
http://www.skyline-eng.com/index.cfm?fu ... ct_ID=5398

I'm not sure if this is exactly how it works, but I think since it's twice the voltage, it will act like a 10400mAh battery at 7.4V.
You need a voltage regulator of course.
Is it huge?
Because that's a pretty rediculous capacity.
I'm talking 8h+.

deviouskoopa · Post by **deviouskoopa** » Thu Jan 15, 2009 12:49 pm

Hmmm I'm not sure it doubles the mAh like that... And yea the battery's case is like 13.5 inches long haha. I think the cells inside will be manageable though... if I can figure out how to open the damn thing!

jjhammerstein · Post by **jjhammerstein** » Thu Jan 15, 2009 12:50 pm

My portable is looking at being 13" wide, and my batteries are only 6".

Stoweboarder · Post by **Stoweboarder** » Thu Jan 15, 2009 1:44 pm

dude, you posted it in a day and you already expect an answer only a coupe hours later....chill - we have stuff to do

and its 14v unless you wanna use a step down regulator

plus it looks like an odd shape to stuff in somewhere

deviouskoopa · Post by **deviouskoopa** » Thu Jan 15, 2009 2:45 pm

Haha ok...

So I just need the step-down regulator, cool. But Harshboy's diagram says you need "9V battery (but no more than 12V)", so I'm just making sure...

And the 8 battery cells are actually only 6.5 x 3.5 mm each (for each connected set of 2), so they should fit alright. I'll get a picture up soon.

deviouskoopa · Post by **deviouskoopa** » Thu Jan 15, 2009 3:41 pm

Here's the batteries, there are 4 sets of 2 cells, which I could split up even further if need be:
http://img150.imageshack.us/my.php?image=img0125se6.jpg

And the PCB with it... can anyone tell what this is? Is it a protection circuit or what?
http://img405.imageshack.us/my.php?image=img0129gp7.jpg
(sorry for the low quality, my roommate's camera is crappy as hell)

I'm also confused as to how these batteries are rigged up... there are 5 total wires going to the PCB (red, yellow, yellow, white, black) as shown below:
http://img141.imageshack.us/my.php?imag ... ramuf9.jpg

Any help is appreciated, I'm stuck

deviouskoopa · Post by **deviouskoopa** » Thu Jan 15, 2009 4:35 pm

Hmmm maybe it would be better to just chop off the yellow and white wires, and the PCB, and just buy a standard protection circuit and wire the red/black up to it like normal. That would work right?

bacteria · Post by **bacteria** » Fri Jan 16, 2009 5:09 am

You need a 7.4v protection circuit, if you either buy one or buy a 7.4v Li-ion battery and use the protection circuit from that.

In my PSone portable I went overboard and had each pair with a protection circuit, could have got away with only one (so I have three in there), you can use one, however again, to be safe might be good to wire two pairs of cells in parallel to each of the two protection circuits and then have those two outputs in parallel.

If you retain your existing protection circuit, which is rated 14.8v and use that for a pair of cells (total 7.4v) you will overcharge the batteries and they will explode and catch on fire. You need 7.4 protection Li-ion circuit boards. I got mine from the Canon BP-915 batteries I use.

deviouskoopa · Post by **deviouskoopa** » Fri Jan 16, 2009 12:03 pm

bacteria wrote:If you retain your existing protection circuit, which is rated 14.8v and use that for a pair of cells (total 7.4v) you will overcharge the batteries and they will explode and catch on fire. You need 7.4 protection Li-ion circuit boards. I got mine from the Canon BP-915 batteries I use.

Okay thanks! So what I actually have is 4 sets of 7.4V, which I will wire in parallel to a 7.4V protection circuit (I'm guessing then that the previous arrangement was 2 sets of 14.8V wired in parallel to a 14.8V protection circuit). I think that's exactly what I needed to know for now, until I get my 7.4V protection board...

deviouskoopa · Post by **deviouskoopa** » Fri Jan 16, 2009 12:12 pm

http://www.batteryspace.com/index.asp?P ... rodID=3954
Is this what I should buy? Or is there another protection circuit you could point me to? Just double-checking before I order it...

EDIT: That description says it only takes 2 cells (7.4V or 3.7V?)... so do I need 2 protection PCBs or what? Can someone draw a diagram of how I should hook this all up? Thanks again...

bacteria · Post by **bacteria** » Fri Jan 16, 2009 4:01 pm

Ok, if it says two batteries for one of these protection circuits, then buy four (one per pair) to be safe - bit like I had in my project - connect all the positives together to one wire and all the negatives into one wire and you are running all 4 battery packs in parallel and each of the four packs with their own protection circuit.

Not worth risking it, get four protection circuits.

Interestingly, the larger Canon BP-911 Li-ions seem to be 4 cells with one protection circuit and the smaller one 2 cells and one protection circuit.

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Battery question (with pics/diagram)

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