Let's Make Robots!

Tearing apart Nicd battery packs?

I was wondering if you could take apart a Nicd battery pack and use the cell like you would with any other battery.  Also would you be able to just put them in a regular battery charger to charge them.  Right now i can find 9.6v 600ma nicd battery pack for $3 so wanted to know that way I could have some for future use.

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Yes you can take the nicd pack apart and remove a battery or two. Back in the day, we used to build the 7.2 matched packs for rc racing. Only problem I could see would be seperating them while trying to avoid getting the battery too hot from the soldering iron when removing the extra batteries.
I thought about seeing if I could separate them so I could just use them to power my robot.  Like I said there $3 so it would be worth it if I could recharge them.  I have 4 rechargeable AA 2450ma and 4 rechargeable AAA 850ma. So I have a charger to use.  Didn't know if it would be safe or if I should just go ahead and use the battery I have now to power my robot 3 servo, board, and sensor.

Right, I wasn't sure if you were going to keep a couple(4 or so)  in pack form or if you wanted to take them all apart and and just use a battery holder.

If you use the battery as is(9.6v) you will need a vreg to lower the voltage.  You don't need 6v to run the servos from my exp, but thats up to you.A 7805 will work for your needs right here.

 If you do use a 6 volt setup, you may run into an issue with the running a standard vreg like a 7805. This type ususally needs at least 7v to run properly at 5v.You could optionaly run 6v and use a zener diode to drop your setup down to 5v.(mine dropped to 4.8 on a similar setup.)

Going back to using the 7805, I've run a 6v setup on it and get around 4.6vout...so it's a little low. The servos will run fine on 4.6+(just metered it right now to confirm) volts as I've tested multiple servos before with this voltage rang and with my setup. Make sure to add caps to the setup as the vreg won't run as well without them. I used two 470uf 16v caps in my setup and it ran fine.

The simplest recommendation, just use 4 cells to get up to 4.8v. if you want 6, set up 1 more 1.2v cell inline with the + side of the servo leads.

Edit here is an example of what I'm talking about drawn in wonderful windows paint...

48_and_6v_mixed.jpg