NiCd charger

I found a battery that will work in my project:

However, it's a sub-c type battery. With tabs. Do I just get a AA/AAA NiCd charger and then wire the batteries to it to charge? Or are there special chargers for this?

I'm not sure if this should be a new topic or not, since it's a completely different question.

Its not rocketsience, Just apply current to charge the battery.(in this case 1.2V per cell, you can put them in series and charge them that way, 4 batteries = 4.8V or 5V :wink: )

Its not rocketsience, Just apply current to charge the battery.(in this case 1.2V per cell, you can put them in series and charge them that way, 4 batteries = 4.8V or 5V :wink: )

Wow... reCreate, you should never post again..

Do NOT attempt to charge your batteries like that, unless you feel like burning down your house.. there's steps you need to take to prevent damage..
Here's a very good walk through, using a sample from Maxim.
http://letsmakerobots.com/node/9272

Wait. So to charge a non-standard NiCd size, you have to build your own charger?

Or get a flexible charger. There are lots of chargers out there that simply have a molex-style connector for the battery, instead of a pre-formed holder designed for a single cell of a specific size. It would be easy to make a harness for this type of charger to charge anything you want.

Look at the R/C hobby, for examples:

http://www.hobby-lobby.com/chargers.htm

Also, note that the tabbed cells like the one you linked are designed purposely to be soldered into a battery pack, so if you're using multiple cells in your project, you might as well solder them together and solder a wire harness with a plug on it, so you can plug it in to your project or in to a charger. If you want to buy those cells and use them as "loose" cells, you should probably pull the tabs off. They're normally spot welded on but will come off with a bit of effort. Or you could just buy loose cells.

When charging nicads, you really should be more concerned with the current, than the voltage - you need to find the charge rate your batteries can handle, then apply that current. Typically, charge rate is expressed in terms of multiples of capacity - 1C, or 1/2C, for instance. Your cells are 1500mAh, so 1C would be 1.5A. If you were building your own charger, you'd want to apply that current until the voltage peaked. When flat, the voltage will be pretty low, like .9v per cell. As you charge, it'll climb, and when the batteries are full, it'll level off and then drop a bit. That drop indicates that additional charging is just being wasted as heat (and damage to the battery) so that's when you turn the charger off. So-called peak detection chargers will look for this peak automatically and shut off.

Or, as mentioned above, you can just buy a commercial charger designed for the correct number of nicad cells, and wire in a harness to connect it to your battery. Most cheap commercial chargers are designed to be pretty safe (really low charge currents) and will be totally safe for that cell, since it can take a fair amount of abuse. If you get one that's not peak detection and features a charge rate higher than a hundred or two mA, just feel the battery from time to time and turn it off when it starts getting warm. Or, keep a voltmeter on the batter while it charges and look for the peak.

If you don't need them to charge quickly they are pretty tolerant of a degree of abuse. You could use anything to charge them providing you limit current to less than 10% of their aH rating. You just put a resistor in series with your supply voltage, they will stand days left on charge like this. (If you open up a slow multi cell charger, thats all they have inside) If you want to charge them quickly (in less than 10 or 12 hours), you need something with a degree of intelligence to stop 'em overheating and possibly exploding. At the crude end of fast charging, you stick a thermistor next to the cells and switch it down to trickle charge or off when the cells start getting warm.

If you want tetchy battery technology with lots of fireworks if you get the charging wrong I hear LIPO is pretty good :smiley: