I'd just like to preface this by saying I'm a complete newbie with electrics, so please bear with me.

I just went out and bought a battery pack for my RC Car controller as well as a balance charger. The battery pack is an 8 cell NiCd pack, which as labeled as "9.6v 650mAh" (although I doubt quite a lot that the entire pack is only rated 650mAh). I knew the battery would not be charged off the bat, so I quickly got home, plugged in this charger and started reading the manual. This is where my problem starts.

The manual is in very poorly translated English, and it seems to expect that you have prior experience with chargers and such.

After some fumbling, I figured out that I needed to give it a charging current (which can range from .1A to 6A). I went with what seemed to be the safest option of 0.1A and let it go. It then started a cycle of charge-rest-charge-rest and so on. I have no idea of knowing when it is fully charged and didn't want to risk it, so after about 5 minutes of having the battery on the charger I unplugged it and put it in my controller, which has a battery voltage readout. It said 11.7V, which was more or less the voltage I got when I used to put in 8 separate conventional NiMh rechargable AAs. I thought that was good enough and started playing with the trim on my RC car. Very soon afterwards my control started beeping indicating the battery was low. It's now on about 8.9V.

So I'm assuming I either gave it the wrong charging current or I took it off before it was fully charged (or both). Can anyone give me a crash course on do's/dont's or a formula of what charging current I should use and how I should charge this battery?


closed as off-topic by Joe Hass, PeterJ, Dave Tweed, Daniel Grillo, Kaz Dec 23 '13 at 16:39

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Questions on the use of electronic devices are off-topic as this site is intended specifically for questions on electronics design." – Joe Hass, PeterJ, Dave Tweed, Daniel Grillo, Kaz
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  • \$\begingroup\$ Try the "Battery University" website to gain all kinds of enlightenment about batteries. \$\endgroup\$ – Kaz Dec 23 '13 at 16:39

If the battery's capacity is 650mAh then in a perfect world (and with a discharged battery) you'd need to charge it for 6.5 hours with 100mA.

But, unfortunately it's not a perfect world and you'll need to charge it maybe ten hours at 100mA.

Why don't you look-up the data sheet of the battery and see what it recommends. It might let you charge it at 650mA then you'll need something between an hour and 2 hours to fully charge it.


  • \$\begingroup\$ Where does one find such a datasheet? There's no model number on it or anything, just "Nikko Ni-Cd 9.6V-650mAh" and some health and safety instructions. \$\endgroup\$ – ldam Aug 10 '13 at 16:11
  • 1
    \$\begingroup\$ Try googling "Nikko 1296 9.6v 650mah Ni-Cd Battery Pack". My first hit on your description found the "1296" model number. Let's see what you can find. I've also found out that Nikko appear to have gone out of business so data sheets may not be available. \$\endgroup\$ – Andy aka Aug 10 '13 at 16:18
  • \$\begingroup\$ I bow to your superior googling skills, because I looked all over for that model number and couldn't find anything. After posting this question, I did find some explanations on the charging current thing. Basically from what I've found, you shouldn't use a current more than (capacity in mAh)/1000 = current in A. Is this accurate? \$\endgroup\$ – ldam Aug 10 '13 at 16:34
  • \$\begingroup\$ @LoganDam please read the charging section of this en.wikipedia.org/wiki/Nickel%E2%80%93cadmium_battery \$\endgroup\$ – Andy aka Aug 10 '13 at 16:47

I do not find figures indicating the voltages as measured in full charge state and also whether the charger contained auto cut off when fully charged. Ni-Cd and Ni-Mh cells have memory that makes them to charge and discharge at an accustomed pattern. If the battery is found draining out fast without reference to this fully charged condition, they are prevented by the internal memory. You should "ZAP" the batteries at some 4 times the rated volts. Read separate articles on how to "ZAP" Ni-Cd and Ni-Mh batteries.


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