Radio Preppers

General Category => Batteries & Solar => Topic started by: gil on October 13, 2016, 07:54:10 am

Title: Reviving NiCad Batteries.
Post by: gil on October 13, 2016, 07:54:10 am

Yesterday I received a Clansman NiCad battery for my RT-320. The battery showed 13V when I got it. Ah... Minimum voltage is supposed to be 0.85V per cell. For this 20-cell battery that's 17V minimum to avoid damage. The battery was built in 2007; it's NOS (New-Old-Stock). I put it on my Pro Peak Supernova charger and ran a few charge/discharge cycles... The battery would discharge to less than a Volt in 45secs! Darn... And that's starting from 28V... Dead as a doorknob.

After some research on YouTube it seems one way to revive a NiCad battery is to zap it 6-8 times with twice the voltage and high current. You connect the negative of the bad battery to the negative of the power source and tap the positive on the battery's positive briefly, making a lot of sparks. It is supposed to destroy crystals inside the cells.

It didn't work for me... Some even say to inverse polarity to zap it... Seems dangerous... Suggestions?

Title: Re: Reviving NiCad Batteries.
Post by: gil on October 17, 2016, 03:55:00 am
The battery works! I was waiting for a Turnigy Accucell 8150 to charge my LIPOs but it also can charge NiCads. As soon as I got it I tried the Clansman battery, and bingo! Current was getting in. The battery took 3Ah on the first charge, 3/4 of the rated capacity. The Supernova just could not deal with it.

The Turnigy is a great charger but I did read a lot about quality control issues. Mine is no exception: The 7S balanced connector is soldered upside down! So I had to shave off the battery pack's balanced connector's edge so I could plug it in the other way.. Highly unacceptable, even by Chinese standards. I'm not returning it because it only affects charging 7S LIPOS, but still, I hate when things do not work as they should..

Title: Re: Reviving NiCad Batteries.
Post by: Jim Boswell on October 17, 2016, 12:11:09 pm
Most of the time I cycle the battery pack and try to find the cell that is performing the worst, replace that cell and the battery pack is usable once again. I have used a relay to pulse a cell, a short blast of higher rater current and voltage. The application will burn the whiskers that form across the nicad layers. Good to get it going. 73'S  KA5SIW
Title: Re: Reviving NiCad Batteries.
Post by: gil on October 17, 2016, 01:44:58 pm
Interesting Jim. I was surprised that only one charger worked though both are dedicated to NiCad charging. The Turnigy is more modern. Clansman battery cells are molded into expanding foam. The newer plastic ones can't be opened either. The seller sent me a replacement one so I'll have two! I told him so I owe him now.

Even though the Clansman batteries are heavier and bigger than my 7S LIPO pack, they are more convenient because they clamp onto the radios, RT-320 and RT-351; no cables..

The advantage of Nicad in this case is that the radio stops working before the critical 0.85V per cell. No need to monitor voltage, just use the radio until it quits.

Now I need to be able to charge batteries without grid power. The chargers use 11-18V input, so I can solar-charge a 12V battery then use the charger for the 20-cell Nicad. There is always the optional hand-crank, for the patient, dedicated body builder in all of us...