Ni-Cad Batteries

[bborr01]

Gentlemen,

I would like to share some information about Ni-Cad Batteries.

I doubt that it is a secret to most of the people on this site that Ni-Cad batteries have a memory, but wonder how many get the most out of their batteries.

Case in point: I recently bought one of those attachments that goes in a 1/2 inch drill to raise and lower the knee on my vertical mills. (Best $35 I have spent in a while). It uses some pretty good torque to lift the knee so the maker recommends using a corded drill.

I also have a bunch of DeWalt 18 volt tools and XRP batteries, some of which are nearly 10 years old. While the old batteries are not up to new standards, they are probably about 70 or 80 percent of new level.

One of my brothers bought the same kit that I have a couple of years after I bought mine and he is on his third set of batteries. When he needs the drill, he charges the batteries without discharging them first. Bad mistake.

What I do is when my batteries get too low to be useful for the task at hand, I put them in my vacuum and let them run down until the vac is hardly turning. Before I bought the vacuum, I used the flashlight to run them down. It took longer, but it worked fine. One other thing. I always let them cool down before charging them and again after charging them before use.

Hope this helps save my fellow HSM'ists some $$$$$$ on Ni-Cads.

Brian

[The Artful Bodger]

Aside from the question of the different types of rechargable batteries I think it is important to understand the difference between a 'battery' and a 'cell'.

A cell is a single unit such as a 'C' cell whereas a battery is a number of these connected in series.

If a battery is discharged to zero one of the cells will reach zero first and from that point on is being effectively 'reverse charged' which will destroy the cell and once that cell is destroyed the entire battry is useless.

[Black_Moons]

bborr01 is very correct on that you must fully discharge nicads aprox once a month, Reguardless if your using them or not for best life. 'babying' them is not good for them, they thrive on 'abuse'.

Its not the so-called 'memory effect' as that does not affect modren cells or even consumer cells period, But crystal growth that results when you charge the cell, this growth is reversed by discharge, with deep discharge being the most effect at reverseing it. Once the crystals puncture the seperator of the cell the battery will self discharge quickly and may even appear as a near short depending on crystal size. (Shorted nicads have been known to be revived by giving them a controled surge of current, but its not something you want to have to do)

[Allan Waterfall]

I thought NiCad batteries were being phased out now.

Allan

[Black_Moons]

I thought NiCad batteries were being phased out now.
Allan

Oh, they have long since been made illegal for consumer use!...
Except for power tools, Medical applications, industral applications and anyone else who ever wanted to actualy use nicads over nimh or any other battery type.

[bborr01]

I have had some of these same batteries sit for many months at a time and go so dead that the drill would not even make a noise. Put them in the charger and FULLY cycle them a couple of times and they work pretty good. As I said, some of these batteries are nearly ten years old.

I have 5 of these xrp batteries in 3 different kits. Some kits like the right angle drill don't get used very often and the batteries just sit. Now I have put them in a row and intend to rotate them so they all get used regularly.

Brian

[Bob Fisher]

I have a 9.2 V Makita drill that is at least 12 yrs old. Both batteries still hold a charge. I have since scrapped a 12V Dewalt, cause the batteries would not hold a charge. I treated them the Same and have no idea what accounts for the difference in longevity. On another note, I had a 18 V Milwaukee batteries rebuilt for about$40 each. Performance is better than new. Go figure! Bob.

[Boostinjdm]

Now I have put them in a row and intend to rotate them so they all get used regularly.

Brian

I numbered mine and always use them in order. When they won't turn the screw or drill the hole, they go on the charger and they stay there until needed I get years of heavy use out of them. I have 3 batteries right now and depending on what I'm doing, all 3 of them could go through multiple charge cycles in one day.
I don't even own a corded drill.

[Black_Moons]

I numbered mine and always use them in order. When they won't turn the screw or drill the hole, they go on the charger and they stay there until needed I get years of heavy use out of them. I have 3 batteries right now and depending on what I'm doing, all 3 of them could go through multiple charge cycles in one day.
I don't even own a corded drill.

Ah, Don't leave em in the charger, That trickle charges em and thats bad. With slow chargers it can be downright fatal to a battery, though some modren fast chargers properly shut off.

[J Tiers]

Go pay attention to what TA Bodger said.....

AS SOON AS the speed starts to slow on whatever the tool is, swap to a charged battery and continue, while charging the "low" one you took out.

"Fully" discharged is discharged to the point the voltage reaches a "knee" and starts to drop fast. As TAB said, if you try to get the last bit of use, you almost certainly reverse charge at least one cell, and that kills it fast.

Don't worry about "memory".... "memory " won't kill a battery as fast as reverse charging does, and you can always drain it to the "stop using this" point, and let it self discharge from there, if you want.