NiCad battery pack revival

guido

Well-known Member
Hello,

Pack won't take a charge! This question comes up often. Here are a couple of things to do to try reviving the pack, before giving up and recycling it! With the charger plugged in and the pack in the charger, unplug and plug in the charger from the AC outlet several times. This spikes the pack and it may start charging. If this fails, try spiking it with a battery charger or a battery. Five to ten taps may get the pack to take a charge. Anyone get lucky post back.........

Guido.
 
No, not for me I tried it with different chargers. Tried different voltages and amps on several dead battery packs.
 
Hello Cas,

I guess you did not get lucky! If you had open the pack you may have found just one bad cell. Also many times it is just a bad connection,

Guido.
 
(quoted from post at 13:05:21 03/01/15) Hello Cas,

I guess you did not get lucky! If you had open the pack you may have found just one bad cell. Also many times it is just a bad connection,

Guido.
one hundreds of them. Open pack is pretty much necessary or you can't spike the correct cell(s). Lick? Majority respond initially, but over the following weeks, I would estimate about 30% longer term success. You might ask, how so many? I used to have a virtually free source of bad battery packs.
 
Just a few weeks ago I pulled an old camcorder off the shelf for the first time in near 10 years

One of the long neglected (3.7 volt ?) Ni-MH batteries took a charge, the other refused.

I connected my 6V battery charger to it for a few 2 second shots, keeping them short enough to not overheat the battery. It then took a charge from the stock charger.

Both batteries will run the camcorder for a normal 1.5 hours, but indicate "low battery the whole time. Dont know if more charge / discharge cycles will restore them, or if the years of neglect will be fatal. They are still avalible, so I can replace them if I must.
 
Hello JMOR,

That was my response. Older pack may have 1/2 of the cell pack bad, make one pack out of two or three. Opening the pack would be the next step. I do have a large supply of free battery packs from more then one source as well. I just do it for fun, and give them away. When someone asks on this forum asks if they can be fixed, what does that tell you?

Guido.
 
Hello John Hagen,

SO............you got lucky. Then it does work hey!

Guido.
 
Guido, I know you are a fan of Ni-cd. I am not, partly because I may not know how to properly care for them like you do. I may have not respected their memory. I think mine suffered from lazy battery syndrome. Mine would self discharge at a much faster rate than 10%/mo. I read some place they discharge at 1%/day. At the end mine would fully discharge in 2 weeks. Again this could all be my fault for doing everything you do to your batteries.

That said I got the following information from wikipedia.org

Recently, nickel–metal hydride and lithium-ion batteries have become commercially available and cheaper, the former type now rivaling Ni–Cd batteries in cost.(My experience, much cheaper on ebay) Where energy density is important, Ni–Cd batteries are now at a disadvantage compared with nickel–metal hydride and lithium-ion batteries.

When not under load or charge, a Ni–Cd battery will self-discharge approximately 10% per month at 20°C, ranging up to 20% per month at higher temperatures.

Ni–Cd batteries may suffer from a "memory effect" if they are discharged and recharged to the same state of charge hundreds of times. The apparent symptom is that the battery "remembers" the point in its charge cycle where recharging began and during subsequent use suffers a sudden drop in voltage at that point, as if the battery had been discharged. The capacity of the battery is not actually reduced substantially.

An effect with similar symptoms to the memory effect is the so-called voltage depression or lazy battery effect. This results from repeated overcharging; the symptom is that the battery appears to be fully charged but discharges quickly after only a brief period of operation. In rare cases, much of the lost capacity can be recovered by a few deep-discharge cycles, a function often provided by automatic battery chargers. However, this process may reduce the shelf life of the battery.

I have had very good luck with Ni-Mh batteries and they are less expensive than rebuilding Ni-cd's. No self discharge. No menory problems. Don't do anything special, just use them and dump them in the charger to top off. New dewalt charger shuts off when battery is fully charged, no cooking the battery like my old Ni-cd charger did. At sub zero temps I need to warm up my Ni-Mh's to charge. But that's no biggie.
George
 
Hello Geo-Th,In,

I'm not a fan exactly, I just have used them for many years. After letting the smoke out on some of them, learned what not to do. I recall telling you that Nichel Metal hydride are a better choice, mow even cheaper. Lithium batteries are now getting cheaper by the day. They have the advantage in longevity by the way they are charged and monitored, each individual cell. Also the have been paralled for more capacity, win, win situation. I have now some Lithium packs and one charger. Will eventually have enough to do all the batteries out there. By the way you better have a charger that states what kind of battery it will charge! I'm not a fan of multi type capabilities. My old NiCad packs are dormant. I have a piece of wire across the terminals, totally dead. Bet you they will charge right up. There is so much that can effect battery capacity. I'm still learning after more them more30 years letting some smoke. Anyway thanks for you input. Now you have to deal with your snow. This battery business is turning out to be time consuming but fun! Here is turning to slitting rain. Stay warm......

Guido.
 
Guido,
dewalt makes a special charger for all 3 types of batteries. I've had good luck using it for past 6-7 years on my Ni-mh and Li ions. My dewalt radios will also charge all three batteries. I like removing a battery from charger and it not boiling hot. Charger shuts off when finished.

I've never had any luck with Ni-cds. As a matter of fact. The Ni-cds on my mother's old electric wheel chair died. Won't hold a charge. Won't fully charge. Perhaps I try draining them all the way and try bringing them back up slowly.

Personally, I'll never spend a dime on NI-cd when I can get a battery with more amp-hrs, cheaper, and lasts a very long time.
 
Hello Geo-TH,In,

I just inherited a 28Volt Milwaukee dual charger, Ni.Cads And Lithium. Its a monster battery pack the 28 volt one. It got cold so I'm waiting to see if it charges. The 28volt battery pack had one set of paralleled cells bad. It won't take a charge the 18V Lithium no charge also. Still learning the fundamentals on lithium cells. Most popular number I found so far are the 18650's. They do come in many colors and capacity. I can't charge them either. I'll need to buy a charger for them. Got one in my sights, just need to get warm here. Just stopped with the slitting and ice and snow and rain. Must be March!

Guido.
 
I've had paks that refused to charge even enough to test each cell after opening the pak. Doing your tap tap trick with shop charger got the pak to charge and alow cells to be tested. Yea,yea,I know better batteries are available but none of them are free like these old discards. Ever time this is discussed someone pipes up about the latest and greatest advancements in batteries. Taking that line of reason,why would you mess with a 80 year old tractor? BTW,I got the idea from you to do this in the first place,so thanks.
 
Hello da.bees,

I now think that my post was not a waste of my rime. I hope that some of the skeptics will read your reply. I know it works....... they do not! If the guy posting is asking for help I read it as he wants to fix what He has! Whether he can afford a new one is irrelevant. Thanks for posting back. Can't buy batteries cheaper then free HEY!

Guido.
 
(reply to post at 11:25:49 03/01/15)

If the charger is a quality unit it should not be throwing large voltage and current spikes.
What you are attempting to do is to burn off conductive hairs that have grown between a batteries + and - plates. And have shorted the cell.
When young and foolish I have brought back almost every shorted cell for a few weeks or at best months of service. Of course I am glad to have been wearing gloves, a face shield and hearing protection. As sooner or later a battery was going to fail, and fail it did.
Some of the cells needed too much voltage and current to clear the shorted hair.
Just went out and bought new batteries after that.
 
Hello buickanddeere,

Battery chargers are not an issue. They do limit the output, which is a pulsating soft output. That is why spiking a battery or a pack with a higher linear output makes some cells start taking a charge. Spiking a battery or cell does not burn off conductive material on the positive side of the battery. Cleaning some of those cells may bring them back, although at a much lower capacity.If you see one like that throw it out. Some of the smoke came out.
 
Hello buickanddeere,

I forgot to include some pictures. You can see the fuzz on one. When this happens the cell is done! Second pictures compares a good and a bad cell. Whenever cells are put together in a pack, regardless of the configuration, series or parallel, any single cell failure will affect the pack performance. The best way to charge a battery pack, is to individually charge each cell. That is why Lithium pack remain strong after use. All cells are individually charged to the same voltage. If capacity is the same, you got a strong pack. Some configurations will not allow single cell charging, as in a lead acid battery. That is why when we raced RC models we rated each cell and assemble the pack with the best matched ones. Some cells we discharged at 30amps, and no they did not blow up. By the way cell lasting for 300 seconds discharged at a 30 amp rate to .9 volts was a good one,

Guido.
a185372.jpg

a185373.jpg
 
(quoted from post at 14:57:07 03/05/15) Hello buickanddeere,

I forgot to include some pictures. You can see the fuzz on one. When this happens the cell is done! Second pictures compares a good and a bad cell. Whenever cells are put together in a pack, regardless of the configuration, series or parallel, any single cell failure will affect the pack performance. The best way to charge a battery pack, is to individually charge each cell. That is why Lithium pack remain strong after use. All cells are individually charged to the same voltage. If capacity is the same, you got a strong pack. Some configurations will not allow single cell charging, as in a lead acid battery. That is why when we raced RC models we rated each cell and assemble the pack with the best matched ones. Some cells we discharged at 30amps, and no they did not blow up. By the way cell lasting for 300 seconds discharged at a 30 amp rate to .9 volts was a good one,

Guido.


Guido

If there is anything you need to know about batteries just ask. I've been working on various types of battery systems in nuclear power plants going on three decades.

B&D
 
Hello buickanddeere,

I had no intention to insult you in any way.
Just giving some info that I thought would be usefull regarding NiCad's.

Guido.
 

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