How do you pamper a NiCd battery pack?

[Turbo DV8]

My cordless drill pack finally took a dump. Even from very early on, it just seemed to always be near-dead whenever I wanted to use it. I don't feel I abused it. Considering dropping $45 on a new one, but I was wondering what is the best way to use/charge a NiCd battery pack to prolong it's life. My other option is creating an 8-cell 'FrankEnloop' battery carrier and stuffing it inside and out the bottom of the old battery case. Any idea how much current a 9.6 volt drill might draw? I'm thinking I'd likely have to solder thicker gauge wires directly to the carrier contacts, instead of the thin supplied wires.

 

[turbodog]

My cordless drill pack finally took a dump. Even from very early on, it just seemed to always be near-dead whenever I wanted to use it. I don't feel I abused it. Considering dropping $45 on a new one, but I was wondering what is the best way to use/charge a NiCd battery pack to prolong it's life. My other option is creating an 8-cell 'FrankEnloop' battery carrier and stuffing it inside and out the bottom of the old battery case. Any idea how much current a 9.6 volt drill might draw? I'm thinking I'd likely have to solder thicker gauge wires directly to the carrier contacts, instead of the thin supplied wires.

A 9.6v drill can easily draw 30-40 amps at stall (full load).

You want to prolong the service life? Don't overcharge the cells and don't overdischarge the cells.

In explicit terms:

stop using drill when you notice it even beginning to slow down

do not leave on charge

do not charge when hot from using, allow to cool

do not "run all the way down" in effort to "condition/etc" cells


I've got some drill packs that I do this with and have gotten 6 years out of them with fairly heavy use.

 

[45/70]

One thing I've found that seems to help large packs (large, as in many cells), is to do a 14-16hr forming charge every once in a while to balance the cells. My 9.6 Volt Makita seemed to do better doing this. I used it daily at work (as a screw gun, ever open up a Mooney for an annual inspection?) and every couple weeks, I'd bring a more or less discharged pack (I had two at a time) home on the weekend, and charge it with a wall wart charger that worked out to a 16 hr charge, instead of the 1hr charger.

The packs seemed to last around 50% longer doing this, like 3yrs instead of 2. It didn't seem to hurt anyway. And, above all, do not run the drill past when you notice it loosing power, but do run them down frequently, for NiCd packs anyway.

Dave

 

[BentHeadTX]

I had a Makita 9.6V NiCad last me 17 years

I would always run the battery dead before recharging. About once/twice per year I would run the battery dead in the drill then hook a light bulb to the output terminals, then let it run to dead over night. The next morning I would hook a resistor bank with amp meter to the dead battery and kill it to 0.00V and go to dead short. Then I would short out the negative to positive terminals of the battery and let it sit over night yet again.

To get some charge into the battery, I would take a 9 volt battery and crack it across the contacts to get some voltage into it before I recharged.

If you have a problem with a NiCad, drain it all the way down...all the way! Light bulb works wonders then use a shorting bar to get it down to 0.00 volts and let it sit over night.

There was another trick we used to do, we called it "ride the lightning" and it involved high volts/high amp power supplies, face shields, coats and gloves.

Just make sure the battery is a NiCad first! That stunt does not work on NiMH, Li-ion or lead acid...aim away from face, etc.

Learned the light bulb/shorting bar trick back in the 80s working on giant NiCad packs for portable x-ray machines. Run the machine up/down the halls until the pack died, hook up light bulb bank over night, follow up with resistor box/amp meter and then... take the pack apart and short the big Saft cells with shorting bars and leave sit over night. We had to do that every 6 months to keep the 5 year battery pack warranty and never had a problem. Now with the use of high frequency generators, digital imaging and AGM cells, those days with the monster NiCad packs are over.

We had a defib battery that was rejected by the charger/conditioner and I handed it over to the Physio Control guy for warranty. He smiled and pulled a device out of his bag and hook the battery to it. Placed the defib paddles on the device and discharged the defib into the battery. Slapped it back on the charger and it took it... ahhhhhh! Ride the lightning...get it now! (Don't try that at home, kids!)

Good, industrial grade NiCads are TOUGH batteries! I do know that the NiMH batteries were rather wimpy when it was time to throw out the amps and you could not kill them like NiCads. Kill them for a day to keep the voltage depression away... (only applies to high quality NiCd chemistry, cheapo NiCd? I have no idea.)

 

[Russel]

Ironically, and speaking in general terms, it is better for your Nicad battery packs if you use the heck out of them.

I've read examples of security guards that pampered their radio batterys only to have them suffer shorted usefullness, and construction workers that used and abused their batteries, having them work well for longer.

In general terms, with Nicad batteries, it boils down to something like use it or loose it.

Most consider one charge/discharge cycle a month minumum for maintaining Nicad batteries.

Note: Discharging a battery pack (more than one cell) to 0.0 volts is not advisable because you can cause cell reversal. In a pack with four cells in series, for example, by the time the whole battery pack is at 0.0 volts the weakest cell in the pack will actually aquire a reverse charge commonly known as cell reversal. Single Nicad cells are a different story.

http://www.batteryuniversity.com/partone-16.htm Scroll down to 'Depth of discharge' for more detailed information.

 

[BentHeadTX]

Defib batteries are 10 NiCads in series,

If they failed on the official defib cycle, I would do the light bulb trick, dead short them for a day and throw them on a Cadex to run the .1C 16 hour break-in charge. Then I would throw them back on the "official" go/no-go cycler and that got them going over 90% of the time.

The main problem with those batteries is they would be charged all the time causing voltage depression. I would notice with the light bulb the voltage would drop quickly, level off then start to increase voltage (and increased bulb brightness) as the crystals broke down in the mix to boost the voltage. Pretty neat to see it happen as the Fluke showed the voltage increasing under load.

The bulb I used was a 24V 150 watt bulb and as the voltage went down, so did the current so maybe the gentle ride down to less than .1V per cell was kinder to the cells. I do know the 0V shorting trick did give a better capacity and watt hour rating than to cycle them down to 0.4V per cell then recharging. On the other hand, the reason for battery "failure" was constant charging of the batteries as they sat un-used on the crash carts.

I can see LiFePO4 packs taking over were NiCads leave off. They give the current required, are lighter/smaller to carry, the BMS will monitor them and they cost more.

 

[Turbo DV8]

And, above all, do not run the drill past when you notice it loosing power, but do run them down frequently...

:thinking::thinking::thinking::huh2:

 

[45/70]

:thinking::thinking::thinking::huh2:

If you run the pack beyond the point where you notice the drill losing power, you run the risk of reverse charging a cell, or cells in the series pack. While NiCd cells are better at being abused in this manner than NiMH's, it can still irreversibly damage cells within the pack.

Dave

 

[UserName]

A stubborn old man who won't listen to me, runs his drill until it won't run the screw in all the way in high gear, then shifts to low gear, and runs until it won't drive the screw in all the way in low gear, then holds down the trigger, and twists the drill like a ratchet to get the last two screws all the way run in, and then wonders why the batteries are shot to hell.

I guess that's a pretty good example of how to rape a nicd pack, then?

 

[Turbo DV8]

If you run the pack beyond the point where you notice the drill losing power, you run the risk of reverse charging a cell, or cells in the series pack.

Even from day one brand new, my main frustration with the packs on both my 9.6v DeWalt and 18v Ryobi is, even though I never drove them until they were dead, they seemed to just always be already dead or near-dead when I went to use them. I never felt I got good service out of them. Certainly not for what they ask for replacement cost.

 

[45/70]

A stubborn old man who won't listen to me, runs his drill until it won't run the screw in all the way in high gear, then shifts to low gear, and runs until it won't drive the screw in all the way in low gear, then holds down the trigger, and twists the drill like a ratchet to get the last two screws all the way run in, and then wonders why the batteries are shot to hell.

I guess that's a pretty good example of how to rape a nicd pack, then?

Been there, done that. That's how I know!

Even from day one brand new, my main frustration with the packs on both my 9.6v DeWalt and 18v Ryobi is, even though I never drove them until they were dead, they seemed to just always be already dead or near-dead when I went to use them. I never felt I got good service out of them. Certainly not for what they ask for replacement cost.

Usually when they get like that, the problem is they haven't been used enough. Through self discharge, they get crystalline growth and then suffer voltage depression which results in just what you've experienced. If you don't use them, running them near, but as I said, not completely down about once a month, this will happen.

Your choices are to just use them repeatedly over and over until they come back to life, or better, discharge them at a very slow rate with some sort of discharge setup (external to the drill) to 0.9 Volt/cell. Then you need to figure out a way to do a "forming" charge on the pack(s). For this you need to charge them at a rate of 1/10th their rated capacity for 16 hours. You may have to do this two or three times , if they are really bad. Actually if they are really really bad, it can be nearly impossible to revive them.

It's much more true in my experience anyway, that with NiCd cells or packs, you have to "use them, or loose them". NiMH's aren't so bad in this regard, but it still can happen to them as well. A lot of people will complain with both chemistries, how they charged their packs up and let them sit for three months, and now they don't work. Now you know why.

Dave

 

[Turbo DV8]

Usually when they get like that, the problem is they haven't been used enough. Through self discharge, they get crystalline growth and then suffer voltage depression which results in just what you've experienced.

Would this make me a candidate for the newer lithium-ion packs? Do they fare better at sitting for spells? Any advantages or disadvantages to them?

 

[Mr Happy]

Would this make me a candidate for the newer lithium-ion packs? Do they fare better at sitting for spells? Any advantages or disadvantages to them?

I think Silverfox had some advice about power tool NiCd packs in the past. As I recall he found they work best if you store them at about 1/3 charge and then charge them up fully the night before you plan to use them.

NiCd cells basically like to be stored in a discharged state. For individual cells, some people have even recommended discharging them right down to 0 V before storage and then storing them shorted out so they remain at 0 V.

 

[SilverFox]

Hello Tuyrbo DV8,

The Li-Ion packs haven't been out long enough to determine if they last longer than NiCd packs or not. I have had good luck with the Li-Ion packs, but then I also have good luck with my NiCd and NiMh packs too.

Tom

 

[45/70]

Would this make me a candidate for the newer lithium-ion packs? Do they fare better at sitting for spells? Any advantages or disadvantages to them?

Sorry, I didn't get back to you Turbo.

That's what I'm thinking, not just for you, but myself as well. When I used my Makita, it was for work, again as a screw gun. I have Snap-on air tools for everything else. The Makita's packs would usually be run down within a couple days, sometimes both packs in a day (Re: the Mooney's), and at the very minimum, once per week. Now, that I no longer do that kind of work, I too, need a pack that can be left idle for months at a time.

As SilverFox said above, the LiIon packs haven't been around that long, but it would seem to me to be a much better and forgiving chemistry, for us anyway, regardless of whether they provide as many "work/hours" in their lifetime. Now, it's the sitting around unused, that's killing my packs.

Dave

Addendum: For those who aren't familiar with Mooney aircraft, they are general aviation aircraft that are composed of, primarily, #2 Phillips head, stainless steel screws. OK, not really but...... :naughty:

 

[Turbo DV8]

For those who aren't familiar with Mooney aircraft...

My brother started building a Teenie Two once...

Is my understanding on Li-ion correct in that deep discharges are to be avoided? My portable DVD player and GPS Li-ion batteries say it is better to keep the pack "topped off" after every use than to use to full discharge then recharge repeatedly. If this is correct, then I think Li-ion is for me and my next drill. I use it for a small job, then it sits for weeks or months. Easy for me to top off the pack after a use, if the chemistry means when I go to use it two months later it will still be pretty much full.

 

[45/70]

Yes, avoiding deep discharges is highly recommended, as it will provide longer cycle life.

Most Li-Ion cells (LiCo, LiMn, and LiFe) like to be stored about half charged (ideally 40% SOC). I wouldn't see that as a problem though. Charge your drill up, use it, then preferably, check the pack voltage so as not to put it away with too little charge left. If you needed to use it right away, after it had been stored, it would work for a while, as it'd still have some charge left. The nice thing about Li-Ion's in general, is they have very low self discharge, comparable to LSD NiMH's, or better. Pulling your drill out of storage shouldn't really be a problem, unless it's been years or something. It's not a bad idea to check on the packs voltage once in a while anyway, so there shouldn't be any surprises.

One thing about Li-Ion's you have to remember though, is that they degrade whether you use them or not. Still, newer Li-Ion cells and especially the LiFe's, have longer storage life than older cells. If I could get at least 5 years out of a drill pack, I'd be ahead of where I am now. I think with proper storage voltage maintained, not keeping the drill in a hot car etc., it'd be possible to do even better than that. I have flashlight LiCo Li-Ion cells that are 5 years old, and still @ 80%+ capacity, and they get used regularly, so......

Dave

 

[Mr Happy]

I'm not sure about the life problem with NiCd packs? For sure, the available wisdom says the quickest way to kill them is to leave them topped up on a charger all the time or to store them charged.

As long as you charge them up before use then put them away nearly discharged, and never store them on the charger cradle, the batteries should give good service. By storing them with a small amount of charge left in them you have some power available for small unexpected jobs, and if you are planning a large job you can charge them up fully before use.

Are you getting bad service by following this advice?

 

[45/70]

As long as you charge them up before use then put them away nearly discharged, and never store them on the charger cradle, the batteries should give good service.

I'm not sure you directed this at me, or not Mr H, but where I have the problem is putting the drill away "nearly discharged". It's easy enough for me to charge the pack, or packs up, but then the drill is rarely used enough to fully, or anywhere near fully discharge the cells. That's where I have the problem anyway. The cumulative self discharge turns the cells into "crystal farms". Yeah, I know that's not the way to do it, but that's the way it ends up getting done! I may consider joining BAA (Battery Abusers Anonymous), but I think Li-ion packs would work out better in my situation, and then I wouldn't run the risk of exposing my otherwise, spotless record.

With flashlights or handheld transceivers etc., it's not much of a problem, as they are rarely stored anyway. The Makita on the other hand probably gets used for 5-10 minutes, two or three times a year, anymore.

Dave

 

[Mr Happy]

I'm not sure you directed this at me, or not Mr H, but where I have the problem is putting the drill away "nearly discharged".

It was not directed really at anyone in particular, but I was just wondering about the practical difficulties of maintaining healthy batteries in power tools. I think you have sort of answered the question though. What you would need is a battery discharger that you can plug the pack into after use that automatically drains it down to 0.9 V per cell. Otherwise I guess you would have to lock the drill in the on position and just leave it to run itself down.