opnions wanted on battery reviving of NiCads

[MrAl]

Hi,

A while back i was checking out the Harbor Freight prices on NiCd battery packs for
cordless power tools and i noticed they were very good, which got me to thinking
about just what quality these packs are. I noticed also that they had some
more expensive ones that they were rating higher, but if the lower priced ones
were good enough (even at only 1.3Ahr) that would be good enough for me.
The question still remains however, just how good these lower priced NiCd
battery packs are?

Anyone ever buy any of these packs from H.F. and use them for some time to
get a feel for how good they are, or more important, how long they last?

Thanks...

[Robert Reed]

Never bought batteries perse, but purchased a couple of batt. operated drills with spare batteries and chargers - dirt cheap! For starters they performed very well, but with each succeeding charge they had less and less duration until recharge was needed again. For example after maybe 15 to 20 charge cycles they only ran half as long.

[Lenp]

For what it's worth, a friend purchased several H/F cordless drills last year. Within a year or so, the chargers all failed. The thermal protectors in the transformers opened. Every battery pack had one or more shorted cells and they overloaded the chargers. The charger is a simple FWB supply with no regulation or other protetion except the thermal fuse.
Len

[dtief]

That's why I don't bother with cheap tools. You're better off buy used quality tools.

[MrAl]

Hi,

Thanks for the tip offs on HF battery packs. I had a feeling something wasnt right there.

I just started playing around with an old battery pack (NiCd) too the other day. Since
we are talking about it here i thought i would give it a try and see what happens.

The pack was sitting for ages, like at least 1 year, with no charging or use at all.
When it was measured for the first time it read dead zero, 0.000 volts.
Applying some current like 300ma or so, the pack voltage came up to about 9v
after a few minutes, which told me some of the cells where shorted because it
is a 12v pack and so it should work up to around 14v while charging.

Took it apart, found two cells shorted (i didnt know it then but there were two more shorted
also). I zapped them with a 13vdc wall wart that had a capacitor inside. The cap inside
gives it a somewhat short but high current zap when it is connected directly across a
single cell or even two cells that are shorted (the cells are all in series).
After that, i could get the two cells to accept some charge so their voltage rose up to
about 1.3v each. I then found the two other cells that were shorted, and zapped them,
but they took longer to come up to 1.3v so i guess they were pretty bad. Looking
carefully at one of them i noticed there was some white powder around the positive
electrode terminal, which told me that that one cell had leaked a bit while charging
during one charge time when the pack wasnt in my possession (someone gave it to me).
After zapping them the pack came up to 14v and then up to 15v and a little higher.
Left on charge of about 120ma overnight, it first rose up to 15.85v and then back
down to around 14v. The pack has been sitting unloaded for two days now and i
have been checking the terminal voltage every now and then. I will keep an eye on
it for a while and then load test it if it looks like it is holding a charge good enough.
There may be some cells still good in this thing even if some of them are not good.

Interesting, the charger that came with it was blown. The wall wart primary is
open. Maybe this is because of a built in thermal switch that opened when some
of the cells shorted while it was on charge and the transformer overheated?

[Janitor Tzap]

Hi MrAl,

It might not be the batteries themselves that are crappy.
But more likely the charger that goes with the battery pack.

One thing that ruins perfectly good batteries, are poorly designed chargers.
These type are just wall-warts that put out a constant voltage and current.
And don't cut back the charging current when the battery pack reaches it's maximum charge.

Thus, say you put your new battery on the charger over night {12 to 14 hours.}
But the battery pack reached full charge in about 8 to 9 hours.
The extra time of sitting in the charger are causing the cells to get warm or even boil.
This starts diminishing the batteries life, and continued over charging can cause cells to fail.

I've seen this problem in cordless phones.
I tried to see if I could install a charging current control circuit into the cordless phone,
to stop the batteries from being over charged.
But there wasn't enough physical space inside the phone to do it.
So, I instead I have taken up the tactic of pulling the phone off it's charging base in the morning. {7:30 - 8:00 am}
Then placing it back into it's charging base before going to bed. {11:30 pm - 1:00 am}
This only places a 7 hour or 8 hour charge on the battery.
So I'm most likely not going to over charge it.

So getting a charger that is designed to sense when the battery has reached full charge.
Will greatly increase the longevity of the battery pack.


Signed: Janitor Tzap

[dacflyer]

i took the metal hydrade batterys back and exchanged them for nicads, the ones i got are actually for a R/C use they are rated for 1,500Ma great . and the pack is configured for what i need already, i just have to modify the top, remove the leads and transfer the tabs from my old pack, should work out fine, and the cost of the metalhydrades was enough in exchange for 2 nicad packs. i got them at the local hobby shop.

[ringo47stars]

I know this is an old post but the topic on class d amp in n & v got me thinking and so I tried something and it worked for ni-cads, both for charging them and reviving them, and I suppose it would work for ni-mh ones too but I haven't tried that yet. I thought I would use it for an answer for the reader to reader q's & a's but I guess I submitted it too late as it never got published and the question (9095) got answered in the current issue. So if any one is still interested I could put the answer here or on a web page or a version of it.

[ringo47stars]

I googled myself to see what they had on me and found one of the first listed was my email I sent to Nuts and volts on the question 9095. I don't know how long it was on there because I hardly use google. I edited the page by taking my email off of it but that was not enough so I changed the name. The circuit works for both charging and repairing batteries but because of the potential harm to batteries this might create i decided not to post it but if someone wants a link to it just PM me. If you google tired94302 you will see it listed but the link no longer works.

[Dean Huster]

The cost of a new drill (or whatever) is often not that much more than that of new batteries, whether new or rebuilt.

The drill is use now is an 18v Hitachi LiIon model ... 2 batteries, 15-minute recharge and as mentioned, each doesn't not last as long as the older NiCd batteries before requiring a recharge. I'm in the building trades now, so I use this thing a lot. I've had it over a year and LOVE it. Of course, I am comparing it to a Craftsman 18v NiCd model and consider Craftsman to be pretty much bottom-feeder stuff these days. I'd never buy another cordless Craftsman product.

As to the "problems" with the LiIon model, it's just a matter of getting used to it. If I'm driving 3" deck screws on high speed, two packs can't keep up, and it isn't because they discharge, it's because they get too hot and the temp sensor won't let me damage the things. So in that case, yes, three packs might work better since you have to wait for the pack to cool before the charger will allow it to charge. And it may be OK (but slower) to drive the screws on low speed where the battery current is lower.

If buying new, I'm going to try Home Depot's Ridgid brand. They come with LIFETIME service INCLUDING BATTERIES and batteries are the weak link as we all know.

Although I detest the brand, Ryobi is the only tool maker that has made their LiIon batteries with the same battery stem as the NiCd batteries so you can upgrade by buying a set of batteries and a charger. It's just a shame that I have at least six Ryobi tools, only one of which is still working properly, that that's only because you don't use an electric hand planer all that often.

Dean

[MrAl]

Hi Dean,


I always wondered about the Li-ion cordless drills. I have read about them in advertisements, but not any reviews yet.
I had to wonder mostly about how the cells could take the constant discharge rate that a cordless drill might demand.
Now i know...they dont take it very well!

I should have guessed so much. They advertise and advertise these days yet produce a bunch of carp.

I did not jump to buy one because i was guessing that there was a problem with them.

[Dean Huster]

Al, I think they do well. One interesting characteristic over NiCds is that because of the built-in electronics that protects the cells, when the battery voltage drops to a certain point, everything just stops. Dead stops. There's no slowing down or reduced torque. It just stops. Swap out the battery and go again. And I certainly can't complain about that 15-minute recharge time.

I have very little negative to say about the Hitachi LiIon drill. It's smaller and LIGHTER than the Crapsman it replaced. I drive 1/4" x 6" lag bolts with the thing as well as 6" Headloc screws. I just finished installing an underdecking system at a customer's house and drove in a total of around 8 pounds of 3" deck screws, 100 sheet metal screws, 20 5" Headloc screws and 150 2" washered #10 roofing screws. I still have to build a short pergola and will waste another 3# of 3" deck screws. During all this, I've had no complaints about the drill or battery system at all, save for maybe wishing for a third battery pack. Last autumn, I built a deck using only that drill. It's been serving me well for about two years now.

I'd buy a LiIon drill again in a heartbeat. However, I see no reason at all to own a battery-operated circular saw, DeWalt or any other brand. The RPM of the blade is just too low for any decent work. I can run a 100-foot extension cord just fine or use my hand saw for those odd cuts.

The one tool that they never have for all those various battery packs is a decent soldering iron. I'm working to mate a Weller 24-volt temp-controlled iron to a pair of 12-volt packs.

[MrAl]

Hi Dean,


Oh that's interesting about the Li-ion drills, i'll have to think about that again i guess.

Another thing that works is to run a standard 12v drill that was NiCd off of a standard 12v jump pack made for automobiles.
The run time is amazing. Short cord to the pack, that's it. I got two NiCd packs with my last drill and since both went dead i converted one to have a short cord plus a cigar lighter plug and have been using it that way ever since (removed all the NiCd cells of course). Was never sorry i did that. I just charge the 12v jump pack once every three months or there abouts.


About the soldering iron, if you can stand 30 or 40 watts Radio Shack makes (or used to make) a 12v iron that worked pretty well.
I have one around there somewhere. It plugs into the cigar lighter outlet.
Another idea is to use a 12vdc to 120vac inverter then you can use your fav soldering iron. Some irons will run off of DC too so you can make your own 12vdc to 120vdc booster and it doesnt have to be isolated, if you care to. Making one probably wont take much because the 50 watt iron should draw less than 0.5 amps at 120vdc, which is still only about 5 or 6 amps from the 12v battery. A single MOSFET and 555 timer ic and a catch diode and 6 amp inductor might do it, without even a control circuit. The duty cycle would be set to provide 120vdc out with the required soldering iron load. Maybe a little overvoltage protection circuit just in case the iron becomes unplugged and that's all there is to it, most likely.

[Bob Scott]

If buying new, I'm going to try Home Depot's Ridgid brand. They come with LIFETIME service INCLUDING BATTERIES and batteries are the weak link as we all know.

Dean,
Do you have more information on this lifetime warranty? Do you have a link? One new battery pack for my son's Ridgid drill went defective (open) over the winter of non-use.

In Ridgid's website, there is no mention of "lifetime" only "3 year":

http://www.ridgid.com/manuals/RIDGID3yr.pdf

[ringo47stars]

I like thinking in terms like positive and negative instead of the more popular proton collector and proton emitter/donor when trying to figure out if the battery is good or not. If a battery doesn't charge up then it has too much base/proton collector or negative that might be interpreted as resistance also. So when zapping a battery with a wall wart you could call this reducing the resistance - base - negative - proton collector. Then if you have a battery charger that uses a battery power supply you should see the batteries connected in series with a shunt or modulating circuit that charges up the batteries that need it. But the charging circuit won't zap the batteries because of the precarious balance of connecting the batteries in series. So to zap a battery without too much fear of it exploding you just put a capacitor in series with the battery, while on the charger, for a short time depending on how many times this was done or the condition of the battery. This should work for most types of batteries because it just reduces the negative - resistance - base. There are other ways to keep the batteries in good shape by adding a positive feed to them but this is only a response to the original post.