I have a cordless drill 18V, i usually store fully charged so it has juice when i need it (not too often), i know all about the dreaded memory effect and tend to fully drain or mostly drain before charging, will i get longer life stored drained or charged?
It seems to self discharge 10-20% a month, and is used 1-3 times a month very lightly
At 18V is it 15 cells in one package (at 1.2V each)?
I know all about NIMH, so its good to know about similarities and differences
Your best bet is to replace it with a Lithium Ion battery drill. NiCad is Sooo worthless. After a few years the batteries cant hold a charge worth a flip. The self-discharge effect is horrible too.
I’d consider looking on Slickdeals and find one on sale. It might be a good idea to get part of a Set if possible…where you can use the same battery pack with multiple tools. I personally upgraded to a Ridgid 18v X4 system and I really like it. Excellent drill, driver, and I got the Sawzall for xmas.
For really light usage, you might look at a 12V system instead as the LiIons have a lot more power density. 12v is good enough for most things. My 18V sawzall cut through 6 inch branches pretty fast. I was impressed.
It was a gift, its a black and decker, and while not being great i can’t justify buying another one when this one works fine, and for such light duty use. I know how annoying nicads were, i had far too many and i didn’t choose it for this device but its here so i want to make the best of it.
NiCd is far, far more robust than NiMH and in my experience doesn't self-discharge as fast as non-LSD NiMH cells do. It'll take far more abuse too. I still have some functional 30 year old NiCd D cells that still read above their nominal capacity. They used to get charged by pulling my motorbike's battery and tossing in 5 of these cells at a time then going for a drive around. Or if I wanted to charge all of them a 5S2P pack got wired in.
The internal resistance is awful now, but they still work fine in relatively low-current applications. After 30 years.
BTW NiCd memory has been shown once. And only once. Largely it is a myth.
You can use your hobbycharger to do a full charge and discharge cycle.
I also have an old cheapo nicd drill and I don’t care about it much and it still works.
I have a timer for charging it because I think the biggest problem is to overcharge it with the stock dumb chargers.
i agree its a myth but i had nicads that were just unreliable unless discharged then recharged (even then reliability was only ok), sometimes you get normal operation, sometimes that damn thing just stops working after 20-30% usage, i hated those pieces of junk
This cordless drill is decades newer and self discharges more slowly, i assume its a better quality pack, that a few lessons have been learned since then, but i am still not convinced it will work as flawlessly as an eneloop (if eneloops had high self discharge)
How many cells in a 18V nicad pack?
So should i be topping it up every few months or just let it self discharge and light usage to rather low then recharge?
I don’t have a hobby charger, but if i get one what should i use for a power supply?
The drill has a crappy dumb charger, not much i can do about it though
Even apparently dead NiCd cells can often be revived by dead shorting them to 0V (Use heavy wire and wear gloves) then charging them again. Packs are harder. An 18V pack will probably have 15 cells in it. Charge them slowly to let charge equalise gently. Once a cell reverse charges on discharge they can be very troublesome. If you like the drill it's worth carefully taking the pack apart and ordering new (and better) cells. Best to use a hobby charger on it after that...
I don’t like it that much, its an appliance that gets used sometimes
I know for li ion if your just storing it you should aim for 40% charge, for ni cad does it matter if i store it charged or partially charged?
it has this battery
http://www.blackanddecker.com/attachments/HPB18.aspx
With NiCd packs I just charge them before use.
excellent, thanks 
18v pack has 15 cells. some are sub c cells, some drills (cheaper\crappy quality) use smaller 3\4sub c cells.
i also still have 15 years old drill that still runs on original cells. and quite good for the age. nicd are most robust cells.
i have replaced cells in pbly 7 or 8 packs, using tenergy subc cells, only 1 time i had pack fail, cuz 1 cell failed, i replaced it, and pack still works just fine.
also if your drill uses 3\4subc cells, (mesure lenght of the cell to see which one you got) don’t bother replacing, no one makes good cells of that size, i tried to recell those too, but all failed before they had 20 cycles on them.
with is strange, the same company “tenergy” makes sub c, and 3\4sub c, but their quality totaly different. may be different branches make them.
if you have sub c cells, get ones with yellow tenergy logo wrap, i’d stay away from their paper or blank wraps,
Also have a NiCd drill with 2 packs, they always self discharge , and when I need it they are flat, I use a hobby charger to do a discharge /charge cycle before use or when I remember on a bi weekly basis.
The hobby charger brought back both battery packs to a useable level as the supplied charger was total Cr@p, the battery packs are 12v.
the case is about 50mm in height and 78mm x 140mm, so not sure what cells it would be if there are 15 of them
I am not sure if I got your question right, the hobbychargers need a standard power supply with a standard DC connector.
I have a really cheap 12V 4A supply which is more than enough for charging everything I have(biggest battery is a 3S 2650mAh pack)
Please be informed that the power ratings of hobbychargers are not so important for us in terms of charging, but in discharging. The standard 50W chargers can only do 10W discharge and 1A max dischargecurrent.
I have a cheap small hedge and lawn edge cutter which had 8 really cheap cells in it. It died very fast and I have replaced the cells with eneloops…man that thing works now like a charm. I also added 2 small banana sockets to the cells so I can charge it with my hobbycharger.
you need to open it and mesure cell not the casing.
but exterior dimentions are just like in mine 18v dewalt drill, it has sub c cells.
FYI,
(approx. 5 seperate parts) video of replacing a battery pack.
I’m not sure if a Black and Decker is worth the effort, I have my doubts.
I know very little, but I believe the current draw of a cordless drill is very high. If you replace with a different battery chemistry, be aware of that requirement.
yea, draw can be up to 30 amps. when dril stalls, normaly under light load about 10A.
i was hoping some of those cells would be too big to fit in the casing i have so the type could be determined by process of elimination because i’m not planning on opening the casing (which is an odd thing for me to say, as i usually take apart practically everything)
NiCads are probably the most robust rechargeable battery around. You can abuse the hell out of them. They actually like to be over-discharged. I have some 40 year old nicads still going strong.
There does not seem to be any consensus as to storing them charged or discharged. Doesn’t seem to matter much. Cells that have not been used in a while do benefit from a few charge/discharge cycles.
Their main failure mode is the growth of crystals in the cell that can short them out (without the standard lithium cell fireworks). You can burn out these shorts with a charged capacitor, but they quickly return.
is there a way to prevent or slow the growth of these crystals?