Nicad C batteries (tabbed or button-top)

[Muse]

I have a flashlight with 4 C size Nicads which I bought almost 9 years ago. One cell shows zero voltage after charge. The others seem "OK." I suppose it would be best to replace the bunch. I could use tabbed cells or button-top cells (what I have now). Tabbed would be less troublesome, once I got the thing wired.

I want to use Nicads instead of NiMh because I often don't use them for months and want them to have a charge. I use this at night on my bike as a headlight, and sometimes I don't ride at night for long periods. Nicads, I'm told, self-discharge rather more slowly than NiMh.

Nicads have gotten harder to find where I live (Berkeley, CA). Where's a good place to get quality cells reasonably? B&M or online? The ones I had were Panasonic, which I figured were about the best. Nine years for Nicads is pretty good, in my experience. TIA.

 

[bruceb]

Digikey has them

http://dkc1.digikey.com/US/PDF/T063/P1.html

Select catalog Page #1774-1775 to see which
ones you want .. they have both Nickel Metal Hydride
and also Nickel Cadmium ... both by Panasonic

 

[Muse]

Originally posted by: bruceb
Digikey has them

http://dkc1.digikey.com/US/PDF/T063/P1.html

Select catalog Page #1774-1775 to see which
ones you want .. they have both Nickel Metal Hydride
and also Nickel Cadmium ... both by Panasonic

Ouch! $6+ apiece before shipping! Thanks, however. I figure maybe go into my local Radio Shack. But I got another idea while on hold with a local hardware store trying to find them. Did Google search on rejuvenating nicads and a site that suggested zapping the apparently dead cell with a couple of other nicads. Nicads supply high amperage in such circumstances and I did it for a couple of seconds with 2 of the other fully charged cells (which I was going to throw out, anyway), and lo and behold, it fried the shorting dendrites in the "bad" cell and it now shows a charge! I am charging it in my trickle charger and it looks like my flashlight will have it's characteristic bright beam back next time I use it. With only 3 cells functioning the beam was real real weak last night!

 

[bruceb]

That's the way it is .. Nicads are not cheap ... and you can be certain the
local Radio Shack will not have them .. Panasonic is a quality battery ... you
want good stuff, it will cost you a little

Right now I am looking to replace my Dewalt 12V XRP 9071 battery pack
for my drill .. that will run on average about $40 or so + tax or shipping
It is also a Nicad

 

[boomerang]

Think about the price ................... then think about how long they last. Give it a good mulling over in your brain.

 

[Muse]

Originally posted by: boomerang
Think about the price ................... then think about how long they last. Give it a good mulling over in your brain.

Well, how do you know how long they will last? Fact is, I burned out the dentrites in my bad battery, so maybe I will get a few more years use out of my old Panasonics.

Doing some internet research this morning, I discovered that Sanyo has developed a NiMH battery that has extremely low self-discharge rates - batteries will retain 90% over a year!! More than 75% over two years! Problem is they only make it in AA and AAA currently.

Or, I could go the NiMH route and just put my flashlight in the freezer. If I know I'm going to use it, remove from freezer ahead of time. That should reduce self-discharge to 10%/month. Or, I could stick to Nicads next time. Amondotech has some 4500 mah C Nicads for around $3 each.

 

[MWink]

Originally posted by: Muse

Originally posted by: boomerang
Think about the price ................... then think about how long they last. Give it a good mulling over in your brain.

Well, how do you know how long they will last? Fact is, I burned out the dentrites in my bad battery, so maybe I will get a few more years use out of my old Panasonics.

Doing some internet research this morning, I discovered that Sanyo has developed a NiMH battery that has extremely low self-discharge rates - batteries will retain 90% over a year!! More than 75% over two years! Problem is they only make it in AA and AAA currently.

Or, I could go the NiMH route and just put my flashlight in the freezer. If I know I'm going to use it, remove from freezer ahead of time. That should reduce self-discharge to 10%/month. Or, I could stick to Nicads next time. Amondotech has some 4500 mah C Nicads for around $3 each.

Hate to tell you but I've "zapped" many NICD's back to life and they usually short out internally again very quickly. I've finally given up and when a battery internally shorts, I just retire it.

Yes Sanyo has developed a low discharge battery but last I checked, it was not available in the U.S. Amondotech does sell a similar battery (which may just be a relabeled Sanyo) called the Titanium Power Enduro. I have tried these batteries and they do have a lower self discharge than normal NICD/NIMH batteries but I don't think they're quite as good as they claim. I doubt they will be anywhere near 90% in a year. If you want you could use these batteries in your light by using them in those russian doll style battery up-sizers.

Also, I don't know why anyone would say NICD's are not cheap because you can find them cheap (though they may not be high quality). Amondotech has NICD C's for as low as $2 each. Other places may be even cheaper.

BTW, one last thing. Are you sure your light has C size batteries and not sub-C batteries? Many devices that have battery packs or built in batteries use sub-C cells which are slightly smaller than a standard C cell. (an interesting side note: many C and D size rechargeables are actually a sub-C cell in a larger case. Usually it's done to save money because true C and D rechargeable's are quite expensive, though they do tend to have a much higher capacity.)

 

[Muse]

Originally posted by: MWink

Originally posted by: Muse

Originally posted by: boomerang
Think about the price ................... then think about how long they last. Give it a good mulling over in your brain.

Well, how do you know how long they will last? Fact is, I burned out the dentrites in my bad battery, so maybe I will get a few more years use out of my old Panasonics.

Doing some internet research this morning, I discovered that Sanyo has developed a NiMH battery that has extremely low self-discharge rates - batteries will retain 90% over a year!! More than 75% over two years! Problem is they only make it in AA and AAA currently.

Or, I could go the NiMH route and just put my flashlight in the freezer. If I know I'm going to use it, remove from freezer ahead of time. That should reduce self-discharge to 10%/month. Or, I could stick to Nicads next time. Amondotech has some 4500 mah C Nicads for around $3 each.

Hate to tell you but I've "zapped" many NICD's back to life and they usually short out internally again very quickly. I've finally given up and when a battery internally shorts, I just retire it.

Yes Sanyo has developed a low discharge battery but last I checked, it was not available in the U.S. Amondotech does sell a similar battery (which may just be a relabeled Sanyo) called the Titanium Power Enduro. I have tried these batteries and they do have a lower self discharge than normal NICD/NIMH batteries but I don't think they're quite as good as they claim. I doubt they will be anywhere near 90% in a year. If you want you could use these batteries in your light by using them in those russian doll style battery up-sizers.

Also, I don't know why anyone would say NICD's are not cheap because you can find them cheap (though they may not be high quality). Amondotech has NICD C's for as low as $2 each. Other places may be even cheaper.

BTW, one last thing. Are you sure your light has C size batteries and not sub-C batteries? Many devices that have battery packs or built in batteries use sub-C cells which are slightly smaller than a standard C cell. (an interesting side note: many C and D size rechargeables are actually a sub-C cell in a larger case. Usually it's done to save money because true C and D rechargeable's are quite expensive, though they do tend to have a much higher capacity.)

Thanks for the detailed post.

Yes, I'm sure they are normal C cells, not sub C's. The flashlight is actually one I got from Radio Shack around 22 years ago, a cheapie that uses 4 C cells. I got a few and am down to my last one (they are fragile and easily broken, so I'm careful not to drop this, my last one). I wired it so I can charge the batteries without removing them from the flashlight.

I saw those "Titanium" C cells at Amondotech today. Didn't know they were reduced self-discharge. That's interesting. They have quite an array of C cells, and as you note, generally quite reasonably priced compared to what what others are selling. 4500 mah cells sound pretty great when I consider that the Panasonics that I have are rated at 1500 mah! Even the 2800 mah cells sound great.

The Titanium cells at Amondotech appear to all by NiMh. I don't see mention of reduced self-discharge properties at the site, though. Where did you see that? I'm thinking of refrigerating the flashlight or even freezing it when I don't expect to use it in the foreseeable future.

 

[MWink]

Sorry I wasn't clear, the C cells they have are NOT low self discharge. The AA (and AAA) Titanium Power Enduro batteries are low self discharge (here). You could use them by putting them in something like this.

BTW I know some say NIMH batteries have a higher self discharge rate than NICD batteries but I never noticed a big difference between them (except for the Energizer 2500mAh NIMH's which run themselves down in about a week). I don't know if freezing the batteries would be a good idea or not (I've never done it). Is there some reason you couldn't just recharge the batteries before you plan to use them?

 

[Muse]

Originally posted by: MWink
Sorry I wasn't clear, the C cells they have are NOT low self discharge. The AA (and AAA) Titanium Power Enduro batteries are low self discharge (here). You could use them by putting them in something like this.

BTW I know some say NIMH batteries have a higher self discharge rate than NICD batteries but I never noticed a big difference between them (except for the Energizer 2500mAh NIMH's which run themselves down in about a week). I don't know if freezing the batteries would be a good idea or not (I've never done it). Is there some reason you couldn't just recharge the batteries before you plan to use them?

Yes, I guess your link is to one of those expanders that let you use a AA in a device using a C battery. But I'd sacrifice mah doing that. Rechargable battery technology has been advancing over the years. People say the Nicads lose charge slower, I couldn't say I have any evidence other than "hearsay." People seem to think that freezing just about any battery other than lead-acid won't harm them, and it will retard self-discharge. I have my rechargeable Li-ion batteries in the refrigerator, but self-discharge isn't the issue there - it's the deterioration of the cells, which is slowed when cooled (and preferably at 40% charge).

The only reason I don't rely on charging before use is that I frequently don't know I'm going to need the device ahead of time. Also, of course, it's a hassle because it's another thing to do. Simpler to pull it out of the refrigerator, but maybe it wouldn't function well at 40 degrees! Really, I was happy enough when the Nicads worked OK. The flashlight usually had enough charge. Every 4th ride or so I had to recharge it, not a big problem. Lately, it doesn't seem to hold a charge well and the last time or two the light was dim, which I discovered today was because one cell wasn't working at all.

 

[0roo0roo]

the question is whether this flashlight is worth such an investment. its probably obsolete, newer nicer flashlights with 1-3watt luxeon leds and such are pretty damn nice these days. plus you'd want to buy nimh not old nicads

 

[Muse]

Originally posted by: 0roo0roo
the question is whether this flashlight is worth such an investment. its probably obsolete, newer nicer flashlights with 1-3watt luxeon leds and such are pretty damn nice these days. plus you'd want to buy nimh not old nicads

You might be quite right, don't know. It would require an investment for batteries, the flashlight and time and effort to find the flashlight. Anyway, I like my flashlight well enough. It casts a very bright light, far brighter than that typical for a bike. When well charged, the light given off is enough to really illuminate the road so that I could veer from a pothole, etc. Most bike lights are (or at least used to be) only good for alerting others, not illuminating the road. I put a halogen light bulb in there instead of the bulb that was orginally in it from around 1985. I don't recall ever seeing a bike that I thought has as effective a front light as I have. I even modified it to accommodate a taillight, which plugs into the main flashlight for juice (at least when the wiring to the taillight isn't snafu, such as it currently is).

 

[0roo0roo]

yea cheap bike lights are like cheap flashlights, pathetic. esp since u really do have to see far ahead when moving at speed. well i haven't tried these myself but a quick google turned up 3 already
just the top 3 links heh
http://www.bikelights.com/Products/vega.htm
http://www.bikeforums.net/archive/index.php/t-42872.html
http://www.amazon.com/Topeak-WhiteLite-3-Watt-Bicycle-Light/dp/B000FI6YMU
and yeausing anything other than aa or aaa rechargables isn't really worth it these days. the c/d tend to be just aa's in an adaptor case, real c/d rechargables are expensive. nimh's are pretty good these days, i use a duracell 15 min charger, you can just top up or charge batteries at the last moment, takes the hassle out of it.

 

[arcas]

Originally posted by: Muse
Even the 2800 mah cells sound great.

Have you considered replacing your C-sized NiCads with 2500+ mAh NiMH AAs? I know you mentioned choosing NiCad because of the lower self-discharge rate but it's not that much lower. According to Wikipedia, NiCads self-discharge at 20% per month while NiMH discharge at 30% per month. So neither is really acceptable for long-term idle storage. Just plug the light into a trickle-charger (say, at, C/20) when you're not riding.

If your light is designed to use 4 full-sized C-cells, you might have enough room to hack it to hold 8 AAs (4 pairs, each pair wired in parallel or 2 sets of 4, each set wired in series). That would give you 5000+mAh at the same voltage. Or you could do 5 AAs and get a full 6V @ 2500mAh (you're currently running 4.8V so your light is probably substantially dimmer than it would be using normal 1.5V cells).

 

[Muse]

Originally posted by: 0roo0roo
yea cheap bike lights are like cheap flashlights, pathetic. esp since u really do have to see far ahead when moving at speed. well i haven't tried these myself but a quick google turned up 3 already
just the top 3 links heh
http://www.bikelights.com/Products/vega.htm
http://www.bikeforums.net/archive/index.php/t-42872.html
http://www.amazon.com/Topeak-WhiteLite-3-Watt-Bicycle-Light/dp/B000FI6YMU
and yeausing anything other than aa or aaa rechargables isn't really worth it these days. the c/d tend to be just aa's in an adaptor case, real c/d rechargables are expensive. nimh's are pretty good these days, i use a duracell 15 min charger, you can just top up or charge batteries at the last moment, takes the hassle out of it.

Yes, that's part of the reason I'm so concerned with self-discharge rates. The charger I use to charge my bike light takes about 12 hours to do a full charge. Since I have Nicads in there I never do partial charges (toping up) in order to avoid the dreaded memory effect. The charger has a miniplug on the end of a long 2 conductor cord. I plug it into a female I installed on the light that's wired to the batteries so I can charge them in the case. It's a royal PITA to remove the batteries from the light and the light is very cheaply made and every time I open and close it, I know it's that much nearer the junk heap. It does provide a great headlight beam on the road, however, and that's why I like the damn thing.

I should really go in the bike shops and see what they are selling these days. Maybe I could find something better. Indeed, my light is great when it works. It has its quirks, but it is great for light and convenience as long as the batteries are behaving and the internal wiring is working OK (there are problems from time to time, because I had to make some modifications in there).

 

[Muse]

Originally posted by: arcas

Originally posted by: Muse
Even the 2800 mah cells sound great.

Have you considered replacing your C-sized NiCads with 2500+ mAh NiMH AAs? I know you mentioned choosing NiCad because of the lower self-discharge rate but it's not that much lower. According to Wikipedia, NiCads self-discharge at 20% per month while NiMH discharge at 30% per month. So neither is really acceptable for long-term idle storage. Just plug the light into a trickle-charger (say, at, C/20) when you're not riding.

If your light is designed to use 4 full-sized C-cells, you might have enough room to hack it to hold 8 AAs (4 pairs, each pair wired in parallel or 2 sets of 4, each set wired in series). That would give you 5000+mAh at the same voltage. Or you could do 5 AAs and get a full 6V @ 2500mAh (you're currently running 4.8V so your light is probably substantially dimmer than it would be using normal 1.5V cells).

I actually got the same idea a couple days ago - using AA's in there and seeing if I could get 8 in there. With NiMH I guess I wouldn't have a memory effect, is that right? Then I wouldn't mind just topping it up from time to time, which I never do with the present NiCds. Even 4 AA's at 2500 mah would have more capacity than the current C Nicads I have in there, which are rated at 1500 mah!

 

[Muse]

After burning out the dentrites in cell 1 (of 4), one of the other cells developed dendrites (well, it went to zero voltage!), and I burned it it's dendrites. Then cell 1 went bad again and I burned it today. It is time to order new batteries (in spite of the season). I'm poking around Amondotech.com for hopefully the best idea in a tabbed NiMH or NiCad set of 4.

Originally posted by: boomerang
Think about the price ................... then think about how long they last. Give it a good mulling over in your brain.

Yeah, that's the thing. I can only guess how long they will last. I've bought once from Amondotech in the past. Got a rechargeable Li-ion battery for my Canon minidv camcorder with charger and it seems OK so far. It was definitely cheaper than buying Canon stuff.

 

[nineball9]

Button "C" NiCad's are available from Radio Shack. Their web site states "available at most stores" but you might want to use their "check availability" link or use the "ship to store" option" if available in CA. Price: 2 for $8.
Rat Shack C NiCads

I had to find 4 solder-tab "C" NiCad's for my old Fluke portable bench DMM earlier this year. I got them from Mouser (they send me a print catalog every 3-4 months).
Mouser

 

[Muse]

Originally posted by: nineball9
Button "C" NiCad's are available from Radio Shack. Their web site states "available at most stores" but you might want to use their "check availability" link or use the "ship to store" option" if available in CA. Price: 2 for $8.
Rat Shack C NiCads

I had to find 4 solder-tab "C" NiCad's for my old Fluke portable bench DMM earlier this year. I got them from Mouser (they send me a print catalog every 3-4 months).
Mouser

Thanks. I figure that after living with button top Nicd's in this flashlight for 23 years or so I'm going to replace them with tabbed cells. It should add greatly to the reliability. 4 of Amondotech's "2800 mah" (yeah, right) Nicd C's will cost me about $14.50 shipped. They claim they are the best in the world (yeah, right).

I'll check a local bike shop first to see if they have anything that will end my addition to this light. If not, I'll probably order from Amondotech. I couldn't find those batteries at Mouser, unless it's one of the battery packs.

Edit: I guess maybe it's this -- Powersonic C Nicd with tabs @ $5.15 ea. They're rated at 2 ah, and that's probably more accurate than Amondotech's rating. I'll probably try the Amondotechs.