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Battery memory on NiCad cordless drill
I have a Panasonic 12v (NiCads) cordless drill/driver with 2 batteries
and it seems to me that the batteries aren't holding a charge very well. They are around 3-4 years old, lightly used. They seem to charge too quickly. If I leave them in the charger after the charger shows them as fully charged and let them trickle charge, will that top them up? I haven't been doing that. Is this a loss of capacity of the batteries? Is there some way I can restore the capacity of the batteries? Any experience with these? Thanks for any ideas, info, suggestions, etc. Dan |
Battery memory on NiCad cordless drill
The traditional way to erase battery memory is to deep-cycle the
battery. For a drill/driver, I would use it until the thing hardly turns at all, then find a way of clamping the trigger down so as to completely drain the battery. You want to get it as close to 0VDC as possible. After that, fully charge the unit and see if the memory has been erased. In article , Dan_Musicant wrote: I have a Panasonic 12v (NiCads) cordless drill/driver with 2 batteries and it seems to me that the batteries aren't holding a charge very well. They are around 3-4 years old, lightly used. They seem to charge too quickly. If I leave them in the charger after the charger shows them as fully charged and let them trickle charge, will that top them up? I haven't been doing that. Is this a loss of capacity of the batteries? Is there some way I can restore the capacity of the batteries? Any experience with these? Thanks for any ideas, info, suggestions, etc. Dan |
Battery memory on NiCad cordless drill
That is very good advice, providing your goal is to kill the cells entirely.
You should not completely discharge NiCd batteries. Read http://www.repairfaq.org/ELE/F_NiCd_...ICDBATTERY_005 for a reasonably technical discussion of this and other properties of NiCds. todd "Andrew Williams" wrote in message news:050820061757313000%andrewSPAMALOT@williamsmus ic.com... The traditional way to erase battery memory is to deep-cycle the battery. For a drill/driver, I would use it until the thing hardly turns at all, then find a way of clamping the trigger down so as to completely drain the battery. You want to get it as close to 0VDC as possible. After that, fully charge the unit and see if the memory has been erased. In article , Dan_Musicant wrote: I have a Panasonic 12v (NiCads) cordless drill/driver with 2 batteries and it seems to me that the batteries aren't holding a charge very well. They are around 3-4 years old, lightly used. They seem to charge too quickly. If I leave them in the charger after the charger shows them as fully charged and let them trickle charge, will that top them up? I haven't been doing that. Is this a loss of capacity of the batteries? Is there some way I can restore the capacity of the batteries? Any experience with these? Thanks for any ideas, info, suggestions, etc. Dan |
Battery memory on NiCad cordless drill
On Sat, 05 Aug 2006 21:47:47 GMT, Dan_Musicant
wrote: I have a Panasonic 12v (NiCads) cordless drill/driver with 2 batteries and it seems to me that the batteries aren't holding a charge very well. They are around 3-4 years old, lightly used. They seem to charge too quickly. If I leave them in the charger after the charger shows them as fully charged and let them trickle charge, will that top them up? I haven't been doing that. Is this a loss of capacity of the batteries? Is there some way I can restore the capacity of the batteries? Any experience with these? Thanks for any ideas, info, suggestions, etc. Dan Four years is past the maximum life of a nicad even you you have only used them lightly. If you love that drill a lot, you can order new batteries and solder them in. |
Battery memory on NiCad cordless drill
True.
"todd" wrote in message . .. That is very good advice, providing your goal is to kill the cells entirely. |
Battery memory on NiCad cordless drill
In article om,
Andrew Williams wrote: The traditional way to erase battery memory is to deep-cycle the battery. For a drill/driver, I would use it until the thing hardly turns at all, then find a way of clamping the trigger down so as to completely drain the battery. You want to get it as close to 0VDC as possible. After that, fully charge the unit and see if the memory has been erased. This is indeed the traditional way and it is also NOT a good idea. The "memory effect" is pretty much a myth for multicell nicads used in cordless power tools. Letting the batteries fully discharge is also potentially harmful to the battery. When all the cells are fully discharged, it becomes possible for one or more of them to go into a reversed polarity state. Once this happens that cell becomes permanently useless. For a good quality cordless tool with a "smart" charger (most any DeWalt, Makita, Milwaukee, etc.) the best place to keep a battery is in a plugged-in charger. For cheaper cordless tools (like Harbor Freight's) with a "dumb" charger, remove the battery after the recommended charging time. -- Larry Wasserman Baltimore, Maryland |
Battery memory on NiCad cordless drill
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Battery memory on NiCad cordless drill
Dan_Musicant wrote in
: I have a Panasonic 12v (NiCads) cordless drill/driver with 2 batteries and it seems to me that the batteries aren't holding a charge very well. They are around 3-4 years old, lightly used. They seem to charge too quickly. If I leave them in the charger after the charger shows them as fully charged and let them trickle charge, will that top them up? I haven't been doing that. some chargers are designed to be able to leave the pack in,some are not. You need to check your manual. Is this a loss of capacity of the batteries? Is there some way I can restore the capacity of the batteries? Any experience with these? Thanks for any ideas, info, suggestions, etc. Dan It's been my experience that for longest life,NiCds are best used often.(use it or lose it) Once you start storing them for long periods,their life decreases. NiCds also have a self-discharge rate;just sitting in storage,they discharge on their own. -- Jim Yanik jyanik at kua.net |
Battery memory on NiCad cordless drill
Andrew Williams wrote in
news:050820061757313000%andrewSPAMALOT@williamsmus ic.com: The traditional way to erase battery memory is to deep-cycle the battery. For a drill/driver, I would use it until the thing hardly turns at all, then find a way of clamping the trigger down so as to completely drain the battery. You want to get it as close to 0VDC as possible. After that, fully charge the unit and see if the memory has been erased. In article , Dan_Musicant wrote: I have a Panasonic 12v (NiCads) cordless drill/driver with 2 batteries and it seems to me that the batteries aren't holding a charge very well. They are around 3-4 years old, lightly used. They seem to charge too quickly. If I leave them in the charger after the charger shows them as fully charged and let them trickle charge, will that top them up? I haven't been doing that. Is this a loss of capacity of the batteries? Is there some way I can restore the capacity of the batteries? Any experience with these? Thanks for any ideas, info, suggestions, etc. Dan then find a way of clamping the trigger down so as to completely drain the battery. Long/joined twistie ties, tie wrap, string are a few ways. |
Battery memory on NiCad cordless drill
"Al Bundy" wrote in message ... Long/joined twistie ties, tie wrap, string are a few ways. To kill your batteries |
Battery memory on NiCad cordless drill
On Sat, 05 Aug 2006 21:47:47 GMT, Dan_Musicant
wrote: I have a Panasonic 12v (NiCads) cordless drill/driver with 2 batteries and it seems to me that the batteries aren't holding a charge very well. They are around 3-4 years old, lightly used. They seem to charge too quickly. If I leave them in the charger after the charger shows them as fully charged and let them trickle charge, will that top them up? I haven't been doing that. Is this a loss of capacity of the batteries? Is there some way I can restore the capacity of the batteries? Any experience with these? Thanks for any ideas, info, suggestions, etc. Dan I read the responses below that state you should not drain the battery but when I googled *NiCad Batteries Drain Completely* there are articles that state you should drain them. Here are a few of the articles.... http://www.nyu.edu/its/pubs/connect/...rdslaptop.html http://www.ehow.com/how_3037_battery-life-laptop.html Frankly, I have no idea which is correct (and I did see some articles to the opposite) but if I'd suggest calling Panasonic tech service. |
Battery memory on NiCad cordless drill
A lot of good info here, but I have some also to offer.
The key problem is "lightly used" - that means the NiCd cells will develop a memory, unlike more modern ones. A memory of being charged, then leak-discharged, then trickle charged, etc, etc. The only good way around avoiding this, is using (as others have said) a discharge cycle (or use to flat) before recharging, and not leaving them flat. The age of the cells has NOTHING to do with the expected performance, as long as you have cycled them properly. I have NiCd cells still working strongly from the mid nineties. wrote in message ... In article , Dan_Musicant wrote: I have a Panasonic 12v (NiCads) cordless drill/driver with 2 batteries and it seems to me that the batteries aren't holding a charge very well. They are around 3-4 years old, lightly used. They seem to charge too quickly. If I leave them in the charger after the charger shows them as fully charged and let them trickle charge, will that top them up? I haven't been doing that. Is this a loss of capacity of the batteries? Is there some way I can restore the capacity of the batteries? Any experience with these? Thanks for any ideas, info, suggestions, etc. Dan Some chargers have a diagnostic or "tune-up" mode that may help if you leave the batteries in for an extended time, so it's worth trying. Unfortunately, at 3 to 4 years it would be common to see some degradation in the performance of a nicad, regardless of how much use they have had. -- Larry Wasserman Baltimore, Maryland |
Battery memory on NiCad cordless drill
Joe Bemier wrote:
I read the responses below that state you should not drain the battery but when I googled *NiCad Batteries Drain Completely* there are articles that state you should drain them. Here are a few of the articles.... http://www.nyu.edu/its/pubs/connect/...rdslaptop.html http://www.ehow.com/how_3037_battery-life-laptop.html Frankly, I have no idea which is correct (and I did see some articles to the opposite) but if I'd suggest calling Panasonic tech service. Draining a NiCd or NiMH cell completely means to remove essentially all the energy it contains. This requires discharging it to a cell voltage of about 1.0 volt. Doing this, then recharging, is the way to reverse "memory" (voltage depression) effects. If the battery has 6 cells or fewer and they're reasonably well matched, you can usually safely discharge the battery to 1.0 volt times the number of cells (e.g., 6.0 volts for a 6 cell battery) without risk of reverse charging one of the cells. If the battery has more cells, this becomes increasingly risky and the only safe way to do it is to discharge the cells in groups of 4-6. This of course requires getting into the battery pack. The folks cautioning against trying to discharge down to 0 volts are absolutely correct. It just about guarantees reverse charging one or more cells, which will permanently damage those cells. Those cells will then have even more reduced capacity, so they'll go into reverse charge even earlier in the battery cycle the next time. There's never any need to discharge a cell below 1.0 volt. A well designed tool or electronic device intended for NiCd or NiMH power should quit operating and drawing battery current when the pack voltage reaches 1.0 volt per cell. Unfortunately, a lot aren't in this category. Roy Lewallen |
Battery memory on NiCad cordless drill
I find nicads in drills last about two years. You got your use out of
them. -- Christopher A. Young You can't shout down a troll. You have to starve them. .. "Dan_Musicant" wrote in message ... I have a Panasonic 12v (NiCads) cordless drill/driver with 2 batteries and it seems to me that the batteries aren't holding a charge very well. They are around 3-4 years old, lightly used. They seem to charge too quickly. If I leave them in the charger after the charger shows them as fully charged and let them trickle charge, will that top them up? I haven't been doing that. Is this a loss of capacity of the batteries? Is there some way I can restore the capacity of the batteries? Any experience with these? Thanks for any ideas, info, suggestions, etc. Dan |
Battery memory on NiCad cordless drill
Jim Yanik wrote:
Dan_Musicant wrote in : I have a Panasonic 12v (NiCads) cordless drill/driver with 2 batteries and it seems to me that the batteries aren't holding a charge very well. They are around 3-4 years old, lightly used. They seem to charge too quickly. If I leave them in the charger after the charger shows them as fully charged and let them trickle charge, will that top them up? I haven't been doing that. some chargers are designed to be able to leave the pack in,some are not. You need to check your manual. Is this a loss of capacity of the batteries? Is there some way I can restore the capacity of the batteries? Any experience with these? Thanks for any ideas, info, suggestions, etc. Dan It's been my experience that for longest life,NiCds are best used often.(use it or lose it) Once you start storing them for long periods,their life decreases. NiCds also have a self-discharge rate;just sitting in storage,they discharge on their own. Probably right about the use or lose it. If you don't use them much you need to keep checking the voltage at least once every 1-2 months and make sure the voltage doesn't drop below 12V. Full charge on a 12V NiCad is about 14V, but that degrades quickly to about 13V and I check the voltage when charging and stop before it reaches 14V. Overcharging is the number one cause of batteries going bad. |
Battery memory on NiCad cordless drill
"todd" wrote in message . .. That is very good advice, providing your goal is to kill the cells entirely. You should not completely discharge NiCd batteries. Read http://www.repairfaq.org/ELE/F_NiCd_...ICDBATTERY_005 for a reasonably technical discussion of this and other properties of NiCds. todd I have two drills, a Makita and a Sears. The Makita is over 10 years old with the original two Batteries, the Sears is about 6 years old with the same two batteries. I always let the drill run down to where it stops turning or pretty close to stopping before recharging. Who knows, but it worked for me. I didn't do this at first, and after about 2 years one of the Makita batteries stopped holding a charge. From something I read on the internet (what the hell, it was worth a try) I took the 12 volts from my car battery charger and quickly touched it on the baterry contacts a couple times, sure enough the battery started working again, and it still works 8 years later! Regardless, I will make sure my next drill uses Nimh batteries. |
Battery memory on NiCad cordless drill
On Sun, 06 Aug 2006 04:39:49 GMT, "George E. Cawthon"
wrote: Joe Bemier wrote: On Sat, 05 Aug 2006 21:47:47 GMT, Dan_Musicant wrote: I have a Panasonic 12v (NiCads) cordless drill/driver with 2 batteries and it seems to me that the batteries aren't holding a charge very well. They are around 3-4 years old, lightly used. They seem to charge too quickly. If I leave them in the charger after the charger shows them as fully charged and let them trickle charge, will that top them up? I haven't been doing that. Is this a loss of capacity of the batteries? Is there some way I can restore the capacity of the batteries? Any experience with these? Thanks for any ideas, info, suggestions, etc. Dan I read the responses below that state you should not drain the battery but when I googled *NiCad Batteries Drain Completely* there are articles that state you should drain them. Here are a few of the articles.... http://www.nyu.edu/its/pubs/connect/...rdslaptop.html http://www.ehow.com/how_3037_battery-life-laptop.html Frankly, I have no idea which is correct (and I did see some articles to the opposite) but if I'd suggest calling Panasonic tech service. That's the problem with netnews and the Internet in general. Lot's of incorrect stuff that gets repeated over and over even by groups that should know better. Always check major manufacturers for the accurate information when there is controversial information. Yes, and that includes the opinions that ppl are posting here - who knows which way to lean. Thats why I say calll Panasonic. |
Battery memory on NiCad cordless drill
JimL wrote:
Four years is past the maximum life of a nicad even you you have only used them lightly. Maybe my 10-year-old nicads never read the book :-) |
Battery memory on NiCad cordless drill
ToMh wrote:
"todd" wrote in message . .. That is very good advice, providing your goal is to kill the cells entirely. You should not completely discharge NiCd batteries. Read http://www.repairfaq.org/ELE/F_NiCd_...ICDBATTERY_005 for a reasonably technical discussion of this and other properties of NiCds. todd I have two drills, a Makita and a Sears. The Makita is over 10 years old with the original two Batteries, the Sears is about 6 years old with the same two batteries. I always let the drill run down to where it stops turning or pretty close to stopping before recharging. Who knows, but it worked for me. I didn't do this at first, and after about 2 years one of the Makita batteries stopped holding a charge. From something I read on the internet (what the hell, it was worth a try) I took the 12 volts from my car battery charger and quickly touched it on the baterry contacts a couple times, sure enough the battery started working again, and it still works 8 years later! Regardless, I will make sure my next drill uses Nimh batteries. Next time you're in Home Despot or the like check out the 36v lithium-ion deWalts. -- --John to email, dial "usenet" and validate (was jclarke at eye bee em dot net) |
Battery memory on NiCad cordless drill
"Stormin Mormon" wrote in message ... I find nicads in drills last about two years. You got your use out of them. Usually nicads are rated in how many charge cycles they can take. Around 300 to 600 cycles. I think that a partical charge is also a partical cycle but not sure. Some rechargables are just rated in number of years even if they are not used very often. |
Battery memory on NiCad cordless drill
Ralph Mowery wrote:
"Stormin Mormon" wrote in message ... I find nicads in drills last about two years. You got your use out of them. Usually nicads are rated in how many charge cycles they can take. Around 300 to 600 cycles. I think that a partical charge is also a partical cycle but not sure. Some rechargables are just rated in number of years even if they are not used very often. True, LiOn Cells will only have a useful life of about two years, after that they should be replaced, the same is true for LiPo batteries. |
Battery memory on NiCad cordless drill
John McFerren wrote:
Ralph Mowery wrote: "Stormin Mormon" wrote in message ... I find nicads in drills last about two years. You got your use out of them. Usually nicads are rated in how many charge cycles they can take. Around 300 to 600 cycles. I think that a partical charge is also a partical cycle but not sure. Some rechargables are just rated in number of years even if they are not used very often. True, LiOn Cells will only have a useful life of about two years, after that they should be replaced, the same is true for LiPo batteries. I keep hearing this. My real world experience is otherwise. -- --John to email, dial "usenet" and validate (was jclarke at eye bee em dot net) |
Battery memory on NiCad cordless drill
On Sun, 06 Aug 2006 05:25:44 GMT, "ToMh" wrote:
:Regardless, I will make sure my next drill uses Nimh :batteries. I got the NiCads because the drill came cheaper that way. It's true that NiMH will have greater capacity. They say that the modern NiCads don't have the memory effect, but I don't know if that's categorically true. However, something to consider is the fact that NiMH will self-discharge at a significantly higher rate than NiCads. For me, that's a very important factor because most of the energy drain on my cordless drill batteries is from sitting around, not from use. I think I'll stick with NiCads for that reason. |
Battery memory on NiCad cordless drill
Dan_Musicant wrote:
most of the energy drain on my cordless drill batteries is from sitting around, not from use. I think I'll stick with NiCads for that reason. If you are letting the thing sit around a lot, get lithium batteries. The self-discharge of NiMH is overstated by many - they do discharge faster than NiCd, but not outrageously so. Li Ion, OTOH, will stay charged for long periods. However, the life of a Li battery is more closely tied to state of charge than to number of charge/discharge cycles. If it sits around fully charged a lot, it will not last as long as if it's allowed to sit around partially charged. Mike |
Battery memory on NiCad cordless drill
Dan_Musicant wrote in
: On Sun, 06 Aug 2006 05:25:44 GMT, "ToMh" wrote: :Regardless, I will make sure my next drill uses Nimh :batteries. I got the NiCads because the drill came cheaper that way. It's true that NiMH will have greater capacity. They say that the modern NiCads don't have the memory effect, but I don't know if that's categorically true. However, something to consider is the fact that NiMH will self-discharge at a significantly higher rate than NiCads. For me, that's a very important factor because most of the energy drain on my cordless drill batteries is from sitting around, not from use. I think I'll stick with NiCads for that reason. Do NiMH short out or fail if self-discharged,like NiCds? If not,then they can be stored,then simply charged up before use,-without needing to buy new packs. -- Jim Yanik jyanik at kua.net |
Battery memory on NiCad cordless drill
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Battery memory( NiCad) Pulse charge it !!
1) Pulse charge and it will return to full energy if it is
still in infancy . Never deep cycle any battery . Batterys die for being NOT fully charged . Leave them discharged is to shorten life . ---------------- 2) NimH and Nicad lose 10% in 1 day , Li-Ion lose 1% . I gambled on 100 NimH "LenMars" 2.5 aH AA's from Buy.com .. 25% loss in 1 day , load tested OK , i tossed them , not worth my time . ----------------------------------------------------------------------- more ........................ Pulse charge a nicad and it "loses" its memory , return full energy .. ......... a 4 amp pow supply with a simple Resistor works great . C cell ( NiCad ,NimH) , as in drills , can take 2-3 amps til about 1pt36 vdc (((Linux crap apps ! Konquerer ..Cant see the text , too small , no way to change it so i use pt for decimal point )))))))) 1 ) so pulse with a very low Z pow supply at 1pt48 to 1pt5 vdc per cell and a Resistor of 0pt25 ohms . Theorectically , you must select R ( 0pt25) carefully , use scope to see the lighter amps , for it will heat up if too much amps above 1pt38 vdc . 2) but since current is so hi and pow supply is likely to help the current limit anyway , just measure the current above 1pt36 to 1pt37 vdc and adj the supply Voltage instead of doin the Resistor . Now the resistor limiter is inside your pow supply and you can simply vary period of pulse to "tame" the circuit and keep batteries cool . Never charge a hot battery ( 110F ) , they dry up , short life . Velleman has o'scope ( HPS-40 for $250 ) . BTW Clever battery chargers use a 2 step current limit , but more clever is to make the heavy current , resistor controlled . BTW Li-Ion need a charge rate of less than "c" til 3.6 to 3.65 VDC at 25 Deg C . ( I.E. Sony 920 Notebook has 2.2 aH cells in parallel so 4.4 times 3 sets in series +12v in | | | | Ground | | -means less than about 4 amps til 3.6 vdc ...Thus the pow supply will show 4.9 amps to pow notebook and charge both ( batts/Notebook) same time . These Li-Ions are worth your while even if you are poor . They will Kill Nicad/Nimh for they have 1) more energy per cubic inch ... 2) same VERY hi discharge rates . 3) but retain energy beyond a week . dont fear paralleling , Li-Ions have much less cross talk ( discharge of lower volt cell by the higher volt cell ) than anything .... Off Topic Your Z-6 Minolta DigiCam will NOT like alkalines You must use NimH for the hi power needed . And it dont like heat , remove batteries to allow heat to escape for 15 minutes and you can shoot again ... I guess refurbished can mean a tax dodge , the Camera IS new ! The price drop is combo of Loss Leader and a pass thru of tax . __________________________________________________ ___________________________________ Dan_Musicant wrote: I have a Panasonic 12v (NiCads) cordless drill/driver with 2 batteries and it seems to me that the batteries aren't holding a charge very well. They are around 3-4 years old, lightly used. They seem to charge too quickly. If I leave them in the charger after the charger shows them as fully charged and let them trickle charge, will that top them up? I haven't been doing that. Is this a loss of capacity of the batteries? Is there some way I can restore the capacity of the batteries? Any experience with these? Thanks for any ideas, info, suggestions, etc. Dan |
Battery memory on NiCad cordless drill
Months ? Nicads ? Wet Cell , in a plane ... OK .
Dry types? from da store , for your drill ? naaaaaah . 50% in a 20 days !! Li-Ion is high rate power , loss can be 1% /month . priced out of reach , ..... I tossed all my Nimh ! Just too good to be intimadated by price ! But they die if too much amps charge above the 3.65 vdc level . All batteries will float if the amps are very low . ( BTW Harbor Fright tiny driver $20 , w/ Li-Ion has no greater than a 1 aH single cell ) . George E. Cawthon wrote: Jim Yanik wrote: Dan_Musicant wrote in : I have a Panasonic 12v (NiCads) cordless drill/driver with 2 batteries and it seems to me that the batteries aren't holding a charge very well. They are around 3-4 years old, lightly used. They seem to charge too quickly. If I leave them in the charger after the charger shows them as fully charged and let them trickle charge, will that top them up? I haven't been doing that. some chargers are designed to be able to leave the pack in,some are not. You need to check your manual. Is this a loss of capacity of the batteries? Is there some way I can restore the capacity of the batteries? Any experience with these? Thanks for any ideas, info, suggestions, etc. Dan It's been my experience that for longest life,NiCds are best used often.(use it or lose it) Once you start storing them for long periods,their life decreases. NiCds also have a self-discharge rate;just sitting in storage,they discharge on their own. Probably right about the use or lose it. If you don't use them much you need to keep checking the voltage at least once every 1-2 months and make sure the voltage doesn't drop below 12V. Full charge on a 12V NiCad is about 14V, but that degrades quickly to about 13V and I check the voltage when charging and stop before it reaches 14V. Overcharging is the number one cause of batteries going bad. |
Battery memory( NiCad) Pulse charge it !!
werty wrote:
NimH and Nicad lose 10% in 1 day... Would you have any evidence for this article of faith? :-) Nick |
Battery memory( NiCad) Pulse charge it !!
In article , Jim Yanik wrote:
Keith Williams wrote in ET: In article .com, says... 1) Pulse charge and it will return to full energy if it is still in infancy . Never deep cycle any battery . Batterys die for being NOT fully charged . Leave them discharged is to shorten life . Nonsense. NiCDs and NiMH batteries love to be discharged. Agreed. That's the only way to store them for long periods. That's wrong. They should be stored CHARGED. Do you have any cites for your claim? Don't "reverse charge" cell(s) in a multi-cell battery by discharging it below about 1V/cell though. They can be left to self discharge without damage. A single cell battery can be discharged to zero. OTOH, lead-acid batteries must never be fully discharged and must be stored with a float charge. Lead-acid batteries are thus better for things like flashlights, UPSs, safety lighting, and such. ---------------- 2) NimH and Nicad lose 10% in 1 day , Li-Ion lose 1% . Not any more. NiCds may be 20% per month, usually less. NiCd Figures I've seen are ~5% self-discharge/day. Storage temperature greatly affects this. I have seen datasheets for NiMH cells indicating that the self discharge rate decreases as self discharge progresses. A cell could self-discharge 5% in a day but less than 20% in a week. I would suspect NiCd can do something similar. - Don Klipstein ) |
Battery memory( NiCad) Pulse charge it !!
"werty" wrote in
oups.com: 1) Pulse charge and it will return to full energy if it is still in infancy . Never deep cycle any battery . Batterys die for being NOT fully charged . Leave them discharged is to shorten life . ---------------- 2) NimH and Nicad lose 10% in 1 day , Li-Ion lose 1% . I gambled on 100 NimH "LenMars" 2.5 aH AA's from Buy.com .. 25% loss in 1 day , load tested OK , i tossed them , not worth my time . ----------------------------------------------------------------------- more ........................ Pulse charge a nicad and it "loses" its memory , return full energy . ........ a 4 amp pow supply with a simple Resistor works great . C cell ( NiCad ,NimH) , as in drills , can take 2-3 amps til about 1pt36 vdc (((Linux crap apps ! Konquerer ..Cant see the text , too small , no way to change it so i use pt for decimal point )))))))) 1 ) so pulse with a very low Z pow supply at 1pt48 to 1pt5 vdc per cell and a Resistor of 0pt25 ohms . Theorectically , you must select R ( 0pt25) carefully , use scope to see the lighter amps , for it will heat up if too much amps above 1pt38 vdc . 2) but since current is so hi and pow supply is likely to help the current limit anyway , just measure the current above 1pt36 to 1pt37 vdc and adj the supply Voltage instead of doin the Resistor . Now the resistor limiter is inside your pow supply and you can simply vary period of pulse to "tame" the circuit and keep batteries cool . Never charge a hot battery ( 110F ) , they dry up , short life . Velleman has o'scope ( HPS-40 for $250 ) . BTW Clever battery chargers use a 2 step current limit , but more clever is to make the heavy current , resistor controlled . BTW Li-Ion need a charge rate of less than "c" til 3.6 to 3.65 VDC at 25 Deg C . ( I.E. Sony 920 Notebook has 2.2 aH cells in parallel so 4.4 times 3 sets in series +12v in | | | | Ground | | -means less than about 4 amps til 3.6 vdc ...Thus the pow supply will show 4.9 amps to pow notebook and charge both ( batts/Notebook) same time . These Li-Ions are worth your while even if you are poor . They will Kill Nicad/Nimh for they have 1) more energy per cubic inch ... 2) same VERY hi discharge rates . 3) but retain energy beyond a week . dont fear paralleling , Li-Ions have much less cross talk ( discharge of lower volt cell by the higher volt cell ) than anything .... Off Topic Your Z-6 Minolta DigiCam will NOT like alkalines You must use NimH for the hi power needed . And it dont like heat , remove batteries to allow heat to escape for 15 minutes and you can shoot again ... I guess refurbished can mean a tax dodge , the Camera IS new ! The price drop is combo of Loss Leader and a pass thru of tax . __________________________________________________ _____________________ ______________ Dan_Musicant wrote: I have a Panasonic 12v (NiCads) cordless drill/driver with 2 batteries and it seems to me that the batteries aren't holding a charge very well. They are around 3-4 years old, lightly used. They seem to charge too quickly. If I leave them in the charger after the charger shows them as fully charged and let them trickle charge, will that top them up? I haven't been doing that. Is this a loss of capacity of the batteries? Is there some way I can restore the capacity of the batteries? Any experience with these? Thanks for any ideas, info, suggestions, etc. Dan It is less painful to buy new batteries than read that post :-) |
Battery memory( NiCad) Pulse charge it !!
In article ,
says... Keith Williams wrote in T: In article .com, says... 1) Pulse charge and it will return to full energy if it is still in infancy . Never deep cycle any battery . Batterys die for being NOT fully charged . Leave them discharged is to shorten life . Nonsense. NiCDs and NiMH batteries love to be discharged. Agreed. That's the only way to store them for long periods. That's wrong. They should be stored CHARGED. Do you have any cites for your claim? Yes, Gates' secondary battery manual. The chemical reaction stops with zero terminal voltage. They store quite nicely that way. In any case, they *will* self discharge and the worse thing possible for a NiCd or NiMH is to float charge it. THis is exactly the opposite as is the situation for Lead-acid cells. Don't "reverse charge" cell(s) in a multi-cell battery by discharging it below about 1V/cell though. They can be left to self discharge without damage. A single cell battery can be discharged to zero. OTOH, lead-acid batteries must never be fully discharged and must be stored with a float charge. Lead-acid batteries are thus better for things like flashlights, UPSs, safety lighting, and such. ---------------- 2) NimH and Nicad lose 10% in 1 day , Li-Ion lose 1% . Not any more. NiCds may be 20% per month, usually less. NiCd Figures I've seen are ~5% self-discharge/day. Storage temperature greatly affects this. Nonsense. They do *not* self discharge totally in a month. ....more like 20% a month. Classically NiMH self-discharges at about twice the rate of NiCD, but AIUI they've gotten much closer. -- Keith |
Battery memory( NiCad) Pulse charge it !!
In article , krw wrote:
In article , says... Keith Williams wrote in T: In article .com, says... 1) Pulse charge and it will return to full energy if it is still in infancy . Never deep cycle any battery . Batterys die for being NOT fully charged . Leave them discharged is to shorten life . Nonsense. NiCDs and NiMH batteries love to be discharged. Agreed. That's the only way to store them for long periods. That's wrong. They should be stored CHARGED. Do you have any cites for your claim? With my Johnson walkie talkies with the42 year old NiCads, i charge some every year or two. I have never found them totally dead. greg Yes, Gates' secondary battery manual. The chemical reaction stops with zero terminal voltage. They store quite nicely that way. In any case, they *will* self discharge and the worse thing possible for a NiCd or NiMH is to float charge it. THis is exactly the opposite as is the situation for Lead-acid cells. Don't "reverse charge" cell(s) in a multi-cell battery by discharging it below about 1V/cell though. They can be left to self discharge without damage. A single cell battery can be discharged to zero. OTOH, lead-acid batteries must never be fully discharged and must be stored with a float charge. Lead-acid batteries are thus better for things like flashlights, UPSs, safety lighting, and such. ---------------- 2) NimH and Nicad lose 10% in 1 day , Li-Ion lose 1% . Not any more. NiCds may be 20% per month, usually less. NiCd Figures I've seen are ~5% self-discharge/day. Storage temperature greatly affects this. Nonsense. They do *not* self discharge totally in a month. ....more like 20% a month. Classically NiMH self-discharges at about twice the rate of NiCD, but AIUI they've gotten much closer. |
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