BU-407: Charging Nickel-cadmium

Learn how to maximize charge, minimize heat and reduce memory.

Nickel-based batteries are more complex to charge than Li-ion and lead acid. Lithium- and lead-based systems are charged with a regulated current to bring the voltage to a set limit after which the battery saturates until fully charged. This method is called constant current constant voltage (CC/CV). Nickel-based batteries also charge with constant current but the voltage is allowed to rise freely. Full charge detection occurs by observing a slight voltage drop after a steady rise. This may be connected with plateau timing and temperature rise over time (more below).

Battery manufacturers recommend that new batteries be slow-charged for 16–24 hours before use. A slow charge brings all cells in a battery pack to an equal charge level. This is important because each cell within the nickel-cadmium battery may have self-discharged at its own rate. Furthermore, during long storage the electrolyte tends to gravitate to the bottom of the cell and the initial slow charge helps in the redistribution to eliminate dry spots on the separator. (See also BU-803a: Loss of Electrolyte.)

Battery manufacturers do not fully format nickel- and lead-based batteries before shipment. The cells reach optimal performance after priming that involves several charge/discharge cycles. This is part of normal use; it can also be done with a battery analyzer. Quality cells are known to perform to full specifications after only 5–7 cycles; others may take 50–100 cycles. Peak capacity occurs between 100–300 cycles, after which the performance starts to drop gradually.

Most rechargeable cells include a safety vent that releases excess pressure if incorrectly charged. The vent on a NiCd cell opens at 1,000–1,400kPa (150–200psi). Pressure released through a re-sealable vent causes no damage; however, with each venting event some electrolyte escapes and the seal may begin to leak. The formation of a white powder at the vent opening makes this visible. Multiple venting eventually results in a dry-out condition. A battery should never be stressed to the point of venting.

Full-charge Detection by Temperature

Full-charge detection of sealed nickel-based batteries is more complex than that of lead acid and lithium-ion. Low-cost chargers often use temperature sensing to end the fast charge, but this can be inaccurate. The core of a cell is several degrees warmer than the skin where the temperature is measured, and the delay that occurs causes over-charge. Charger manufacturers use 50°C (122°F) as temperature cut-off. Although any prolonged temperature above 45°C (113°F) is harmful to the battery, a brief overshoot is acceptable as long as the battery temperature drops quickly when the “ready” light appears.

Advanced chargers no longer rely on a fixed temperature threshold but sense the rate of temperature increase over time, also known as delta temperature over delta time, or dT/dt. Rather than waiting for an absolute temperature to occur, dT/dt uses the rapid temperature increase towards the end of charge to trigger the “ready” light. The delta temperature method keeps the battery cooler than a fixed temperature cut-off, but the cells need to charge reasonably fast to trigger the temperature rise. Charge termination occurs when the temperature rises 1°C (1.8°F) per minute. If the battery cannot achieve the needed temperature rise, an absolute temperature cut-off set to 60°C (140°F) terminates the charge.

Chargers relying on temperature inflict harmful overcharges when a fully charged battery is repeatedly removed and reinserted. This is the case with chargers in vehicles and desktop stations where a two-way radio is being detached with each use. Reconnection initiates a new charge cycle that requires reheating of the battery.

Li ion systems have an advantage in that voltage governs state-of-charge. Reinserting a fully charged Li-ion battery immediately pushes the voltage to the full-charge threshold, the current drops and the charger turns off shortly without needing to create a temperature signature.

Full-charge Detection by Voltage Signature

Advanced chargers terminate charge when a defined voltage signature occurs. This provides a more precise full-charge detection of nickel-based batteries than temperature-based methods. The charger looks for a voltage drop that occurs when the battery has reached full charge. This method is called negative delta V (NDV).

NDV is the recommended full-charge detection method for chargers applying a charge rate of 0.3C and higher. It offers a quick response time and works well with a partially or fully charged battery. When inserting a fully charged battery, the terminal voltage rises quickly and then drops sharply to trigger the ready state. The charge lasts only a few minutes and the cells remain cool. NiCd chargers with NDV detection typically respond to a voltage drop of 5mV per cell.

To achieve a reliable voltage signature, the charge rate must be 0.5C and higher. Slower charging produces a less defined voltage drop, especially if the cells are mismatched in which case each cell reaches full charge at a different time point. To assure reliable full-charge detection, most NDV chargers also use a voltage plateau detector that terminates the charge when the voltage remains in a steady state for a given time. These chargers also include delta temperature, absolute temperature and a time-out timer.

Fast charging improves the charge efficiency. At 1C charge rate, the efficiency of a standard NiCd is 91 percent and the charge time is about an hour (66 minutes at 91 percent). On a slow charger, the efficiency drops to 71 percent, prolonging the charge time to about 14 hours at 0.1C.

During the first 70 percent of charge, the efficiency of a NiCd is close to 100 percent. The battery absorbs almost all energy and the pack remains cool. NiCd batteries designed for fast charging can be charged with currents that are several times the C-rating without extensive heat buildup. In fact, NiCd is the only battery that can be ultra-fast charged with minimal stress. Cells made for ultra-fast charging can be charged to 70 percent in minutes.

Figure 1 shows the relationship of cell voltage, pressure and temperature of a charging NiCd. Everything goes well up to about 70 percent charge, when charge efficiency drops.  The cells begin to generate gases, the pressure rises and the temperature increases rapidly. To reduce battery stress, some chargers lower the charge rate past the 70 percent mark.

Charge characteristics of a NiCd cell

Figure 1: Charge characteristics of a NiCd cell.
Charge efficiency is high up to 70% SoC and then charge acceptances drops. NiMH is similar to NiCd. Charge efficiency measures the battery’s ability to accept charge and has similarities with coulombic efficiency.

Courtesy of Cadex

Ultra-high-capacity NiCd batteries tend to heat up more than standard NiCds when charging at 1C and higher and this is partly due to increased internal resistance. Applying a high current at the initial charge and then tapering off to a lower rate as the charge acceptance decreases is a recommended fast charge method for these more fragile batteries. (See BU-208: Cycle Performance.)

Interspersing discharge pulses between charge pulses is known to improve charge acceptance of nickel-based batteries. Commonly referred to as a “burp” or “reverse load” charge, this method assists in the recombination of gases generated during charge. The result is a cooler and more effective charge than with conventional DC chargers. The method is also said to reduce the “memory” effect as the battery is being exercised with pulses. (See BU-807: How to Restore Nickel-based Batteries.) While pulse charging may be valuable for NiCd and NiMH batteries, this method does not apply to lead- and lithium-based systems. These batteries work best with a pure DC voltage.

After full charge, the NiCd battery receives a trickle charge of 0.05–0.1C to compensate for self-discharge. To reduce possible overcharge, charger designers aim for the lowest possible trickle charge current. In spite of this, it is best not to leave nickel-based batteries in a charger for more than a few days. Remove them and recharge before use.

Charging Flooded Nickel-cadmium Batteries

Flooded NiCd is charged with a constant voltage to about 1.55V/cell. The current is then reduced to 0.1C and the charge continues until 1.55V/cell is reached again. At this point, a trickle charge is applied and the voltage is allowed to float freely. Higher charge voltages are possible but this generates excess gas and causes rapid water depletion. NDV is not applicable as the flooded NiCd does not absorb gases because it is not under pressure.

Last updated 2016-08-15

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On November 22, 2010 at 6:46am
General manager wrote:

Looking for best charger for aa and aaa rechargeble batteries for electronoc locks , Tv remote etc for commercial use and green enegy concepts

On December 6, 2010 at 1:04pm
Harry Spaeth wrote:

For use in a Roland FR-3x electronic accordion, I will need 10 AA type Ni-MH 2000mAh recargeable batteries and a charger for them since they provide only 3 - 5 hours of use per charge.  What is the best of each recommended.  Thanks.

On January 9, 2011 at 8:19pm
Pamela A. Davis wrote:

I need a battery charger for a 7.4V; 2150mAh Ni-MH battery module (used in the Kodak DSC 520 digital camera).

On January 28, 2011 at 8:26pm
H Cohen wrote:

I need either a charger or an adapter for a 18volt NI CAD power tool battery.. I don’t know the brand..I have a set of tools labeled “power to go” with 2 batteries..I do have a Dewalt charger ,so if I can get an adapter to work,that would do it also…The closest battery I’ve seen is one Northern tool sells,that they say is for model # 150785 and # 143396..also no brand given…can you help..

On February 6, 2011 at 6:37pm
Jpette wrote:

About charging Ni-Mh

About this:
“It is difficult, if not impossible, to slow-charge a nickel-metal-hydride. At a C?rate of 0.1-0.3C, the voltage and temperature profiles fail to exhibit defined characteristics to measure the full charge state accurately and the charger must rely on a timer. Harmful overcharge can occur if a partially or fully charged battery is charged with a fixed timer.”

It’s true and false.
I explain.
The result is with the quality of D/A and noise etc…of electronics quality of thes converter
and his algorithms detections.
One good example:
With one Maha C9000 (detect A/N) poor, absolutly ok with you, never use charging less to 0.3C if you want make this, (< 0.3C), this charger “not see” the delta Peak. 

Now you get one BC 700 (Named also RS 700 or Ipc 1L etc), the concerter is fantastic,
here you can catging in less to 0.1C, and the detect of delta Peak is very good.
example: possible without problems charge of 2700mA/H with current of 200mA, and delta peak detection is Good.

and many many examples about this case.
All us in 2 objets: One The quality of converter A/D, and the algorithms for detects the good D Peak.

Best regards

On March 1, 2011 at 12:50pm
Big Kev wrote:

I have a battery charger with a ‘discharge’ button , the instructions though are a bit sketchy! The model no is ‘BC!HU’ and it was sold by 7dayshop here in the UK for about £15 and was advertised as a ‘Smart charger’
What is considered the best practice with regard to ‘discharging’? , pro’s and cons , how often etc , etc.
I’m particularly interested in using Nickel-metal-Hydride batteries with this unit since my wireless keyboard/mouse combo use them!
Many thanks for any advice.

On March 1, 2011 at 1:33pm
Jpette wrote:

@Big Kev
Yes you found this model (BC-700 or RS-700) without problems in UK.
The discharge mode is ine real dischage mode (The processor check in real time slot by slot the state od tension (V) of Ni-Cd or Ni-Mh every 2 sec (average)
In discharge mode, if the Volt is minus of 0.90v, this charger stop the dischange and go
i, mode “charging”....and wait found (emply accus) delta peak.
There are so one security timer (after total cussent sent is more 3700 mA/h, it stop chargin mode), but never fault found (and i have 2 x 100 AA & AAA), old years (some sanyo NI-CD 600mA Yellow), or young (eneloop)

The only default of this charger is:
No respect with new accus (FAD) of trickle current (Many others so..)
For example in charging mode (and current set to 200mA), if you charging one with capacity of 1000mA/h, the tricke current is really average 15mA, it’s many.
The good current “tricke” is average C/300, example for one 1000mA/h it’s 3.3mA
I see this after long time, and it’s verify by this here:
and this “Apply a maintenance charge of indefinite duration at C/300 rate”

Many chargers no respect this….and all people think’s with Ni-Mh a&fter; C/10 non charging element, it’s false…i think if < to C/100 you continue charging (and create memory effect)

After same with GOOD converter AN/DA, charging in C/10 is no problem with detect Delta peak…But ONLY with GOOD detect, if you use charger with one “AN/DA” edge, nerver charging one ni-mh with c/10, the Delta peak is no see, and you can “kill” the charger or the accus (ex never charging ni-mh with one C-9000 with charging current < a t C/3)

The secret of state of your accus (ni-mh & ni-cd), the quality of charger.

Best regards and excuse my very bad english,
and many thank’s so at this wonderfull website.

On March 8, 2011 at 11:49am
Brandon wrote:

This article has been updated as of March 8, 2011 with new information.

On March 14, 2011 at 2:05am
Manjunath Varadaraj wrote:

3 batteries in a set of 20 batteries has failed. They are all are in parallel connection connected to a online UPS. the 3 defective batteries shows low voltage (also it is blotted/buldged on sides). My battery supplier is saying all the 20 batteries have to be replaced instead of replaceing only 3 defective batteries. kindly advise.
All the batteries are more then 2 year old and is presently giving a backup of
approximately 3hrs on full load (5kva). (I haven’t checked exactly since the power failure happens only for 1hr during working hours)

On May 7, 2011 at 8:57pm
Robert Hsu wrote:

Will appreciate receiving info how to maintain Ryobi 9.6V NiCd battery to deliver 800 to 1000 charge/discharge cycles using Ryobi charger.  Are there any more sophisticate charger that will prevent Ryobi 9.6V NiCd battery from over-charging?

On July 14, 2011 at 7:00pm
James L. McCann wrote:

Can you charge the ni-cd batteries with a ni-mh charger?

On July 20, 2011 at 1:02pm
pauline tesnow wrote:


On July 20, 2011 at 3:19pm
Jpette wrote:

“James L. McCann wrote:

Can you charge the ni-cd batteries with a ni-mh charger?”
Yes, no problem, you can charging ni-CD Battery With ni-MH Charger.
The Delta Peak of ni-CD is Up to 16mV (easy for detect)

The reverse is not TRUE (FALSE)
The Delta Peak of ni-MH is AVERAGE (Less or More) 5mV, so, charging ni-MH WITH
one ni-CD charger, the ni-CD Charger “not see” the delkta peak because the converter
analog to digital is too “edge”

Excuse my very bad english, but i think you’re understand me
Best regards

On September 9, 2011 at 1:30am
pratik joshi wrote:

can you tell me about similarity between ni-cd and ni-mh charger

On September 9, 2011 at 7:08am
jpette wrote:

I’m not sure understand your question.
With one ni-MH charger, you can charging without problems one battery type Ni-CD.
The reverse is not possible (You cannot charging one Ni-Mh with one charger type ni-CD)

One battery type ni-MH (detect) is some millivolts, and never UP 1,50v for charging by battery.
If you go more (ex: 1.70v) you break the battery (Create Internal Resistance, etc…)

The ni-Cd (After one long storage for example) for 100% FULL, in some case charging with 1,85v (max) for good 100% full, and the delta peak is strong 16mV and it’s easy for charger to detect the delta peak of this battery.

Now you can understand “about similarity between ni-cd and ni-mh charger”

It’s good for explain ?
Excuse my very bad english

On October 29, 2011 at 1:35am
srswan85 wrote:

      ive just purchesed a nicd 1700ma 7.2v battery and charger backage for my r/c car and i was just wondering if anyone knows how long i should charge hte battery for?
                                      muchly appreciated

On November 19, 2011 at 11:17am
mohamed wrote:

how can i calculate the battery efficiency???

On December 25, 2011 at 9:46am
Salmon randa wrote:

I’ve super brain 989 charger
I want to cycle 8 cell of aa nicd battery
What rate recomend for charge (mAh)
What ampere recomend for charge (A)
What rate recomend for discharge (mAh)
What ampere recomend for discharge (A)


On June 12, 2012 at 2:38am
Loh Win Hoo wrote:

Dear Sir,

Can i use Nickel Metal Hydride battery charger to charge Nickel Cadmium rechargeable battery?

Thanks & Regards

On December 9, 2012 at 1:20pm
james edmonds wrote:

i have bought a nickel cadmium maintenance free battery from halfords, if it should need charging in the future bad winters to come.  can i charge it with my existing charger.

On January 17, 2013 at 2:23pm
Mike Cain wrote:

I have a new18V NiCd battery pack, it has 15 1300mAh NiCd batteries wired in a series.  I wanted to trickle charge it to get all the cells to the same charge level.  When I checked the voltage of the wall charger that it came with, it was outputting around 36V.  That seems really high and I can’t find any information on what would the appropriate voltage to be supplied or even if supplying 36V would be bad.  What voltage should I use to charge that battery pack at .1C?  Thanks

On March 1, 2013 at 4:35pm
Leon Follmer wrote:

Good question. I have 3 18 v chargers and their output ranges from 22 to 24 volts.  36 volts seems marginally high, but would work if you disconnect before it gets too hot.  I am trying to find a better answer.  At the moment I am taking 18 v packs apart and finding a few dead cells and many good ones.  I want to find the optimum v for charging the cells. I have found the zapping a cells with 12 v brings them back to life for a while.

On March 1, 2013 at 9:28pm
jpt wrote:

@Leon Follmer:
If i good anwers your question;, you asking how many voltage (v) you must use for best charging, it’s really easy.
If you use the Ni-Cd ou the Ni-Mh v is not equal.
The full charge (v) of Ni-CD is average 1,415v per cell..
The full charge (v) of Ni-MH is average 1,445v per cell (30 mV more)

For example with 10 Cell, if you want fully 10 cell you must have (in Ni-CD).
1,415 x 10 = 14,15 v exactly.
But…. when the cell is 90% Fully there are not current, why ?
I (A) is too edge, exemple two: When the 10 cells are empty the v is 12 V
14,15v - 12v = 2,15v, here the current of charging is high beceause v is many.
When 14,15v = 14,15v = No current.
For fully chargin, just add edge minor v. exemple: 14,15v + 0,3v = v charge is 14,45v
After is delta peak detection technology, use edge more v again 15v
If ONLY linear charge WITHOUT detection D peak use 14,45v average, it’s better

Sorry for my bad english

On March 2, 2013 at 1:36pm
Leon Follmer wrote:

You almost touch on the point, but I’m confused. I want to find the basics.  It takes more than 18 v to charge an 18 volt battery. My chargers put out 22-24 volts.  I assume that is near optimum.  Does this ratio hold for all battery sizes?

I just landed on this site and have not read all the comments yet.  I plan to go through all the info on this site and I figure that my answers are there somewhere.  If you can give me some pointers I would appreciate it.

On March 5, 2013 at 6:43pm
jerry wrote:

Leon,  In order to charge NiMH and NiCD batteries effectively, you need a constant current source, not a voltage source.  When you say your chargers are supplying 22 to 24v, that would be the voltage swing I would expect across a sample of batteries as the charger is supplying constant current at differing voltage rates to account for the variability in batteries.

Once you have a constant current source, you can charge at differing rates from .1C to 1.5C against time for fully discharged batteries without much worry.  The problems start when you attempt to charge by time at constant current batteries with remaining charge.

The only safe and effective way to charge batteries is either 1) by .1C for 15 hours;  or 2) by .5C or higher using a combination of NDV, dTdt, max temp, max voltage, time, etc.  These features are provided by smart IC or microcontroller based chargers attached to a constant current source.

I’ve recently been designing a charger (with the help of those on this board) that is what I consider the ultimate for single cell NiMH or NiCD batteries as I found most of the smart chargers to be lacking.  I am using a combination of microprocessor and computer control to track voltage & temperature curves.  I am amazed how after plotting about 50 such curves how closely the profiles match for good cells.

Feel free to contact me at clist@hanler.com.  The moderator on this forum is very, very, knowledgeable on all these subjects.


On March 5, 2013 at 6:49pm
jerry wrote:

To answer your question precisely, the voltage ratio you are seeing of 22/18 to 24/18 is 1.22 to 1.33 which is close but I don’t think you can rely on this for maximum efficiency as my single cells are closer to 1.2 for good, newer cells.  Also batteries with thermistors will charge at higher rates and if you are using leads to connect the batteries they will have a voltage drop as well at high current.


On March 7, 2013 at 2:12pm
Leon Follmer wrote:

We are not in phase, no pun intended.  All transformers have an input and output voltage and amperage.  If you measure the voltage at the output clips you get the open circuit emf. On my 18 v chargers I get from 22 to 24 volts. 

I must assume that my charger is a constant voltage output.  So what can I do with it? How can I determine which it is? The discussion above does help me at the stage of a beginner because the discussion has many variables and “code” words which seem ambiguous to me.  Example: how do I achieve 0.1 C?  The concept of C must contain some value for voltage. I assume it is based on the battery.  The discussion above needs examples that show values and calculations, etc.

I did find in a reference that Ni-Cd batteries should be charged at “1.4x the ampere-hours of discharge”.  What does this mean? How do I deconvolute this expression?

On August 13, 2013 at 2:56am
Abdulla wrote:

A 125v transportation ultracap module. Assuming a 2000 kg car deccellerates at a constant rate from 60kph to a stop in 2 seconds. Calculate how much energy could be recovered into this module by the regenerative braking system. Assume the motor/generator is 90% efficient.
hi guys
can u give a hand to solve the problem

On September 21, 2013 at 9:47am
Robert wrote:

I just bought a blow-up bed that has a Ni-Cad battery. The charger they sent plugs into the wall and charges the battery on the pump for the bed. On the charger supplied it reads on it AC/DC adaptor. Class 2 power supply. Input 120v 60 Hz 4.1w Output 7.5V DC 250mA. What I would like is a charger that I could plug into my 12 volt car cigarette lighter and charge the battery’s on the pump. Would you be able to sell me this and if so what is the model #.

On October 11, 2013 at 6:47am
Gizmo wrote:

I have a 20-cell 36Ah battery with a problem.
After performing a main charge @ 0,5A for 2 hours, I continue with a final charge of 0,1A for 4 hours. The voltage gradually increases during the main charge, until it reaches 31V (roughly 1,55V/cell) after which I switch to the final charge.
The final charge starts at roughly 30V (the voltage naturally drops a bit when lowering the Amperage), but instead of slowly increasing over the following 4 hours, the voltage actually decreases in those 4 hours, ending at 29V (roughly 1,45V/cell).
I have now done three cycles and it keeps happening. Water level is sufficient, as I have checked during each cycle. I also discovered that it is not just one or a few, but ALL cells that drop in voltage during final charge.
Does anyone have an idea as to why this happens, and what I could possibly do to remedy the situation?

On February 13, 2014 at 1:00pm
Tim Rujera wrote:

I have an Energizer charger that states in its manual to use only Nickel Metal Hydride (NiMH) rechargeable batteries.
Is it possible for me to use the charger for Nickel Cadmium rechargeable batteries?

On May 27, 2014 at 6:18am
paramu wrote:

How much electrolyte liters we need to fill the SBLE 185 Nickel cadmium battery.
I want to know in liters. please advice and let me know.

On September 12, 2014 at 4:38pm
Donna Davis wrote:

I have several AAA Nic Cad batteries.  Can these be recharged if they do not say rechargeable on them.

On October 30, 2014 at 11:49am
Michael wrote:

I bought a DirtDevil Scorpion that just won’t charge. It goes past its 24 hours and the light remains red, as if still charging and even if left longer the power won’t last more than 4 minutes. Dirt Devil is replacing it so no problem and this one should be thrown away but then I thought is it possible to make this battery come to life? Under its specs it says: Nickel cadmium 6V 6 amps.
  One thing I tried is while charging I removed it from the charger for about 2 minutes then set it on/off/on/off real quick about 6X (having seen this elsewhere for old used batteries) but nothing happened.
  Any advice would be appreciated.  Or could the charger actually be the problem?

On September 4, 2015 at 8:15pm
PCL wrote:

I have a Black & Decker cordless screwdriver with a 3.6 V Lithium Ion Battery.  It was fine for a while, then died; after checking over the owner’s manual and other material on these batteries, I’ve concluded that the charger is too dumb to shut off the current once the cells are charged and that tends to destroy them. Needless to say, I won’t be buying B&D products again for a long while. My Sears drill has a charger that runs its cycle and stops; B&D should learn from them. Anyway, I’d like to stick a NiCad battery in place of the expensive, failure-prone Lithium Ion pack, using the same charger; will that work? I know NiCad cells are more tolerant of dumb chargers than either NIMH or Lithium Ion, so I’m hopeful.

On October 6, 2015 at 10:03am
mayank verma wrote:

My name is Mayank Verma . I’m a student at university of petroleum and energy studies in India. I am currently working on a project called as solar urja lamp, in this we have to make a lamp that is economically fit for making and manufacturing. The main purpose of this lamp is to provide it to the need full people who can not buy a lamp or doesn’t have the reach to electricity.

We have to built a lamp that charges on solar energy and stores it in a battery.
Now the main concern is to choose a battery that can last 1500 charge and discharge cycle and that is cheap and could light up LEDs that gives around 300-400 lumens and store energy for the days where there will be no sunlight.

It would be great if you could help us in any manner, providing any knowledge about which battery is apt and best to use for such purpose.

Mayank Verma

On January 1, 2016 at 9:34pm
David Cassibry wrote:

Hi, I have some nickle cadmium bat. packs. I use them for my rc airplanes . They haven’t been used in 4 to 5 years. They are made by Futaba. 9.6VDC-600mAH, charging says 60mA-15hours. Are these batteries still chargeable ? Also a 4.8v 600mAh . Both take 15hours to charge. And what charger do you recomend?

On February 22, 2016 at 4:20am

Thank you for proving this information.We have Nickel Cadmium Batteries each set of 180 Ah capacity. I understand that there are three types of charging method of Nickel Cadmium Battery namely Initial charging before putting service,Float charging and Equalizing charging if cell voltages become unbalanced or or once every six months if the battery has been in floating charge mode, but not discharged. I want to know the voltage per cell in each type of charging method.

On May 2, 2016 at 4:24am
Engr. Ghazanfar Ali Khan wrote:


On June 16, 2016 at 11:45am
Kushal Gajurel wrote:

I have a Ni-Cd battery rated 2000mAh, 6V. There are 6 cells, 1.2v/cel. How much voltage and current should i use to charge the battery without full charge detection? I read few articles and decided to charge with ac (after using a transformer to reduce the voltage to 8 V dc using a rectifier circuit) with 0.1C( in my case 200mA) current hoping the battery to get charged in about 10-14 hours but the battery reached a voltage of 4.7 V form 2.2 V within half an hour. I really don’t seem to understand the charging speed. Will such a fast charging harm my battery. And how are the cells connected in the pack( series or parallel)? and how does that affect the charging. I am completely new to this realm. Can you help me?

On July 9, 2016 at 9:45am
ray wrote:

hi, my elderly friend left his stairlift in the un-parked position & batteries are flat & even though i’ve now manually moved it back, the batteries won’t charge. they are Freeway Ni-Cd d5000mAh 12v Bison 80. can i bench charge them somehow & if so, what could i buy or use to do this please? i want to save him some money if possible as new batteres seem to be well over £200. many thanks

ray in the uk

On October 11, 2016 at 4:55pm
Morning Dove wrote:

If you want to charge it do not use your Debit Card, but use your Credit Card…...  Swipe and Sign and it is charged.  Thanks for all of the good information.  Being an old-timer, there were no Ni Cad batteries when I got my Masters. 
Have Fun Every Day!

On October 25, 2016 at 3:00pm
Tom wrote:

I have a drill that uses an 18 volt NiCad battery and I have found a 6 volt 500mA charger that has the correct plug in to the battery receptacle but I am not sure that this is the correct charger. Can you let me know how to verify that this charger is the correct one. Thanks.

On December 15, 2016 at 10:04pm
T Putman wrote:

I inherited 4 NiCad ED-240 batteries. & a Cragg railcharger 15N-1/Anyone know the lifespan on them? Theyve been sitting in barn for 5 years. Need simple advise how to charge them? Settings, how long on charger, how to test them, Im totally clueless.
Appreciate and layman term help here…Thankyou

On January 14, 2017 at 3:45pm
anita wrote:

Tom wrote:  On October 25, 2016 at 3:00pm
not recommended!

1 you mentioned a 18V battery (they typically charge at 21V)
your charger 6V, the plug may fit, but could be wrong polarity…hence why use only appropriate charger

On January 14, 2017 at 3:55pm
anita wrote:

ray wrote:    On July 9, 2016 at 9:45am
I hope you got some answer before now, but

yes they may be bench charged

It is very difficult to make suggestions without knowing what tools and knowledge you have
I understand you got the battery pack out of the machine
are the celles accessible? cans you open the battery case?
often in NiCad batteries cells short-out due to dendrites
I would strongly recommend that you give the project to a local technician
I am sure you can find some equivalent batteries in an electronic store near you

On January 14, 2017 at 4:27pm
anita wrote:

mayank verma wrote:    On October 6, 2015 at 10:03am
Unfortunately, we cannot suggest or make designs for you
you have to do your homework
look what is available on the market and reverse engineer them

this is the best I can do

On February 11, 2017 at 4:23am
Alex wrote:

lately I noticed the level of electrolyte in Nickel-cadmium batteries less than the max marking level indicated on the batteries. what should I do ? Is there electrolyte selling in the market as I am looking to top up the loosing of the electrolyte.
Thank you.

On August 7, 2017 at 3:05am
Nelson Lee Bailey wrote:

My 18 volte power tool battery wont take no charge what can I do