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Are you thinking of using a charger designated for the nicd battery type for NiMH? Battery chargers see designed for specified battery types and are recommended for others as they could cause undesirable damage.
If you are planning on attempting to use a nicd charger for NiMH, wait until you read this article to the end to find out how safe or unsafe this is to your battery.
So, can I use a nicd charger for NiMH? No, you can’t. This is a highly risky endeavor, nicd charger should never be used for NiMH battery type nor should any other recommended charger be used. Nicd batteries, when compared to NiMH batteries are significantly different and do not have the same charging conditions. This necessitates the use of different charger types in charging these batteries.
There should never be a time when the battery charger designed for nicd batteries is used to charge NiMH batteries, doing this could lead to some catastrophic outcomes such as battery leakage.
Over time, such action could also lead to depletion of the battery’s service life, that is, the battery goes out of use before the expected life span.
Often time, those found attempting to pull such stunts are individuals who have a device that uses nicd battery type and recently got another that makes use of NiMH battery.
Rather than getting the specified charger for the NiMH battery, they wish to save themselves some money by cross using their nicd charger for the NiMH battery. They do this, not realizing how much risk they are putting on the NiMH batteries.
These batteries have different specifications and different charging conditions, nicd chargers should not be used to charge NiMH batteries nor should the reverse be the case.
Why can’t I use a nicd charger for NiMH?
No two different types of batteries have the same type of chemistry. The chemical components of different battery types differ and so does their charging condition.
It is a risky thing to do, attempting to use a charger recommended for nicd for NiMH. This puts the battery at great risk. It could cause it to develop some leakages or shorten its life span or worse.
There are various reports from individuals who have tried such and ended up with a permanently damaged NiMH battery.
If you were trying to save money on a charger and this led to using a nicd charger for NiMH, then the goal is defeated when you have to get a new NiMH battery due to the permanent damage done to the previous one.
Why this happens is because the two types of batteries, that is, nicd and NiMH have different requirements for charging current, time current as well as time voltage profile, and voltage endpoint, as a result, they can not both share the same charger type.
Using the same charger for both outs one of your batteries is at great risk and could lead to losing the battery.
There is no need for sharing your nicd charge with the NiMH battery, especially now that affordable NiMH chargers are readily available in the market and can be ordered any time. This is therefore risk not worth taking.
There is a high tendency of overcharging the NiMH batteries whenever nicd chargers are used to charge the battery.
Given that the nicd chargers are not designed for NiMH batteries, the charger is unable to detect a fully charged NiMH battery and will continue to send in current, leading to overcharging the battery which eventually causes permanent damage as NiMH batteries are susceptible to overcharging and can not handle it.
Yes, some claim calculating the battery’s amperage and timing when the battery begins to get warmer than usual is an effective way of estimating the charging time and avoiding overcharging the NiMH battery.
Rather than going through this stress, which by the way may or may not save you from overcharging your battery and causing it permanent damage, simply spend a few extra bucks and get yourself a recommended NiMH charger.
There are chargers with a switch option that allows you to change from a nicd charging mode to a NiMH charging mode. With such a charger, you can easily switch in between the two modes and charge the two types of batteries appropriately.
However, such charger is unable to switch to NiMH mode, then, charging your NiMH battery on it should not be done.
Because the nicd mode will most likely overcharge the battery. The temperature of the battery can be closely monitored and the charger disconnected when a temperature change is noticed, or as soon as the voltage readout shows a peak voltage. This is however risky for your NiMH battery.
It is something of stress for you to sit there holding the battery in your hands waiting patiently to detect a change in temperature of the battery.
That is when the battery becomes hot or watch the digital readout of the voltmeter waiting to see the peak reading. Rather than doing this if the battery charger does not switch mode, it’s best to get a new one for your NiMH battery.
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How to charge NiMH battery?
To get the best performance from your NiMH battery, the battery must be charged properly. Charging the battery the right way also ensures the life span of the battery is not shortened but rather maintained or prolonged. It is therefore important to learn about the proper way of charging NiMH batteries.
NiMH battery cells unlike the nicd battery are more difficult to charge. The nicd battery came before NiMH and is built quite simple including their charging requirement.
In the case of nicd, the charger detected a fully charged battery via the voltage peak and its subsequent fall. This system however does not work for NiMH.
NiMH batteries are “nickel-metal hydride cells” and are highly susceptible to getting overcharged. When overcharged, the battery gets hot and overheats leading to permanent battery damage.
In light of this, the chargers for NiMH are crafted in such a way that they prevent overcharging of the NiMH battery. Anyone using a NiMH battery must also understand the battery’s sensitivity to getting overcharged and be more careful when charging it.
Battery charger designers are challenged with producing a battery charger that takes into account the sensitivity of NiMH batteries and prevents this from ever happening.
The love span of the battery is considerably reduced each time it is overcharged. the battery follows a similar discharge curve as the nicd battery and can take an extra charge as does nicd.
The voltage peak sensed by nicd chargers which signifies to the charger that the battery is fully charged is too small for the NiMH battery and is not detected by its charger.
Coupled with this voltage peak, the temperature change in the battery is also taken into account as the battery gets a little bit hotter when fully charged. This heat however decreases the charging efficiency of the battery.
NiMH cells require a more complicated charging condition than many other types of cells, they require that the current is kept constant and that the specified rate for each cell is kept.
The various methods for charging the NiMH battery include timer charging, thermal detection, negative delta voltage detection, slow charging NiMH batteries. These techniques help prevent the battery from being overcharged.
The timer charging method is the easiest of them all, it involves building an electronic timer in the charger to determine how long the battery is plugged.
Before plugging the battery, it’s the state of charge is well noted and taken into consideration. The drawback of this method however is that in the case where the NiMH cell may have lost its charge capacity, the charger being unaware of this will send in the estimated charge based on the initial charge state of the battery, which could lead to the overcharge of battery.
Temperature detection is a relatively effective method in charging NiMH cells. Its drawback however is inaccuracy in accessing the battery core temperature as its exterior which is more accessible is usually less hot than the center.
Also, when the battery is being slowly charged, its temperature rise is usually not significant enough to be detected. The battery can therefore be overcharged even while the thermal detection method is at play.
A helpful tip on Charging the NiMH battery is to ensure that the right charger is used for the battery. Wrong chargers will lead to leakage, short end life span, or permanent damage.
The battery should be charged at room temperature as the batteries do not cope with being charged at either a high or low temperature.
While charging the battery, remember to always check the battery’s temperature as this is indicative of being fully charged.
Can I Use A Nicd Charger For NiMH – Conclusion
NiMH batteries are not suited for being charged with nicd chargers, they get extremely hot and can become permanently damaged.
With a few extra bucks, the designated charger for the NiMH battery can be purchased to enable you to charge your battery appropriately.