The discharge voltage profile of a NiMH battery is considered “flat” (see Figure 3.7. 2 C/10 Discharge Profile @ 25°C) and varies with the rate of discharge and temperature. As a fully charged battery is discharged the voltage begins at about 1.5 volts followed by a sharp drop to around 1.3 volts.
How fast do NiMH batteries discharge?
about 1% per day
A: NiMH batteries self discharge about 1% per day so if used in a low energy consummation or stand-by device, the battery will only last about 90 days before requiring recharge.
Do NiMH batteries lose charge when not in use?
All cells will lose their charge over time, even if they are not used, but this is a particular problem for NiMH cells. Typically it might be expected that a fully charged cell might self-discharge over a period of a few weeks.
How far can you discharge a NiMH battery?
NiMH cells start at about 1.5 V right when fully charged, drop to about 1.2 V most of their discharge life, and are pretty much empty at 900 mV. Stopping there is usually safe. 800 mV is where you definitely want to stop to avoid damage.
Do NiMH batteries need to be discharged?
Do NiMH Batteries Need To Be Discharged Fully? NiMH life can be significantly extended by never fully discharging them on any occasion.This effectively means that you should never discharge your NiMH cells and should try to avoid doing so.
Can I use 1000mAh instead of 800mAh?
So a battery rated at 1000mAh basically delivers 1000mAh (1 ampere) of current for one hour. A battery rated at 800mAh delivers . 80% of the charge of the 1000mAh battery and therefore, in an ideal world, would last 48 minutes instead of one hour powering the same device.
How do you know when NiMH battery is fully charged?
Usually, a fully charged battery would display a voltmeter reading of around 1.5 volts. That means your battery is in good shape if your voltmeter shows a voltage anywhere between 1.3-1.5 volts. 4)A strong indication that your battery has excessive voltage is any voltage above 1.5volts.
Why do batteries discharge when not in use?
A minuscule amount of the chemical substances inside the batteries reacts even without any connections between the electrodes. Those internal reactions reduce the stored charge of the battery and thus decrease the capacity of the battery little by little. This phenomenon is called self-discharge.
Do NiMH batteries have a shelf life?
The life cycle for NiMH batteries is approximately 700-1,000 charges. Because they have a high energy density, nickel metal hydride batteries don’t deplete as quickly. As a result, they have a shelf life of 3-5 years.
Does battery drain if not used?
Battery self-discharge: perfectly normal
However, the reaction could also happen at a smaller scale, when the battery’s electrodes are not connected. That means that the battery’s charge gradually reduces over time. This phenomenon is called self-discharge.That way, you can store your batteries without too much worry.
What happens if you overcharge NiMH battery?
Excessive overcharging of a NiMH cell can result in permanent loss in capacity and cycle life. If a cell is overcharged to the point at which pressure begins to build up, elevated temperatures are experienced and can cause the separator to lose electrolyte.
What happens when you overcharge a NiMH battery?
Overcharging older NiMH batteries can also cause hydrogen to build up inside the cells. When that happens, increased pressure can cause the battery cells to rupture, rendering the battery unusable. In some cases, the buildup of hydrogen can also pose the risk of explosion.
Should you store NiMH batteries charged?
Duracell NiMH Battery Storage
Batteries should be kept clean and dry both during use and storage. They can be stored for many months in a charged or discharged state without any detrimental effects as long as they are not exposed to extreme temperatures for any long period of time.
Do you need to discharge rechargeable batteries?
New batteries come in a discharged condition and must be fully charged before use. It is recommended that you fully charge and discharge the new battery two to four times to allow it to reach its maximum rated capacity. Keep the battery healthy by fully charging and then fully discharging it periodically.
Why do NiMH batteries go bad?
Standard NiMH AAs will deteriorate with disuse. They will lose their charge and then hold less power as a result over time. Newer “hybrid” AAs such as Rayovac NiMH hybrids that I use hold a charge a good long time without use. I won’t buy a standard NiMH again.
Can I replace 300mAh battery with higher?
You can replace your battery with a slightly different mAh capacity, as long as it is the same voltage; we would recommend choosing your replacement batteries with the nearest possible mAh rating. It is not recommended to replace your batteries with a much higher mAh capacity.
Can I use 1.2 V batteries instead of 1.5 V?
Q : Can I use 1.2 V rechargeable batteries in devices that usually take 1.5 V throw away batteries? Yes, most definitely. Using 1.2 V rechargeable batteries will have no effect on the use of the equipment. In fact an alkaline battery only benefits from 1.5 V voltage at the beginning of its discharge.
How long does it take to charge a 5000mAh NiMH battery?
So, how long does it take to charge an 800-5000mAh NiMH battery? The charging time can vary anywhere between 2.5-15 hours.
How do I know if my NiMH battery is healthy?
How to check the NIMH battery condition – Quora. Just like any other battery technology, you test it in a device that charges it fully, then discharges it while keeping count of the energy it delivered until it reaches a set depletion level.
How do you test a NiMH RC battery?
Press the start button and leave the analyzer and battery alone for a few hours. The analyzer discharges the battery, measures the discharge time then recharges the batteries. After the discharge is completed the analyzer shows your battery’s capacity.
How long does it take to charge a 3000 NiMH battery?
A 3000 mAh battery can take up to 45 minutes to charge. It’s not a good idea to use timed charging. If you put it on charge without fully discharging it, you’ll end up with a massive overcharge.
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