Posts Tagged ‘low self discharge NiMH

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Alkaline batteries are a type of primary batteries dependent upon the reaction between zinc and manganese dioxide, they are called alkaline because they use alkaline electrolyte. Alkaline batteries are usually a single use type, though recent developments allowed rechargeable alkaline batteries as well, though they are not suitable for deep cycle use as they offer very few recharge cycles in such usage scenarios. The capacity of an alkaline battery is dependent on the load of the battery, the useable capacity for low loads can be significantly higher than in high load applications. The nominal voltage of a new alkaline cell is 1.5V, though the open circuit voltage can be higher, the fully discharged cell has a remaining voltage of about 0.8V. Alkaline batteries are usually used in low power applications where they can be used for longer periods of time as they have low self discharge over time. Carbon-Zinc batteries can sometimes be confused for alkaline batteries, though they are not, although they are also offering the same operating voltage and are single use batteries and are not rechargeable. Carbon-Zinc batteries can be used in most cases where you would use an alkaline battery with no problems at all as they are compatible, though they may not be the best choice in all cases.

A Nickel–metal hydride battery (NiMH) and Nickel–cadmium battery (NiCd) are two similar types of type of rechargeable batteries. The main difference between the NiMH and NiCd is the chemistry they use, with the NiMH batteries capable of having higher capacity than the NiCd. The NiMH and NiCd batteries have a nominal voltage of 1.2-1.4V, though the open circuit voltage can be higher, when discharged they are down at about 1.0V. One of the significant disadvantages ot this type of batteries is the high rate of self-discharge that NiMH and NiCd (lower than on NiMH) batteries have and they do not come charged. The problem with faster self discharge and the fact that you need to charge them before use has been addressed with the more recent low self-discharge (LSD) NiMH batteries that are becoming more and more popular in the last few years. These LSD NiMH batteries come pre-charged and loose their capacity when not use at a much slower pace than traditional NiMH batteries. There is a lot of controversy going on around NiMH and NiCd batteries about the so called “memory effect” they are supposedly suffering from, but this has become more of an urban legend and a marketing tactics than something that you should be worried about as a possible problem in 99% of the time.

A Lithium-ion battery as well as other variations such as Lithium-polymer battery or Lithium-iron phosphate batteries are rechargeable (secondary cell) batteries in which lithium ions move from the anode to the cathode during discharge and back when charging. The rechargeable Li-ion, Li-Poly and LiFePO batteries are different from the standard Lithium batteries that are not rechargeable. The rechargeable Lithium-based batteries provide lightweight, high energy density power sources for a variety of devices and are becoming more and more popular and widely used in portable electronic devices such as mobile phones, game consoles, tablets and laptops. The lithium-ion batteries usually have a 3.6V or 3.7V nominal voltage, the LiFePO4 (LiFe in short) have a nominal voltage of about 3.2V or 3.3V and the lithium-polymer batteries have a nominal voltage of 3.7V per cell. With Li-ion and LiPo batteries the recommended per cell safety zone is usually between 3V (fully discharged) and 4.2V (fully charged), though you normally can discharge the batteries up to about 2.8V without problems, going below may damage them irreversibly, so these batteries often have built-in safeties not to be over-discharged, also overcharging can be dangerous. LiFe batteries are a bit different as they have a bit lower operating voltage of about 3.2V – 3.3V, the minimum discharge voltage is 2.8V and the maximum charged voltage is 3.6V. The LiFePo4 batteries have more constant discharge voltage are considered to offer better safety than other Lithium-based batteries. Other advantages of the Lithium-based rechargeable batteries include the ability for much faster charge and higher discharge rates than other chemistries mentioned and usually higher number of recharge cycles, meaning longer life when not fully discharged.

These are some of the most common types of batteries that we are going to be testing and comparing in terms of performance here on the pages of RightBattery.com, though there are many other types of batteries using different chemistry and with varying performance and features, but these are not very widely used. And since they are either too specific or nor widely spread and used, you would probably not going to need to use any of them, aside maybe from Lead-Acid (Pb) batteries which are the the oldest type of rechargeable battery we are probably not going to test most of them, again aside from maybe Pb batteries.


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