In the Part 1 and Part 2 of Battery series,  we have discussed two different kinds of Lithium batteries; Li-ion and Li-po, that can be used with Taranis X9d Plus FrSky Radio.  As you can see from the title of this article, It is the continuation of the last article in which we are going to know more about Ni-Mh batteries in general. That is exactly what I promised in the last article.

               Ni-Mh and Ni-Cd batteries come under the family of Nickel Batteries. They are quite famous in RC Hobby as many RC Cars make use of this battery as the power source. Those Ni-Mh Car batteries, especially used in Traxxas brand, are pretty cool because it looks like an array of capacitors.  Above all, Ni-Mh is the stock batteries that come with Taranis x9d plus FrSky radio.

              Qx7S also comes with Ni-Mh batteries. Many people like these Ni-Mh batteries that come with the FrSky Radios. But, they lose their energy holding capacity after a few months or in one or two years. So you will have to get a replacement battery from Frsky dealers or look for an alternative that is available in the market. Many Pilots find it a worthy upgrade to replace the batteries with Li-fe or Lipo.   

               Well, we have started this Battery series to give an insight on different types of batteries so that you will be able to choose a battery by yourself when you are looking for a replacement. So it is important to learn about all these batteries before jumping to someone else recommendation.  I hope you will be able to choose a battery yourself when we complete the battery series. So be patient and get started!

Ni-Mh

               Ni-Mh batteries stand for Nickel-Metal hydride and they come under the family Nickel batteries. Ni-Cd (Nickel-cadmium) is another example in the family. Actually, Ni-Mh are very similar to Ni-Cd batteries in terms of the chemical reaction at the positive electrode with both having a nickel oxide hydroxide electrode. The main difference lies in the negative electrode where Ni-cd batteries use cadmium where Ni-Mh uses a hydrogen-absorbing alloy.

               Ni-Mh batteries are usually on satellite applications. It has a nominal voltage of 1.2v which is the same as of Ni-Cd batteries as well. The biggest disadvantage of Ni-Mh battery is the “memory effect”. It is explained as the reduction in the longevity or reduction in the capacity to hold a charge due to the recharge of incomplete or partially discharged batteries.

               When you charge the Ni-cd or Ni-Mh battery, it is unable to know if it completely discharged or how many portions of unused charge is left in it. When you charge a partially discharged Ni-Mh battery, the battery will consider only the used portion of the battery as the whole battery and it will gradually forget about the unused portion which actually holds half of the total charge.

When the next time you use it, the battery will only use the portion that it has charged last time and will not use the other half. So it will be like a battery that only uses half a portion of it to charge and delivers current without even realizing it has another portion remaining. That is a major drawback of Ni-Mh battery.

The memory effect can be overcome by repeatedly fully discharging the battery using a suitable charger. Moreover, Ni-Mh is less prone to a Memory effect than a Ni-Cd battery. The number of the life cycle is around 5000 cycles claiming up to 10000 cycles which more when compared with Li-ion. Perhaps that is why the stock battery on FrSky Taranis X9d Plus is Ni-Mh?

Pros:

  • Greater number of life cycles
  • Not expensive
  • Environmental friendly
  • 30% higher capacity compared to Ni-Cd Batteries
  • Does not catch fire (like a Li-Po and li-on does)

Cons:

  • Memory effect
  • Not lightweight
  • Performance degrades at elevated temperatures (if stored)
  • Generates more heat during charging

 

               So we have briefly discussed some of the different attributes, pro’s and con’s of the Ni-Mh batteries and now you have understood why it comes with FrSky X9d Plus Frsky radio. They are nature friendly so that the recycling process is easy or can be discarded at ease. Moreover, they are very stable batteries and does not catch fire.

               Ni-Mh are really great batteries if memory effects can be put aside, but it’s not a big problem at all if you completely discharge it before charging it. I hope this article has helped someone to understand Ni-Mh batteries in general. In the next article, We will be discussing Li-Fe batteries. Stay Tuned!