The differences between Ni-MH and Li-Po battery
RC car racing beginners often get confused about the different kinds of batteries.Some even waste money in buying the wrong chargers for their batteries. Here we Gens ACE and Tattu,a professional manufacturer of Li-po battery,will show you some difference between these RC batteries so you can make your good purchase choice for you RC models.
NiMH battery, short for Nickel-metal hydride battery , is an upgraded version of NiCd battery. NiMH battery uses hydrogen to store energy, with nickel and another metal keeping a lid on the hydrogen ions. It often comes in a cylindrical shape as below.
Lipo battery, short for Lithium polymer battery , is a newer kind of technology. It’s made of carbon and highly reactive lithium, which can store a lot of energy. Below is the structure of a lipo battery. With the flat structure the inner resistance is smaller.
Besides the most distinctive component difference, we can compare them in the following aspects too:
Voltage: NiMH’s nominal voltage is 1.2v per cell. So the common voltage for NiMH battery is 3.6V, 7.2V etc. But the voltage for each LiPO battery cell is 3.7V. So we usually find LiPO batteries in 7.4V, 11.1 v, 14.8V and 22.2V lipo battery.
Cost: LiPO battery is more expensive than NiMH battery at the moment. But now the production scale of LiPO battery gets bigger and bigger, the production cost drops down a lot more and so as the price for lipos.
Weight: LiPO batteries are smaller and can be made in almost any shape and size while NiMH batteries CANNOT.
Charge and discharge:LiPO batteries can be discharged and charged within a shorter time. But LiPO batteries can never be over discharged or over charged while NiMH is not that dangerous in that case.
Memory effect: Technically, NiMH batteries do not have a "memory effect". However NiMH batteries can experience voltage depletion, also called voltage depression, similar to that of NiCd batteries, but the effect is normally less noticeable. In contrast,7.4V Lipo battery has no memory effect.
Safety:because of the soft package of the Li-po batteries,it hardly burst or catch fire while Ni-MH has this risk.
Capacity:LiPo batteries have large capacities, meaning they hold lots of energy,around 2-2.5 times of Ni-MH batteries in a small package.
Lifespan:The lifespan for Li-po batteries can be over 500 while 200-300 for Ni-MH.
To make a conclusion, These Li-po batteries benefits are important in any RC model, but for airplanes, helicopters, and multi-rotor they are the reason electric flight has become so popular.
So Li-po battery is generally a better choice than NiMH battery in RC cars, helicopter etc. But Ni-MH is cheap and safe if you do not know how to care about the battery. So for beginners they can choose cheep NiMH battery packs. But for racing or serious player, Gens Ace and Tattu battery is a perfect choice for you with high quality and high C rating.Now Gens Ace and Tattu are still working on the new type of lipos with higher energy density. And we are looking forward to the new type of LiPO battery to lengthen the flight time and take place of the gasoline as the main power source for larger UAVs.