The 7.4V Lipo and 9.6V NiMH batteries are undoubtedly the best in the market. So, we know how hard it can be to choose between the two.
Now, you just got a radio-controlled (RC) car for yourself? Can’t decide on which of the two batteries would give better performance? Don’t worry! We’ll help you out in making a decision.
So, where do you stand in the 7.4v liPo vs 9.6v NiMH dilemma?
Although some features of these two batteries are the same, there are some significant differences. There are differences in their weight, capacity, charging and storage options, the safety of usage, etc.
The features mentioned above are very crucial to consider, right? Then, read along to know more!
7.4V Lipo vs 9.6V NiMH: Quick Difference
The main difference between the two batteries is their chemical composition. LiPo uses lithium-ion technology. On the other hand, NiMH uses nickel-based technology. Chemical composition plays an important role in certain features of course.
Here’s a table to help you briefly visualize the differences-
|Feature||7.4V LiPo||9.6V NiMH|
|Configuration||2 or more LiPo cells in Series/ Parallel Combo||8 NiMH cells in series|
|Power Capacity||Less than its NiMH counterpart||Denser and energy-packed than LiPo|
|Charge Rate||Slow, Normal, and Fast Charging||Slow and Normal Charging|
|Discharge Rate||Usually, Up to 50C||Usually, Up to 10C|
|Voltage Deviation||Pretty stable voltage||Less stable voltage|
|Shelf Life||Up to 5 years||Up to 2-3 years|
|Heat Catch Up||Heat resistant.||More voltage. So, it pulls more current. Hence, heats up easily.|
|Storage Maintenance||High(needs stable recharge and storage bag)||Low|
|Fire Hazard||Can turn into a fire hazard||Safe with Fire|
|Disposal||Need to follow some instructions before disposal.||Recyclable. So, easy to dispose of.|
So, noted above for you are the basic differences. We can see that for most of the features, LiPo is definitely standing out! However, the table above is only giving you a gist of what you can expect. Following this, you will find some more resourceful takeaways!
7.4V Lipo vs 9.6V NiMH: Head to Head
Now, it’s completely normal if the information in the table above seems vague. To come to a decision, we obviously need to dig deeper. So, read along to find everything in detail and also some additional info that may intrigue you!
Physical Comparison: Configuration and Weight
Apart from being two different battery technologies, a 7.4V Lipo and 9.6V NiMH are pretty different in terms of cell chemistry as well. Let’s have a look-
Configuration of 7.4V LiPo
The simplest configuration of 7.4V LiPo is to connect 2 single cells in Series(s), a.k.a. 2S. A single LiPo cell has a nominal voltage of 3.7V. So, two of them combine into 7.4V.
However, when a battery needs to house more power with the same voltage, it can be 2S1P(2 cells in series, 1 in parallel), 2S2P(2 cells in series, 2 in parallel), etc as well.
Now, the weight of a 7.4V LiPo actually depends on how much capacity is poured into it. For example- a 2S1P 7.4V LiPo weighs only 20g if it has 300mAH in it. For 800mAh, the same LiPo weighs 50g at 800mAh. Moving on, a 2200mAh 7.4V is 136g and a 5700mAh 7.4V is as heavy as 315g.
Configuration of 9.6V NiMH
A 9.6V NiMH contains 8 Sub-cylinder/AAA type NiMH battery cells, connected in series. Each of these cells offers a nominal voltage of 1.2V. So 8 of them combine into 1.2×8=9.6V.
Each Sub-C cell weighs around 74g and is 43mm(L)x23mm(D) in size. On the other hand, each AAA cell weighs about 15g and measures 44.5mm(L)x10.5mm(D).
So, 9.6V NiMH packs weigh around 600g/1.3 lbs if it’s made of Sub-C cells. And 120-130g/0.26-0.28 lbs if it’s made of AAA cells. Note that the weight can be significantly different based on how much capacity(mAh) a 9.6V NiMH has.
Takeaway: 7.4V LiPo is way lighter and smaller than its 9.6V NiMH counterpart.
The Battery Capacity and Power Capacity
Power Capacity(Wh) is a different measure than the battery capacity(Ah), and they mean two different characteristics as well. Wh indicates how densely ‘power’ is poured into it, and the capacity is the amount of fuel(charge) in it.
However, both 7.4V LiPo and 9.6V NiMH can vary in capacity(mAH), varying the runtime you’d get from them as well. Both of them are available in 800mAh, 1000mAh, 1200mAh, 1500mAh, and up to 5000mAh.
But if it comes down to the power capacity of two 7.4V LiPo and 9.6V NiMH packs of ‘Same’ capacity, the answer is pretty definite. The NiMH would have held more power than the LiPo counterpart. If it can stick to its nominal voltage, it’d lead to more runtime compared to its 7.4V LiPo competitor.
Let’s say we’re sticking to a 1000mAh capacity of both. So,
Power Capacity(Wh) = Voltage(V)*Capacity(Ah)
The 7.4V LiPo would have 7.4(V)*10(Ah)= 7.4Wh
The 9.6V NiMH would have 9.6(V)*10(Ah)= 9.6Wh
Takeaway: Both 7.4V LiPo and 9.6V NiMH have a diverse range of capacities(Ah). But for two of the packs of the same capacities, the 9.6V NiMH would hold more ‘power’ than the 7.4V LiPo.
The Charge and Discharge Characteristics
As long as it’s a hobby purpose, both charging and discharging properties matter a lot. The question of ‘how long it’d take to charge?’, and ‘how long it’d run for?’- are two of the most frequent questions asked by hobbyists.
Charge and Discharge Rate of 7.4V LiPo
LiPo’s can be charged in a number of ways- Fast Charge, Normal Charge, and Balanced Charge. And all of this applies to a 7.4V pack. With Fast charge, you can fill it in just 4-5 minutes, whereas with a balanced charger(1-2C), it’d take up to 15-20 mins.
But it’s recommended to balance-charge the battery and that’d keep the battery health good as well. Also, forget not to put it in a charger bag while charging. Safety first!
About discharging, 7.4V LiPos are well known for offering a high discharge rate of 50C. When your RC toy needs a massive kickstart, that’s what you’d need.
Charge and Discharge Rate of 9.6V NiMH
NiMH packs need to take slow when it comes to charging. Charging it for the first time might even take up to 20 hours.
The rule of thumb for NiMHis- the slower you charge it, the better. And a 9.6V NiMH abides by the same rule.
Usually, you can charge a 9.6V at 0.1-1C charging rate- based on how quickly you want to get done with it. Slower chargers would take 2-10 hours to recharge and empty 9.6V NiMH but will keep the battery healthy. And vice versa.
Regarding discharging, this pack can offer up to 10C-30C of rapid discharge, but 10C is the limit for most of them. It still gets the job done when your RC model needs a kickstart or a big leap.
Takeaway: 7.4V LiPo can be charged faster than 9.6V NiMH, and also can offer a more powerful discharge rate.
Storage Facts: Self-Discharge Rate and Shelf Life
While you’re not using any of these two battery packs, each of them would be giving up charge capacities anyway.
For 7.4V LiPo, its self-discharge rate of being 4-10% per month, depending on the storage. Stored in a cold place, LiPos loses less charge and vice versa. But you should never leave a 7.4V LiPO fully charged before storing it. A 40-50% charge should be nominal for storing.
Also, considering LiPo’s fire vulnerability, store it in a safety bag. Here are our best safety bag suggestions that will help you in this case:
A 9.6V NiMH on the other hand might have a higher discharge rate(15-20% per month), but it’s way less hassle to store. You can store it while fully recharged, and you won’t need any storage bag as well. The shelf life can be much less than LiPo, which will lead to a manual discharge-recharge cycle over again before it functions properly.
Takeaway: A 7.4V LiPo offers longer shield life and lower self-discharge rate, but is high-maintenance. A 9.6V NiMh is less hassle to store but lasts for a shorter timespan.
Safety and Stability
Lipo is very unstable when it comes to safety. Lipo batteries can catch fire quite easily if they face the slightest inconvenience while charging. And if they are remotely punctured, then it is better to get rid of them as soon as possible. Some additional setup would be needed for safe usage.
This is where NiMH has an upper hand as it is safer and easier to use. However, there are many categories of NiMH. So, to get the best NiMH battery for ourselves, we should dig deeper into it.
How long does a 7.4 LiPo last?
The duration of a battery’s performance also depends on its mAh. However, simply put, it generally lasts for approximately 1200 shots. That means it would help your RC device to run for a minimum of 6 hours without recharging.
Do LiPo batteries last longer than NiMH?
Lipo batteries can preserve greater voltage for a longer period of time. And their discharge rate is very steady. So a longer and steady performance can be achieved as they have a greater size to capacity ratio.
Is LiPo better than NiMH?
Lipo batteries are lighter. They have a better weight to capacity ratio. Hence, these batteries are better in quality because of their higher power output. RC devices can perform better with LiPo batteries for their lightweight and high capacity.
As we can see, for most of the crucial features, LiPo batteries have an upper hand. As NiMH batteries are cheaper and require low maintenance, it is usually provided complimentary with many RC devices. It was also a more widely used one. But, LiPo is apparently taking over now and we clearly have a winner!
So, are you looking for a low-maintenance and cheaper battery? Then go for NiMH. But if these are not an issue for you, then why even have doubts? Go for LiPo!