LiPo vs Li ion vs LiFe Batteries Explained

In this blog we're gonna be covering three battery chemistries that all come from the same lithium family. We're gonna talk about their high level specifications and where you can possibly use these battery packs.

3 Examples all come from the lithium family and that is going to be our Lipo battery pack , our light ion battery pack, lastly our LiFe battery pack or LiFe, depending on how you wish to pronounce it.

Let's first kick things off by talking about the voltages of each one of these battery packs.

Our Lipo battery pack has a nominal voltage of 3.70 volts, where our Li ion battery pack has a nominal voltage of 3.6, nd our Leife battery pack has a phenomenal voltage of 3.30 volts. You can see that already here there's a major advantage for the lithium polymer battery pack because it has a higher nominal voltage, all these voltages are per cell so when you go and multiply these voltages, by the total amount of cells that you have in a battery pack, you can get a much higher voltage out of our lithium polymer battery pack without the need for a high cell count.

Let's talk about the second value that we have here up on the board and that is our maximum voltages for every cell. There are some differences there between each one of the battery chemistries. The biggest thing to focus on is the difference between the maximum as well as your nominal voltage. For the first two battery chemistries, we have about 0.5 volts difference for every cell that you have within that battery pack. However our LiFe battery pack only has a difference of point three volts this is going to suggest to us that during the course of the battery's life from 100% state of charge down to 20% state of charge. We are going to see lesser of a voltage drop within a LiFe battery pack. So when it comes to the difference between maximum versus nominal this definitely takes the cake.

Now when it comes to for the 3^rd specification, this is the absolute minimum voltage here that we have on the board. You absolutely want to make certain that you never actually hit the values that are written on the board in green 3 volts for our Lipo 3 volts for our lithium ion and 2.5 volts for our LiFe. If you happen to hit these voltage with these battery packs, you can be certain that the lifespan of that battery pack in terms of how many years you're going to have that battery pack around is going to degrade and it's going to decrease. You want to make sure that we have a drop dead minimum of around 3.4 volts per sell for the first two battery chemistries and 3.00 for our last battery chemistry.

Now when we talk about the next item that we have up here, this is the maximum capacity that we want to discharge from a specific battery back. If we have a 5000 milliamp hour battery pack and we only want to discharge 80% of that capacity, that is going to be equal to 4000 milliamp hour. The remaining state of charge is going to be one thousand million hour in our five thousand million hour battery pack. So this is something to think about when you are using these batteries, and it's going to aid especially when we talk about Lifespin of the packs, this is what gets you maximum life by making sure that you follow this rule. Luckily enough for us, it's going to be equal for all the lithium based family that we're talking about here today.

Now let's talk about the typical use for each one of these battery chemistries as it would apply in our RC world. So when we first start out by talking about our Lipo battery pack. You would typically see one of these battery packs used in high output power systems. The big advantage of a Lipo battery pack is that it can dump a ton of power out, especially for its size and its weight. This makes it perfect for those high output scenarios where we need to deliver lots of current,  specifically what we're talking about here is the rate at which we're able to discharge that battery pack, which is going to be equal to the amount of current, that we can actually get out of a Lipo battery pack. When you're talking about your lithium ion battery, this is going to be where you have applications within RC that is of slow drain, this typical example is an RX a TX, this is our receiver battery pack or a transmitter battery pack even if you want to run some LED lights on board or even a sound card on board. Any one of these examples and you could easily get away with using a lithium ion cell. Now even some long range radio controlled airplanes or drones use and can get away with using this specific battery pack.

Now the last item that we do have up on the board here is our LiFe. This is used in multiple different locations especially with larger radio control vehicles. We can see these battery packs being used in transmitters as well as receivers even ignition systems or turbine ECUs. A nice thing about the LiFe battery cell is that it has a nominal voltage of 3.3 volts , which actually makes it ideal for RX applications. I can use this battery chemistry for all of my 6 volt nominal servos, and it will work without any issue. The total voltage that we get out of that battery pack can be 7.2 volts, but as soon as you pull it off the charger and start to use it, it dropped very quickly down to that LiFe battery pack over.

Let's talk about some of them for our Lipo and Li ion. Typical cells you will see in the lithium polar battery pack will come in this rectangular shape. This is an example of what a 3s LiPo battery would be and you can tell that because you can see three layers of cells stacked on each other. This type of cell is very easily damaged in any type of radio control vehicle crash. Just something to keep in mind if you are flying a radio control airplane, or you're jumping one of your radio control cars if that battery pack comes flying out and hits the ground it is more than likely going to be permanently damaged physically in some way shape or form. Now for our lithium ion battery pack this typically comes in a cylindrical shaped cell a common configuration is the 18650.

Now for our last one the whole reason why I put this special characteristics here is because of this specific battery chemistry. The resting voltage if you were to look at a resting voltage anywhere between 20% and 80% of the battery capacity here, you are going to see a relatively constant voltage, this is something that blows my mind because you do not typically see this with any battery chemistry. The resting voltage of a battery pack in my experience for a LiFe battery is not something that I would use to actually determine what its state of charge is. It is common for me to go and utilize the milliamp hour of usage for this battery pack so that I can get an understanding as to where I am within the state of charge for that battery.

Now let's talk about the lifespan of our battery packs. Our Lipo battery pack here is ranked in last place 3 out of 3 because it does perform the weakest when we are talking about the lifespan of our battery pack. A great example would be an electric ducted fan jet, typically from batteries I get about 2 or 3 years of the battery pack before I would have to go and purchase a new one for our electric ducted fan jets. The reason is I'm not going to get the same performance when new from that battery pack for my electric powered jet, and as a result I cannot fly it with such a reduced amount of performance.

Now let's talk about the rank for our lithium ion. This actually has the highest amount of lice ban, you can get a significant amount of years out of a lie ion cell. This is by far one of the top advantages of a lithium ion battery pack. The lice ban of these are significant, and finally our last one here is going to be the LiFe battery pack coming in on the rank between these three battery packs as No. 2. So these have a good lifespan they're somewhere in between our Lipo and our lithium ion pack.

Now let's talk about the maintenance. Now all three of these battery pack chemistries require us to maintain them in order to maximize lifespan. A better word to describe exactly what we're going to talk about here may actually be the damage due to abuse. The damage due to abuse for not maintaining your Lipo battery pack is going to be quite high. Relative to the damage from abuse if you don't maintain your LiFe battery pack that is going to be relatively low.