Is LiFePO4 the same as LiPo?

[pamalot]

Sorry is this is a stupid question, but I've had LiPo batteries in my RC cars for some time now (used to be NiMh) and a few weeks back converted my electric bike to also run on LiPo batteries which has dramatically increased the range of it. So I'm pretty familiar with the requirements of LiPo battery management and charging. Therefore my thoughts have turned to whether or not I could use the same technology to store the excess power of my solar. I'm going to do a load of reading on hear before I go any further, but if someone could answer this simple question it would really help a lot. Is LiFePO4 the same as LiPo?

These are the battery packs I use in the RC cars and the e-bike:

http://www.hobbytown.com/Shop/VNR15059-Venom-Racing-50C-11-1V-5000mAh-3S-LiPo-Universal-Plug/

[Sunking]

No they are not the same. Ironically what you call LiPo, I am an RC pilot and use the same batteries, are not really a polymer battery as the name implies because the electrolyte in them is gelled rather than a thin plastic polymer. The reason for this the extremely high charge and discharge rates use din RC batteries. Today you can find 100C just about everywhere. The LiPo you use also have a fairly high energy density of 140 to 160 wh/Kg. Their big disadvantages are cycle life, expense, and safety. Depending on quality of the battery have a cycle life of 150 to 400 cycles, cost are very high from 60-cents per watt hour on the low end and up to $3 per wh on the high end for 100C cells. In addition to keep weight down nearly all of them are Pouch design coupled with high energy density make them fairly dangerous. Many a fires have been documented charging them, and easily punctured which also leads to fires in crashes. Additionally the voltage of LiPo cells nominal voltage is 3.7 volts which does not really work well as 3S is 11.1 volts, 4S is 14.8 volts and so on does dot fit a 12 volt world.

LiFeP04 aka LFP is a different animal all together. LFP has lower energy density of 90 to 100 wh/Kg, lower C Rates of 2 to 4 vs 20 to 100, much higher cycle life of 1000 to 2000 cycles, very stable and safe electrolyte, and the lowest cost of all the lithium batteries.

So when you look at the big picture, you can only justify the cost of LiPo in RC models and Electric Racing vehicles that require the high C-rates, high energy density, and low cycle life is not important. Solar does not need high C Rates, high energy density, and needs to be as inexpensive as possible with high cycle life.

[pamalot]

No they are not the same. Ironically what you call LiPo, I am an RC pilot and use the same batteries, are not really a polymer battery as the name implies because the electrolyte in them is gelled rather than a thin plastic polymer. The reason for this the extremely high charge and discharge rates use din RC batteries. Today you can find 100C just about everywhere. The LiPo you use also have a fairly high energy density of 140 to 160 wh/Kg. Their big disadvantages are cycle life, expense, and safety. Depending on quality of the battery have a cycle life of 150 to 400 cycles, cost are very high from 60-cents per watt hour on the low end and up to $3 per wh on the high end for 100C cells. In addition to keep weight down nearly all of them are Pouch design coupled with high energy density make them fairly dangerous. Many a fires have been documented charging them, and easily punctured which also leads to fires in crashes. Additionally the voltage of LiPo cells nominal voltage is 3.7 volts which does not really work well as 3S is 11.1 volts, 4S is 14.8 volts and so on does dot fit a 12 volt world.

LiFeP04 aka LFP is a different animal all together. LFP has lower energy density of 90 to 100 wh/Kg, lower C Rates of 2 to 4 vs 20 to 100, much higher cycle life of 1000 to 2000 cycles, very stable and safe electrolyte, and the lowest cost of all the lithium batteries.

So when you look at the big picture, you can only justify the cost of LiPo in RC models and Electric Racing vehicles that require the high C-rates, high energy density, and low cycle life is not important. Solar does not need high C Rates, high energy density, and needs to be as inexpensive as possible with high cycle life.

Perfect info. This is my first baby steps into this world and your explanation was pitched perfectly for me to understand. Thanks.

A lot more further reading and research from me will now begin.

[Sunking]

Perfect info. This is my first baby steps into this world and your explanation was pitched perfectly for me to understand. Thanks.

A lot more further reading and research from me will now begin.

You are welcome, but what you will find out soon enough is Lithium Batteries are just not ready for mainstream solar applications. First is Pb batteries are just far less expensive today, and thus no demand of lithium to be used in solar applications. That means no equipment is on the market to support Lithium batteries yet.

There is one exception in the Marine World for very small scale systems called GenSun who makes a controller for Lithium but has no real BMS built into it. Take a look and you will see what I mean. Gensun has two offerings limited to 12 volt only at 5 and 10 amps. Works to keep you boat battery charged up while setting at the Marina waiting for you to go out, but not practical for any off grid applications except toys.

To use Lithium on solar today is going to require a lot of equipment modification. For example all Solar Charge controllers out there use 3-Stage charging algorithm tuned to Pb batteries. That will not work with Lithium. There are a few high end controllers you can program voltage set point to use with Lithium, but you have to build an interface to **** them off or disconnect when charged up. So you really have to know what you are doing and have some electronic experience with prototyping to pull it off. Otherwise you risk destroying expensive LFP batteries.

[PNjunction]

Pamalot - right off the bat notice the difference in max charging voltages: Lifepo4 - 3.6v per cell. Everything ELSE: about 4.2v. If you apply 4.2v to lifepo4, that will damage it so just a reminder not to just be swapping things out.

And unless you have the resources of a vehicle manufacturer, lifepo4 being the least energy dense and most stable of the lithium chemistries, is the only chemistry I'd consider sitting on. I don't want an RC battery under my butt. Lifepo4 from an amateur standpoint makes a lot more sense.