One of the new (it’s been out a while, actually) battery options on the scene for airsoft is the LiFe battery, also known as LiFePO or LFP. LiFe stands for “Lithium Iron Phosphate.”
When LiFe batteries first hit the market, they were known for having low electrical conductivity – this unfortunately has followed the reputation of the LiFe battery around like a dead turkey tied around the neck. Better engineering and technological advances have overcome this shortfall, and as such, the LiFe batteries of yesterday share nothing of their modern day counterparts except in name alone.
LiFe batteries have a few notable advantages over LIPO’s:
1) Most batteries have a highly constant discharge voltage. Voltage stays close to 3.2v during discharge until the battery is fully exhausted. This allows the battery to deliver virtually full power until it is completely discharged. This can greatly simplify or virtually eliminate the need for voltage regulation circuits.
2) LiFe cells typically experience a slower rate of capacity loss than traditional LIPO batteries. What this ultimately means is a much longer shelf life. A typical LiFe cell will have a capacity loss of up to 10% over the course of a month, whereas a NiMH can experience 30% or greater if the temperature isn’t in its favor.
3) LiFe cells are considered safer to charge and discharge than LIPO’s. The chemical composition of the cells resists heat, short circuiting, and abuse far better than LIPO’s. Granted, LIPO’s have come a looooong ways of late, and the gap between the two battery types has decreased dramatically. So short answer is yes, they are more stable and safer than LIPO’s – with the important caveat that you do your part and take care of your batteries. I have read a few accounts of individuals failing to buy the proper charger that has a “LiFe” setting and destroying their battery / personal property. Regardless of battery, type, etc. the key lesson to take away here is always: “NEVER, EVER, EVER, CHEAP OUT ON YOUR CHARGER.” I also recommend charging in a fire proof “Lipo-Sack” or even better is a .50 cal ammo can to store your batteries in. Airtight, and metal, so it’s not going to burn. No point in saving a buck today to torch a $100,000 house tomorrow.
4) LiFe cells are constructed of cheaper components than LIPO’s, but ironically, this hasn’t really trickled down to the consumer yet – LiFe cells are usually more expensive than their LIPO counterparts. Shop around and you can find some good deals, however.
5) LiFe cells are more compact than NiMH cells, so you can enjoy the benefits of small size and more power. They also come in some different voltages such as 9.9v with a 20c discharge rate, which puts it right between a 7.4v and 11.1v LIPO both of which usually have a 25c discharge rate. LiFe cells offer you more voltage per cell than NiMH. For example: the maximum voltage for a NiMH cell is 1.2v. Maximum voltage for a LiFe cell is 3.7V. This is over three times more! This also means they pack more capacity per ounce than a NiMH. An 8-cell 9.6v 600mAh NiMH battery weighs 5.7 oz. But a 3-cell 9.9v 1500mah LiFe pack offers you 250% more capacity, but only weighs a miniscule 1.2 oz.
6) The charge life of a LiFe cell is half again greater than a NiMH. Typically a LiFe pack will last over 1000 charge cycles, while the similar NiMH will run about 500 or so before it is shot. Charge capacity does not degrade as badly as a NiMH battery does over time either.
There are a few disadvantages to LiFe cells. One of them being that they haven’t really stormed the airsoft market in the same fashion as LIPO’s and NiMH batteries have. In fact, they aren’t altogether that common at all. As a result of their non-commonality, it can be a lot harder to find sizes that fit your particular AEG. Additionally, one should factor in the expense of a charger that will charge a LiFe cell if you don’t have one already.
Considering all the advantages of LiFe, it would make sense to make use of them as an upgrade – especially if you’re coming from NiMH. Switching from LIPO to LiFe is kind of a wash in my opinion if you already have a bunch of LIPO packs, and it doesn’t make a lot of sense if you can’t find LiFe packs that fit your AEG’s. If you’re getting into the Lithium technology game from the start, LiFe batteries should warrant a serious look, however.