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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.
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