for years we have used rechargeable lyon
batteries for our projects
they are widely available but are they
still the best solution
let's have a closer look at the newer
kit in the block the live apo 4
batteries
how do they compare and more importantly
how are they used
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in this video we will answer the
following questions
what is life844 and how does it compare
with lyon batteries
how can we charge them how can we use
them in our three point three and five
volts projects
how can we protect them against deep
discharge
and a small excursion towards higher
voltage life hippo4 packs when i first
covered lifeapo4 on this channel in 2016
few such batteries were available and we
did not know much about them during the
following years they always were the
little sister or brother of the lion
batteries
but more and more offers appeared on the
platforms today liveapo4 is a respected
technology and especially for power
walls it is the de facto standard
why is that
life apo 4 was discovered in 1996
but was not widely used because its
power density is smaller than other
lithium technologies
from the start energy density was lyon's
main argument against technologies like
nickel cadmium and we saw a race on this
parameter
with its diameter of 18 millimeters the
length of 65 millimeters and the nominal
3.7 volts the 18650 cells established as
standard also for bigger battery packs
in the beginning we saw capacities of
around 2 thousand million per hours and
today we see capacities up to three
thousand four hundred million per hours
if we forget the chinese promises of ten
thousand million per hours
they still sell cells with less than
three thousand million per hour mainly
because the batteries with the highest
capacity have other disadvantages like
fewer charging cycles till they die
liveapo4 always lacked in the capacity
per weight race
maybe this is why it did not get much
attention
other parameters were also improving
during the last years the time to charge
a battery today we can charge lyon
battery packs nearly in minutes
charging rates of 10 and more are common
those days
lifevepo4 is still lower in this respect
but the rates also increased over time
energy density is significant for mobile
applications and charging time becomes
more and more a deciding factor for
electric cars or smartphones
a next parameter is the number of
charging cycles a battery offers till
its capacity is only eighty percent a
critical factor for a costly battery
pack of a car
live fipo four batteries can be charged
nearly endlessly if you believe the
specifications
lie on batteries usually stay below 1000
complete cycles
how relevant are these factors for our
project and is there other essential
factors
the output voltage for sure is
fundamental we either need 3.3 or 5
volts for most of our projects
if we need more than that for motors or
transmitters generally we use battery
packs
live fipo 4 and lighon batteries have a
very different output voltage
two aspects are important the charging
voltage of lyon is 4.2 volts and the one
of lifevapo 4 is only 3.65 volts
during discharging the safe area for
both ends around 3 volts so we cannot
use the same charges for both
chemistries
however the under voltage protection is
the same
obviously the voltage drop of lyon is
much bigger with the advantage that we
can determine the remaining capacity by
measuring its output voltage
lifi 4 has a very flat discharge curve
with a sharp drop at the beginning and
in the end
so measuring the voltage only tells us
if it is completely charged or very
close to the discharge cut off point
in between we do not get good
information
because most 3.3 volt logic chips are
rated up to 3.6 volts but not up to 4.2
volts we generally need a voltage
regulator for light yawn batteries
liveapo4 batteries can be directly
connected to our 3.3 volt projects
only if we need 5 volts we need a boost
converter for both chemistries
or we use 2 batteries plus a 5 volt
regulator
how important is energy density for our
typical projects
not too much if you ask me usually we do
not care too much about the size or
weight of our projects
if so like john probably would be the
winner but only if you use an efficient
voltage regulator otherwise it will burn
the excess capacity
and what about charging time
none of the lyon charges i use in my
projects offer a lot of current
so it anyway takes a lot of time to
charge them if you fly model planes this
is a different story then lion batteries
are the better choice
and what about the charging cycles
because i do not want to charge my
projects every day even my lion
batteries will never reach the rated
charging cycles before they die an
unnatural death
now we come to a fact also crucial for
my projects safety i do not want my
projects to suddenly burn as it happened
with one of my lyon batteries
unfortunately lyon has a nasty property
they can start to burn during charging
if you deeply discharge them before or
if their structure is hurt in any way
and we all know that lithium polymer
batteries blow up after a certain time
which also does not establish a deeper
trust in this technology
and the worst you cannot distinguish a
burning lyon cell with water as
firefighters know from burning teslas
liveapo4 batteries are less problematic
because their chemistry does not
encourage a thermal runaway
therefore they are considered to be safe
good to know
but still they have to be protected
against under voltage as well as
overcharge
as we saw before under voltage
protection is similar for both
chemistries the overvoltage protection
of course is different because of the
different maximum voltages
in past videos we saw different boards
to protect lyon batteries from deep
discharge and charger boards that also
offer overcharge protection
these
tp4056 boards are typical for that
purpose
what about lifevapo4
how do we charge them and how do we
protect them against deep discharge
is there a
tp4056 for lifehippo4
you find hundreds of offers for
tp4056 boards but nearly none for life
before
the only small charge board for single
cells i found are these two using a
tp5000 chip and this one with a cn
cn3058
the tp5000 ports also serves as chargers
for light yawn batteries if we add a 10
kilo resistor here
so you see the main difference between
charging a lion and a lifo apo4 battery
is the maximum voltage
another deciding factor could be the
form factor fortunately you get both
chemistries in 18650 as well as square
formats
recently i discovered new formats like
this
32700 or this aa format
fortunately both chemistries are
available in those formats
however i did not see a lot of small
live fibo liveapo4 flat packs
so for small projects like this one you
have to use lion
because of apparent reasons laws in many
countries forbid the sale of unprotected
cells
but you can still buy a lot of them they
are just labeled for professionals who
know how to deal with the dangers
and because the under voltage protection
circuit on the 18650 batteries extends
the length of the battery they often do
not fit into the standard holders
so i suggest doing the protection
outside like using a tp4056
many lyon flat packs come with
protection circuits included
if not i suggest you add one yourself
you get them ready made for both
chemistries
if you use this captain tape it's easy
to mount them directly to the pack
and of course we have to use lyon
batteries for all boards with included
battery management like the newer tt go
boards i wonder how long it will take
till one comes out for lifevapof4
the advantages are apparent to me
as the last point there is temperature
range many sources say that lion
batteries should not be used below zero
degrees celsius and above 55 degrees for
large currents
this source distinguishes between
charging and discharging but makes no
difference between the chemistries
so both chemistries can be used down to
-20 degrees centigrade however they
should not be charged below zero degrees
so they should be okay for most of our
outdoor projects
this is also in line with using
smartphones and cameras in winter when
they only lose capacity but are not
harmed otherwise
i promised a small excursion to bigger
packs for a long time we could buy these
lyon packs for model planes for example
they come in various voltages as well as
current ratings most if not all are
unprotected
another fact to consider as soon as we
have more than one cell in series we
encounter a problem
balancing it is evident that cells in
series are charged and discharged with
precisely the same current
if the capacities of the two cells do
not match one cell goes flat before the
other and if the capacity difference is
significant
you do not quickly discover it from the
outside the same can happen during
charging the smaller cell tops up before
the other and has to dissipate the
excess current
not good or even dangerous
this is why we need balancing the lyon
battery packs usually have a second
connector for balancing a special
charger like this one can balance the
cells through this connector
many lifo 4 battery packs only have one
connector and contain the balancing
circuit inside the pack
usually combined with under voltage
protection these boards are called
battery management systems or bms and
also can be purchased alone
this concept fulfills the laws and is
much easier to handle you just feed your
pack with your bench power supply and
whatever current you want as long as you
are below the maximum rating everything
is good the bms will switch off when the
battery is charged and during operation
the bms switches the load off if one
cell reaches the critical level
i propose to charge completely
discharged packs as soon as possible
because of further self-discharging they
can get into a critical area the bms
cannot avoid this
here is the comparison between the two
technologies starting with the essential
factors for small projects
the cell voltages as well as the
discharge curve are different
this is why lifi4 batteries are a better
fit for 3.3 volt projects for 5 volt
project there is no difference
unfortunately we still do not get a lot
of charger boards for lifehippo4 and all
battery-operated mcu boards use lyon
batteries
fortunately we found such boards using
the tp5000 or the cn3058
the energy density the charge and
discharge current as well as the
lifetime are not so important for our
small projects
safety however is also important for our
projects even if we did not hear of
another samsung battery disaster i still
do not 100
trust my lion batteries particularly the
flat packs tend to blow up after a few
years
all in all live april 4 will get more
important over the next years
particularly for stationary applications
and maybe we will get even more
fascinating battery technologies
as always you find all the relevant
links in the description
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