Are LiFePO Batteries better? How to Use them For Small Projects

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 gritsy youtubers here is the guy with the swiss accent with a new episode and fresh ideas around sensors and microcontrollers remember if you subscribe you will always sit in the first row 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 i hope this video was useful or at least interesting for you if true please consider supporting the channel to secure its future existence thank you bye

Channel: Andreas Spiess

Views: 46,417

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Id: eiyBavjQ1Rk

Length: 14min 17sec (857 seconds)

Published: Sun Nov 14 2021