What are the disadvantages of lithium iron phosphate (LiFePO4) batteries?

Discussion in 'General Technical Questions and Answers' started by MIKELAM, Dec 4, 2019.

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    MIKELAM QRZ Member

    In addition to the price, what are the disadvantages of lithium iron phosphate (LiFePO4) batteries?

    If the price of lifepo4 comes down, will no one buy the lead-acid battery?
  2. K7RJB

    K7RJB Ham Member QRZ Page

  3. SM0XHJ

    SM0XHJ Ham Member QRZ Page

    If it has a built in BMC the only real disadvantage I can think of is that you cannot charge it at low temperature (below freezing).
  4. AG6QR

    AG6QR Premium Subscriber QRZ Page

    • They shouldn't be charged with the same charging algorithms that work for lead acid. So new chargers may be required.
    • They can't be recycled as easily as lead acid.
    • It's hard to know the state of charge, since voltage stays nearly constant while discharging.
    I don't think any of these are very serious, and I'd prefer LiFePO4 if it weren't so expensive.
  5. K6BRN

    K6BRN XML Subscriber QRZ Page

    Another limitation of LiFePo is the maximum charge rate. It's a hard limit. With lead acid batteries, it is possible to alternate high charge and discharge rates without too much problem.

    LiFePo batteries built as replacement starting batteries are designed for high peak discharge/charge rates but tend to have low total amp/hour capacity.

    The Bioenno LiFePo storage (not starting) batteries sometimes have to be oversized for a given (standby) solar installation in order to avoid damage from peak charge currents. This is expensive to do. Lead acid batteries are much more tolerant of high peak charge rates.

    Nits, really. But these differences mean that you cannot simply drop a LiFePo battery into ahead acid application without some modifications in equipment and thought about collateral consequences.

    Brian - K6BRN
    WA7ARK, MIKELAM and AG6QR like this.
  6. W9WQA

    W9WQA Ham Member QRZ Page

    i have an 'imax b6ac" charger for lithium batts. works good and proper. instructions need work.

    MIKELAM QRZ Member

    I found that some lifepo4 batteries can charge below freezing temperatures, If it can be charged at -20℃.

    MIKELAM QRZ Member

    Why you prefer LiFePO4 rather than LA, is it for some specific applications? The basic function of BMS can monitor the state, and you can try to buy online or DIY.
  9. AG6QR

    AG6QR Premium Subscriber QRZ Page

    I prefer LiFePO4 over lead-acid because it's smaller and lighter for a given storage capacity, and you can repeatedly use it to its full capacity without damage. Lead acid is heavy, and should be limited to 50 percent depth of discharge for best life. But it is cheaper.

    My context of use is portable operation of radios, mostly. I have a little 5Ah LiFePO4 for hiking long distance with QRP, and a couple of 35Ah AGM batteries for when I'll be operating within 30 feet of the car.
    KB0MNM and KB2SMS like this.
  10. K2XT

    K2XT Premium Subscriber QRZ Page

    If a LiFPO4 battery was used on a workbench, and the leads were accidentally shorted the battery is capable of extremely high currents as I understand them. This could result in a fire if the leads were not huge.
    On the other hand I do not know if they have built in overcurrent protection, so an inline fuse would not be a bad idea.

    I have a 6 amp-hour Bioenno one here and am reluctant to use it on the bench for low current stuff. An old gel cell is safer.

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