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Thread: Lithium battery test with a 6.4 amp power supply

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    Lithium battery test with a 6.4 amp power supply

    I have been doing some tests with the new 20 amp/hr lithium batteries.

    I discharged the battery until it cut out (9.6 VDC), it took about 18 hours before it shut down. My concern was when I switched the grid power back on. The battery was drawing 2.6 amps DC, I decided to shut down the test because the device (looks like a MOV of sorts) just after the battery plug on the PC board got to 200 degrees C, so I decided to rather shut down the grid power, removed the battery and rather used the Victron charger to recharge the battery. The battery was drawing 10 amps DC from the 10 amp lithium charger.

    The lithium battery spec sheet indicates that the charge current should be less than 5 amp.

    So much for drop in lithium batteries, I contacted the company who supplies the power supply and was told "DO NOT CONNECT A LITHIUM BATTERY" to their power supply it is not designed for lithium batteries, which could explain the 200 degrees on the electronic components.

    Just imagine if I had sold this to a customer without doing the tests first

    I would be very cautious of offering lithium batteries as a drop for lead acid on security systems and gates. Not only will you be stuck with a warranty claim from the power supply, but you could burn down someone's houses or building.

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    Diamond Member Justloadit's Avatar
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    Can you take a picture of the "Black Thing" that got hot.
    Does it have 2 or 3 legs?
    Victor - Knowledge is a blessing or a curse, your current circumstances make you decide!
    Solar pumping, Solar Geyser & Solar Security lighting solutions - www.microsolve.co.za

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    Its a brown looking thingy mabob next to the battery plug on the PCB, the power supply is a sherlo 6.4 amp.

    The pcb has F7 and the thingy mabob has the letters XX H4.5 PLLA

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    Quote Originally Posted by Justloadit View Post
    Can you take a picture of the "Black Thing" that got hot.
    Does it have 2 or 3 legs?
    This is your department, I was hoping you could give us a little better understanding of why this component would get so hot.

    I was told it has to do with the charge characteristics of the lithium battery. Maybe you can do a better job of explaining more about charging lithium batteries and why it wqould heat up components on a the power PCB.

    I have a blue nova and a seuri prod lithium battery on other test rigs (X64 alarm panels) and they seem to be doing ok, I have drained them both and recharged them both, I haven't scanned them with the thermal imager yet. I plan to drain them both till the BMS low voltage cutout, then power them up still connected to the alarms panels and do a thermal test.

    At the end of the day it doesnt help dropping in a lithium battery if t is going to affect the PCB life span due to overheating issues. I would rather just stick to using lead acid for the next 12 months. I hear both suppliers are in the process of testing new PCB's with lithium charging capabilities.

    By the way I have cut open both Blue Nova and the securi prod lithium drop in batteries, and as expected you basically get what you pay.

    The Blue is a well built unit with the cells in a solid resin, compared to the Securi prod, its just look like a home made shrink wrap with the cells enclosed with the BMS, dropped into a 7 amp/hr PVC enclosure.

    I would love to see the cells and BMS specifications for both these batteries.

    From the little research I have done, Blue Nova has different levels of lithium cells, one which is rated for daily use and the other for backup. The life cycles and warranties are considerably different.

    I believe it is important you look at a life cycles, the BMS and cell warranty period when deciding on the lithium battery you buy. It is also important to check the charge and discharge rates.

    I believe the battery industry should be regulated with standard data and specs shared by everyone.

    I am no expert in this field, just trying to find my way through the maize, feel free to set the record straight and share your view.

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    Diamond Member Justloadit's Avatar
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    Quote Originally Posted by Isetech View Post
    This is your department, I was hoping you could give us a little better understanding of why this component would get so hot.
    Without knowing what this component is, I can not offer any further information.

    Lithium batteries, unlike Lead Acid, internal resistance remains almost constant throughout the charging cycle, accept for when it reaches fully charged state, in which the current practically drops to almost zero, unlike a Lead acid in which the current remains fairly high, causing battery damage if the charger is not removed.

    So any Lithium charger must maintain a constant current, constant voltage(CCCV or CVCC) through out the charging cycle. By regulating the amount of current, you can match the 'C' requirements of the particular battery.
    Of course there is always a trade off between minimum charging time and battery temperature. The Lower the 'C' charge the longer the battery lifespan cycles.
    Victor - Knowledge is a blessing or a curse, your current circumstances make you decide!
    Solar pumping, Solar Geyser & Solar Security lighting solutions - www.microsolve.co.za

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    I cant risk, hot spots on a PCB, I have canned the tests and will not be using the battery with the power supply.

    I will do the test again using a lead acid battery and see how it responds.

    When the equipment suppliers tells you not to use lithium batteries, best you listen otherwise you could find yourself in a sticky predicament. Warranties, insurance claims etc.

    I will be patient, I am told the supplier should have a lithium charging facility by the end of the year. IF not they are going to get left behind.

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