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Thread: Dead battery?

  1. #21
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    Default Re: Dead battery?

    Quote Originally Posted by An3s View Post
    2x 100 Ah batteries in parallel will give you 200 Ah, yes.

    Battery capacity is (may also be) stated in Wh or kWh (not kVA). Battery mfrs. state a recommend continuous discharge current and max. short term discharge current. This means that there will be a minimum recommended number of batteries needed depending on the size of the inverter. You cannot for example use just one (say) 3.5 kWh battery on a 3 or 5 kVA inverter, as the inverter's current draw will exceed the maximum rated discharge current of the battery.

    As an example, for Pylontech batteries, Victron recommends 2x batteries for their 3 kVA 48 V inverters and 4x batteries for the 5 kVA 48 V models.

    I would not discharge to 100% DOD though,
    On my 5kw inverter the maximum volts for the 4 gel batteries is set to 58volt and the minimum voltage i can set on the inverter is 42 volts ....sure wish that the inverter allowed for at least 5 volts less in the minimum....inverter trips out at 40 volts...
    Last edited by John.oosthuizen95; 2022/05/22 at 06:22 PM.

  2. #22
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    Default Re: Dead battery?

    Quote Originally Posted by John.oosthuizen95 View Post
    On my 5kw inverter the maximum volts for the 4 gel batteries is set to 58volt and the minimum voltage i can set on the inverter is 42 volts ....sure wish that the inverter allowed for at least 5 volts less in the minimum....inverter trips out at 40 volts...
    You would need to check if the inverter supports lithium.

    A gel battery is lead acid, so essentially it is considered to be discharged at just about 12.1 Volt (approx. 50% DOD). This means in a bank of 4 in series, 48.4 Volt is the limit where the inverter should cut off. 42 Volt is 10.5 Volt per battery - completely dead and will kill the batteries in no time. It sounds like the batteries have been cycled too deeply, if you used the 42 Volt low battery cutoff setting.
    ZS6VL




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  4. #23
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    Default Re: Dead battery?

    Quote Originally Posted by John.oosthuizen95 View Post
    On my 5kw inverter the maximum volts for the 4 gel batteries is set to 58volt and the minimum voltage i can set on the inverter is 42 volts ....sure wish that the inverter allowed for at least 5 volts less in the minimum....inverter trips out at 40 volts...
    Your setting of 42V is about 100% discharged for gel and very low. If you could set it 5V lower would be a very bad idea.
    48V is more a setting used to get a good few years out of them. It remains a problem as one wants to use the most power the battery can produce.
    Always best to consult the values provided by the manufacturer.
    Sorry An3s. You answered while I was looking for the table.
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    Last edited by ekkekan; 2022/05/22 at 08:13 PM.

  5. #24
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    Default Re: Dead battery?

    Quote Originally Posted by ekkekan View Post
    Your setting of 42V is about 100% discharged for gel and very low. If you could set it 5V lower would be a very bad idea.
    48V is more a setting used to get a good few years out of them. It remains a problem as one wants to use the most power the battery can produce.
    Always best to consult the values provided by the manufacturer.
    Sorry An3s. You answered while I was looking for the table.
    Would the battery values for LifePo be for the LifePo4 battery..?

  6. #25
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    Default Re: Dead battery?

    Hi All. Sorry to crash this thread, but I have a similar issue. My 4 102ah batteries no longer get us through a loadshed (we only pull around 300W for lights/tv, so I'm pretty sure at least 2 of them are dead).

    So I could buy 2 or 4 more deep cycles. I'm using the ACDC ones, which cost ~3500 each. But considering that my current batteries only lasted just over a year, I'm thinking of moving to lithium. My Axpert 3kva inverter (https://www.takealot.com/axpert-type...r/PLID68131293) does not have a lithium profile, but I can set the bulk and float voltages. Can I get rid of the lead, and buy 2 new Bluenova 108ah lithiums to replace, or will I need to add a lithium charger as well?

  7. #26
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    Default Re: Dead battery?

    Quote Originally Posted by bobhof View Post
    Can I get rid of the lead, and buy 2 new Bluenova 108ah lithiums to replace, or will I need to add a lithium charger as well?
    It looks like this Blue Nova battery is a 'drop in replacement' for a lead acid battery.
    But check with Blue Nova themselves so that there's no misunderstanding.

  8. #27
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    Default Re: Dead battery?

    Quote Originally Posted by Richard Mackay View Post
    It looks like this Blue Nova battery is a 'drop in replacement' for a lead acid battery.
    But check with Blue Nova themselves so that there's no misunderstanding.
    Thanks Richard. I called Blue Nova and they said it should be fine as long as I set up a custom charge profile.

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