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Battery charge cycle


MartinKoch
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If someone can give me an explanation please, I suppose it will be the same for all batteries but for me it if for Pylontech lithium batteries. What is the meaning or definition of a charge cycle? It makes sense if the batteries run out at say two o clock in the morning and then gets fully charged via the grid, but for instance with overcast / rainy weather as is currently the case I will set the inverter to Grid at 17:30 in order to fully charge batteries that are 76 to 80% charged, when fully charged switching back to solar first, only using about . 70kwh to maybe 1.2kwh,creating a situation where batteries will last through the night until solar or PV takes over again, saving on full charge cycle, more or less 5.5kwh for full charge. After long explanation, will the charge from 80% also count as a charge cycle? Or even solar charging during the overcast day when swimming pool pump uses more power than what PV can produce until the sunlight allowed PV charging in between, reason for the question is how will it affect battery life in the long run, as the battery life is defined by changing cycles

 

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Battery cycle would be a dik vm discharge and charge cycle. So 30% discharge and back to 100% on day one and 70% discharge and back to 100% would be one cycle. 

kWH in ≠ kWh as there are conversion losses. For every 1kWh in you will get about 0.9kWh out. I've put in 1.47MWh into my batteries but only discharged 1.3MWh. About 140 cycles. 

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same question as @MartinKoch, ive had a lithium battery installed a few days ago paired with a SunSnyk inverter, so on these overcast days, pv and battery are blended to provide the ac loads before it draws from the grid, but this also means that the battery is constantly discharging and charging sometimes to 80%SOC. Is this "bad" for the battery?

@Achmat, based on your explanation, so would 10 charge and discharge "cycles" from 100% down to 90% and back up to 100% be counted as a single cycle?

can anyone advise how they use their lithium battery with a SunSnyk inverter for day to day operation?

 

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6 minutes ago, Iiceman said:

same question as @MartinKoch, ive had a lithium battery installed a few days ago paired with a SunSnyk inverter, so on these overcast days, pv and battery are blended to provide the ac loads before it draws from the grid, but this also means that the battery is constantly discharging and charging sometimes to 80%SOC. Is this "bad" for the battery?

@Achmat, based on your explanation, so would 10 charge and discharge "cycles" from 100% down to 90% and back up to 100% be counted as a single cycle?

can anyone advise how they use their lithium battery with a SunSnyk inverter for day to day operation?

 

Yes it will count as 1 cycle. 

 

I set my minimum SOC to 15% and let it carry the loads when the sun sets and then recharge in the morning. I only charged from the grid twice when it was overcast and we were having load shedding. 

When load shedding is announced I turn off the time settings on the sunsynk to keep the batteries at 100%. 

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7 hours ago, Achmat said:

Battery cycle would be a full discharge and charge cycle. So 30% discharge and back to 100% on day one and 70% discharge and back to 100% would be one cycle. 

kWH in ≠ kWh as there are conversion losses. For every 1kWh in you will get about 0.9kWh out. I've put in 1.47MWh into my batteries but only discharged 1.3MWh. About 140 cycles. 

Fixed. Can't edit this post. 

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3 minutes ago, Achmat said:

Yes it will count as 1 cycle. 

 

I set my minimum SOC to 15% and let it carry the loads when the sun sets and then recharge in the morning. I only charged from the grid twice when it was overcast and we were having load shedding. 

When load shedding is announced I turn off the time settings on the sunsynk to keep the batteries at 100%. 

@Achmat, thanks for the info.

are you able to share a pic of your configuration?

it seems that i cannot set my SOC to less than 35%, unless im doing it incorrectly...

 

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My SOC is defined by the battery minimum voltage, 48v less than that battery warning lights on, on 46v as per default setting on the inverter I get total power blackout as there is not enough power to run the inverter, thus according to me battery defines most inverter parameter settings, had to sort it out by trail & error together with this forum feedback 

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