Why we need batteries for solar PV systems?

  • The vast majority of PV systems today are grid-connected. If the grid fails, power cannot be drawn from the PV systems even when the sun is shining. This is a precaution taken to protect the utility workers repairing the failed lines. So you’ve the PV systems (which you’ve paid a huge amount for), sitting idle and unable to output power even when the sun is shining. A battery backup in this case could have prevented this idling period and powered the houses/industries.
  • Sometimes in areas with poor grid connectivity, people go for off-grid systems where it’s just the solar PV systems without connections to the grid. In this case, battery backup usually takes over at night or when the sun isn’t shining

Now, can power be generated the whole day from solar PV systems with batteries?

Yes, it can.

With accurate battery storage system sizing, it is possible to power the loads for a whole day with Solar      PV systems backed with batteries.

How do solar PV systems with batteries work?

  • In grid-tied PV systems, the batteries are charged either from the grid or the solar panels. The battery is discharged during blackouts and used to power the loads.
  • In off-grid PV systems, the batteries are charged during the day from the solar panels and discharged when required.

Now, there are quite many challenges in getting your Solar PV systems with batteries to power your appliances for a whole day.

  • A 1 kW solar panel requires an inverter with a minimum of 1 kW rating. These inverters require a battery of minimum 24V.So if the wattage of the total load of the household is higher, the battery backup required for it will also be on the higher side. This directly translates into higher costs.
  • Batteries of high ratings capable of powering houses in case grid power fails or when there is insufficient sun, require more maintenance, adds more complexity in order to regulate charging cycles and again additionally means more upfront investment costs.

So, to summarise, we can say that Solar PV Systems with batteries bring with them the assurance and comforts of never losing power through the day, at the expense of significant additional costs to the systems.

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