Sizing & Selection

Sizing your battery bank correctly is THE key to the profitability of a solar storage system. If it is too small, it will not cover your night-time needs. If it is oversized, it represents a poorly optimised investment with a longer return on investment.

This sub-category guides you through the precise sizing of your battery storage: calculating the capacity required according to your consumption profile, choosing between 48V and high-voltage technologies, and analysing profitability according to the context in France/Belgium (end of the meter running backwards, Wallonia incentive tariff).

How to calculate the required battery capacity? Three complementary methods: night-time consumption method (1 night's autonomy = consumption from 6 p.m. to 8 a.m.), days of autonomy method (2-3 days without production for isolated sites), and optimised economic method (cost-effective capacity vs. cost per kWh stored). Our ultimate guide (2,395 views) details calculations with real-life examples.

48V (low voltage) vs high voltage: which to choose? 48V-51.2V systems (Pylontech, BYD, Marstek) dominate the residential market: simplicity, broad compatibility, increased safety. High-voltage 150-400V systems (Huawei LUNA, BYD HVM, LG Chem) offer superior efficiency and compactness, but are more expensive and limit the choice of inverters. Our comparisons analyse optimal use cases.

You can also discover profitability scenarios by country: in Wallonia, with its incentive tariff, storage becomes relevant from 5-6 kWh. In France, with off-peak hours, charge/discharge arbitrage optimises ROI.