• In case of a MPPT Connect a Smart battery sense to the battery and match it to a MPPT via the VictronConnect App.
Voltage sensing in an Energy Storage system with DC Solar In an ESS system with DC solar, the charger of the inverter/charger is disabled. Battery charging and feeding excess solar is taken care of by the MPPT solar charger. This controlled by the CCGX. It will set the MPPT at a higher voltage than the inverter/charger. This will result in a slightly higher DC voltage when the battery is (nearly) fully charged and the inverter/charger will attempt to reduce the “overvoltage” by feeding power back into the grid. In a 48 V system this overvoltage is set at 0.4 V and in a in a 24 V system it is 0.2 V But the DC cabling, fuses and connections will cause a voltage drop in the system. The voltage drop can reduce the “overvoltage” the inverter/charger needs before it can feed power into the grid. Example: In an ESS system with 100A MPPT with 2x 1m cable 35mm² and a 150A DC fuse the resistance is: Connections: 0.35 mΩ 150 A fuse 0.35 mΩ 2 m cable 1.08 mΩ The total resistance is 1.78 mΩ and the voltage drop at 100A is 178 mV The solution is to use an MPPT with automatic voltage drop compensation this will result in that the output voltage of the MPPT will slightly increase with increasing current. But if the MPPT does not have voltage sensing, then it is best to connect the MPPT directly to the MultiPlus.
4.10 Solar array design Multiple solar panels together are called a solar array. If you connect solar panels in series the voltage increases and when you connect them in parallel the current increases. The same as is the case when constructing a battery bank with individual batteries.
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