If you use more than one Any-Grid PSW-H unit then each one will handle its own PV array and the PV modules may not be inter-connected between more than one unit. So if you are multiplying the number of devices you are also multiplying the number of MPPT’s and the MPP trackers work independently of each other. This optimizes the PV harvest with partial shading or other suboptimal situations. For PSW-H models that have two MPPTs, these are also independent from each other and may not be connected to the same PV array at a time. So a small PV array would be connected to just one MPPT with the other MPPT left unconnected. A large PV array would be separated so that half of it connects to one, and half to the other MPPT. This also brings advantages in shading situations or allows connecting different models of PV modules to each MPPT.

Yes, multiple different lithium battery models are supported in terms of a BMS (battery management system) communication link between the battery and Any-Grid PSW-H. We have very many different battery settings and as long as your battery has 48 ~ 54 Vdc nominal voltage, you can modify the settings of the Any-Grid PSW-H to cater toward those batteries. For batteries where we do not support BMS communication, make sure the batteries will function even without such communication and will not simply shut down after some time. Our list of list of supported batteries with BMS communication can be found here and is updated regularly.

Example: Lightning strikes or irregularities on the utility grid can create voltage spikes beyond the power equipment’s maximum voltage ratings. A surge protective device (SPD) is designed to prevent higher energy voltage peaks from reaching sensitive equipment and thus potentially causing damage. If properly designed, how does an SPD work in a power system? Excess voltage (beyond the rating of the equipment) is prevented from building up by controlled energy discharge between the affected DC or AC conductors. If a ground connection is present on the SPD, the SPD also monitors voltage differential between ground and the other conductors. If necessary, energy is discharged to prevent excessive voltage differences such as in a surge event. For this to work properly, the path to ground must be of low resistance. SPDs cannot protect from prolonged over-voltage for multiple seconds or minutes. This must be prevented by correct system sizing. Steps to ensure your equipment will not get damaged when a surge in voltage takes place: 1. Make sure your system and SPD has a good, low-resistance connection to ground. 2. Match the SPD to the inputs of your power conversion equipment you want to protect by ensuring the “Uc” voltage in the SPD datasheet is at or just slightly (preferably 0 to 10 V) above the maximum continuous voltage on the conductors to be protected, or the maximum voltage rating of the power equipment connected. If the SPD’s “Uc” rating is well above the maximum voltage rating of the power equipment connected, it can no longer effectively protect from voltage surges. The SPD will protect devices or equipment by activating well above the maximum continuous operating voltage “Uc” and will not interfere at voltages below “Uc”. 3. Phocos recommends protecting at least the PV input of the charge controller or inverter/charger and if using a public electric grid, protect the AC input as well. 4. If used on the PV conductors, ensure the SPD is rated for DC voltages, if used on the AC input, ensure the SPD is rated for AC voltages.

Yes, if the grid fails and the AC input voltage drops below a threshold voltage or the frequency drops out of the window of 40-65 Hz the Any-Grid PSW-H will declare the AC source invalid and will disconnect it completely by mechanical relays. The Any-Grid PSW-H will then automatically act as an Off-Grid inverter within 10 milliseconds and provide power to your loads without any risk of back-feeding into the grid because it is then galvanically isolated from the grid on both neutral and line wires.

When it comes to pairing battery banks with your Any-Grid PSW-H inverter, the main thing you need to consider is nominal voltage. That is, if you have a 24 Vdc inverter, make sure that you have a 24 Vdc battery bank. In terms of bank size, theoretically there is no upper limit, but there is a practical one. This is heavily influenced by overall system size, budget, and of course space. Whatever your battery bank size may be, it is important to have a good quality bus bar and correct wiring cross-section. As for the minimum size, we recommend at least 200 Ah of battery capacity per PSW-H, if lead-based batteries are used. For lithium batteries smaller battery sizes may be usable, but make sure the battery and its battery management system (BMS) can handle the current requirements of the inverter(s) for both charging and discharging.