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FAQ On System Design

Make sure the solar array operating voltage is within the MPPT voltage window and do not exceed the maximum power rating inverter allowed
There are generally 2 scenarios; to give users a peace of mine as power outage do happens and for saving of utility bills. If power backup is the top priority, one should minimise the consumption during normal operation saving power for power outages. Should the priority is to save utility bills, one need to program the system to provide energy when utility price is high and consume power from utility when its cheap.
We recommend at least 30% battery energy reserve in places where utility is generally stable. In places where power failure does happen, we recommend at least 50% battery energy reserve.
We recommend important loads/appliances such as refrigerator, lighting, computer, WIFI, TV, etc. Loads like air-conditioning, washing machine, oven, microwave, etc are not critical loads. Make sure the total critical loads chosen do not exceed the inverter power rating
Depending on the expected duration of blackout, one need to look at the historical information to make decision. Do you want to reserve energy for blackout? If yes what are the loads/ appliances you need to operate in case of blackout? How long you intend to power the loads/ appliances?
It is always good to over-size the battery capacity considering that solar array may not produce enough energy during cloudy or raining day. Depending on the expected duration of blackout, one need to look at the historical information to make decision. Should bad weather are expected, one should either increase the battery capacity or program the system to consume power from the grid when its at the lowest cost.

FAQ On Technical Issues

Low power generation can be cause by many reasons, weather, temperature, shade, inverters, panels orientation and tilt angle and so on. Weather: fog, rain, cloud, bad weather can cause low power generation. Higher temperature reduces the panel performance resulting in a lower power generation. Shading should check the site environment first, including trees, power pole, water tank, clothes, bird droppings, other solar modules are the typical problem that affect the system performance. Panel orientation: check if the orientation is the best angle. Generally, the highest solar generation point is from 11:00AM to 2:00 PM. Panels: different type or size of solar panels are not allowed to connect to the same string/ same MPPT. A broken solar panel can significantly lower whole system’s power generation, please change broken panels immediately. Inverter: once the inverter is down the whole system will not generate any power. Trouble shooting of inverter will be needed. Check trouble shooting guide.
PV voltage low means the string’s voltage is low. DC connector loose connection, or no connection of the panels, or the number of PV module in series is few. Need to set multimeter to voltage, use the red pen to connect to positive electrode, use the black pen to connect to negative electrode, read the multimeter, if the voltage is in voltage range and it is positive, we can say the PV voltage is normal or low.

Step 1: Connect inverter to computer RS232 port via the RS232 port (WIFI plug port) of the inverter. if not equipped with RS232, a device of USB-to-232 converter is needed.

Step 2: make sure the PIN connection is correct.

Step 3: Set device address and parity type (no parity check) via software.

FAQ On Comparison between Lithium Iron Phosphate (LFP) & Lithium Nickel Manganese Cobalt Oxide (NMC) Battery

NMC battery are higher in energy density compare to LPF battery i.e. they are smaller in physical size compare to LFP battery. They are therefore ideal for space constraint products like EV car, phone, laptops, power tools, etc. LFP battery on the other hand are approximately 15% to 20% physically bigger and 30% to 40% heavier are not as ideal for very compact requirement.
However, there are several advantages of LPF battery over NMC battery. It is safer as their thermal runaway temperature is higher 800 Deg. C compare to around 200 Deg. C for NMC. I.e. if BMS loses control on current control or over charge situation, the cell temperature rises quickly NMC battery releases a flammable hydrogen gas that will catches fire and explode. Whereas LPF battery is more chemically stable and does not generate hydrogen gas and less combustible.

Below is a video on nail penetration test on NMC and LPF battery confirming the safer LFP technology

Video
Many independent test reports show LPF has a longer life compare to NMC battery. As you can see that the discharge capacity retention for LPF is better than NMC. The test also shows that the round efficiency is better by dividing discharge energy by the charge energy. Typical useful life span of LPF and NMC batteries are between 3000 to 5000 cycles but could last up-to 7000 cycles depending on usage and environment conditions. LPF is more efficient and economical to conclude.