A: SLPO series 48V LiFePO4 battery can be used with all inverters with a specified battery voltage of 48V, whether they can communicate with each other or not.
Since this battery cannot be connected in series, it cannot be used with HV inverters.
Communication between LiFePO4 battery and inverter can bring benefits, but they can also be used together without communication. You can set the battery-related parameters on the inverter to manage battery charging and discharging, such as charging voltage, charging current, discharging cut-off voltage, etc.
A: The closer the production date and the use date are, the smaller the difference in charge and discharge performance between batteries will be. After the new and old batteries are connected in parallel, there will inevitably be a difference in charge and discharge. If there is no great difference in their usage (for example, if the battery is purchased within three months, and the old battery is not used frequently), then they can be connected in parallel. If there is a difference in performance after a parallel connection, it will not affect the actual use.
We have encountered such an instance: the customer purchased 48V 200AH akkuspeicher several months apart and connected them in parallel. At first, their SOC differed by as much as 10%. We recommend that customers continue to use them and let them fully charge and discharge them every once in a while so that the BMS can learn more fully.
If one battery is discharged and the other battery still has a charge, there is no need to stop discharging at this time. This is because the battery with electricity will discharge to the outside, and it will also discharge to the battery with no power at the same time. At this time, the two batteries will continue to discharge until they are both at 0% and then charge them again. Likewise, when one battery is fully charged and the other is not, wait until they are both fully charged. After some time, the client can see that the gap between them is slowly reducing. If the purchase time and frequency of use of two batteries are very different, we do not recommend using them in parallel.
If the purchase time and usage frequency of the two batteries are very different, we do not recommend using them in parallel.
A: This is not feasible and there will be great risks. They look similar because they use a standard case, but their internal design might have very big differences, e.g. the differences between cells and between BMS.
A: Lithium iron phosphate cells will have normal capacity degradation after long-term and frequent use. But in our experience, the SOC inaccuracy you describe is usually not due to reduced capacity, but rather to the fact that the SOC is not calibrated. The SOC of our SLPO series LiFePO4 battery is calibrated using a 100% depth of discharge.
If you don't run the battery through a full charge-discharge cycle for a long time, the SOC will have some deviation. Therefore, we recommend performing a full charge and discharge (i.e. discharge 100% SOC to 0% SOC and then fully charge the battery pack) after every several-month use of the battery pack to allow the chip to record the actual maximum capacity of the battery pack in order to calculate the SOC to calibrate.