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Closed-Loop Communication: What is it, and why it is important?

There is no doubt that RV and Marine Boat users are increasingly installing lithium-ion phosphate batteries in their mobile power systems to store solar energy or shore power for a steady supply of electricity. One leading cause of the recent surge in demand for these solar batteries has been the rise of Closed-Loop communication between the inverters and batteries.

Opened-Loop Communication

Most Lithium batteries on the market have no communication at all, or they can only offer a very limited communication, which we call “Open-Loop”. This does not allow the battery management system (BMS) of the battery to send and receive data or “talk” with inverters. For sure, the BMS with Open Loop communication could broadcast on a USB cable or embedded Bluetooth internal BMS information (like SOC, Temperature), but with that kind of open-loop communication, there is no information transfer between inverter/charger: such as instructions like “OK, I’m almost full; now reduce the charge current to optimize the lifetime of the cells”. Or another example: Open-loop doesn’t allow for broadcasting the SOC to the controller unit to start a generator, for example.

As previously mentioned, the inverter detects battery voltage and determines State of Charge (SoC). With countless different SoC calculation algorithms, opened-loop communication is not precise enough to give an accurate result since it’s merely a simple approach. This means that Opened-loop communication leads to an incorrect State of Charge estimate. For example, the SoC shown on the inverter could be 50% while in reality the battery’s SoC is 30%, making this discrepancy clear.

Recalibration may temporarily fix the SoC calculation of the inverter/charger, however it is an inefficient solution that would need to be executed multiple times throughout a 10-year life cycle. Constantly having to repeat this procedure will only cause more frustrations and headaches in the long run.

Closed-Loop Communication

Generally, Closed-Loop Communication is a sequence of evidence and confirmation between batteries and inverter/charger. To put it simply, the communication medium closes off while in Opened-Loop Communication only transmission and reception happens without any validation process.

The form of Closed-Loop Communication is kind of like the early radio interactions. Sending shortcodes like “low voltage”, “start charging” and “OvertTEMP-C”, but there are several specific codes to close the loop, for example, “Over Temperature during Charge” will broadcast “OTC” and so on.

The Volthium LiFePO4 Batteries are outfitted, since end of 2021 with RS485 and CANBUS protocols, which facilitate Closed-Loop Communication between the batteries and inverter. This allows them to not only communicate within themselves but also pass on vital State of Charge (SoC) information effortlessly to the inverter.By providing RS485 and CANBUS support, the installer can link up the battery bank to either communication port needed on the inverter/charger for a more intelligent and efficient charging process.

This setup offers an optimized working environment where discharging occurs with ease.

Why is Closed-Loop Communication Important to Off-Grid Solar Battery System?

Closed-Loop communication between the BMSs and inverter/charger can be a lifesaver for batteries, with an accurate SoC (State of Charge) maintained by avoiding both over-charged and over-discharged. This reduces unnecessary charge cycles while lengthening battery life, ultimately leading to increased efficiency in the system’s operations! Moreover, as previously explained, the battery will send commands to the charger to reduce the charge current and extend battery life while optimizing the charging process.

On the other hand, Closed-Loop Communication also helps the installation to achieve faster and easier.

Volthium’s Closed-Loop Communication technology facilitates communication between batteries and inverter/charger, creating a safer, more efficient, and dependable energy system. Additionally, their external communication device adds Bluetooth functionality to Volthium Lifepo4 products for simple remote access and oversight of the solar system – all at your fingertips! By incorporating Closed-Loop Communication technology, Volthium is devoted to supplying its clients with a superior energy storage solution that ensures the utmost security and efficiency. Volthium’s superior Lifepo4 batteries are an inexpensive, dependable and efficient way to harvest solar energy for later use.

Customers can feel secure when using Volthium products due to its innovative Closed-Loop Communication technology which includes accessories such as external adapters, LCDs and Bluetooth broadcast devices produced by us here at Volthium. Don’t forget that our advanced electronic development protocols were also developed in house!

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