Renvu

The Universal 10/4 by Humlesss (manufactured by Fimer) is a great product for homeowners looking to add simple and functionally flexible backup energy storage to their homes. Whether it be for new systems or existing systems, off-grid or on-grid, this product can do it all. 

The Universal 10/4 is an AC- and DC-couplable Energy Storage System (ESS) that comes with an integrated 10 kWh battery bank. Note that while some products claim to be an ESS and have external batteries from the equipment enclosure, the Universal 10/4 comes fully integrated as a single unit, essentially ready to “plug-and-play”.

Most battery inverters come as individual units and the components (i.e. charge controller, batteries, and battery inverters) need to be purchased separately and manually integrated). The Universal 10/4 eliminates this hassle through its consolidated design and engineering.

The DC-couple feature allows this ESS to connect directly into a new PV array and the AC-couple feature allows for connection into an existing array where the existing inverter(s) can be connected to the ESS. Revising an existing system to be energy storage capable through an AC-coupling method is what is typically referred to as a “retrofit”. 

The Universal 10/4 can output up to 3.8 kW continuous output, stack up to 2 units, and oversize up to 150% on the DC array or potentially more, which is not recommended but the specifications dictate that it could be possible. While the oversizing capability is not necessarily unique, it is a huge benefit for low-light areas or simply making the most out your energy production per square-footage. The ability to stack in parallel allows for scaling the energy storage system if necessary.

This ESS unit can operate on-grid and off-grid. Meaning if the power goes out, the Universal 10/4 can still operate and supply power to the home. Even more, the grid does not have to be present at all, which is helpful for situations where the homeowner is isolated and wholly self-consuming.

The Universal 10/4 configuration allows for charging the batteries directly from the grid or from a generator and charges the batteries at 45A at about 92% efficiency. For residential size, a charging current of 45A is considerably large, which is important for always ensuring a charged battery bank, especially for when its needed most and even if the battery is being cycled (or depleted) on a consistent basis.

This ESS enclosure houses 10 kWh of battery storage that is made of LFP chemistry, a top-of-the-line type of li-ion battery that has among the highest cycle-durability in the market, meaning that they will last long even with heavy use. The customer can forget about having to wire the battery bank as they come pre-installed into the system.  

A Practical Look

Now, let us take a practical look on where the Universal 10/4 shines and might come short from the installer and homeowner perspective. Considering that the Universal 10/4 is such a flexible unit that comes ready for most smaller residential applications, this inverter is a great option for installers to revert to as their main option for battery storage operations. The ability to use the same product for a wide variety of applications makes procurement, installation, and maintenance a more stream-lined and easily manageable process.  Delving more into the installation side, the wiring setup is relatively simple as the batteries already come pre-installed and solar panels or a PV inverter can plug directly into the ESS with no additional electronics needed. For other systems with energy storage, dealing with individual components and having to assemble them (i.e., hybrid inverter, charge controller, inverter, batteries, fuses, etc.) can be cumbersome and make troubleshooting/maintenance a nightmare.

For homeowners, the Universal 10/4 is a simple and elegant solution to adding energy storage to their homes. Whether they are DIYing or having their system professionally installed, the ease of maintenance and integrated design makes for a user-friendly experience in terms of diagnostics, maintenance, and spatial equity. 10 kWh of battery is substantial for a small residential home or a small number of critical appliances (i.e. fridge, lights, small electronics, etc.) for a day or two (~100 hours depending on energy usage habits). If the power goes out, this ESS will continue to operate and supply power where it is needed. Also, this ESS is great for mitigating TOU rates through the capability of discharging the battery bank at set times during the day. This is especially useful for homeowners with existing non-energy storage systems who are not getting credits for energy given back to the grid and are not meeting their energy offset needs. 

The main down-side to the Universal 10/4 is its scalability and size. This inverter has a relatively small output of 3.8 kW (continuous) and limited 10 kWh bank. Although, this inverter can be stacked up to 2 units, this is not sufficient for a large portion of residential applications requiring more than 10 kW of PV and 20 kWh of battery storage. Also, for applications where a flexibility is not required, it may not be the most economical decision to go with a fully integrated ESS as it could be more economical to purchase and utilize individual components specific to the application. 

Main Takeaway

The Universal 10/4 is a 3.8 kW (continuous output) ESS that houses a 10 kWh LFP battery bank and can be used for AC- and DC-couple and on/off-grid applications – perfect for new and existing PV systems. The Universal 10/4 is a great option for installers and homeowners due to its wide variety of applications and simplicity. While the ESS has a small output, battery bank and scalability, it makes up for its elegant design and ease of installation. For homeowners and installers looking for a small to medium-sized residential energy storage solution, the Universal 10/4 will not disappoint