EcoFlow Stream Unleashes Savings with a Smart Balcony Storage System
Innovative Balcony-Based Energy Storage System Shows Notable Ingenuity
by Klaus Wedekind More Info Facebook Twitter WhatsApp Email Print Copy Link
The EcoFlow Stream balcony power storage system is not just a smart solution for powering devices with over 800 watts of self-produced electricity; it intelligently integrates dynamic tariffs and redistributes energy smartly within the home network. With a bit of planning, it can quickly pay for itself.
Compare it to larger PV systems, small balcony power plants produce the most electricity when demand is low, making them perfect candidates for storage. The same applies to dynamic tariffs, where prices are incredibly low when energy is generated but little is consumed. A storage solution is needed to store excess or cheaper electricity and feed it back into the home network when the sun isn't shining and/or prices are high. The new EcoFlow Stream batteries are said to perform this efficiently. We've put them to the test.
Triple Power Models
EcoFlow offers three different Stream battery storage systems with a capacity of 1.92 kilowatt hours (kWh) each, each model looking remarkably similar and can be expanded modularly. The batteries store electricity in long-lasting lithium iron phosphate cells (LiFePO4), which can retain at least 70% of their capacity after 6,000 charge cycles (up to 15 years) with a 10-year warranty.
The Stream Ultra costs 950 euros and includes a built-in bidirectional inverter and four connections for solar modules (MPPT) as an all-in-one solution. Its maximum photovoltaic input power is 2000 W, and it can deliver up to 2300 W alternating current (AC) to directly connected devices.
The Stream Pro is a stripped-down Ultra with three PV connections and a maximum input power of 1500 W. The Stream AC Pro is a pure power storage system without solar module connections, serving as an extension battery for other Stream models or being charged via the home network.
Stylish and Robust
The high-quality EcoFlow storage systems aren't small, measuring 28 × 25 × 46 cm, but their tower design makes them easy to integrate into the home without being too noticeable. If they do stand out, they can still look good thanks to a metallic finish. Unfortunately, the LED strips that indicate the charge level cannot be turned off at night.
If necessary, the Stream batteries can be moved to a less desirable location as they are protected against dust and water to IP65. EcoFlow provides wall brackets for secure placement, and an integrated heating function allows operation down to minus 20 degrees.
Swift and Easy Setup
To test all possibilities, EcoFlow provided us with a Stream Ultra and two Stream AC Pros. Installation is incredibly simple. The Ultra is connected to the PV modules (mounted on the roof, balcony railing, or facade), and then it's connected to the home network via a standard socket in the apartment. This allows it to feed electricity back into the grid and be charged.
In the corresponding EcoFlow app, the device is automatically recognized. After connecting it to WLAN, a firmware update is performed if necessary, and the Ultra is assigned to a room. Now you have a functioning storage system that can power devices via two top sockets with a total of 1200 W.
Clever Cooperation
Utilizing 400 watts of excess production is already beneficial without storage from 800 watts, as plug-in solar systems may not feed more into the household grid. The surplus is often fed into the power grid, which currently only pays around 8 cents/kWh in Germany.
If that's not enough, two storage systems can be combined. By directly connecting an Ultra to any other device in the series, they can deliver up to 2300 W together. The unique thing about the EcoFlow system is that it's also enough to connect another storage device to any other socket in the household grid. The devices communicate with each other via WLAN and reassign power to each other as needed. Up to 2000 W is possible. If a connected device requires more, the additional requirement is covered from the grid as usual.
In testing, a 1200 W espresso machine could be operated without issue. A washing machine could also be supplied with nearly 200 W in the 60-degree program. It didn't matter which of the three installed storage systems they were connected to. Only with a 2500 W water boiler was the fuse of the connected battery triggered.
Charging with Solar Power or Dynamic Tariffs
In most households with a balcony storage system, it's smart to charge storage systems exclusively with solar power. Using additional grid power for this purpose is pointless with fixed tariffs, unless they serve as emergency power batteries. Since energy is lost in the conversion from DC to AC and vice versa, which can be up to 15 to 20 percent, it's better to use the power from the socket directly.
It becomes interesting if one has a dynamic electricity tariff. Current prices are adjusted hourly based on the stock market prices. This means that when the sun is shining and the wind is blowing, one pays particularly little. If one looks at the pure energy costs, they are often even in the negative range from spring to autumn. Since more than half of what one pays per kWh are taxes, network charges, and other levies, only a small fraction represents the actual cost of electricity.
Unfortunately, according to a survey by the Federal Association of Consumer Centers in October last year, at most 7% of German households have a dynamic tariff, and estimates are even lower. Since this year, suppliers have to make corresponding offers, and the intelligent electricity meters required for use are now also provided by the network operator, the number of households with dynamic tariffs could increase rapidly.
Exploiting Price Fluctuations
Fluctuations during the day are often enormous. On 3rd June, for example, the total price (Tibber) per kWh in Berlin ranged between just under 22 and 45 cents. To take advantage of this, one charges storage systems at the cheapest times, if the PV modules do not produce enough electricity. This is particularly common in the dark season. Then, wind power is usually decisive, and the prices are often lower at night due to lower demand.
The simplest way to take advantage of price fluctuations is with the TOU mode (Time-of-Use mode/usage time mode), in which the EcoFlow app synchronizes charging times with a dynamic tariff. With AI support, a plan is then created that arranges solar and grid charging, storage discharge, and grid usage to achieve the greatest savings.
Standard Tariff Usually Sufficient
The AI-powered Energy Management Mode is initially available, which costs around 10 euros per month or approximately 100 euros per year. It's free for the first three months and offers additional analyses and solar forecasts, which can help manage complex systems. For most households, the free tariff should be sufficient.
This also applies to the demand analysis using a Smart Meter from EcoFlow. It only works if there's a wireless connection to the meter. In the test apartment on the fourth floor of an apartment building, this was not possible. Alternatively, smart plugs for consumers that are not directly connected to a Stream storage device can be used. They then provide the necessary data to the app. Estimating consumption for lighting, routers, etc, can also be useful.
Successful AI Plans
We initially wanted to intervene manually and set charging times to the most favorable times, but that's not possible in the AI mode. It was also not necessary. After a few days, the app presented plans that were faultless. The charging and discharging times, as well as network usage (idle time), then almost perfectly matched the dynamic tariff and consumption. Conversion losses were also taken into account.
The Ultra was only charged to a certain level when the weather forecast was sunny, leaving enough free capacity for PV power. The other two were charged up to their set limits. The balancing between batteries was also trouble-free, even if one was particularly stressed.
Conclusion
The EcoFlow Stream system has proven to be an excellent supplement to balcony power plants for using generated power as efficiently as possible and saving money. It works even better with a dynamic tariff, which unfortunately only a few households can currently use.
Even with fixed network prices, a battery storage system for a balcony power plant can pay off quickly if it's properly dimensioned. Often, a Stream Ultra, which currently costs around 950 euros, is sufficient. If the battery helps to consume an additional kilowatt-hour of self-produced power per day on average over the year, the costs are recouped after approximately six and a half years at a total price of 40 cents.
Source: ntv.de
- Technology Tests
- Connected Home
- Solar Panels
- Renewable Energies
- Energy Transition
Enrichment Data:
- Overall: The EcoFlow Stream battery storage system optimizes energy usage and savings by leveraging dynamic tariffs and self-produced solar electricity through several key features, including:
- Key Features for Optimization: 1. Dynamic Tariff Management, 2. Self-Produced Solar Electricity, 3. AI-Powered Energy Management, 4. Modular Design and Expansion, and 5. Automated Control.
- The EcoFlow Stream Ultra, a smart battery storage system, can significantly reduce costs by integrating dynamic tariffs and self-produced solar electricity.
- Renewable energy from solar panels can be optimally stored and managed with the AI-powered energy management mode of the EcoFlow Stream system.
- With a properly dimensioned EcoFlow Stream storage system, energy savings can be achieved even with fixed network prices, making it a viable solution for various households and industries.
