Store your solar power and use it when you need it. FlexxWatt offers Ultimati in the Standard version: a low-voltage system for single-phase homes and a high-voltage system for homes with a three-phase connection and higher consumption. Battery, inverter and energy management work together as one system.
Two worked-out starting configurations. In the advice we match the number of modules to your consumption.
Single-phase hybrid inverter with three low-voltage modules, commercially referred to as 15 kWh.
12 kW three-phase hybrid inverter with four high-voltage modules: 15.2 kWh of storage for homes with a three-phase connection and higher consumption.
FlexxWatt supplies Ultimati in the Standard version. The data below comes from the Standard datasheets.
| Modules | System energy (kWh) | Usable (kWh) |
|---|---|---|
| 1 | 5.1 | 4.86 |
| 2 | 10.2 | 9.72 |
| 3 (reference) | 15.3 | 14.59 |
| 4 | 20.4 | 19.45 |
According to datasheet RE-LA1-5kWh: max. 5,000 W charge / 5,400 W discharge with UE-5K-S2-LA1, LFP, ≥6,000 cycles, IP66, floor mounted. The 3-module configuration is commercially called 15 kWh.
| Modules (3.8 kWh) | Total (kWh) | Usable (kWh) |
|---|---|---|
| 2 | 7.6 | 7.2 |
| 3 | 11.4 | 10.8 |
| 4 (reference) | 15.2 | 14.4 |
| 5 | 19 | 18 |
| 6 | 22.7 | 21.7 |
According to datasheet RE-HA1 Standard (Rev02, January 2025): LFP, ≥7,000 cycles, IP66, floor mounted, backup output for 2 circuits with 10 ms switchover. Rated apparent output 8, 10 or 12 kVA; FlexxWatt supplies the 12 kW version. Grid connection and export power are agreed per installation.
Power stored during the day is used in the evening and at night.
Battery, hybrid inverter and energy management are matched.
Start with the capacity you need now and add modules later.
Follow generation, consumption and battery status in the app or web portal.
| Expansion | Low voltage 1 to 4 modules; high voltage 2 to 6 modules. |
|---|---|
| Solar panels | New panels connect directly to the hybrid inverter. With an existing installation we assess the combination per situation. |
| Energy management and contract | We only offer control based on dynamic tariffs once it is confirmed for your configuration and contract. |
The high-voltage RE-HA1 system has a backup output for two circuits, with a switchover time of 10 ms. With the low-voltage system, backup depends on the chosen configuration.
| Placement | Floor mounted, IP66 (both Standard datasheets) |
|---|---|
| Battery technology | LFP (lithium iron phosphate) |
| Warranty | Low voltage: inverter 5 years (expandable to 10), battery 10 years. High voltage: 10-year manufacturer warranty with at least 70% remaining capacity after 10 years. Always under the manufacturer's terms, including registration. |
Further reading: buying questions for all five brands · choosing the right capacity · savings calculator
Sources: Ultimati Energie datasheets RE-LA1-5kWh and RE-HA1 (Standard); RE-HA1 datasheet Rev02 (January 2025); warranty performance according to supplier confirmation (October 2026). Subject to change. Price and availability after advice.
We compare your consumption, connection and wishes with the five brands we work with and give you a substantiated proposal, without obligation.
