Tesla, SigEnergy and SolarEdge Battery Review
So which is the best battery system Tesla, SigEnergy or SolarEdge? Just scroll down and consider which features are important to you.
For a quick answer, if you have shade or want a more control go for Solaredge. If you want a less expensive system go for Tesla. Otherwise, and typically our preferred solution, choose SigEnergy.
1. Ecosystem
SigEnergy came second with a market leading DC bi-directional car charger.
They have also just released compatibility with a range of Shelly home automation control devices such as relays and plugs.
SolarEdge is a very clear winner since they have a “whole home” approach to solar and battery systems.
SolarEdge certainly has the most comprehensive system including the One Controller, which can control Valliant heat pumps and some electric car chargers.
SolarEdge even has a load controller which automatically switches off non-essential loads in the event of a power cut.
They have an API (application interface) for linking to Home Assistant, so your SolarEdge system can be part of the control of your entire home.
2. Modular
Tesla has a single box housing the solar inverter, battery controller and 13.5kW battery.
SigEnergy has all the components separate, but they combine into a neat stack.
It is a scalable and flexible system with any combination of 5kWh and 8kWh battery modules.
If there is an issue with a controller or battery pack it can be easily replaced – the ultimate solution from an environmental and cost perspective.
SolarEdge comes second since it has a 10kWh battery separate to the solar inverter and battery controller. This makes it easier to replace these parts, compared to Tesla, if something goes wrong in the future.
3. Charge and Discharge Speed
Many battery systems have a maximum discharge speed of around 2.5kW. This is not even enough energy to run a standard electrical kettle (3kW). You need a higher discharge speed if running:
- Electric showers (up to 12kW)
- Heat pumps (a 15kW heat pump will use around 7.5kW of electricity)
- Immersion element (3kW)
- Electric fan heater (3kW)
- Induction hobs (7.2kW)
- Electric oven (6.6kW)
- Electric AC car charger (7.2kW)
Your charge and discharge speed is determined by the lowest speed of the battery and controller. For example 6 x SigEnergy 8kWh batteries can discharge at 24kW; however, the single phase controller maximum size is 12kW – therefore limiting discharge of the batteries to 12kW.
4. Backup capability
The types of backup power supply are split into two categories depending upon how fast they switch to backup in the event of a power cut.
Uninterrupted Power Supply (UPS) is designed so there is minimal interruption to the power supply when there is a power cut. Customers with sensitive electronic equipment such as computers or medical equipment might require a high quality power supply such as UPS.
Emergency Power Supply (EPS) is typically a little slower to transfer into backup mode and devices such as computers might turn off.
5. Compatibility with Octopus Energy Tariffs
Tesla and SolarEdge have an Application Programming Interface (API) which allows them to communicate with other software, such as Octopus Energy’s software, Kraken. SolarEdge and Tesla can communicate with home automation applications such as Home Assistant, Alexa, Google Assistant and Loxone. SigEnergy has announced they will be releasing an API, but for the time being you would need to use Modbus communication protocol to talk with other applications.
6. Charges for Artificial Intelligence Mode
7. Charge Below Zero
To enable charging below 0°C requires heating pads to be installed inside the battery packs. This not only allows charging below 0°C, but is likely to prolong the life of your battery when charging in the 0-10°C range. The disadvantage is energy is used to heat the batteries before charging. Once the cells start to charge they generate their own heat through the charging process. Therefore a workaround without heating pads is you can discharge the battery to add heat before charging.
8. Prices
To ensure a fair review, I added up the wholesale cost price of all the components including the power cut backup gateways. For the comparison I used:
- Tesla 13.5kWh
- SigEnergy 13 kWh
- SolarEdge 10kWh
SolarEdge excludes the cost of the required optimisers for the solar panels.
Prices accurate as at 31 March 2025.
