Note: Solar Choice is not affiliated with SAJ Batteries or any other manufacturer. Our reviews are independently written using technical documentation and industry analysis.
At a Glance: SAJ Batteries score 3.4 out of 5
Scoring is based on our solar battery scorecard, which is consistently applied to each brand and battery available on the Australian market. This scoring reflects SAJ’s residential battery systems including the B2 and HS2 series.
$$$ Price: Based on data from Solar Choice’s network of solar installers, the average price for an installed SAJ battery is $950 per usable kWh. This places it in the lower cost price category.
- Company Backing and Trustworthiness (3 out of 5): SAJ has operated in Australia since 2019 and is supported by a small but active local team. While their global reputation is growing, their smaller local presence slightly lowers their trust rating.
- Warranty Offer (2.5 out of 5): SAJ batteries come with a throughput warranty of 3.06MWh per usable kWh, a 10-year product warranty, and a minimum capacity rating of 70% at the end of the warranty period. This positions their offering around the market average.
- Customer Reviews (5 out of 5): SAJ has received excellent customer feedback, with a verified average rating of 4.8 from 8 reviews on Solar Choice’s independent platform. This earns them a full score in this category however it should be noted that the sample size is fairly small and mostly from customers with new batteries.
- Functionality (3 out of 5): SAJ batteries are IP65 rated, modular, and support AC connection. However, they lack built-in fire suppression and modular battery balancing, and new batteries in an expanded system may be impacted by the performance of older batteries. These limitations reduce their flexibility and safety relative to higher-scoring systems.
Overview of SAJ – Company History
SAJ (Guangzhou Sanjing Electric Co., Ltd.) is a Chinese energy technology company established in 2005. With a core focus on solar inverters, motor drives, and energy storage systems, SAJ has grown to become a known player in the global solar market, particularly in Europe and Asia. Their battery product line has gained traction since their first model launched in 2015. Their products fit in the budget segment of the residential storage market.
SAJ Australia Pty Ltd in was established in 2019 and they now have an Australian website and support team working form an office in Victoria.
SAJ Battery Range and Options
SAJ’s battery portfolio includes two primary product categories suitable for residential installations: the HS2 all-in-one hybrid battery systems and the modular B2 high-voltage stackable batteries. Both solutions use lithium iron phosphate (LiFePO4) chemistry and are approved by the Clean Energy Council.
HS2 Series (All-in-One)
SAJ’s HS2 series is their latest addition to the Australian market and was approved by the Clean Energy Council in early 2025. The battery is an all-in-one solution which means it can be use for a new solar and battery system or retrofitted to an existing solar system.
Key models include:
- HS2-3K-S2 to HS2-6K-S2 (single phase)
- HS2-5K-T2 to HS2-10K-T2 (three phase)
Each system pairs an inverter and battery management system with SAJ’s high-voltage BU2 battery modules. The inverter’s capacity charge or discharge the battery stack, depends on the model and whether the solution is single or three phase.
The single phase solution an be stacked with battery modules up to 20.48kWh (nominal) and 25.6kWh for the 3 phase alternative. The BU2 batteries have a depth of discharge of 93.75%.
The system is built for outdoor use with a weatherproof IP65 rating and can switch to backup power in under 10 milliseconds during a blackout. It also includes optional safety features like AFCI (Arc Fault Circuit Interruption) and RSD (Rapid Shutdown), and stays cool using a fan-free, silent natural convection system
B2 Series (High Voltage Batteries)
The B2 series comprise SAJ’s standalone high-voltage batteries. These modular systems can be stacked to build storage systems from 5.0kWh to 25.0kWh and effectively only include a stack of battery modules with a control unit on top. They are compatible only with SAJ hybrid inverters.
The B2 series batteries have a depth of discharge of 90% which means that each 5kWh battery module has a usable capacity of 4.5kWh. The battery solution also has a great environmental protection rating of IP65 which means they are a good option if your battery installation will be outdoors.
How Much Does a SAJ Battery Cost?
SAJ batteries are positioned in the budget segment of the Australian market. Installed pricing typically around $950 per usable kWh, placing it among the more affordable battery brands available.
For example, a 10kWh (9.0kWh usable) system might cost between $5,000 and $6,000 installed after the federal battery rebate has been applied. The final price you get will depend on installer margins, additional components (inverter, switchboard upgrades), and site conditions.
This pricing advantage makes SAJ a compelling entry point for households looking to add storage without the higher upfront costs of premium brands.
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SAJ’s Warranty Offer For Australian Customers
SAJ provides a 10-year product and performance warranty for its B2, BU2, AS2, and HS2 series batteries.
Key warranty terms:
- Minimum capacity guarantee: 70% of usable energy retained after 10 years
- Throughput guarantee: Minimum of 3.06MWh per usable kWh, which equates to approximately 3,060 full cycles or around 0.84 cycles per day over 10 years
While the 70% capacity retention aligns with most industry standards, the throughput guarantee is relatively low, reflecting the budget nature of the product. Still, this qualifies for Australian rebates and is supported by SAJ’s local team based in Melbourne.
Important caveat: If the battery is disconnected from the internet or does not receive regular firmware updates, the warranty may be compromised. If the battery is installed outdoors it must be installed with a cover or out of direct sunlight.
Read through SAJ’s full warranty T&Cs.
SAJ Battery Technical Specifications: HS2 vs B2 (10kWh class)
| Specification | HS2 Series (10.24kWh) | B2 Series (10.0kWh) |
|---|---|---|
| Usable Capacity | 9.6kWh (2 x BU2-5.12-HV1 modules) | 9.0kWh (2 x B2-5.0-HV1 modules) |
| Max Output Power | 5.0–6.0kW (model dependent) | 6.14kW |
| Scalability | Up to 20.48kWh (S2) / 25.6kWh (T2) | Up to 25.0kWh |
| Inverter Integration | Inverter and battery combined (all-in-one) | Separate battery only |
| Back-up Power Functionality | Yes, <10ms switch time | Depends on inverter |
| IP Rating | IP65 | IP65 |
| Mounting | Wall or Ground | Wall or Ground |
| Battery Chemistry | LiFePO4 | LiFePO4 |
| Operating Temp Range | -40°C to +60°C (derated above 45°C) | -10°C to +50°C |
| Cooling Method | Natural convection | Natural convection |
| Monitoring/Comms | Wi-Fi, Ethernet, 4G (optional) | CAN bus; local app |
| Warranty | 10 years | 10 years |
Pros and Cons of SAJ Batteries
| Pros | Cons |
|---|---|
| ✓ Affordable entry-level pricing – among the lowest $/kWh in market | ✗ Warranty throughput is lower than many premium alternatives |
| ✓ Modular and stackable design up to 25.6kWh | ✗ Shorter history in Australia, with lower market presence that other major brands |
| ✓ IP65 rating – suitable for outdoor installs | ✗ No advanced safety systems (e.g., fire suppression, active cooling) |
| ✓ All-in-one HS2 series simplifies installation for new systems | ✗ Limited compatibility outside SAJ ecosystem |
Conclusion: Our Verdict on SAJ Batteries
SAJ have put together a complete solar battery offering catering to new solar and battery installations and homeowners looking to add a battery to an existing system. The batteries environment protection rating, scalability and price point make it attractive for customers looking for a cost-effective solution. So far the customer feedback has been reasonable, although there are not a lot of reviews to base this on.
However, the trade-off is SAJ systems are locked into their own inverter ecosystem, have lower throughput guarantees, and lack high-end safety or performance features found in premium offerings. While the product line is technically sound and rebate-compliant, it’s best suited for moderate daily use, rather than for households seeking intensive daily cycling or off-grid capability.
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