The brand new Solar MD 8.3kWh SS4083 battery is finally here:
“And it promises to be a game-changer!” Solar MD spent a full year researching, designing, prototyping, testing, and preparing their facilities for manufacturing this addition to their product line.
LiFePO4 cells
The SS4083 is assembled from high-grade CALB Lithium Iron Phosphate cells, and built into the trademark robust, black casing which can be floor-standing or wall-mounted.
Interesting perspective: CALB is one the largest manufacturers of Lithium globally, some of the massive Energy Storage Projects supplied by CALB can be viewed here. This confirms that Solar MD has chosen a well-established, high-quality supplier for the SS4083’s LiFePO4 cells, while most battery suppliers in South Africa do not declare the origin or quality of their cells at all.
The packaging of the cells inside the battery is also crucial for sustained long-term performance of the battery. For the SS4083, Solar MD has deployed the same proprietary compression cradle found in the 14.3kWh. This is one of the most significant upgrades from its 7.4kWh predecessor.
CALB cells at the Solar MD factory
Fig 1: CALB cells at the Solar MD factory
On the left: Cells are sorted and matched for optimum compatibility and performance
On the right: Cells assembled into Solar MD’s proprietary compression cradle for extended lifetime and increased cell performance
Battery Management System
Beyond the cells, the most important differentiating feature of the Solar MD battery range is the Battery Management System (BMS). Lithium cells can very easily enter a thermal or electric runaway scenario, which is very dangerous, and also catastrophic to the battery itself. Solar MD’s BMS was developed and perfected in-house over time. This BMS offers cell-level voltage control, charging and discharging current control, temperature monitoring, cell balancing etc.
The BMS can of course communicate with most premium inverters such as Sunsynk, Deye, Victron etc. Setup of the control device is still done via the multifunction pushbutton, so installers familiar with this process can hit the ground running when installing this unit. As with their other batteries, the Solar MD logger can also connect to the BMS for remote monitoring via MyPower24, for executing firmware updates, advanced faultfinding and programming by the Solar MD Support team back at the factory, without having to remove and return the battery.
Solar MD Battery-Management System BMS
Fig 2: Solar MD’s BMS was developed completely in-house and offers unrivalled control and performance
Performance
The biggest advantage this battery offers to resellers, installers and the end-user alike, is the discharge rate. Discharge rate is probably the most important of all battery specifications, but at Solar Spot we have noticed that this crucial parameter is often completely overlooked during the decision-making and purchasing process. Choosing a battery bank which cannot meet the demanded discharge current from the inverter, will not only throttle the output of the entire inverter system, but will also potentially damage the battery and very often void the warranty on a battery (be sure to read the fineprint on your battery warranty documents from all premium manufacturers).
Due to the cells chosen for this new battery, the SS4083 can discharge and charge continuously at 150A DC, which at the nominal voltage of 51V is approximately 7.5kVA, and at the fully charged voltage of 56V, is 8.4kVA. This means this battery can be paired successfully with firm favourites such as the Deye 8k, Sunsynk 8k and Victron 8kVA inverters. Until now, very few single batteries could meet or exceed the demand current from the 8k Deye / Sunsynk, and all of the available options were 10kWh or larger. Alternatively, 2x 5kWh batteries are often linked, but this is even more expensive than a single 10kWh battery and is often done incorrectly without employing a common busbar system. The Solar MD 14.3 was and remains one of the best value for money options for pairing with powerful inverters, but for cost-conscious clients who want a fully operational, premium system with the possibility of future battery capacity expansion, the Solar MD 8.3 is a fantastic new option. The cost saving now puts premium systems into grasp of clients who previously would’ve had to settle for sub-standard equipment. The SS4083 also has integrated busbars like its 14.3kWh big brother, and therefore adding a second or third battery in parallel is very easy. It can even be paired with the 14.3kWh, an option for existing clients who want to expand their storage capacity, but do not want to purchase an entire additional 14.3kWh.
Solar MD Integrated Busbars
Fig 3: Like its siblings, the SS4083 features integrated busbars to make parallel connections between batteries effective, safe and easy
The high charging rate of this battery makes it suitable for loadshedding back-up scenarios where charging time is of the essence between multiple daily outages, and also for solar PV applications where the available sunlight needs to be harnessed and stored quickly at times of intermittent weather, thereby optimising the usage of the Solar PV Panel array.
Solar MD SS4083 Datasheet
Fig 4: Solar MD SS4083 Datasheet Summary
Design Life
As is typical of Solar MD, the design life was calculated very conservatively and in great detail. This means no grey areas or wild promises – a client knows exactly what they can expect, and will most probably get better service than the minimum which is specified here. Solar MD’s warranty is split into 2 sections: (1) Workmanship & Materials, (2) Cycles & Capacity. This is a similar approach to the way in which Solar Panel manufacturers specify their warranties (you can read more about this in this article)
A 5 year guarantee is offered on Materials and Workmanship, and very importantly this also covers the BMS. Many batteries with 10 year warranties only cover their BMS’s for 2 years, and this fact is often not noticed by sellers, installers or users. Since the BMS is so critical to safety and performance, and integral to the functioning of the battery, a warranty which excludes it is equivalent to a car warranty which excludes the engine and brakes.
The SS4083 also offers a 10 year warranty on the derating of Energy storage capacity vs Cycles. Very often the number of cycles are indicated in battery warranties, but without much detail as to what the user can actually expect after so many cycles. Solar MD specifies this in great detail, as can be seen in the figure below. If the battery is discharged 85% and charged fully again on a daily basis, the battery will maintain 75% of its original storage capacity after 10 years of use. 4000 cycles might also seem less than the 6000+ cycles often promised by competitors, but considering that this amounts to almost 11 years at one charge-discharge cycle per day, along with the detailed performance characteristics and the specified remaining storage capacity, this is actually a very confidence-inspiring promise by Solar MD.
Solar MD SS4083 8.3kWh Warranty Cycles vs DoD and Residual Capacity
Fig 5: Clients know exactly what performance to expect as their Solar MD batteries age, no wild claims or opaque promises here.
Quality Assurance
Instead of merely quickly spot-checking quality after manufacturing, Quality is monitored at every step of the manufacturing process at Solar MD’s manufacturing plant in Montague Gardens, Cape Town. The following steps are integral to their Quality Assurance program:
• In-house assembly of all sections of the battery, no critical parts are left to a 3rd party’s mercy
• Careful grading and matching of cells to ensure the variability between the CALB cells are minimised as much as possible, thus making the BMS’s task easier and more precise
• Advanced assembly techniques which ensure the cells always operate at their optimum. Most of Solar MD’s manufacturing and assembly machinery and robotics are designed and built in-house for the specific purposes they have to fulfill.
• Laser welding of cell terminals instead of screws or other fasteners, to ensure absolutely perfect contact and continuity in the power circuit
• In-house design, manufacturing and programming of the Battery Management Systems, along with an in-house Technical Support Team who can log into a client’s battery BMS remotely for troubleshooting and updating (Logger V2 required)
• Every Solar MD battery is tested thoroughly before leaving the factory. This includes connecting the battery to an inverter and performing a full charge and discharge cycle under load, to ensure all components are performing as expected and within acceptable parameter ranges
• Every Solar MD battery is packaged carefully by hand to ensure it is shipped in perfect condition to its new owner
Solar MD Individual Quality Control Testing
Fig 6: No random spot-checks here – each and every Solar MD battery and BMS is tested thoroughly, including a full charge and loaded discharge cycle before leaving the factory
Solar MD 8.3 kWh SS4083 Completed and packaged
Fig 7: After assembly and testing is complete the SS4083 is carefully packaged for transport.
Disadvantages
The only possible perceived disadvantage of the Solar MD SS4083, is its price (Please check the latest up to date retail price on our website)
Considering the quality of every component in this battery, the price in R/kWh is actually perfectly on par with other high-end Lithium Iron Phosphate batteries available in South Africa. The discharge current and the implied suitability for pairing a single SS4083 with 8kVA inverters, still makes this battery excellent value for money.
In Summary
It would be difficult to find a better premium range battery than the Solar MD SS4083. It is not a cheap battery, but there are plenty of cheap batteries on the market, it is not the market space where Solar MD operates or intend to operate. The advantages of this battery are numerous, and any client who is serious about their investment in an Energy Storage System should have this battery high up on their shortlist. Solar MD’s transparency, quality and support (being a local SA-based manufacturer) inspires confidence among resellers, installers and end-users alike.
If you are interested in purchasing one of these batteries, they are available on our Online store
Other Solar MD Products can be viewed here
Contact us for more information about the Solar MD SS4083 battery.
Installers can also contact us for special pricing, or register here
The complete datasheet is available for Download here
Other links for Solar MD: Specialises in Lithium-Ion battery storage for residential, commercial and utility scale applications:
