In Fall 2015, Surrette Battery Company Ltd. engaged Renewable Energy Storage Lab (RESL) at the Dalhousie University Department of Mechanical Engineering to conduct independent testing of the Rolls Battery S-480, one of its most popular 6-volt models, to confirm rated performance.
The standard L16-size battery has grown to be one of the most widely used in the Renewable Energy industry, primarily due to its size, high capacity and voltage options. After 4 years of R&D, including an improved and more durable case design & cover, separator materials and increased plate size offering additional Amp-hour capacity, Rolls 2-volt & 6-volt L16 models were replaced with a new line in 2013. Used in all 2-volt & 6-volt L16 Series 4000 models, the new plate design offers an increase in total capacity up to 28AH in 6-volt models and 145AH in the 2-volt options. To-date, the new L16 product line has performed at or above rated specifications.
Charging
As off-grid and grid-tied Renewable Energy systems continue to grow in popularity, the company continues to see more and more charge controller manufacturers including automatic parameters based on temperature compensation. This added convenience often prevents over/under-charging in many cases, however, due to common deficiencies in system design and inadequate charge sources, high capacity battery banks are continuously being undercharged and/or deficit cycled.
With this trend in mind, the company has reviewed its recommended charging parameters to provide updated Bulk/Absorption, Float and Equalization voltage settings based on charging and usage which is more in line with a typical PV system.
Results: S-480 Batteries Tested Above Rated Specifications
It is widely know that deep cycle lead acid batteries increase in capacity during the initial break-in period. Typically, capacity measures at approximately 82 to 85% of potential at the time of installation, increasing over the initial 50-60 cycles as the plates continue to form and become less resistant to charge. With this in mind, RESL tested the product over 100 cycles, allowing the batteries to complete formation, reaching maximum capacity.
Discharge and cycle testing results:
- As per IEC standards, capacity rated to 1.280 specific gravity (S.G.) Adjusted down 5% for 1.265 S.G. 10% for 1.250 S.G.
- Tested modules: S-480 at 1.265 S.G.
- Charging to 2.55VPC @ 20ºC to 110-115% of discharged AH capacity
- Discharge cutoff 1.75VPC
- Results achieved within first 50 cycles
RESL Findings:
This testing not only confirmed the S-480 model met rated specifications, but noted battery performance has been slightly under-rated, recording capacities above expectation at the C2 through C10 rates.
– At 2.55VPC charge, 10 Hour Rate (C10) rated capacity was reached by the 20th cycle and continued to increase, performing 5% above rated capacity at cycle 50.
– At the 4 Hour Rate (C4) the batteries performed above rated specification (232 AH), testing at 260 AH by cycle 20, 270 AH by cycle 50.
– At the 10 Hour Rate (C10) the batteries performed above rated specification (303 AH), testing at 305 AH by cycle 20, 320 AH by cycle 50.
Summary:
Rolls Battery 4000 Series L16 2-volt & 6-volt models are manufactured with the same case design, separator materials and plate construction in varying quantities. The results of RESL discharge and cycle testing confirms performance for these models meets and exceeds rated specifications.
News item from Rolls Battery Engineering.