Sealed Lead Acid To Lithium Iron Phosphate UPS Battery Replacement
To reduce this UPS' (uninterruptible power supply) battery weight by approximately 66% and avoid replacing batteries for the next 10-20 years (1,200-2,000 full battery cycles), we replaced the standard Yuasa NPW36-12 12 volt 7.2 amp hour sealed lead acid batteries with Battery Backup Power, Inc. BBP-LiFePO4-12V-7AH 12 volt 7.5 amp hour lithium iron phosphate batteries. It was not necessary to change the UPS' existing firmware to accept the new lithium iron phosphate batteries as they include an internal battery management system which regulates, maintains, and protects the lithium iron phosphate cells.
Pictured above are the recommended charging instructions for the lithium iron phosphate battery.
The other side of the battery includes the specifications which can also be found here.
First, we removed the main panel and front panel of the UPS. The battery cartridge is accessed through a hatch in the front behind the front face plate.
The cartridge was removed and opened revealing the 3x sealed lead acid batteries that come with the UPS.
The Yuasa sealed lead acid batteries are connected in series, NOT parallel in this UPS. The result is a voltage of 36 (12 V + 12 V + 12 V).
We placed the replacement lithium iron phosphate batteries next to the old sealed lead acid to ensure we connected the wires up correctly.
Once the lithium iron phosphate batteries were wired correctly, we needed to place them securely in the battery cartridge.
The cartridge was reassembled with the new batteries. Luckily, we won't have to be doing this again for a decade or so thanks to the lithium iron phosphate technology in the new batteries.
The cartridge was placed back in the UPS and connected to the main board.
Here is the UPS reassembled with the new lithium iron phosphate (LiFePO4) batteries inside. Charging temperature ran at 24° Celsius (75.2° Fahrenheit). The room temperature was 74° Fahrenheit.