Fortress Power eFlex MAX 5.4
Last updated: 28 October 2026
Battery and charging
- Energy returned
- >98%
- Maximum continuous discharge
- 100
- Highest charge current it will take
- 100
- Working voltage range
- 48-55
Row from the maker’s page: “Round Trip Efficiency” | “>98%”
Source: fortresspower.com/products/eflex-max-5-4kwh
Row from the maker’s page: “Max. Discharge Current (Continuous) [A]” | “100”
Source: fortresspower.com/products/eflex-max-5-4kwh
Row from the maker’s page: “Max. Charge Current (Continuous) [A]” | “100”
Source: fortresspower.com/products/eflex-max-5-4kwh
Row from the maker’s page: “Voltage Range [V]” | “48-55”
Source: fortresspower.com/products/eflex-max-5-4kwh
Battery care and safety
- Temperatures it may be charged in
- 32 ~ 114
- Temperatures it may be run in
- -4 ~ 131
- Temperatures it may be stored in
- 20 ~ 95
“Charging Temperature [F] 32 ~ 114 Discharging Temperature [F] -4 ~ 131”
Source: fortresspower.com/products/eflex-max-5-4kwh
“Discharging Temperature [F] -4 ~ 131 Storage Temperature [F] 20 ~ 95”
Source: fortresspower.com/products/eflex-max-5-4kwh
“Storage Temperature [F] 20 ~ 95 Dimension [L x W x H, inch] 17.5 x 24.2 x 7.2”
Source: fortresspower.com/products/eflex-max-5-4kwh
Sources
- Archived document
Source: fortresspower.com/products/eflex-max-5-4kwh
Retrieved October 28, 2026