VICTRON lithium iron phosphate batteries

VICTRON Lithium-iron-phosphate (LiFePO4 or LFP) batteries have integrated cell balancing and cell monitoring. Up to ten batteries can be paralleled and up to four batteries can be series-connected, so that a 48V battery bank of up to 3000Ah can be assembled. The cell balancing/monitoring cables can be daisy- chained and must be connected to a Battery Management System (BMS).

Battery Management System (BMS)
The BMS connects to the BTV and will:
1 - Prevent cell undervoltage (lower than 2.5V) by timely disconnecting/switching off the load.
2 - Prevent cell overvoltage (exceeding 4.2V) by stopping the charge process.
3 - Shut down the system in case of overtemperature (exceeding 50° C).
4 - Carry out cell balancing.
5 - BMS supplies up to 200 A with any CC load (inverters and inverters/battery chargers included);
6 - More features may be included: see the individual BMS data sheet.

Advantages:
1) Lithium-iron-phosphate (LiFePO4 or LFP) is the safest of the mainstream li-ion battery types. The nominal voltage of an LFP cell is 3.2V (lead-acid: 2V/cell). A 12.8V LFP battery therefore consists of 4 cells connected in series; and a 25.6V battery consists of 8 cells connected in series.
2) Up to 70% more lightweight and compact in comparison with traditional batteries.
3) A lead-acid battery will fail prematurely due to sulphation:
•If it operates in deficit mode during long periods of time (i.e. if the battery is rarely, or never at all, fully charged).
•If it is left partially charged or worse, fully discharged.
An LFP battery does not need to be fully charged. Service life even slightly improves in case of partial charge instead of a full charge. This is a major advantage of LFP compared to lead-acid.
4) Other advantages are the wide operating temperature range, excellent charge cycle performance, low internal resistance and high efficiency (see below).