Datasheet

75
www.victronenergy.com
Why lithium
-
iron phosphate?
Lithium-iron-phosphate (LiFePO4 or LFP) is the safest of the mainstream li-ion battery types. The nominal
voltage of a 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.
Rugged
A lead-acid battery will fail prematurely due to sulfation if:
• 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 (yacht or mobile home during winter time).
A 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.
Other advantages are the wide operating temperature range, excellent cycling performance, low internal
resistance and high efficiency (see below).
LFP is therefore the chemistry of choice for very demanding applications.
Efficient
In several applications (especially off-grid solar and/or wind), energy efficiency can be of crucial importance.
The round trip energy efficiency (discharge from 100% to 0% and back to 100% charged) of the average lead-
acid battery is 80%.
The round trip energy efficiency of a LFP battery is 92%.
The charge process of lead-acid batteries becomes particularly inefficient when the 80% state of charge has
been reached, resulting in efficiencies of 50% or even less in solar systems where several days of reserve energy
is required (battery operating in 70% to 100% charged state).
In contrast, a LFP battery will still achieve 90% efficiency under shallow discharge conditions.
Size and weight
Saves up to 70% in space
Saves up to 70% in weight
Expensive?
LFP batteries are expensive when compared to lead-acid. But in demanding applications, the high initial cost
will be more than compensated by longer service life, superior reliability and excellent efficiency.
Endless flexibility
LFP batteries are easier to charge than lead-acid batteries. The charge voltage may vary from 14V to 16V (as long
as no cell is subjected to more than 4,2V), and they do not need to be fully charged. Therefore several batteries
can be connected in parallel and no damage will occur if some batteries are less charged than others.
With or without Battery Management System (BMS)?
Important facts:
1. A LFP cell will fail if the voltage over the cell falls to less than 2,5V (note: recovery by charging with a low
current, less than 0,1C, is sometimes possible).
2. A LFP cell will fail if the voltage over the cell increases to more than 4,2V.
Lead-acid batteries will eventually also be damaged when discharged too deeply or overcharged, but not
immediately. A lead-acid battery will recover from total discharge even after it has been left in discharged state
during days or weeks (depending on battery type and brand).
3. The cells of a LFP battery do not auto-balance at the end of the charge cycle.
The cells in a battery are not 100% identical. Therefore, when cycled, some cells will be fully charged or
discharged earlier than others. The differences will increase if the cells are not balanced/equalized from time to
time.
In a lead-acid battery a small current will continue to flow even after one or more cells are fully charged (the
main effect of this current is decomposition of water into hydrogen and oxygen). This current helps to fully
charge other cells that are lagging behind, thus equalizing the charge state of all cells.
The current through a LFP cell however, when fully charged, is nearly zero, and lagging cells will therefore not
be fully charged. Over time the differences between cells may become some so extreme that, even though the
overall battery voltage is within limits, some cells will fail due to over- or under-voltage. Cell balancing is
therefore highly recommended.
In addition to cell balancing, a BMS will:
- Prevent cell under voltage by timely disconnecting the load.
- Prevent cell overvoltage by reducing charge current or stopping the charge process.
- Shut down the system in case of over temperature.
A BMS is therefore indispensable to prevent damage to large Li-ion battery banks.
12,8 Volt l
i
thium iron
phosphate batteries
12,8V 90Ah
LiFePO4
b
attery
LFP-CB 12,8/90
(cell balancing only)
12,8V 9
0Ah
LiFePO4
b
attery
LFP-BMS 12,8/90
(cell balancing and BMS interface)
Victron Energy B.V. | De Paal 35 | 1351 JG Almere | The Netherlands
General phone: [phone] | Fax: [phone]
E-mail: [e-mail] | www.victronenergy.com
With cell balancing, but without BMS: 12,8V LFP batteries for light duty applications
In applications were excessive discharge (to less than 11V), overcharge (to more than 15V) or excessive charge current will never occur,
12,8V batteries with cell balancing only may be used.
Please note that these batteries are not suitable for series or parallel connection.
Notes:
1. A Battery Protect module (see www.victronenergy.com) may be used to prevent excessive discharge.
2. The current draw of inverters and inverter/chargers is often still significant (0,1A or more) after low voltage shutdown. The
remaining stand-by current will therefore damage the battery if the inverters or inverter/chargers are left connected to the
battery after low voltage shutdown during a long period of time.
With cell balancing and interface to connect to a Victron BMS: 12,8V LFP batteries for heavy duty applications and
parallel/series connection
These batteries have integrated Cell Balancing, Temperature and Voltage control (BTV). Up to ten batteries can be paralleled and up to
four batteries can be series connected (BTV’s are simply daisy-chained) so that a 48V battery bank of up to 2000Ah can be assembled.
The daisy-chained BTV’s must be connected to a battery management system (BMS).
Battery Management System (BMS)
The BMS connects to the BTV’s and its essential functions are:
1. Disconnect or shut down the load whenever the voltage of a battery cell falls to less than 2,5V.
2. Stop the charging process whenever the voltage of a battery cell increases to more than 4,2V.
3. Shut down the system whenever the temperature of a cell exceeds 50°C.
More features may be included: see the individual BMS datasheets.
Battery specification
Cell balancing only Cell balancing and BMS interface
VOLTAGE AND CAPACITY
LFP-CB
12,8/60
LFP-CB
12,8/90
LFP-CB
12,8/160
LFP-CB
12,8/200
LFP-BMS
12,8/60
LFP-BMS
12,8/90
LFP-BMS
12,8/160
LFP-BMS
12,8/200
Nominal voltage 12,8V 12,8V 12,8V 12,8V 12,8V 12,8V 12,8V 12,8V
Nominal capacity @ 25°C*
60Ah 90Ah 160Ah 200Ah 60Ah 90Ah 160Ah 200Ah
Nominal capacity @ 0°C*
48Ah 72Ah 130Ah 160Ah 48Ah 72Ah 130Ah 160Ah
Nominal capacity @ -20°C*
30Ah 45Ah 80Ah 100Ah 30Ah 45Ah 80Ah 100Ah
Nominal energy @ 25°C*
768Wh 1152Wh 2048Wh 2560Wh 768Wh 1152Wh 2048Wh 2560Wh
*Discharge current ≤1C
CYCLE LIFE
80% DoD 2000 cycles
70% DoD 3000 cycles
50% DoD 5000 cycles
DISCHARGE
Maximum continuous
discharge current
180A 270A 400A 500A 180A 270A 400A 500A
Recommended continuous
discharge current
≤60A ≤90A ≤160A ≤200A ≤60A ≤90A ≤160A ≤200A
Maximum 10 s pulse current 600A 900A 1200A 1500A 600A 900A 1200A 1500A
End of discharge voltage 11V 11V 11V 11V 11V 11V 11V 11V
OPERATING CONDITIONS
Operating temperature
-20°C to +50°C (maximum charge current when battery temperature < 0°C: o,05 C, i.e. 1A in case of a 200Ah battery)
Storage temperature -45°C to +70°C
Humidity (non condensing) Max. 95%
Protection class IP 54
CHARGE
Charge voltage Between 14V and 15V (<14,5V recommended)
Float voltage 13,6V
Maximum charge current 60A 90A 160A 200A 180A 270A 400A 500A
Recommended charge current
≤20A ≤25A ≤40A ≤50A ≤30A ≤45A ≤80A ≤100A
OTHER
Max storage time @ 25 °C* 1 year
BMS connection n. a.
Male + female cable with M8 circular connector, length 50
cm
Power connection (threaded inserts) M8 M8 M10 M10 M8 M8 M10 M10
Dimensions (hxwxd) mm
235x293x139 249x293x168 320x338x233 295x425x274 235x293x139 249x293x168 320x338x233 295x425x274
Weight 12kg 16kg 33kg 42kg 12kg 16kg 33kg 42kg
*When fully charged
12,8 Volt lithium iron phosphate batteries