The consumption of the DC contactors
Our tests show the following consumption of the DC contactors:
12V/100A model - 0.45 Amp at 13.4V
48V/200A model - 0.13 Amp at 53.5V
Say NO to Li-ON! Say YES to LiFePO4
We keep discouraging our customers from using the Li-ON (3.6V or 3.7V per cell) technology. We strongly recomend using the safe LiFePO4 technology (3.2V per cell).
The diagram shows the discharging characteristics of the Li-ON versus LiFePO4. The LiFEPO4 batteries have much more stable discharge curve, with less performance degradation.
Overview of the Cell Terminal Connectors and the Compatilibity Guide
Check the PDF with the dimensions of the terminals connectors for the battery cell models. Download here.
LiFePO4 Cell Test Data - abuse and extreme conditions
The abuse test data show the results of hazardous situations and lithium cell extreme conditions: Overcharge by 1C and 2C current, overdischarge test by 0.5C current, cell damage – short Circuit, cell crush Test (50% of the cell), nail penetration test (3 mm), high temperature (150*C and 175*C), temperature performance, cycle life (0.5C).
Check the data at the PDF file.
These tests show that the LiFePO4 technology is really safe and can be used without worries about the danagers.
The summary of the technical specification for WN-models of LiFePO4 cells
Check the specifications of the individual models:
The summary of the technical specification for WN-models of LiFePO4 cells, information in the PDF file WN36AH, WN50AH, WN72AH, WN100AH.
High current peak discharge of 40AH LFP cells
The graphs show the discharge of 40AH LFP cells with 100 Amp and 500 Amp currents. These high current tests prove that the performance of the cells is very identical and that there is no defect of these cells.
Depth of discharge (DOD)
All battery manufacturers recommend to keep the Depth of Discharge (DOD) bellow the maximal limit of 100%. Ideally 80% DOD or less is recommended. The rule is quite simple: the smaller DOD the larger number of cycles. With 50% DOD the LiFePO4 cells may have well above 5000 cycles. However it is imporatnt to keep the DOD at the cetral part of the capacity range. If the DOD is not in the center of the capacity range, the cell performace may degrade faster.
As a matter of fact, since it is better to avoid deep cycle discharging, it seems to be better to charge as frequently as possible. It is better to “charge (to full) and drive” rather than “drive and charge (from null)”.
Example of discharge of 20Ah cells at 360A (18C)
The graph shows discharge characteristics of 12V batteries using 20Ah cells at 360A.
FAQ: Questions to high speed discharge for LiFePO4 cells
Question: What is the maximum impulse current for 1 second and 2 seconds for 40Ah, 100Ah and 180Ah LiFePo4 batteries?
Question: Do you have discharge’s curves for such discharge times?
Question: What is the internal resistance?
Question: What is the life cycle number using the batteries in the high current conditions, for 1 and 2 seconds of discharge?
- When discharging with 10C currents, the lifetime is about 1000 cycles.
- For discharging with 20C currents, the cycle lifetime is about 500 to 800 cycles.
Question: Which is the advisable period between 10C discharges of 1 second, and the advisable period between discharges of 2 seconds and of 30 seconds?
- 1 second impulse of 10C current: max 10 times in 1 minute (e.g. discharge for 1 second - wait for 5 seconds)
- 2 second impulse of 10C current: max 5 times in 1 minute (discharge for 2 seconds - wait for 10 seconds)
- 30 seconds discharge - wait for 2 minutes
LAN controller with the relay – your second brain
The LAN controller is a very smart device that can help you to manage a lot of equipment based on the detection of measured values and a time schedule. It is possible to connect a variety of detectors or signal sensors.
The current status of the inputs can be monitored on-line over Internet using the web server. The settings of the LAN controller are made remotely over web page as well. The status data can be also reported using the SNMP protocol. This allows to process statistics, get the history of events, etc.
In addition the LAN controller allows sending data using plain email. This means you can get the information to any PC or pocket device (e.g. smart-phone) without the need to check the web page.
Examples of applications:
Automatic regulation of heating or ventilation based on the temperature range
Over voltage detection and warning
Battery pack monitoring
Remote controlling of equipment (turning on/off)
Watchdog for LAN based devices (routers, IP cameras)
There is an optional relay module available. It allows adding 4 more power relays!
Check the Documentation for the LAN controller on-line.
Simple Battery Management Board (SBM)
The easiest way to protect a lithium battery pack. The SBM board manages a pack of cells and disconnects the load under any unfavorable circumstances: cell over voltage, cell under voltage.
The SBM is connected between the battery pack and the load and the charger. There are additional wires from single cells to the SBM to monitor each cell. (Marking of the contacts: B+/B- to connect to the battery; B1, B2, B3….. to connect to each cell; CH+/CH- to connect charger (optional); P+/P- the whole PACK (battery with SBM) output to the load.)
Check the PDF with detailed specification of the SBM boards and their installation.
See additional tips for the installation at the GWL/blog section for SBM
Voltage of the packs:
- SBM for 4 cells 12V
- SBM for 8 cells 24V
- SBM for 12 cells 36V
- SBM for 36 cells 48V
Please observe the maximal current of the pack including the peak currents when starting or connecting the equipment.
Note: the balancing currents of the SBM boards are very low (only few milliamps), this means it is not possible to balance large capacity cells. We suggest using additional CBU modules to increase the balancing current of the cells.
Overview of the technical specifications for the CALB cells
The images show the dimensions of the SE series of the CALB cells.