Proper Fusing is Vital for LFP Safety
We remind all customers to apply proper fusing for any DC power installations. The fusing and/or DC circuit brakers will limit the risks of serious accidents in case of battery DC short-circuit.
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)”.
Building a LiFePO4 battery - charging and initiation
Check a useful article published by one of our customers.
RT-BMS Cell Balancing Module dimensions and mounting specifications
The drawings show the CBU sizes and installation.
FAQ: Charging individual cells using the regulated (laboratory) power supply
Many of the laboratory power supplies allow charging of the individual cells. Using such a regulated power supply is a suitable method for performing the initial charging or for the balancing of a single cell in a battery pack (by means of charging to a fixed voltage level).
There are usually 3 steps to follow: 1) set the target voltage (open voltage) – without the connection of the battery (3.65 at the picture), 2) start charging and set the current to be used (3.0 A at the picture), 3) when the charger reaches the target voltage – it usually starts to reduce the charging current until a low value. (3.66 V reached at 0.04A). It is a time to stop charging and disconnecting the charger.
Training: Lithium Battery Technology Expert – October 2011
Photos from the one-day training that helps you to become the lithium battery expert and to understand the advantages of the lithium battery technology. The training consists of a block of lectures together with seminars, question and answers sessions and practical labs. These labs will help you to assemble your own battery pack and practice proper charging and discharging....more >>
The application of the Cell Ballancing Module
16 CBM units are used to balance the final stage of the charging of the EV scooter GWL/Scooty. The 16 lithium cells make the total of 48V (nominal voltage). Each cell using one CBM for balancing.
Installing 6 Akumons to monitor up to 6 pcs of 12V LP packs
This is a photo from our customer showing an installation of 6 pcs of Akumon management boards together with a service battery and relay. This installation is designed to monitor up to 6 pcs of 12V LP block batteries.
Simple solar solution for off-grid applications
This is our demonstration panel for simple solar solutions based on the 12V LP batteries. Check with us if you need such solutions.
Multiplying Socket to allow parallel charging of 12V blocks
We have made a Multiplying Socket to allow to charge more 12V LP block from a high speed charger.
One charger can charge up to 3 blocks at one time.
Cell Balancing Module (CBM) - easy installation
The photo shows a four-cell testing pack with CBM installed. On the right there is a single CBM - balancing up to 1.7A. On the left, there is a cascade of 3 CBMs that increase the balacing current to up to 5A (3x ~1.7A).
High speed balancing with high currents using Akumons
A simple solution using the automotive 12V relay and the 12V halogen bulbs.
Simple solution to make a 24V battery pack
Two 12V batteries (here 12V 60A) are packed together. A plastic handle is mounted too, to allow easy carrying of the pack.
A high power fuse (400A) and two Akumons are mounted inside a plastic box.
Another installation diagram for the off-grid solutions
Using the LiFePO4 batteries for off-grid solutions
Combining the "easy to get components" to build off-grid solutions: solar chargers (charge controllers), wind-turbine invertors, UPS…..
To get a reliable and highly efficient energy storage the LFP batteries are used.
Installing the LFP batteries for UPS
The two LP 12V 20AH batteries provide up to 500Wh of energy, a double value of the SLA batteries. Using bigger batteries (40AH, 60AH…) can even multiply the performace.
Replacing SLA in the UPS with LFP
Multiply the performance of any UPS (Uninterruptable Power Source) by replacing the SLA (Sealed Lead Acid) batteries with the LFP (Lithium Phosphate) technology.
The old battery pack on the photos is from APC 1000VA rack UPS model. The nominal capacity of the pack is 24V 14Ah (2S2P configuration). The real energy available from the pack is max 250Wh. This means that a 250W computer may run up to 60 minutes from the UPS with the original SLA battery.
RT-BMS CAN Bus definition
Following datagrams are sent by the RT-BMS master over the CAN bus at speed of 250 kb/s. The CAN module uses the version 2.0 of the protocol.
Address : 0x14A10101
D0 : Battery pack total capacity (0 .. 100 %)
D1 : Current (-127 … +126, value * 5 = current [A])
D2 : Total voltage (low byte)
D3 : Total voltage (high byte) - range 0 … 65535, value / 10 = voltage [V]
D4 : Highest temperature on the cells (-127 … +126 deg. C.)
D5 : Bit 0 - reading, Bit 1 - waiting, Bit 2 - balanicing , Bit 3 - running, Bit 4 - low voltage, Bit 5 - error (not serious), Bit 6 - error (serious)
D6 : The address of the CBU causing last error.
D7 : Internal error code (only for service purposes)
Address : 0x14A10102
D0 : Lowest voltage of the cell (low byte)
D1 : Lowest voltage of the cell (high byte) - range 0-65535, value / 100 = voltage [V]
D2 : The address of the cell with the lowest voltage
D3 : Highest voltage of the cell (low byte)
D4 : Highest voltage of the cell (high byte) - range 0-65535, value / 100 = voltage [V]
D5 : The address of the cell with the highest voltage
D6 : Lowest temperature on the cells (-127 … +126 deg. C.)
D7 : Reserved
Assembling 12 pcs of 3.2V cells into a 36V 20Ah pack
Installation diagram for a battery pack based on the 12V monolithic LP batteries
This diagram give details on how to install the battery pack using the 12V monolithic LP batteries. This solution is especially suitable for small systems like EV boats operating at 24V (2 batteries), 48V (4 batteries) or EV cars (with 6 and more batteries). Download the PDF file with the installation.
The management of the battery pack is done by means of the AKUMON AKM-A1. The low discharge warning can be optionally given by the BM1 - battery monitor connected to each 12V battery. The voltage of each battery is provided by means of the APM1 - Battery Indicator....more >>
Simple Hand Drawing - The Serial Connection
This is a serial connection, using the 12V LFP battery blocks.
The RT-BMS System Components Installation Diagram
The RT-BMS is designed according to the concept of single real-time balancers managing and balancing up to 192 individual cells. The individual cell-balancing units are controlled by the central Master RT-BMS Control Unit.