lithium & solar power LiFePO4
The alarm output for CellLog
One of the Cell Logger’s functions is the alarm output. The Alarm output can be triggered according to several settings of the CellLog. It uses the open collector design - this kind of output can be found on many integrated circuits or electronic modules.
How to connect a DC relay to this alarm output: The output forms either an open circuit or a connection to ground. This gives you the advantage of switching loads up to 50V and 500mA. In other words it can be possible to control 12/24V relay easily. In most cases the power to trigger such a relay will be provided from a separate power supply (e.g. isolated DC-DC). In case you connect the relay to the battery directly, please note that ground pin of the ALARM is not isolated! It is connected to the GND of the battery pack.
See an example connection of 24V relay to 8 cell LiFePO4battery pack. This way you can turn off your charger or disconnect the main contactor in case alarm is triggered. Do not forget to connect the protective diode parallel to the relay-coil otherwise you will most probably break the output!

The alarm output for CellLog

One of the Cell Logger’s functions is the alarm output. The Alarm output can be triggered according to several settings of the CellLog. It uses the open collector design - this kind of output can be found on many integrated circuits or electronic modules.

How to connect a DC relay to this alarm output: The output forms either an open circuit or a connection to ground. This gives you the advantage of switching loads up to 50V and 500mA. In other words it can be possible to control 12/24V relay easily. In most cases the power to trigger such a relay will be provided from a separate power supply (e.g. isolated DC-DC). In case you connect the relay to the battery directly, please note that ground pin of the ALARM is not isolated! It is connected to the GND of the battery pack.

See an example connection of 24V relay to 8 cell LiFePO4battery pack. This way you can turn off your charger or disconnect the main contactor in case alarm is triggered. Do not forget to connect the protective diode parallel to the relay-coil otherwise you will most probably break the output!

Dual battery monitoring BMS + CellLog8
An example of a real installation: 24V battery pack consisting of 8 pcs of LFP cells. The monitoring and management is done by the BMS123 system. In order to have a fast overview of the status of the cells, the CellLog8 is added in parallel to the cells.
This allows to have a fast overview of the status of the cells. Also additional alarm can be triggered using the ALARM output of the CellLog8.
Check the CellLog8 and BMS123 at EV-POWER.EU.

Dual battery monitoring BMS + CellLog8

An example of a real installation: 24V battery pack consisting of 8 pcs of LFP cells. The monitoring and management is done by the BMS123 system. In order to have a fast overview of the status of the cells, the CellLog8 is added in parallel to the cells.

This allows to have a fast overview of the status of the cells. Also additional alarm can be triggered using the ALARM output of the CellLog8.

Check the CellLog8 and BMS123 at EV-POWER.EU.

Multiple CellLogs on computer cables

See a hint how to join multiple CellLogs together using the computer dataline cables.

Note: never connect the USB port of multiple CellLogs connected on a the same battery pack. The USB ports have different voltage potentials and the connection will lead to a short-circuit.

Order CellLogs here at EV-POWER.EU

EVBike Battery Cell Balancing
Inside the EVBike battery: the graph shows the results of EVBike battery balancing - with CellLog 8 used for monitoring. As seen from the graph, the cells are balanced to the same voltage level at the end of the charge.

EVBike Battery Cell Balancing

Inside the EVBike battery: the graph shows the results of EVBike battery balancing - with CellLog 8 used for monitoring. As seen from the graph, the cells are balanced to the same voltage level at the end of the charge.

Connecting cable to CellLog and PowerLog
Computer mother-board cable can be used to connect CellLog and PowerLog to batteries.
CellLog8 - http://www.ev-power.eu/_d1747.html
PowerLog 6S - http://www.ev-power.eu/_d2116.html

Connecting cable to CellLog and PowerLog

Computer mother-board cable can be used to connect CellLog and PowerLog to batteries.

CellLog8 - http://www.ev-power.eu/_d1747.html

PowerLog 6S - http://www.ev-power.eu/_d2116.html

CellLog 8S - latest firmware - V208 - download
Please download the latest firware for the CellLog 8S - version 2.08 - CellLog(8S)_V208.bin

CellLog 8S - latest firmware - V208 - download

Please download the latest firware for the CellLog 8S - version 2.08 - CellLog(8S)_V208.bin

A bug report for CellLog8

The CellLog8s has a bug in the firmware.  I’ve contacted the OEM via a radio-controlled model forum and he provided me with an updated firmware (v2.08).  The problem with the original firmware was that the alarm output from the cell / pack alarms did not trigger reliably when beyond the set points.

The CellLog8s also has a hardware bug in it that causes a cell load imbalance when used with more than 6 cells.  As delivered from the factory, it draws power from only cells 1-6 for the CPU and display.  So cells 7 and 8 would gradually go out of balance with cells 1-6.  The makers posted a picture of a hardware modification (adding a wire jumper) that cures this so that all 8 cells are drained equally. Unfortunately, it then does not work with 2 cells only after the mod (but I’m always going to be monitoring 8 cells so that’s ok).  They also posted an optional modification to replace one SMD resistor to reduce power consumption when using more than 6 cells. I’ve made both of these modifications.

http://www.rcgroups.com/forums/showpost.php?p=13452879&postcount=143

I’m using the CellLog8s alarm output with some external relay logic to provide an ENABLE/DISABLE input to the AC inverter load.  All AC inverters are designed for lead acid batteries and their Low Voltage Disconnect (LVD) settings are too low for lithium batteries (21V on a 24V battery inverter). So I use the CellLog8s to send a DISABLE signal to the inverter when the pack Voltage reaches either 24.0V or any one cell in the pack reaches 3.00V. That guarantees that the battery isn’t discharged by more than 90% in normal use.  The system then has to be manually reset by pressing a button on the relay logic controller, which provides an ENABLE signal to the inverter. This allows the normal remote control for the inverter to send a START command. The reset button cannot work until the CellLog8s alarm condition is cleared (by recharging the battery) so even if you try to force the load to restart, it cannot until the battery has been recharged enough.

Using LiFePo4 for off-grid solar application with CellLog8 monitoring
Check the “Solar Power - A Bodger’s Guide" blog to see the application of the LFP cells for solar applications. 

Using LiFePo4 for off-grid solar application with CellLog8 monitoring

Check the “Solar Power - A Bodger’s Guide" blog to see the application of the LFP cells for solar applications. 

CellLog8 video

A Youtube video showing the CellLog8 functions and button operation.

Battery Monitor and Recorder Technical Specification
Please see the technical specification of the CellLog monitor.
ONLY EUR 27.00 !!! Please contact us for express delivery in Europe.

Battery Monitor and Recorder Technical Specification

Please see the technical specification of the CellLog monitor.

ONLY EUR 27.00 !!! Please contact us for express delivery in Europe.

Battery Monitor and Recorder Connection Diagram
To measure a single pack (a single battery), the voltage must be at least 4V. Please connect inbetween PINS (-) and (1).

Battery Monitor and Recorder Connection Diagram

To measure a single pack (a single battery), the voltage must be at least 4V. Please connect inbetween PINS (-) and (1).

Battery Monitor and Recorder in Real Use 
CellLog 8S has been 100% calibrated before it enters to the market, at the same time, it supports the calibration by users themselves. 
CellLog 8S has a 16Mbit flash storage, which can log offline data in 36 hours. 
Support upgrading the hardware program by USB port. The CellLog 8S also supports the “logview” software and can display, plot and analyze the charge and discharge data by it. (See detail information about logview in the following website: http://www.logview.info)
ONLY EUR 27.00 !!! Please contact us for express delivery in Europe.
ENGLISH MANUAL DOWNLOAD

Battery Monitor and Recorder in Real Use 

  • CellLog 8S has been 100% calibrated before it enters to the market, at the same time, it supports the calibration by users themselves.
  • CellLog 8S has a 16Mbit flash storage, which can log offline data in 36 hours.
  • Support upgrading the hardware program by USB port. The CellLog 8S also supports the “logview” software and can display, plot and analyze the charge and discharge data by it. (See detail information about logview in the following website: http://www.logview.info)
  • ONLY EUR 27.00 !!! Please contact us for express delivery in Europe.

    ENGLISH MANUAL DOWNLOAD

    Battery Voltage Monitor, Logger and Recorger
Small size with multiple functions, backlight 128*64 lattices LCD and Buzzer Tone Reminder; the interface can be operated smoothly.
It can not only measure 2-8S Li battery individual voltage, but also measure NiMH, NiCd, Pb battery pack voltage.
It can be set Individual Voltage Alarm and Pack Voltage Alarm, Overvoltage Alarm, Low Voltage Alarm, Differential Voltage Alarm and Time Over Alarm. What’s more, the extra alarm output can be linkage controlled by the users.
It has 8 sets default monitor alarm settings, which can be selected for different battery packs.
 
ONLY EUR 27.00 !!! Please contact us for express delivery in Europe.

    Battery Voltage Monitor, Logger and Recorger

  • Small size with multiple functions, backlight 128*64 lattices LCD and Buzzer Tone Reminder; the interface can be operated smoothly.
  • It can not only measure 2-8S Li battery individual voltage, but also measure NiMH, NiCd, Pb battery pack voltage.
  • It can be set Individual Voltage Alarm and Pack Voltage Alarm, Overvoltage Alarm, Low Voltage Alarm, Differential Voltage Alarm and Time Over Alarm. What’s more, the extra alarm output can be linkage controlled by the users.
  • It has 8 sets default monitor alarm settings, which can be selected for different battery packs.
  •  

    ONLY EUR 27.00 !!! Please contact us for express delivery in Europe.