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16.02.2018
 
3.2V LFP cell initial charging

Question: How should new cells 3.2V  40AH, 60AH, 90AH, 100 AH, etc. be formed before first usage?

Answer: The new 3.2V LFP cells delivered from the warehouse are partially charged. However before the first use, it is essential to charge each cell to full capacity. The initial charging should be done with the charging current set to less than 1C (typically 0.5C), till the voltage level of 4.0 V is reached.

There is no other need for LFP 3.2V cells to be formatted or otherwise specially prepared for the use. After the first charge to full, the cell is ready to be used for use.

The above charging rule is also applied to the initial charge after the cell has been unused or stored for a long time. If not used more than 1 month, it is recommended to make again an initial charge to full.

   ...more >>

16.02.2018
 
12V LP battery balancing and charging

Question:  Can I charge the 12V LFP battery using a conventional auto-moto charger 12V?

Answer:  With most of “cheap” car battery chargers you **cannot** charge the 12V LFP battery. Cheap chargers often end charging at 14V.  As a result the LFP batteries are not charged sufficiently. In order to charge to full you need to reach above 16V.

If you have an “advanced” manageable charger, it can be used provided you can set the charge level to at least 16V.

Simply said: you can charge with any kind of charger if you make sure that the battery voltage reaches at least 16V, but does not exceed the maximum limit of 17V.

 

Question: What are the experiences of balancing 12V batteries, when, for example, four pieces of 12V/40Ah in the series?

   ...more >>

16.02.2018
 
You must charge the LiFePO4 before the first use!

Charge levels

 

You must charge before the first use!

We remind all users of the LFP cells and LP batteries that the cells and batteries MUST be charged to full voltage level BEFORE assembling into a pack and before starting to be used.

For the 3.2V cells, the full charge voltage level is 4.00V and the charging is described here.  For the 12V LP batteries the full charge voltage level is 16.00V. More details about the use of 12V batteries is here.

   ...more >>

16.02.2018
 
Charging individual cells using the regulated (laboratory) power supply

Regulated laboratory charger

 

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.

16.02.2018
 
Initial charging FAQ

Initial charging FAQ

Check these FAQ published on our blog to understand the initial battery charging

 

We remind all users of the LFP cells and LP batteries that the cells and batteries MUST be charged to full voltage level BEFORE assembling into a pack and before starting to be used.  source

The new 3.2V LFP cells delivered from the warehouse are partially charged. However before the first use, it is essential to charge each cell to full capacitysource

   ...more >>

16.02.2018
 
Initial charge voltage levels of LiFePO4

Voltage levels of LiFePO

 

 Initial charge voltage levels

Question: I wish to equip my workshop with the proper tools. Can you offer me following chargers: one model with cut off voltage at 3.65V, one model with cut off voltage at 3.80V and one model with cut off voltage at 4.00V?

Answer: There is no need to have so many different chargers.  The typical chargers that are sold by GWL charge to 3.65V (for single cell).  Please see some additional comments.

   ...more >>

09.02.2018
 
Sudden battery discharge

Sudden discharge of LiFePO4

FAQ: “Sudden” battery discharge

I have bought a several of LFP cells and made the pack with them to replace the lead-acid battery in my houseboat. The LFP battery was working great and it gives much more capacity than the lead acid. However after several weeks of usage, I came back after the weekend and I found out that the battery is completely discharged. Why this happen?

Please note that unlike the lead acid batteries, the LFP batteries will be completely damaged if you discharge them bellow the minimal voltage (usually >2.5V per cell, or bellow 10V for 12V battery). This may happen if you have some equipment that takes the power from the battery continually. Maybe you simply forget some light or some equipment „on“, and after few days the battery is deeply discharged and damaged forever.

   ...more >>

09.02.2018
 
LFP as starting battery

LFP as starting battery

LFP as a starting battery – two concerns

Question: I want to use the LFP battery (4x 3.2V cells) for starting of my car. What SBM should I use to protect the battery?

You cannot use a SBM to protect the starting battery. For starting the car, the current will be very high, hundreds or even nearly 1000 Amps, it is not possible to disconnect such high currents.

WARNING: Additionally it is not possible to disconnect the battery from vehicle circuits. The car electronics may burn or become faulty of the battery is suddenly removed from the circuit, as a result of disconnection, during the operation (when the engine is running).

   ...more >>

09.02.2018
 
Operating temperature of LFP Cells

Temperature of cells

The temperature of the LFP cells

What is the operating temperature of the LFP cells?

The operating temperature of the LFP cells is based on the specification and the application.  There are several points to be clarified in this matter.  The first to clarify is the three different temperatures in relation to the batteries.

The ambient temperature

The ambient temperature is usually given as the air temperature of any environment where the batteries and related equipment are kept.  The ambient temperature is given at the specification of the cells.  It is also called the operation temperature.

   ...more >>

30.01.2018
 
Can you recommend a device to protect a 12V LP battery?

 

Can you recommend a device to protect a 12V LP battery?

In the past we used to offer a solution called Akumon. However due to a small demand, the production of Akumon was discontinued. We also offered some Battery Guard, Battery protector, Battery protect, PowerTector, etc.  

   ...more >>

29.01.2018
 
LFP battery discharged to ZERO volts

LFP battery discharged to ZERO volts

Question: I have installed a LFP battery in my car. But when I came today to the car, the car was completely dead and all electronics stopped working. What is wrong?

Answer: What you describe may happen with the car. When the car is parked, over some days, then some equipment will discharge the battery to complete emptiness (full deep over-discharge).

  • This may happen when the small “inside” lamp is by mistake left “on”, or when the door is not closed properly. 
     
  • It may also happen that the radio was left “on” – but silent, or some other equipment drained the battery (e.g. alarm system that turned on for some reason).
     
  • In some cases the driver may accidentally forget the main headlights on, and the battery will be depleted just in a few hours.
     
  •    ...more >>

28.01.2018
 
Charging a single cell from a 5V USB adapter

Charging a single cell from a 5V USB adapter

Question: On your blog you wrote this: Simple Battery Management Board 1 cell (3.6V/20A).

Warning: any battery charging must be continually monitored by human operator!

Note: the photo shows some “home-made” connection to charge a cell from USB power supply.

28.01.2018
 
Using a DC adapter to charge a battery

Using a DC adapter to charge a battery

Question: Can I use this type of 12V/3A adapter to charge a 12V LP Battery?

Answer: Most likely no, you cannot use this adapter for changing, because the voltage of the DC adapter is too low to make the charging.

With 12V LP battery, the nominal voltage is 12.8V (4x 3.2V). To charge you need a power supply (a charger) that will have higher voltage than the nominal voltage of the battery.

When charging the 12V LP battery, you should charge up to 14.6V (3.65V per cell). This means you need to use a 15V power supply (and stop the charging when reaching 14.6V).

However we need to give you some warning when you try to charge a battery from a power supply:

1) You need to monitor the charge process and stop the charging when the charge voltage is reached.  If you keep charging above the full charge voltage (typically 14.6V) you will be over charging the battery and dedicated charger designed to charge a battery.

   ...more >>

01.12.2017
 
Changing the number of cells for BMS123-Smart

 

Question: I have BMS123-Smart with 4 cells. When I add more cells, they are not recognized by the system.

Answer: You need to change the setting of the BMS123-Smart to match the number of the cell that will be recognized.

See the manual section “Hidden factory settings”.  This setting allows changing the size (rating) of the current sensor and the number of the cells in the pack.

The setting is recorded by the opening of the switch No 8, as the manual explains:

Set all switches below in the right positions for current sensor and number of cells and toggle switch 8 ON and OFF again. The hidden settings are now stored in the BMS. Set the switches back in the original positions. Please be aware it could be necessary to follow the current sensor calibration procedure again.

   ...more >>

21.11.2017
 
How often should I check my cells (or my battery pack)?

Check_cells

 

The answer depends on the type of application. See some examples.

1. Simple installations

Simple installations with one battery (12V) or with just a few cells do not need any special inspections. If you have a SMB to handle the protection of the pack, you can just monitor the voltage level. This kind of pack should be inspected once or two times in a year. Or perhaps each time after a longer pause in usage.  Note: do not forget to disconnect all electronics if not using the pack.  The pack should have a dual protection, as explained here.

 

2. Advanced installations

More advanced installations (typically with 8 cells and more) should be monitored regularly. It is recommended that the inspection of the pack is performed in these intervals (ie, after number of discharge / charge cycles):

   ...more >>

09.11.2017
 
Determining the number of cells for a battery pack

 

Question:  I need a 100V DC pack. How many cells do I need (for LFP or for LTO)?

Answer: The above table shows the various configurations of the number of the cells and the voltage levels that will be reached with the configuration.

For a 100V pack, the typical installation will be based on serial connection of 32 cells of LFP or 40 cells of the LTO technology

09.11.2017
 
Determining the size of cells based on current and operation time

 

FAQ: Determining the size of cells based on current and operation time

Question:  I need a battery pack to supply 60 Amp continuously for 8 hours. What size of the battery do you recommend?

Answer: The above table shows the size of the battery packs (in Ah) based on the 100% DOD (depth of discharge) and 80% DOD. 

The 80% DOD cycle is typically used according to the specification of the manufacturer to reach the optimal life span (cycle life) of the battery pack.

For a pack running for 8 hours at 60 Amp, at 80% DOD, the capacity of the cells should be at least 600Ah.  

Tip: you can assemble the 600Ah cell using the 3x200Ah or 2x300Ah single cells in parallel

07.11.2017
 
LTO cells for industrial packs and solutions

GWL/Power is offering a variety of LTO technology based cells that allow to assemble the battery packs for special applications:

  • high speed charge and discharge
  • low temperature operations  (up to -35°C)
  • high temperature applications (up to +70°C)
  • extended life span of the cycle life:  4000 cycles at 1C and more

Be sure to contact the GWL/Power team with your demands for details on the LTO solution. 

 

07.11.2017
 
LTO cell specifications

 

 

 

Check the basic specifications and dimensions of the LTO cells now available for your projects. 

  • Very small capacities 0.1 to 1.3 Ah 
     
  • Middle capacities 3.4 Ah to 10Ah 
     
  • Large capacities up to 65Ah

We will be happy to supply these cells for your packs. Be sure to let us know what you need.

07.11.2017
 
LTO cell test results

 

 

 

The diagrams show the test results of the specifications of the LTO cells. 

  • Charge and discharge characteristics at different rates 
  • Discharge characteristics at different temperatures
  • Discharge characteristics measured in time scope

We will be happy to provide these cells for your applications. 

11.06.2017
 
GWL/GreenEye at Intersolar/ESS 2017

GWL/GreenEye at Intersolar/ESS 2017

GWL/Power was showing the 12V batteries with the GWL/GreenEye smart technology for monitoring using the mobile phone application. 

16.03.2017
 
Using multiple chargers for one pack

Question:

I need a 96V charger for my LiFePO4 battery pack. Do you have any one ? 

 

Answer:

If you need charging 96 volt pack with 32 cells, you can use same two 48V LiFePO4 charger. First charger connect to cell number 1 to cell number 16. And second charger from cell number 17 to number 32 cell. 

1 - charger 48V/10A No1

2 - charger 48V/10A No2

3 - cells 1-16

4 - cells 17- 32

 

Check the offer of LiFePO4 chargers.

02.11.2016
 
EVSE PIN setting priority

Question:

What is the PWM output if on pin 4 a voltage is applied to allow 20A AND at the same time pin 5 is shortend to ground (pin 3)?

Answer:

The PIN5 has higher priority as described at wiki for EVSE:
 
than the PIN4
 
The result of described connection in question will be limited current to 6A.

04.01.2016
 
Multiple chargers

How should I connect multiple chargers to charge a battery pack?


 With galvanically separated chargers, it is possible to have more chargers to share in charging of the same battery pack.  The chargers must be always connected to the battery pack directly.

If possible, we always suggest to have one charger to charge the complete battery pack.  Of cause for some occasional situations or for less frequent charging, it may be possible to charge with multiple chargers. However the function of this kind of “shared charging” must be verified by each type (model) of the charger. 

     

26.08.2015
 
Contactor wiring

How can I connect the DC contactor in my application?

----------------------------------------------------------

For more information about DC contactors please follow technical blog GWL Power.

 

 

16.06.2015
 
PowerBank capacity

Why has my PowerBank lower capacity then the nominal value?

----------------------------------------------------------

PowerBank capacity is necessary to measure at voltage of one cell (3V).

 

For example power bank with capacity 13.6Ah made by 3V cells has 40.8Wh of energy (13.6Ah x 3V).

If we charge / discharge at 5.1V:  Capacity = 8Ah (40.8Wh / 5.1V)

If we charge / discharge at 12.8V:  Capacity = 3.18Ah (40.8Wh / 12.8V)

04.06.2014
 
Automated guided vehicle

How to make AGV (automated guided vehicle) with automatic charging of LiFePO4 cells?

----------------------------------------------------------

We must design battery pack with protection (BMS, SBM) and charger.

Battery pack

The operating voltage of the AGV is 24V. To obtain a nominal voltage of 24V we will need 8 cells. We recommend using at least 40Ah capacity due to the reserve - WB-LYP40AHA LiFeYPO4 (3.2V/40Ah)

Please check our LFP Cell Model Calculator to decide which cell you need to buy:

See information here.

Before first use charge the cells, please view link below:

Initial charging information.

You can use Charger 3.6V/18A for LiFePO4 cells

   ...more >>

19.04.2013
 
Solar and Storage

Solar and Storage

The initial charging of a battery pack for the energy storage solution. This battery pack will be using the WINA cells of total capacity 28.8 kWh.

 

30.03.2013
 
QUESTION: Are the lithium cells charged before shipping to the customer?

QUESTION: Are the lithium cells charged before shipping to the customer?

ANSWER: No. The cells are not charged. They are shipped in the same condition as received from the factory. The cells are shipped with 50% and less energy left in them. The cells must be charged to full and balanced (equilibrated) by the customer before the installation of the battery pack.

For safety reasons it is forbidden to transport the batteries that are fully charged. In case of an accident the fully charged cells would release all energy and could cause serious damage. The less energy is left in the cells during transportation, the safer the transportation is.

During the manufacturing process, the initial charge is made at the factory. Following this initialization charge, the introductory charge and discharge cycles may be performed at the factory to verify the cells specification, capacity and internal resistance. After these test cycles the battery is usually left at 50% capacity, ready for the shipping.

   ...more >>

29.03.2013
 
QUESTION: I want to make the initial charge of all the LiFePO4 cells to the same maximal voltage level of 4.0V. How can I do that?

QUESTION: I want to make the initial charge of all the LiFePO4 cells to the same maximal voltage level of 4.0V. How can I do that?

EDIT: This article gives the example of 4.00V charge level. The same information is to applied for charging to other voltage levels: e.g. 3.65V, 3.70V, 3.80V, 3.90V. Different voltage levels may be applied for initial charging based on the manufacturer specification.

ANSWER: The best way it to find a power supply or a charger that will charge to the 4.0V directly.  Another solution is to charge using the laboratory power supply or the regulated power supply that allows to set the final (maximal) voltage limit. We suggest to check with the local electronic components suppliers for these products.

Optionally it may be possible to use the single cell charge for 3.6V (for example the 3.6V/20A model). It can be used to make the bulk charging to 3.6V. After making the charging with this charger (to 3.6V), it may be possible to make the final charging from 3.6V to 4.0V using a 4V or 5V power supply. 

   ...more >>

18.02.2013
 
The consumption of the DC contactors

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

http://www.ev-power.eu/DC-Contactors/

12.01.2013
 
The 5 kWh Universal Energy Storage Setup

The 5 kWh Universal Energy Storage Setup

A practical realization of a mid-sized energy storage solution with 5 kWh of energy capacity. The modular design to work with the 230V AC grid.

The practical demonstration of the basic components to realize the energy storage solution with an easy expansion and many options to increase the size of the storage and the power output.
 
Components description of the universal energy storage

* Lithium Battery Pack 36V
Battery pack 36V 130Ah made of 12 units of finely balanced  SE130AHA LiFePO4 cells. The nominal capacity is 5 KWh of energy (38V x 130Ah).  Bigger sized cells can be easily used to increase the total capacity of the storage.
http://www.ev-power.eu/_d2904.html (USD180 per unit, total USD 2160 for 12 pcs)
 
* BMS system - BMS123 Solution 
The BMS system protects the batteries against deep discharge and against over charge. It also monitors every cell and provides data to the BMS Main Controller. Each cell has the BMS Cell Module installed. The setting is set for 44V as max charge voltage (3.70V per cell) and 35V as deep discharge voltage (2.95V per cell). The BMS is powered from a 12V battery independently of the main power battery.
http://www.ev-power.eu/BMS123-System/ (USD430 Main Unit, USD200 Cell Modules, USD150 additional components)
 
* DC contactor relay
The relay is designed to disconnect the DC/AC inverters from the batteries in case of deep voltage discharge.  The DC contactor is managed by the BMS Main Controller. http://www.ev-power.eu/_d2649.html (USD20)
 
* DC/AC Grid-tied   ...more >>

12.12.2012
 
Remote LED signalling for the TC Chargers

Remote LED signalling for the TC Chargers

The TC Chargers support signalling via Remote Dual Color LED.

  • Remote LED should be dual color common cathode
  • The voltage is recommended to be 3.3V
  • Pins 4 for red and 5 for green leds.
  • Remote LEDs, it should be totally isolated from other circuits

Check our offer of the TC-Chargers.

07.12.2012
 
RT-BMS cooler installation

RT-BMS cooler installation

The photo shows the design of aluminum cooling plate to install the RT-BMS high power modules on top of the 200AH cells

11.11.2012
 
The power of electric induction

The power of electric induction

A simple mistake:  the cable rolled up on a wheel-cable extension cord used to charge an EV. Never forget that even few loops on a cable can cause severe heating by electric induction.

26.10.2012
 
EVDock at the eCarTec

EVDock at the eCarTec

We were showing the EVDock at the eCarTec 2012 in Munich.

10.09.2012
 
DC Power Latching Relay 100A, Coil 12V and 48V

DC Power Latching Relay 100A, Coil 12V and 48V

High current latching relay designed for AC and DC voltage with a maximum current 100A DC (at 48VDC) or 120A AC (at 250VAC). The advantage of the lachting relay is that there is no need for continueous powering of the operating coil.

The voltage of the operating coil is 12V or 48V DC. See our offer at EV-POWER.EU

   ...more >>

07.05.2012
 
FAQ: Questions on charging LFP cells

Q: I am using a new laboratory Power Supply (PS). This PS is able to charge to a max. of 30 Volts and a current of max. 10 Amp. What I do is setup the PS to 4 Volts and 3 Amp. At the end of the charging, the PS automatically reduces the current to 0.01 Amp.

This is 100% correct.  For large capacity cells (40AH and more) you can even charge with the full power (of 10A current), there is no need to reduce the current to 3 Amp.

During the final stage of the charging, when the cells is “full” it does not absorb any more energy and the current will decrease to a very small value.   The charging can be stopped when the current is 1% or less of the nominal capacity (1% of 40AH cell is 0.4A).

The voltage of 4V should not be kept at the cell terminals after the current has already dropped; the power source needs to be disconnected. After the charging is finished and the PS is disconnected, the voltage of the cell will drop back to some 3.40V ~ 3.20V after some period of time.

Q: Please explain how you can charge a cell to 4.00V volt. And why some people suggest charging to 3.65 Volt.

We recommend to reach 4.0V for the initial charge. The 3.65V is a usual charging level for the regular operation of the cells.  This means after you make the initial charge to 4.00V you continue to use the cells and charge to 3.65V (or 3.80V or some similar level) for the regular operation.  Simply said charging to a lower level will extend the cell’s total life span (in number of cycles).

   ...more >>

11.04.2012
 
RT-BMS Monitor Screen Demonstration

RT-BMS Monitor Screen Demonstration

   ...more >>

11.04.2012
 
Question: My mistake I discharged my battery pack very low voltage and the cells are misbalanced. I think the RT-BMS system does not work properly. What shall I do?

Question: My mistake I discharged my battery pack very low voltage and the cells are misbalanced. I think the RT-BMS system does not work properly. What shall I do?

Deep discharge:  please avoid the deep discharge of the battery pack at any case. You need to monitor the battery pack continually to protect against such deep discharge. You should stop using the pack when the voltage gets too low.  You should disconnect the pack from the load in case the pack will be left unattended for a longer period of time. You should never operate the equipment with no supervision.

RT-BMS operation:  the RT-BMS system CBU modules measuring input is powered from the cell voltage. If the voltage of the cell drops too low, the CBU unit does not work properly. See the BMS instruction document, page 2: „Operating voltage of the measured cell min 1.8V. max 5.0 V“.  In fact the BMS units (CBU modules) may not work reliably under 2.0V! The CBU will stop working with 1.8V and less.  The BMS cannot report correct values for these under-voltage cells.

   ...more >>

11.04.2012
 
RT-BMS Monitor unit released - product and manual information

RT-BMS Monitor unit released - product and manual information

RT-BMS data monitor unit with a touch display (for RT-BMS Master unit).  Designed to read and display data from all software versions of RT-BMS Master unit starting from HW version 2.0. The BMS Master Unit is connected to the board using a special I2C to RS232 cable.

In addition to the display of the data, the monitor can be configured to save gathered data from the BMS to a CSV file to be downloaded to your PC.

Check the RT-BMS Monitor documentation on-line.

 

02.04.2012
 
Check these FAQ published on our blog to understand the initial battery charging

Check these FAQ published on our blog to understand the initial battery charging

We remind all users of the LFP cells and LP batteries that the cells and batteries MUST be charged to full voltage level BEFORE assembling into a pack and before starting to be used.  source

The new 3.2V LFP cells delivered from the warehouse are partially charged. However before the first use, it is essential to charge each cell to full capacity. source

The cells must be charged individually to full voltage level (typically 4.0V) before assembling the battery pack. This way the cells will be fully charged and balanced before the first use of the battery pack and there will be no need to balance the cells using the BMS with balancing. source

   ...more >>

01.04.2012
 
Battery Charging Guidelines as published by Sinopoly

Battery Charging Guidelines as published by Sinopoly

The charging diagrams (in PDF file) show the steps of the charging process for the best state-of-art charging process.

01.04.2012
 
Radox Shielded Battery Cables

Radox Shielded Battery Cables

Check the specifications of the high quality battery and EV cables. PDF File.

15.03.2012
 
GWL to distribute the TC Chargers in Europe

GWL to distribute the TC Chargers in Europe

With the introduction of the new EV-POWER.EU web shop, GWL/Power has begun the promotion of the high-quality and top-performance DC power chargers under the TC Charger brand. The complete listing if products includes the 1.5 kW, 3 kW, 6 kW and 8 kW single phase 230V AC models.

The specification data of the available models, the nominal and maximal voltages are listed in the specification PDF file.

   ...more >>

04.03.2012
 
FAQ:  What is the charging voltage of the 12V battery?  16V or 14.4V?

FAQ:  What is the charging voltage of the 12V battery?  16V or 14.4V?

Question: Some web pages and the GWL blog says that the final voltage of the charge for 12 LP battery is 16V. But some other pages and some charger specifications give information about charging to 14.4 ~ 14.6V. What is the difference?

Answer: The maximal charge voltage for the LiFePO4 technology is 4.00 per cells (16.00V per battery). This is the recommended charge voltage for the initial charging to balance all the cells to the same full level.  Check additional information at this post.

18.02.2012
 
FAQ: How should the PCM battery be protected against improper use?

FAQ: How should the PCM battery be protected against improper use?

Even though the PCM battery does contain the PCM board (Protective Circuit Module), the purpose of the PCM board is not to be used instead of the proper battery protection. The battery with the PCM  needs to be protected as any other lithium battery.

Proper fusing – it is necessary to protect the battery against accidental over discharge by a proper fusing.  Using a proper fuse protects not only the battery but also it protects the equipment, as the fusing does not allow too high currents to pass through the device in case of a failure. You should always install a proper fuse to protect the battery. (For example for a 12V/100W equipment you should install a 10AMP fuse. For the 12V batteries it is easy to use the 12V fuses manufactured by the automotive suppliers.)

   ...more >>

07.02.2012
 
High Current Charging and Discharging Report for Lithium (LiFeYPO4) Cells

High Current Charging and Discharging Report for Lithium (LiFeYPO4) Cells

How will a LiFeYPO4 cell behave after 13000 cycles of high speed charge and discharge?  Will the battery overheat or have any other malfunction? Will the battery age and lose its capacity?

Study the results in the The LiFeYPO4 cell test data after 13,000 cycles

26.01.2012
 
CAN Bus equipment operation

 

CAN Bus equipment operation

Question: I have a BMS with CAN option. I have a battery charger with CAN connector, I also have a dash board (display unit) with CAN option.  How can I make these components work together over the CAN bus?

Answer: In most cases you need a master CAN bus unit to make the equipment work together. Most of the CAN bus equipment is only either sending data (Read Only mode) or receiving commands (Write Only mode). This equipment has no additional logic to make decisions of operation for other equipment or to control it. The logic of the operation must be set by the master CAN bus unit.

Example:  BMS system is sending data (about the status of the battery pack). A ventilator with CAN input is only receiving data (turn on/off and the rotation speed). The BMS itself cannot manage the ventilator. There must be the CAN BUS master unit to process the data from the BMS over CAN and to decide if the temperature is over the limit and when the ventilator is to begin the operation. Then the CAN bus master unit i will send data to the ventilator over the CAN bus.

26.12.2011
 
FAQ: balancing of the cells at the inital charge

FAQ: I have assembled a new battery pack. I have a BMS that balances with 2A of heat discharge on each cell. I keep charging my cells for many hours already and some cells are already full and some cells are not charged yet. What is the problem?

Answer: Please follow the lithium battery operation instructions closely:  the cells must be charged individually to full voltage level (typically 4.0V) before assembling the battery pack. This way the cells will be fully charged and balanced before the first use of the battery pack and there will be no need to balance the cells using the BMS with balancing. (Additionally to the first installation, we recommend to checking the cells of the battery pack from time to time and making the full balancing of all the cells, by means of the individual charging.)

Note: Concerning the balancing using the heat dissipation (over the BMS modules): keep in mind that it takes a lot of time to balance the cells this way. If you have 300Ah cells with +/- 20% misbalance, you need to balance up to 40 Ah of capacity. With 2 A balancing current, you may need 20 hours to finish the balancing. Even more, you waste a lot of energy that will be discharged at the cells that are already fully balanced. That is why we do not recommend to balance the cells this way.

22.12.2011
 
PowerLog Data Storage

PowerLog Data Storage

Description of  logging the data traffic to internal 16MB storage. PowerLog 6S enables to store data during operation of the internal memory.  Please see PDF description.

Note: This instruction supplements Detailed manual / EN /.

08.08.2011
 
Charger max voltage adjustment

I have a charger for 16 cells (POW48V30A/BMS). However I am using only 14 cells. Is it possible to adjust the output voltage of the charger?

Answer: Please note that the charger has two operating modes: the automatic mode and the BMS mode. In the automatic mode the charger will charge automatically till the full voltage (Vmax) is reached. There is no way for the user to change the Vmax voltage.  In the automatic mode you need to charge the exact number of cells as given by the type of the charger.

However in the BMS mode, the charging can be stopped or the charging current reduced using the BMS connector for managing the operation of the charger. This means if you have a BMS system that can control the charger, you can use the BMS decide when to stop charging. This way you can charge only 14 cells using the charger originally designed for 16 cells.

HOWEVER: We strongly recommend only to use the charger that has the voltage setting corresponding to the total voltage of the battery pack! In case of a failure of the BMS or in case of a problem with the communication, the charger will be in the automatic mode and it will charge the cells to the full voltage, despite the fact that the number of cells is lower. This will result in over-charge, possibly even burning the cells and a complete distruction of the cells. This is a serious WARNING!

   ...more >>

08.08.2011
 
FAQ: charging multiple 12V batteries

FAQ:  Can I charge multiple 12V batteries in series at the same time with one charger?  (i.e. 2 batteries for 24V, 3 batteries for 36V, etc…)

Answer:  Yes, it is possible to charge a battery pack consisting of multiple 12V batteries in series at the same time using one charger. However following needs to be observed:

1) The initial charge – you need to charge all the 12V batteries individually to full voltage level BEFORE you start using them together as a pack.

2) We strongly recommend to use some kind of management to make sure all the batteries are working within the proper operating voltage levels.  For example the Akumon may be used to monitor the status of the batteries.

Additionally we remind the need to observe the general instructions concerning the use of the 12V batteries.

26.06.2011
 
You must charge before the first use!

You must charge before the first use!

We remind all users of the LFP cells and LP batteries that the cells and batteries MUST be charged to full voltage level BEFORE assembling into a pack and before starting to be used.

For the 3.2V cells, the full charge voltage level is 4.00V and the charging is the 12V LP batteries)

Even in simple installations, it is important to make the first charging. Example: when assembling a 48V pack using 4 pieces of 12V batteries, it is very important to charge all batteries to the same voltage (16V) before assembling the whole pack.  Only after the batteries have been balanced to the same voltage level, it is possible use them as a pack and to charge the whole pack together using the 48V charger.

Please remember:  FIRST CHARGE, THEN USE!

30.05.2011
 
Simple solar solution for off-grid applications

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.

22.05.2011
 
Testing Solar-charge controllers with LP batteries

Testing Solar-charge controllers with LP batteries

Sample 1:  STECA SOLARIX MPPT 2010

This is a Maximum Power Point Tracking (MPPT) solar charge controller. It works perfectly. It gets the maximal power from the solar panel. The ideal peak reached was 200W of power input from 217Wp solar panel. The average solar input was 130W to 150W (from 217Wp panel during a sunny day in Prague, Czech).

Sample 2: PHOCOS CIS20

This is a Pulse-width modulation (PWM) solar charge controller. This controller will limit solar panel output voltage according to the battery voltage.  It is not suitable to be used with the high voltage FV panels (e.g. our 217Wp panel with max 36V). It is designed to be used with the so called “12V” solar panels.

The ideal peak reached was 140W of power input from 217Wp solar panel. The average solar input was 80W to 90W (from 217Wp panel during a sunny day in Prague, Czech).

   ...more >>

21.05.2011
 
The LiFePO4 charger characteristics

The LiFePO4 charger characteristics

The chart shows two instances of the charging of 12V 20AH battery.

First, a fully charged battery is charged again: the voltage increases very fast from 14.1V to 15.8V and the charge limits the current and stops charging.

Second, a partially discharged battery is charged: the voltage increases from 14V till 15V while being charged at full current (19.5A). After reaching 15V the current is gradually reduced untill the full charge voltage (15.8V) is reached. 

07.04.2011
 
Solar charging of the LFP(LYP) batteries

Solar charging of the LFP(LYP) batteries

The high powel solar panels are used to harvest the solar evergy into the LFP batteries. A specialized solar charger manages the charging of the battery pack. The solar charging allows to be full independant (off the grid).

14.03.2011
 
High speed balancing with high currents using Akumons

High speed balancing with high currents using Akumons

A simple solution using the automotive 12V relay and the 12V halogen bulbs. 

16.02.2011
 
New model of charger - 12V 5A

New model of charger - 12V 5A

Ideal pro the PCM packs or for the 12V LP batteries (slow charging). Check here Charger 12V/5A for LiFePO4 cells.

14.02.2011
 
The Charging 12 pcs of 20Ah cells

 

The Charging 12 pcs of 20Ah cells

The initial charging of the number of cells. For charging we are using a laboratory power supply capable of 5V 100A. We set the nominal voltage for 3.8V and connect the cells.

These 12 cells in parallel make a big 3V 240AH cell together.

Warning: when charging in parallel, it is a MUST (!) to double check the correct polarity of the cells. Connecting a cell in reverse polarity will cause a dangerous short circuit that may result in a strong sparking. BE EXTREMELY CAREFULL (!).

Warning: we suggest to wear protective eye-glasses to avoid a possible damage to the eyes by sparks or melted metals in case an accident happens.

14.02.2011
 
Charging 12V batteries in a parallel pack

 

Charging 12V batteries in a parallel pack

Six 12V 60AH batteries chargered with 12V 100A charger. The batteries are in parallel and make 12V 360AH pack. 

Hint 1: Note that the terminals of the charger are connected on the oposite sides of the pack. This is a small hint to make sure that all the batteries will be chargered equally during the high speed charging.

Hint 2: Additionally after the charge cycle is finished, it seems good to let the batteries rest and equalize over 1 or 2 hours and then make another charge to full. This may be repeated 2 to 3 times to make the batteries in the pack equally charged.

01.02.2011
 
The Float voltage for the LiFeYPO4 batteries

 

The Float voltage for the LiFeYPO4 batteries

Unlike the lead acid batteries, there is no need for lithium batteries to apply the constant voltage to maintain the cells in a fully charged condition. (Typical for lead acid batteries 12V -  Gel 13.05V, Flooded 13.4V and AGM 13.6V values @ 25°C). 

In case you replace the lead acid battery with the LiFeYPO4 battery, it is good to check how the device behaves when charging the battery.  When applying the unmanaged float voltage (all called trickle charge), the voltage for LP 12V battery should be always bellow 14.4V  (3.60V x 4 cells).  Simply said the AGM value of 13.6V should be always OK with the LP batteries / LFP cells.

13.02.2010
 
High-speed charging test 30A with 4 pcs of LP12V 20Ah batteries including temperature

High-speed charging test 30A with 4 pcs of LP12V 20Ah batteries including temperature

Download the XLS data file including graphs. If you have any questions and/or comments, please let us know.

12.02.2010
 
high-power charger for LiFePO4/LiFeYPO4

Do you need a high-power charger for LiFePO4/LiFeYPO4? Please check our Lithium Charger products. Be sure to contact us for the quote.

09.02.2010
 
Highspeed Charging - The Reality

Highspeed Charging - The Reality

Charging a 12V battery pack with 100A current.

20.12.2009
 
12V 100A high speed charger for lithium cells

12V 100A high speed charger for lithium cells

The full photo of the charger.

20.12.2009
 
12V 100A high speed charger for lithium cells

12V 100A high speed charger for lithium cells

The high speed charger for LFP / LiFePO4 / LiFeYPO4 batteries and cells. Using this charger you can charge lithium batteries just in few minutes.  Operating range 10V to 17V. Max current DC 100A. Input 230V 10A max.

25.10.2009
 
A full cell cannot charge an empty cell!  You need to charge the cells to the same full level together!

 

Just another photo….. This way you can simply balance a fully charged cells with the discharged cells…. We just leave them connected over night and the next morning the cells are ready to go on….  they are partially balanced, BUT NOT COMPLETELY.

Note: A full cell cannot charge an empty cell!  You need to charge the cells to the same full level together!

25.10.2009
 
The first step

 

Installing a battery pack? The first step is ballancing all the cells at the same voltage level. This can be done easily…. as you see on the photo. And here is the photo of the whole pack.

13.09.2009
 
High power Battery Charger

 

High speed Lithium Battery Chargers. We are supplying high-speed high-power battery charges. These chargers are designed according to customer needs. Please conctact us with your demand. (The photo shows 48V/66V 60A/40A inteligent charger)


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