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Our 10 years of Lithium Iron Phosphate experience shared within thousands of articles, hundrends of tests and examples.


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19.12.2017
 
Three million AH - Sinopoly Test Data and Project Reference

 

Check the update for the Sinopoly Test Data for the test of the 200AH cell. 

See the project reference using the Sinopoly battery products. 

See more here at  special page: Celebrate with us - over 3 milion Ah sold in the Sinopoly cells!

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

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. 

03.11.2017
 
Internal resistence


 

The value of the internal resistance

Question: In your promotional materials you mention several times that the internal resistance of the LTO cells is “very low”“lower than for the LFP cells”, is “only 1 mOhm and less”. However we have tested the internal resistance and the value is more than 20 mOhm. We think your information is not correct.

Answer:

First, note that the internal resistance of the cell is not a constant value. The internal resistance increases when the cell is fully charged and also increases when the cell is getting discharged. To measure the internal resistance for reference value, you should measure within DOD of 80% to 20%.  This means after you charge the cell to full, you let the cell discharge to 80% first and only after that you perform the tests.

   ...more >>

16.10.2017
 
The temperature of the LFP 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.

The cells can be stored and operated within these temperature limits. However the performance of the cells is dependent on the temperature so the performance of the battery differs in various temperatures.  In simple words, when the cell is cold (bellow zero) the performance is limited, when the cell is hot (above 40 °C) the drain of the cell must be limited as well in order to protect against overheating.

   ...more >>

16.10.2017
 
The value of the internal resistance

 

The value of the internal resistance

Question: In your promotional materials you mention several times that the internal resistance of the LTO cells is “very low”, “lower than for the LFP cells”, is “only 1 mOhm and less”. However we have tested the internal resistance and the value is more than 20 mOhm. We think your information is not correct.

Answer:

First, note that the internal resistance of the cell is not a constant value. The internal resistance increases when the cell is fully charged and also increases when the cell is getting discharged. To measure the internal resistance for reference value, you should measure within DOD of 80% to 20%.  This means after you charge the cell to full, you let the cell discharge to 80% first and only after that you perform the tests.

   ...more >>

28.04.2013
 
Custom battery pack 48V 10AH using WINA cells

Custom battery pack 48V 10AH using WINA cells

A photo from a customer project using 16 cells WN10AH to make a 48V 10AH battery pack for a “super EVBIKE”. The management of the pack will be done by means of the SBM board.

The details about the small capacity LiFePO4 cells
http://www.ev-power.eu/LiFePO4-small-cells/

The SBM boards at this GWL/Blog
http://gwl-power.tumblr.com/tagged/sbm

The SBM boards at EV-POWER.EU
http://www.ev-power.eu/SBM-CBM-1-1/

14.04.2013
 
Testing the ESS solution - 1.5 MegaWatt of cycled storage reached

Testing the ESS solution - 1.5 MegaWatt of cycled storage reached

We keep running and testing the Energy Storage Station. During each cycle we store and release about 5 kWh of energy. For testing we make 3 cycles a day. In the last 100 days we made 300 cycles already and stored and released the total of 1.5 MegaWatt of energy.

11.04.2013
 
EVDock - more photos!

EVDock - more photos!

The spring is coming. Sun is shining. More reasons to park your car under the EVDOCK. Park your car, protect it from the sun-shine and change the energy into solar power, using the MicroInverters. (The MicroInverters and other electrical components must be purchased seperately.)

See more details about the EVDOCK at EV-POWER.EU
http://www.ev-power.eu/_d3281.html

Check also this link with more photos
https://plus.google.com/photos/115213892379162921447/albums/5795065140543064225

13.02.2013
 
The Energy Storage in Action

The Energy Storage in Action

See the testing results of the Energy Storage solution. Our 5 kWh energy bank is working at 3 cycles a day. This means we store and release 15 kWh energy in a day.

We use the mFi technology to monitor the AC power of the solution.

12.02.2013
 
Is there a difference between 100AH and 100AH?

Is there a difference between 100AH and 100AH?

The test data prove quite some difference in the performance of LiFePO4 cells from various manufactures. This test shows the difference between discharge results of GBS 100AH and WINA 100AH.

The discharge times at 1C (105Amp) from full charge to 12V are: 3000 seconds for GBS100AH, 3790 seconds for WINA100AH. The difference is 26%.  When calculating the total energy, it is obvious the performance of the WINA100AH cell is 20% to 30% higher.

Which cell will you choose?

03.02.2013
 
Safe Disposal of Damaged Batteries

Safe Disposal of Damaged Batteries

Some times it happens that the LiFePO4 cells or batteries get damaged due to an improper use such as deep discharge or over charge.  Such cells or batteries cannot be repaired and must be disposed of properly.

If necessary, to dispose of damaged batteries with LiFePO4 technology, we strongly recommend that you first discharge down to 0V [zero] and then link the terminals of the cell or battery with a simple wire jumper. This way you will prevent from the battery to regain some energy from the continuation of the chemical processes.

28.01.2013
 
CALB CA Cells Series Test Reports

CALB CA Cells Series Test Reports

Download and check the latest test reports for the CALB CA100 and CA180 series. The tests show the results of full cell abuse, including short-circuit, cell crushing, braking and nailing.  The cells show that no fire or explosion occured.

http://www.ev-power.eu/docs/pdf/Test-Reports/CALB-CA100FI-TestReport.pdf
http://www.ev-power.eu/docs/pdf/Test-Reports/CALB-CA180FI-TestReport.pdf

28.01.2013
 
The CALB SE70AHA Test Report

The CALB SE70AHA Test Report

Download the test report of the SE70AHA LiFePO4 cell.

http://www.ev-power.eu/docs/pdf/Test-Reports/CALB-SE70AHA-TestReport.pdf

28.12.2012
 
mFi Technology Demonstration Board

mFi Technology Demonstration Board

We are finishing the installation of a demonstration board to show the possibilities and functions of the mFi technology. This board will be visible to customers who come to our facility, or we may take it to exhibitions in 2013.

18.11.2012
 
The same is not the same….

The same is not the same….

two energy meters in series start showing a difference on the diplay. Why so? The registered meters used for billing are produced in the accuracy class “2”. Simply said class 2 meters are allowed to have a +/- 2%.  This means your neigbour may have 98.01 kWh and you may have 101.98 kWh for exactly same quantity of electric energy.

15.11.2012
 
The gardening and the farming is so easy with EVBarrow!

The gardening and the farming is so easy with EVBarrow!

Check some model photos of the EVBarrow.

The technical parameters of EVbarrow

  • Weight: 28 kg
  • Maximum load capacity: 120 kg
  • Travel speed: 3.2 - 4 km / hr.
  •    ...more >>

15.11.2012
 
EVBarrow - detailed photos

EVBarrow - detailed photos

Check the technical photos of the EVBarrow - electric wheel barrow components: the 12V-inwheel motor and the installation, the electric hand-grip, battery installation under the chasis, details of the mechanical brake switch,

27.10.2012
 
Customer project reference: Solar offgrid installation with WB cells

Customer project reference: Solar offgrid installation with WB cells

Harvesting the solar power from the photovoltaic modules 240Wp -12 pcs, 2880Wp. Storing energy into Winston battery LYP200AHA, 32pcs, connected in 48V/400Ah battery system. Making the 230V AC network using SLI inverters 1500VA, 4pcs, 6kVA max power.

12.09.2012
 
EVSlider - innovative way to travel in the city

EVSlider - innovative way to travel in the city

We are coming with the concept of EVSlider, an electric street-slider (scooter) to allow an easy travel for short routes in cities and neighbourhoods.

The EVSlider is based on the EVBike components. Keep checking our blog for more details.

21.07.2012
 
Checking the performance of cells after 2 years of usage in EVBike application with 100+% for most cells

Checking the performance of cells after 2 years of usage in EVBike application with 100+% for most cells

Based on a customer request, we performed a cell performance verification for the capacity of the cells.  Despite a heavy usage and some abuse instances, the capacity of majority of the cells was above 100% of the nominal capacity.

08.07.2012
 
EVTrike - making an electric tricycle using the EVBike components

EVTrike - making an electric tricycle using the EVBike components

A simple way to make an electric tricycle. Installing the EVBike components to get a mobility solution for elderly people or for goods-transportation.

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 >>

10.04.2012
 
CellLog 8S - latest firmware - V208 - download

CellLog 8S - latest firmware - V208 - download

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

31.01.2012
 
Can a battery be charged when being discharged?

Can a battery be charged when being discharged?

Answer:  If the charging current is higher than the discharge current, it is possible to charge the battery when being under load. When charging the charging current will be first consumed by the load and only the current in extra will be used to charge the battery: Example:  the discharge current is 4 Amps, the charging current is 5 Amps. The effective charging for the battery will be the difference: 1 Amp.

27.01.2012
 
LP 12V/20A – customer reference – 530 cycles

LP 12V/20A – customer reference – 530 cycles

I am using LiFePO4 batteries for 1.5 year in a cyclic use. The energy drop after 530 cycles is in average about 2 percent. The batteries have always had higher capacity than given by the manufacturer. At this time they still have higher capacity than the nominal value - in average 110%. I am using 12V/20Ah batteries. I have altogether 50 batteries. The weakest of them still has 21 Ah of useable energy. To get ideal performance, it is best to keep the voltage of each cell in between 3.0 to 3.5V. When voltage is dropping bellow 2.8V the battery may become misbalanced and the cells may be damaged.

14.01.2012
 
FAQ: What is the capacity of a SuperCap?

 

FAQ: What is the capacity of a SuperCap?

The calculation is showed in the picture. For a 6000 F capacitor working with 2.5V nominal voltage, the total energy is 5.2 Wh. Divided by the discharge voltage of 2V, the capacity is 2.6 Ah.

The Result: 6000 Farad  SuperCap at 2.5V has about 2.6 Ah capacity.  To make a 12V 40Ah SuperCap “battery” you need 112 pieces of 6000 F super capacitors (16P7S configuration).  (Source)

26.11.2011
 
Discharge of 90AH and 100AH batteries - Test Report at 220A (2.2C)

Discharge of 90AH and 100AH batteries - Test Report at 220A (2.2C)

The test report shows the discharge characteristics of Winston 90AH, Winston 100AH, CALB 100AH at 220A discharge currents (2.2C). Download the test data here (XLS 1.3 MB)

26.11.2011
 
The PCM circuit of the LFP batteries cannot replace proper fusing

The PCM circuit of the LFP batteries cannot replace proper fusing

Recently there were several cases of customers who damaged the LFP batteries with the PCM by over current or short-circuit.  As any batteries, the batteries with the PCM protective board need to be fused by a proper size fuse. In case of an accidental short-circuit connection, the fuse will protect the battery against high current that can cause the damage the PCM board and the whole battery.

The photo shows one instance of improper use of the LFP battery with the PCM. The two places on the battery connector plus pole prove the repeated over-current that even melted the connector.

The damage by over-current is not covered by manufacture warranty and there is no way to repair a battery that was damaged this way.

11.11.2011
 
Discharge of 90AH and 100AH batteries - Test Report at 102A (1C)

Discharge of 90AH and 100AH batteries - Test Report at 102A (1C)

The test report shows the discharge characteristics of Winston 90AH, Winston 100AH, CALB 100AH at 102A discharge currents (1C). Download the test data here (XLS 1.6 MB)

09.11.2011
 
the CBM unit balances the voltage of a cell

 

The diagram showing how the CBM unit balances the voltage of a cell when voltage level has reached over 3.6V.  Check CBM price here.

06.11.2011
 
Discharge of LFP based on temperature

The winter is coming: The discharge voltage for LFP cells in relation to the cell temperature.

06.11.2011
 
Solar charging test data - October 2011

 

Solar charging test data - October 2011

   ...more >>

29.09.2011
 
Using solar chargers to harvest solar power

Using solar chargers to harvest solar power

We are testing different solar chargers to see their performance with the LFP battery packs.  Here is the summary of our tests:

Figure 1 - shows the initial charging of a completely empty 48V/20AH LFP battery pack. We were able to charge 25Ah of power. We are using two 217Wp solar panels in series. They provide the peak of 350W.

Figure 2 - shows the discharge of the 48V/20AH LFP battery pack until the low voltage level of 44.4V is reached. The discharge with is a resistive load, so the current changes at the beginning and decreases as the heat spiral warms up.

Figure 3 - shows the charging mixed with periods of discharging.

   ...more >>

18.09.2011
 
battery quality, the new 12V LP models

What is the real experience with LiFePO4 batteries?

Answer: The Winston Battery (formerly Thunder Sky) has been producing the LiFePO4 batteries since 2004. The first large volume customers were from the USA. These American customers have been using the LFP batteries from some 5 ~ 6 years with full satisfaction. (Even though there were some problems with the quality of the cells from some of the early production batches.)  It is important to note that over the years the technology has been developing. The new LiFeYPO4 technology is much more stable and production quality also continues to grow.

FAQ: I purchased a new LP 12V battery. Why is the battery different from the model I purchased several years ago?

Answer: The original Thunder Sky 12V LP batteries used to have electrochemical balancing (with a floating electrolyte). There were produced from 2007 till spring of 2009. Later versions contained individual cells with mechanical separation. The production of the original LP batteries was stopped in 2009. The news models (40Ah, 60Ah, 90Ah) are produced using individual single cells that are selected in the factory to match the performance and capacity.

29.05.2011
 
EVBIKE - EVBAT36V10A discharge characteristics

EVBIKE - EVBAT36V10A discharge characteristics

The 36V 10Ah battery provides more than 360Wh of energy for the electric bike. Check out discharge test to show the performace at 2C discharge (20A).

Download the PDF file here.

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 >>

22.05.2011
 
The demonstration of function of the CBM boards

The demonstration of function of the CBM boards

The CBM boards (Cell Ballancing Module) will start balancing of the cell as soon as the full charge level is reached. The full charge level is is at 3.60V for LiFePO4 cells.

The diagram shows the charging of a 4-cell battery pack with following configuration:

Cell1 - no CBM board installed
Cell2 - one CBM board installed (balancing up to 1.7A)
Cell3 - two CBM boards installed (balancing up to 3.4A)
Cell4 - three CBM boards installed (balancing up to 5.1A)

The first part of the diagram shows the charging with 1A current. The Cell1 (with no CBM) goes over the 3.8V level and the voltage would increase very rapidly. Cells2, 3, 4 are ballanced with the CBM modules and the voltage is kept bellow 3.6V.

The second part of the diagram shows the charging with 3A current. The Cell1 (with no CBM) goes over the 4.4V level and is OVERCHARGED. The Cells 2 (with one CBM) is balanced and the voltage increases slowly. However ONE CBM (balancing up to 1.7A) is not enough for the 3A charging current. As a result the voltage would also increase above 3.8V, if not stopped. Only Cell3 and Cell4 (with 2 and 3 CBM boards) are ballanced sufficiantly and the voltage is kept bellow 3.6V.

   ...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. 

15.05.2011
 
The demonstration of battery overcharge

The demonstration of battery overcharge

The analysis of the RT-BMS data log supplied by customer:  Cells #3 and #6 were overcharged, as the voltage reached above 4.0V. These cells are already fully charged. It is necesarry to balance these cells untill the voltage level of all the cells in the battery pack reaches the same level.

Suggestion:  it is extremely important to balance all the cells to the same voltage level (4.0V) at the beginning of the usage of the battery pack.

04.05.2011
 
Testing the CBM performace

Testing the CBM performace

We tested the CBM boards before releasing them to our customers. You can see the voltage level of the 3 cells (on the left side) kept bellow 3.6V, while the right cell is not ballanced and the voltage increases above 3.9V.

22.04.2011
 
FAQ: LiFePO4 - LiFeYPO4 cell cycle voltage levels

FAQ: LiFePO4 - LiFeYPO4 cell cycle voltage levels

The LFP (LiFePO4 or LiFeYPO4) cells operate within the 2.5 V to 4.0V voltage levels. In order to extend the life-span, many users prefer to operate within narrower voltage levels - as seen from the table above. 

Check also the settings for the RT-BMS as explained here.

03.03.2011
 
LP12V17AHP - 12V/17Ah - Test results

LP12V17AHP - 12V/17Ah - Test results

The deep cycles for the LiFePO4 cells used in these PCM batteries is as low as 2.00V. This means the minimal cut-off voltage is approx 8.00V.

Note that the PCM inside this type of battery is designed only for last moment safety power-disconnect. In normal operation, the user must stop discharging the battery when the voltage gets bellow 10V (for 12V batteries). This means the battery voltage MUST be monitored outside the battery and the load must be stopped when the voltage is getting to 10V level.  For the proper operation the PCM board inside is not designed to replace a battery management!

12V batteries on our e-shop

01.03.2011
 
Testing of the 36V 20AH battery pack with SBM

Testing of the 36V 20AH battery pack with SBM

(SBM - Simple Battery Management)

21.02.2011
 
LFP20AH - deep frozen test (-18 deg C)

LFP20AH - deep frozen test (-18 deg C)

The test data of a fast discharge at 60A (3C). Download here.

21.02.2011
 
LFP20AH cells test data

LFP20AH cells test data

Discharge of the 20AH cells at 1C (20A current). Download here.

19.02.2011
 
100AH cell needs 0.66Ah to charge from 3.4V to 3.5V

100AH cell needs 0.66Ah to charge from 3.4V to 3.5V

Cell was held at 3.397V until the current was below 50mA before start of test. Initial current was 3.486A and ending current is 38mA. Amp-hours put into cell: 0.6588Ah. Source

07.02.2011
 
Testing the 20AH cells 

 

Testing the 20AH cells  (from our customer)

Please notice the circuit-braker attached to the pack. 

12.02.2010
 
Thundersky LiFePo4 Battery Cell Chemistry and Disassembly

Inside TS battery (1)
Inside TS battery (2)
Inside TS battery (3)
Inside TS battery (4)
Inside TS battery (5)
   ...more >>

12.02.2010
 
The data of the 30A load test on 4 pcs of LP12V 20Ah batteries incl. temperature

The data of the 30A load test on 4 pcs of LP12V 20Ah batteries incl. temperature

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

27.01.2010
 
The LiFePO4 12V battery serial connection cycle tests

The LiFePO4 12V battery serial connection cycle tests

Please download the XLS with real data of our performance tests of 12V 20AH batteries. This is a demonstrattion of high speed discharge @40A and high speed charge @30A. If you have any questions and/or comments, please let us know.

13.12.2009
 
ThunderSky 160AH capacity test

ThunderSky 160AH capacity test

Please see another test by JRR Nortec tetsing equipment. Base on this report, you can see the capacity of the 160Ah cell reaches the total of 165.4Ah. This makes 103% capacity level.

28.10.2009
 
TS-LFP160AH TEST REPORT

TS-LFP160AH TEST REPORT

Please download an indepedent test report of the performance of the 160 AH TS cells. These tests were made by JBI Corp - http://www.jbicorp.com/ 

28.10.2009
 
TS-LFP400AH TEST REPORT

TS-LFP400AH TEST REPORT

Please download an indepedent test report of the performance of the 400 AH TS cells. These tests were made by JBI Corp - http://www.jbicorp.com/

25.10.2009
 
Batterry voltage data for last 8000 sec.

Batterry voltage data for last 8000 sec.

Please download the battery data for the last 8000 seconds of the drive. Check the Auto88.cz forum link.

10.09.2009
 
the demonstration of the ThunderSky LFP 40 Ah cells

 

Our company and our partners are extensively testing the BMS system for the high power traction batteries. The photo shows the demonstration of the ThunderSky LFP 40 Ah cells.

04.09.2009
 
LiFePO4 self discharge test

 

LiFeYPO4 battery self-discharge rate at normal temperature conditions, plus 20°C.

04.09.2009
 
LiFePO4 discharge test based on life cycles

 

LiFeYPO4 battery discharge characteristics based on the number of actual life-cycles. The cycle life is 5000 cycles at 80% capacity level, 8000 cycles at 70% capacity level. (The discharge rate is at 0.5 C.)

04.09.2009
 
LiFePO4 discharge test at different temperatures

LiFeYPO4 battery discharge characteristics in different temperature conditions. (The discharge rate is at 0.5 C.)

04.09.2009
 
LiFePO4 discharge test at 20°C

LiFeYPO4 battery discharge characteristics under normal temperature (20°C).


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