Blog - LiFePO4

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

04.03.2019
 
Winston cells passed the China Army military safety tests

Winston cells passed the China Army military safety tests
The photo shows the punch-through simulating a shooting from 45 mm calibre anti-tank gun. Fully charged cells are punched through simulating the shoot-through from a military weapon. The purpose of the test is to see the safety and stability of the lithium cells. As visible from the photo, the cells remained complete, did not burn, did not set on fire and did not explode. This kind of extreme abuse proved that superiority of the Winston Battery lithium cells. These cells are suitable for all kinds of applications including the heavy duty and military grade installations.

28.02.2019
 
What is the Peukert’s Exponent for LiFePO4 cells?

What is the Peukert’s Exponent for LiFePO4 cells?
The is used for the lead-acid batteries. Simply said this exponent is the ratio between the charging and discharging of a battery. It means how much energy you need to charge compared to the energy you get when discharging. For the LiFePO4 cells, the efficiency of the charge and discharge rate is very high – above 97% and more. That is why the Peukert’s Exponent is close to 1.00. The battery producers do not give this value because it is not necessary for the LiFePO4 cells. You can find that consider using the value between 1.01 to 1.03 for different models of the LiFePO4 cells. If you need additional support, don't hesitate to ask the for help. We will always try to find the best solution for you.
eukert’s Exponent
ome discussions on the internet
Power team
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20.01.2019
 
How to calculate the cost of stored energy in a LiFePO4 cell?

How to calculate the cost of stored energy in a LiFePO4 cell?
Lead Acid or LiFePO4? This is the price per kWh stored and cycle life comparison. The two following graphs will show you the comparison between the Lead Acid and LiFePO4 batteries. The first one compares the average number of cycles (cycle life) according to the battery type and a depth of discharge. The second graph applies these figures to calculate the cost for one kWh of energy stored – again according to the battery type and the depth of discharge. If you wonder how we got these figures or even would like to calculate the costs for a kWh stored for your own battery storage system, follow the steps below the graphs. How did we get these numbers? Plus some basic terms definitions > A 300Ah battery costs around 330€ > It has a voltage of 3.2V. The battery capacity in kWh is then:3.2 * 300 = 960 Wh = 0.96 kWh ~ 1 kWh > Because we want to gain the longest possible battery durability, we will use it only for 50% of the capacity (this is so-called 50% DoD – depth of discharge). The usable battery capacity is therefore 0.5 kWh.
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20.07.2018
 
Sailing Yacht with a 12V/200AH battery bank

Sailing Yacht  with a 12V/200AH battery bank
A reference project for a battery bank on a sailing yacht using the 4x WB-LFP200AH cells for the board battery and the BMS123 Smart. The battery pack is charged from the on-board AC/DC charger (35 Amp) and the generator (up to 80 Amp).

20.07.2018
 
Low priced cells on the market

Low priced cells on the market
Low priced cells on the market Question: We have received a quote for a battery pack from a Chinese supplier. The quote is considerably lower than the price of the LFP cells on the market in Europe. Why is this so? Answer: Yes, the pricing that is available from some suppliers in China is astonishingly low. Some offer only price as low as $0.50 to $0.60 per Ah. Of cause this “low” price creates a suspicion about the quality of the products. We suggest customers should review these questions: What is the original of the cells used in the pack? Are they new cells? Or are they some cells that were recalled from some projects and are now resold “as new”? Can you verify the production date of the cells? What is the brand and the specification of the cells used in the pack? What are the references of these products? How long has this type of the cells been on the market and what is the real customer experience?
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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.
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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?
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16.02.2018
 
You must charge the LiFePO4 before the first use!

You must charge the LiFePO4 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 . For the 12V LP batteries the full charge voltage level is 16.00V. More details about .
escribed here
he use of 12V batteries is here
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16.02.2018
 
Using BMS to analyze the cell performance

Using BMS to analyze the cell performance
Why is the BMS needed for a LFP battery pack consisting of many cells? Answer: The Battery Management System (BMS) allows you to monitor the battery pack operation. Since the battery consists of a serial string of many cells, you need to monitor each cell to prevent from deep discharge or over charge. The BMS will give you information about the cell voltage levels and can issue warnings if there is a problem with any of the cells. The BMS with balancing option will balance the cells (usually during charging) to make sure all cells have the same capacity (=voltage) levels. The BMS also allows data logging so that you can see the history of the operation of the each cell in the battery. This way you can detect if there is any problem with one or more cells in the battery pack.

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

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