eCarTec booth design
The eCarTec exhibition is in partnership with CALB.
eCarTec update - new booth location: HALL B3, booth 514
For some technical reasons our location was moved to a new place marked as Booth B3.514.
We look forward to meeting you at eCarTec.
Lithium battery price developments for EU market
Recently some of our partners asked about the price developments of LiFePO4 batteries on the European market.
From May 2014 to September 2014 the US dollar has increased its value by nearly 8%. This means the raw price of imported goods from China against original pricing in Euro has increased significantly.
In addition to raw costs of goods, there are more costs based on USD currency: shipping and logistic costs, insurance for sea cargo, bank fees and currency operation cost. All of these costs multiply the raw change of the USD/EUR value of the goods. As a result there is a total shift of operation costs in EURO up to approx. 10%.
In addition, the manufacturing costs in China keep increasing as previously explained in these articles:
GWL on Twitter
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FAQ: Difference between the Poly and Mono solar panels?
Question: What is the technical difference between the 250Wp Poly and 250Wp Mono solar panels?
Answer: In fact there is not much difference. In 2014 the solar technology has progressed to same levels both for poly and mono types of cells, so that there is no significant difference between the technical specifications of these two panels. The only difference is visual: some customers prefer the mono panels, because the cells are of the same color and seem to look nicer. Also the black frame solar panels are usually made with mono type of cells, so black color panels are often mono. On the other hand the poly panels are usually sold in higher quantities and the price for poly panels is little bit lower.
Note: on internet, there are some older articles that discuss the differences between the poly and mono panels. In the past times the mono panels used to be more stable and more yield-efficient. Keep in mind that these articles and the tests were made usually several years ago. The results are no longer valid, because the modern panels have very similar performance.
See our offer for solar panels at EV-POWER.EU.
Lithium VS Lead-Acid
See the facts for yourself! Say now to lead acid soon.
(sourced from /metro-board.com)
FAQ: Cycle life of LiFePO4 versus Lead-Acid
Question: I talked to a supplier of Lead Acid battery. They told me that they have special stationery lead-acid battery for solar applications that can make 1500 cycles. For me it seems better to buy the cheaper lead-acid battery with 1500 cycles than to buy expensive LiFePO4 with only 2000 cycles.
Answer: Recently some lead-acid battery suppliers have been promoting their products highlighting the number of cycles. However to compare the charge/discharge cycle in real performance additional parameters need to be taken into consideration:
1. The depth of the cycle (also called DOD – the depth of discharge).
The DOD value gives the real energy received from the battery during one cycle. For example the DOD 80% means that 80% of the nominal capacity will be taken: with a battery of a capacity 100h, it means 80AH will be taken from the battery during discharge (without any additional charging).
The LiFePO4 cells support the deep charging. They allow taking 100% of the energy, even though for general application the DOD of 80% is recommended.
The Lead Acid batteries usually do not support deep discharge with many cycles. To reach long cycle life the DOD must be low: 20%, 30%.
2. The charge and discharge speed (also called the C-rating)
The C-rating value gives the time of the charge and discharge. The value of 1C means the battery is discharged (or charged) in 1 hour. The higher the C-rating the faster time of charge and discharge is supported.
The LiFePO4 cells support the high speed charge and discharge. The typical value for LFP technology is 0.5C (or C2) this means the batteries are discharged (or charged) in two hours.
The Lead Acid batteries usually do not allow high speed charging or discharging. The typical discharge rating may be given at C6, C10, or C20 which means recommended discharge is 6 hours, 10 hours or 20 hours. With such type of batteries there is no way to store and release energy quickly.
3. The remaining capacity (also called aging index)
The aging index means the decrease of the capacity during the cycle life. The new battery has 100% of capacity. With more and more cycles the capacity is reducing. The battery is getting weaker and weaker.
The LiFePO4 cells have very low aging index. After 2000 cycles that batteries will stay keep 80% of the nominal capacity. This means the batteries can be used even after the nominal number of cycles was carried out.
The Lead Acid batteries often age gradually. The typical lifespan of 1500 cycles means that after these 1500 cycles the capacity of the battery will be 20% or perhaps less.
4. The effectiveness of the charging cycle (ECC) - also called the effective energy yield
The ECC value means how much energy can be gained from the amount of energy stored. For example the effectiveness of 97% means that for a 100Ah battery you may need 100 Ah energy to charge and you will get 97Ah energy back (in case of 100% DOD).
The LiFePO4 cells have very high effectiveness. The new cells have some 97% of effective energy yield. The old cells (e.g. after 10 years of daily usage) still have some 90% effectiveness..
The Lead Acid batteries have a natural low effectiveness. Because this value is low, it is often never mentioned in the official data sheets. The effectiveness may be between 60 to 70% for high performance batteries. The old batteries may degrade to some 40% or less.
When comparing the LiFePO4 cells with other technology all of these factors need to be taken into consideration. After detailed consideration it is obvious that the LiFePO4 technology is far ahead of the other battery technologies. The other technology is lagging behind (see the animation).
The power of EVBike
Any ordinary bike can become the EVBike! Do not throw away your old bike. Give your bike another chance - turn it into EVBike!
FAQ: What is the real cycle life for lithium LiFePO4 cells?
Question: I study the specifications of the LiFePO4 (LFP) cells and I see that the information about the cycle life of the cells is changing. For example in some older technical sheets the cycle life is only 2000 cycles. In the new ones there is 5000 cycles. Some manufacturers give 2000 cycles, other give 3000, 5000 or even more. What is the real cycle life and how to compare the values given by various manufacturers?
Answer: GWL/Power has been doing the business with LFP cells since 2008. The 7 years have proved that the LFP technology is very stable, lasting and reliable. The manufacturers have the same results and feedback from their battery applications and customers. In addition to this, the technology, production methods and the purity of the raw materials keep improving over the years. Based on these real results the manufacturers are updating the estimated life span in the official datasheets. That is why the new datasheets publish higher cycle number data.
Simply said: all of the manufacturers, GWL is working with, give the same basic specification of the cycle life: at 2000 cycles at standard discharge conditions. This kind of cycle life is defined as an irreversible drop of the capacity from 100% to 80%.
However, the real life of the cells in much higher. It means the cell can be used even after the 2000 cycles. This information is given not as guaranteed warranty information, but as an estimation reference of the future life expectancy. Some manufactures give 3000, 5000, 8000 or even more cycles.
This is the same as with a car: How many kilometers can a car drive until a serious breakdown? The manufacturer may give the basic warranty of 100 000 kilometers, but everybody knows the car will of cause drive much longer. Depending on the driving style, driving conditions, the maintenance and the behaviors towards the car, the car may drive 300 000, 500 000 or even 1 million kilometers without a serious defect. However this cannot be provided as official “guaranteed information”. Everybody knows this, everybody understands it, but it is never given by the car manufacturer as some official data.
And the lithium battery life span is the same. The manufacturers give the basic warranty of usually 2000 cycles, but what is beyond this is only an approximate estimation.
Some manufacturers can be rather conservative, giving the “safeway” estimation, some may give the higher “nominal” estimation. Other manufacturers are very optimistic about their products and can give more far reaching results. This is seen from the attached graph.
Keep in mind that the life span of the LFP cells is really very long. Making the thousands of cycles means many years of continuous service. It is again the same logic as with a car: the investment in purchase will return in some 5 to 7 years and beyond that the car (LFP cells) will keep serving many additional years, as if free of charge.
The functional service life of the LFP cells is given as 10, 20, 30 or even more years. When the cells are stored in a stable environment and charged and discharged properly, they will keep serving years after years.
Final note: the very long life- span for LFP cells is a completely different approach from other types of battery technology (like Ni-Cd, Lead-Acid, Sodium-sulfate, etc): all these types of cells need a complex maintenance and service cycles - this keep increasing the operational costs. There is nothing like this for LFP cells.
We encourage to start using the LFP technology for all new installations. Get your DC power now!
EVSE charging - manual switching between different power ratings
The EVSE project allows a simple switching between different charging speeds. Just install a switch and connect different resistor values (optionally you can set the value by changeable resistors, as seen in the picture). For a 16 Amp household charging you can make setting to full power (when charging form a dedicated 16 amp socket), 10 Amp for safe charging from sockets with other equipment in the same AC circuit and/or 6 Amp for low drain charging in public areas where you wish to avoid the overload.
See the EVSE products on-line at EV-POWER.EU.
Visit CALB and GWL/Power at eCarTec 2014 - October 21st to 23rd
GWL/Power in co-operation with CALB is inviting all customers, partners, friends and supporters to visit the CALB + GWL Booth at eCarTec 2014 show in Munich.
Check more details about the eCarTec 2014 in Munich, Germany.
What is the connector used for GWL MicroInverters?
It is the WIELAND ELECTRIC RTS 20 series type.
Check also the support article related to the MicroInverter connectors.
No need to be queuing at EV-POWER.EU
Be smart and simple place your order on-line and you can proceed fast to receive your DC powered products.
Overview of support information for the LiFePO4 cell charging
Customer reference for Winston Lithium Cells
Our current small-scale experiments with Winston lithium iron phosphate batteries (two projects of a car starting battery and a project of a small solar-powered server installation for about 3 years) have proven the high capabilities of this technology. Hence, we are highly encouraged to use this type of batteries to build a larger scale storage solution (100 to 250 kWh using a 48V-based system) for fully powering our future residential building. We will be happy to keep working with you. A.H. Germany