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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.

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).

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?
     
   ...more >>

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.

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?

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.

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.

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.

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

 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.

 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.

How does GWL/Power support the customer’s co-operation?

We always look for partners who are active in promoting and supporting the DC-power solutions. These partners are usually individuals and companies who are creating solutions with the DC power components. For example the installers of home energy storage solutions, solar panel installers, boat installers, people who convert cars to EV, companies and business that use the lithium batteries for their products, etc.

See the ideas we published in the past:

• How to increase co-operation with GWL and to promote your own business

We are happy to support such partners by special pricing and favorable delivery and payment terms so that we can help to make bases for sustaining their business.  When our partners create information about their work, we are always pleased to support the co-operation by directing customers to our partners.

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.

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).

Difference between Winston Battery and other brands (1)

What is the primary difference between the Winston Battery LiFePO4 products and other brands that also offer prismatic cells?

1. Technology history

Thundersky Winston Battery

The Thunder Sky Winston Battery company was the originator of the large capacity technology for the prismatic cells. The technology was created by Mr. Winston Chung. By means of partnerships with several companies TS-WB transferred the production facilities to partner factories. However the core know-how and technology processes were retained by Mr. Winston Chung.

A combined Energy Solution - Alfons Container

GWL/Power supplied the Winston Battery cells for the integrated hybrid energy solution called “Container Alfons”.  This solution integrates the energy from three sources - solar, wind and a backup diesel generator.

Be sure to contact GWL/Power for more details and for the reference to this and similar projects. 

Welcome in 2018!

It is the 10th year of our battery related activities. We started in 2008 with the support LiFePO4 high power industrial cells.  We keep working after the 10 years and we keep building on our experience over the many years. 

Stay with us for more news and details. 

The GWL/Power team!

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 >>

The shipment of Winston Battery cells

The shipments of the Winston Battery cells are on the way, arriving in end of February and early March. Get ready for your orders. Contact the GWL Power team for more inquiries.  

Winston Battery New Factory – Winston Battery (Changtai) Limited

All cells delivered since mid 2017 have been made in the new factory. The factory provides enough space to accommodate the growing demands for the LFP prismatic cells. 

 

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.  

The photos show the packing of the Sinopoly cells. The cells are packed in wooden boxes that meet the ADR safety regulations for the transport of dangerous goods. 

The Battery Technology Training Seminar – March 9th 2017, Prague, Czech Republic

Become the battery specialist and visit GWL/Power in Prague for a battery technology training seminar. 

GWL/Power invites you to come, meet members of GWL and Sinopoly team face to face, learn more about LiFePO4 technology and other related topics.  The training includes the presentations, discussions and technology demonstrations.

Check here for more details

he BMS provided by GWL are primarily designed for the LFP cells (2.0V to 3.8V). Some BMS models support the LTO and Li-Ion cells as well. 

BMS123Smart - supports LFP and Li-Ion, does not support LTO 

BMS2405 - supports LFP,  Li-Ion and LTO

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!

Some customers are rather exotic. We had a customer who came to our training in the mask of the Mickey Mouse.  This is not a fun, this is a reality. 

The customer was wearing the Mickey Mouse dress the whole training and was happy to take many photos. 

Simply do not worry, be happy! Everything is possible at GWL/Power!

New extension accessory current sensor for LAN Controller 2.0 is available for your projects - LAN-MOD-CS709. It allows to measure up to +/- 75A in circuits up to 277V AC/DC. Check our offer of LAN Controller extension sensors. Follow the pictures for complete installation and setup instructions.

The SBM04/16H is designed for a simple protection of the 12V battery packs using the 3.2V LFP cells. 

The SBM has higher rating resistors (bigger ones) so that the balancing current is little bigger. For even higher balancing currents we suggest adding the CBM1 module or modules. The examples of the installation are here: 12V battery, 24V battery, 48V battery.

The SBM board SBM24/40 is specially designed for high-power EV-Bikes and e-Scooter projects with voltage 72V (24 LiFePO4 cells).

GWL/Power has organized a specialized seminar for the LiFePO4 battery technology. See the photos from The Sinopoly Battery Technology Training Seminar on 9th of March.

he EVMosquit is a hybrid between an electric bike and scooter! Enjoy the comfort of the electric bike with the speed of the electric scooter. 

We will be showing the EVMosquit at InterSolar 2017. Come to check with us at Intersolar 2017: Hall B2, Booth 459. 

If you want more details about EVMosquit now, please contact our technical department. 

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. 

For 8+ years, GWL/Power’s main focus is on the large industrial prismatic cells for energy storage, traction systems and all purpose applications. 

Together with our key supplier Thudersky Winston Battery, we were promoting the large capacity cells from 40AH to 1000AH. 

Did you not have chance to get more details at InterSolar? Do you wish to know more?  Be sure to contact us for more technical details, projects applications and solutions.

The GridFree inverters for the energy solutions

The 1000W and 2000W GridFree Smart inverters for energy self-generation. 

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. 

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.

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 >>

 

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.

 

The world of the LTO technology 

The 2.4V high performance cells for your packs and battery applications. 

 

The LTO customized pack solutions - life is easy!

The innovative LTO cells allow a simple and easy assembly into the packs. As a result any company or individual with basic skills in electronics is now able to produce the battery packs with excellent performance. There is no need to use the welding machines to fix the contact terminals to the cells.  

The LTO cells have the outstanding energy performance and mechanical safety. 

The LTO cells bring the energy solutions into a new level. 

The team of GWL/Power will be happy to assist you in your projects. 

 

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

 

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.

 

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. 

Warning of the Internet Frauds

We kindly remind the customers of the need to be very careful about some types of internet frauds related to payments and refunds.

In recent months GWL/Power has experienced some kind of attacks. Some hackers pretended to be the sales person of GWL and asked the customer to change the payment information to another account.   The hackers compromised the email account and sent faked emails and created faked modified order confirmations with a fake bank account.

We kindly ask all of our customers to take note of these illegal activities.   In case there is any change in payment details, it is always better to wait, resend the copy to more employees of GWL/Power and verify by phone, Skype or some other channels.

When making the payment, always verify the payment details as published on our web pages.

 

The GridFree inverters for the energy solutions

The 1000W and 2000W GridFree Smart inverters for energy self-generation. 

 

GWL/Power and Winston Battery Booth at Intersolar/ESS 2017

The photos of the GWL/Power booth at Hall B2, Booth 459.  Together with our main partner ThunderSky Winston Battery, we have setup the booth in our favorite design. We have been using this design for last 3 years (2015, 2016, and now 2017). 

We thank to all of our customers, partners, old  and new friends to come to our booth. 

We are happy to be available to realize your DC power related projects.

EVMosquit at InterSolar 2017

We will be showing the EVMosquit at InterSolar 2017. Come to check with us at Intersolar 2017: Hall B2, Booth 459. 

If you want more details about EVMosquit now, please contact our technical department. 

EVMosquit is here!

The EVMosquit is a hybrid between an electric bike and scooter! Enjoy the comfort of the electric bike with the speed of the electric scooter. 

More details coming soon.

Question:

Can I use two inverters with limiter with one battery pack? 

Answer:

Yes you can use more inverters at one battery pack by following connection. You can use 3 inverters on each phase too.

Legend:

1 - electricity meter

2 - inverter with limit 1

3 - inverter with limit 2

4 - Battery

5 - place of consumption

6 - Limit Current Sensors

Check all inverters with limiter.

Question:

Can I monitor multiple microinverters GF-YC500T connected to different phases by a single ECU monitoring gateway?

Answer:

Yes, enter the identification codes of all your microinverters placed on the label on the bottom of the microinverter after you will installed the ECU monitoring gateway. The gateway will communicates with all microinverters on all phases.

Please note you have to always connect the batteries first to the solar regulator then the solar panels and load.

The solar regulator should be demaged If you connect the solar panels before the bateries.

Switch off the solar panels first, Load after and the batteries as last if you need to disconnect the solar regulator from the whole system.

New current measuring options for LAN Controller

New extension accessory current sensor for LAN Controller 2.0 is available for your projects - LAN-MOD-CS709. It allows to measure up to +/- 75A in circuits up to 277V AC/DC. Check our offer of LAN Controller extension sensors. Follow the pictures for complete installation and setup instructions.

Mickey Mouse at GWL/Power Training

Some customers are rather exotic. We had a customer who came to our training in the mask of the Mickey Mouse.  This is not a fun, this is a reality. 

The customer was wearing the Mickey Mouse dress the whole training and was happy to take many photos. 

Simply do not worry, be happy! Everything is possible at GWL/Power!

Faktor - our partner in Germany

If you look for GWL/Products in Germany, be sure to contact our partner 

Faktor GmbH, Herr Johann Eisenbichler
Spinnereiinsel 3D, 83059 Kolbermoor
Telefon +49 (0)8031 2080023 
E-Mail faktor@faktor.shop (faktor@faktor.de)

Web: http://www.faktor.de/

The Factor company is selling all kinds of products distributed by GWL. 

Technical support articles at EV-POWER.EU

In addition to the topics published at the GWL/Blog, you can find the answers to the technical questions at the Technical Support section of the EV-POWER.EU.

If you need help and support for your project, be sure to contact us using the technical support contact form.

Multiple solar panels - use whatever you have

It is ever more easy to get a second hand (or refurbished) solar panels. It is simple to use these for your energy solutions. Its is possible to combine various panels for one installation.

For grid-tied installations, we suggest to use the variety of micro-inverters we offer. 

For off-grid installations, we suggest using the MPPT tracking charge controllers. 

FAQ: What is a GridFree Solution

Question: What is the difference between the GridFree and the Grid-tied installation?

There are basically just two possible types of installations:  Grid-tied and Off-Grid.  

The grid-tied installation means the inverters work in synchronization with the AC grid and supply the energy to the Grid.  The off-grid installation means the inverters product energy for the consuming equipment (appliances), they do not connect with the grid, or even must not be connected with the grid (by the technical requirements).  The off-grid installation usually requires batteries to provide a continuous energy supply.

The GridFree is one type of a Grid-tied installation. The only difference between the commercial grid-tied installations (typically requiring an energy producer license) is that the GridFree installation does not send any surplus energy to the outside grid. In a proper GridFree installation all energy is consumed locally. The GridFree installation is in fact reducing the consumption from the grid by providing self-produced energy.

The Connection of Solar Panels

When you connect the panels in series, you connect the MC4 connector of one panel to the other. The voltage of the panels will increase. The current will be the same.  

FAQ: Adding the solar microinverter to the central inverter

Question: I have a permit to connect a 2 kWp solar installation. At this time I have a 1.5 kW inverter. I consider connecting another set of two 250Wp panels with microinverters to increase from 1.5kW to full power of 2 kW. Are the microinverters from GWL compatible with my solar inverter? Will they work together?

Answer: Yes, these inverters will work together on the 230V AC line. They all work on the same AC line and they follow the same international standards (in EU defined by EN50438 norm). So it is possible and very easy to “mix” various inverters on the AC line together.

Your idea is very clever and we recommend to all customers: With microinverters it is possible to add additional solar panel or panels to the existing installation (with other inverters) to get the full maximal power peak that is permitted by your grid license. As there is no change of your original installation, there is no need to update your license or permit from the Grid operator. This expansion of existing solar installations is also called solar retrofitting.

Understanding the EN 50438 for MicroInverter Operation

The EN 50438 gives the specifications of the Grid parameters. The microiverters are required to operate within the limits of this EN standard.

The parameters mean if the grid frequency is above 52 Hz or bellow 47.5 Hz, the microinverter has to stop operation in max 0.5 s. 

If the voltage is above 264.5 V or bellow 195.5 V, the microinverter has to stop operation in max 0.2 s.

In case the voltage is above 253 V and bellow 264.5 V for longer that 600 seconds (10 minutes), the microinverter has to stop working as well. (This is required by EN 50160.)

In case the there is no grid (voltage is 0 V or bellow 195.5 V), the microinverter must disconnect in 0.2 seconds. If fact the disconnection time of the microinverter is about 50 ms (0,050 seconds, max 5 half waves of the sine curve.)

Moreover Germany (and some other countries) give a regulation that says that in case that frequency is above 50.2 Hz it is necessary to reduce the power (VDE4105). However this standard applies only for inverters that feed energy to the public grid. It is not applicable for the self-consumption installations.

A solar powered ebike - possible?

I wish to make an ebike powered by solar panels in the wheel. What do you think about this?

It is a nice idea. We are always happy when our customers bring about some innovative ideas.

For the solar panels in the wheel (as suggested by the picture) we come to this calculation:

• Taking the size of the rim 26", the diameter is 66 cm, making the flat area of the wheel some 0.34m2.
• If you happen to fill this area with 60% by solar cells, you will get some 0.20m2 of solar panel flat space.
• The regular solar panel is 1m x 1.6m making some 1.6m2 of the flat area. Such panels have typically about 260Wp of solar power rating. With 0.20m2 of the wheel, you will get the solar power rating of some 32Wp.
   ...more >>

A simple off-grid installation (customer photo)

Making a solar installation is easy. Just 4 components needed: 1) solar panel(s), 2) the solar charge regulator, 3) the battery and the DC/AC inverter. 

GWL/Power has supplied the solar panels and the LS1024E PWM regulator.

What is correct:  the panels (80Wp small size panels) have the MPPT voltage approx 10V, this means two panels must be in series to get the voltage above the battery voltage (some 15V at max charge).

What is wrong: 1) there is no DC fuse on the battery…. whoops …. always use fusing!  2)shame on the shading: the panels are shaded by the solar cables and also by the battery. This is simply wrong…. the panels will not provide full power potential. Always avoid shading of the panels.

Tracer Remote Monitor MT-50

Check details on-line 

Tracer BN connection solution

GWL/Power Status display for Solar MPPT Tracer BN (MT50)

GWL/Power Solar Controller Monitor for Tracer BN series (RS-485/USB)

on-line

Tracer BN MPPT Series

Tracer1215BN, 10A, 12/24V 
Tracer2215BN, 20A,12/24V 
Tracer3215BN, 30A,12/24V 
Tracer4215BN, 40A,12/24V 

Check Tracer BN product on-line.

Raspberry Pi (RPI) is a successful piece of hardware and it is often used in industrial applications. But what to do if you need to use it in a place without a connection to the power source?

The solution is the possibility to power it by solar panel RPI!

RPI is powered via 5V microUSB, which is in many cases advantageous. But there is a problem with smaller solar panels because of their typical nominal voltage of 12V. To change the voltage with a DC-DC convertor is not a suitable solution either because of power loss. There are small solar panels, but their performance is obviously too small.

RPI has to be powered at least with a source of 700 mA 5V ie with some reserves it is possible to count with the consumption of 5W without other associated peripherals. The connection of the 5Wp solar panel is not sufficient, since it is its maximum performance in ideal conditions and with a cloudy sky the panel powered like this will have output only 0.5W. You must also have enough power to recharge the battery during the day to cover consumption overnight.

Small solar panel with the solar micro-inverter

Question: I have a 185Wp panel. How will this panel work with a 250Wp microinverter?

Answer: The panel will work with the microinverter only if the voltage of the panel matches  the operating voltage of the inverter. If the voltage matches, the inverter will produce the energy in the amount  provided by the panel.  See the example:

A) The microinverter has the operating voltage (MPPT range) between 24V and 55V. The 185Wp panel has the open voltage 36V and the max point voltage 30V.   This type of panel will work with the microinverter.  When at the full sun shine the panel will provide some 180 watts of energy and the microinverter will convert this energy to the AC output.

B) The microinverter has the operating voltage (MPPT range) between 24V and 55V. The 185Wp panel has the open voltage 18V and the max point voltage 14V.   This type of panel will NOT work with the microinverter.  The voltage of the panel is out of the range of the microinverter.  Tip: you can connect two identical panels in series to increase the voltage – this support article with ideas of regulating the solar power by means of more small size panels used for one micro-inverter.

Some more inspiration - simple GridFree installations

In fact it is so easy to make the GridFree installation at many places of your house, including the balcony of the housing complex. 

Get the idea for your own solar self-consumption (GridFree) installation.

Replica of a 1907 trolleybus powered by GWL/Power

GWL/Power has supplied the batteries and the BMS system for a project of rebuilding the replica of the Mercedes electrique Stoll electric bus (trolleybus). 

Promotion for the LTO cells

Check our promotion for the LTO cells.  

China Electric Vehicle Magazine - No 84

Download here:

http://www.ev-power.eu/docs/pdf/CEV/CEV84-01.pdf  
http://www.ev-power.eu/docs/pdf/CEV/CEV84-02.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV84-03.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV84-04.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV84-05.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV84-06.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV84-07.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV84-08.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV84-09.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV84-10.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV84-11.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV84-12.pdf
   ...more >>

China Electric Vehicle Magazine - No 83

Download here:

http://www.ev-power.eu/docs/pdf/CEV/CEV83-01.pdf  
http://www.ev-power.eu/docs/pdf/CEV/CEV83-02.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV83-03.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV83-04.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV83-05.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV83-06.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV83-07.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV83-08.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV83-09.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV83-10.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV83-11.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV83-12.pdf

China Electric Vehicle Magazine - No 82

Download here:

http://www.ev-power.eu/docs/pdf/CEV/CEV82-01.pdf  
http://www.ev-power.eu/docs/pdf/CEV/CEV82-02.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV82-03.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV82-04.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV82-05.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV82-06.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV82-07.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV82-08.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV82-09.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV82-10.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV82-11.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV82-12.pdf
   ...more >>

FAQ: Multiple micro-inverter installation

I have a microinverter installation with products from ABC Company. I have 2kW installation (8x250Wp). Now I wish to increase my installation with more inverters. My questions:

1) The products from ABC Company use a PLC communication to work with the gateway. Is the YC-500 and YC-500 gateway compatible with the ABC products and the PLC communication?

No, sorry. There is no compatibility of the products from different manufacturers. Each product has its own protocol and the products cannot be managed together.    

2) Can the ABC products and the YC-500 inverters work on the same AC line (same phase)?

Yes, there are many installations where inverters (and microinverters) from various manufacturers work together in the AC 230V grid line (phase). Since the grid requirements are the same for all products, observing these requirements makes all product compatible on the AC line – for the energy production. (Not for the communication protocols).

Micro-Inverter –  Combined Energy at Your Hand

Combining the existing water/wind power plants with additional energy supply from solar panels. 

Smart energy handling with solar micro-inverters, especially for small water power plants: if there is a lot of sunshine, usually there is less water-fall and water-flow. The energy from the sun can be used during sunshine days and the water power generation can be used less or preserved for use at night or during cloudy days.

Micro-Inverter – Solar Retrofitting

Adding additional permanent or temporal modules to increase the yield of the solar installations. Increase the yield from your existing solar installation by simply adding one or more extra solar panels with microinverters.

FAQ related to LTO technology and solar charging

Q: Can I use the LTO pack without BMS?  

No! We always recommend some kind of monitoring.  And we strongly suggest to have several methods of protection of the operation of the battery pack.

See more details:

• BMS versus Circuit Breaker – understanding the BMS operation 

Q: I have a 12V equipment, should I use 5 or 6 cells?

It depends on the voltage levels you with to reach and on the voltage level supported by your equipment.

For 5 cells LTO pack, the voltage levels are:
Charge voltage 13.25V -  2.65V/cell
Discharge voltage 9V  - 1.80V/cell

For 6 cells LTO pack, the voltage levels are:
Charge voltage 15.9V  - 2.65V/cell
Discharge voltage 10.8V -  1.80V/cell

   ...more >>

Moving forward in the electric mobility

Electric cars and electric planes are here:  Tesla S and the Phoenix electric two-seat plane.

Voltage levels for LTO and LFP packs

The table shows some combinations of the number of cells and the full charge voltage levels. 

What solution do you suggest for a small 12V/40AH solar installation?

The solar panel (fig. 1) needs to be the 18V model (not the 36V - 60 cells or 40V - 72 cell model), for example the 150Wp model will work fine, providing some up 8 Amp charging current.

The fuses (fig. 2.) should be always connected to protect against short circuit. In this type of installations you can use the automotive 12V/24V fuses with 10 Amp rating (here for AWG)

Any question?  Just let us know.  We are here to help you.

The test data for the LTO 55AH cylindrical cell

The CP-LTO-55AH cell is discharged at 10A, it provides 57AH of energy.

EVBike Wheel Kit - detailed photos

Check the high resolution detailed photos of the EVBike Wheel Kit.

EVBike Central Kit - detailed photos

Check the high resolution detailed photos of the EVBike Central Kit.

The YC500 - dual microinveter

The YC500 is a dual micro-inverter with two MPPT units for higher yield of solar energy. See the comparison of the real yield using two different configurations. 

One configuration is with 2x 260Wp panels, the other is with 2x 300Wp panels.

When using the 300Wp panels, the energy yield is significantly higher.

Another EVBike Central Kit reference

EVBike Central Kit + the 36V battery.

Using the infra-red camera to analyze solar panels

All customers using solar panels should perform a yearly inspection of the solar installation. With the help of the infra-red camera (thermo-camera), it is quite easy to detect the defective cells or other problems that are reflected as thermal irregularities. 

If you wish to get support for  the infra red camera monitoring, be sure to let us know.  We are here for you.

Micro Inverter installation diagram - single phase (using YC500) 

A suggestion of the installation diagram for the micro-inverter installation.

Note: for small site installations the power rating in Europe is limited to 16Amp (some 3500 Watts) - this corresponds to 7 microinverters per one 16Amp wiring branch. Of cause for higher rated installations (e.g. in industrial buildings) there may be a higher number of inverters per single wiring branch.

China Electric Vehicle Magazine - No 81

Download here:

http://www.ev-power.eu/docs/pdf/CEV/CEV81-01.pdf   
http://www.ev-power.eu/docs/pdf/CEV/CEV81-02.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV81-03.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV81-04.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV81-05.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV81-06.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV81-07.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV81-08.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV81-09.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV81-10.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV81-11.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV81-12.pdf
   ...more >>

VW CityStromer with a solar roof

A customer EV project using Winston cells and Solar Flexible panels in the original VW CityStromer. Of cause the solar panels provide only auxiliary charging as explained here.

The lithium cells - price increasing 

Get ready for higher pricing of the Lithium based technologies. Quoting one of the suppliers from the Samsung SDI chain:

Recently, as the growing needs of li-ion Battery, the supply of materials of li-ion battery cannot meet the market needs,. The prices of materials have soared, which leads to the sharp rise of the cost of the cell production. Samsung SDI and other battery cell companies already officially informed the rise of the price. The price of each cells grows 0.32USD.

China Electric Vehicle Magazine - No 80

Download here:

http://www.ev-power.eu/docs/pdf/CEV/CEV80-01.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV80-02.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV80-03.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV80-04.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV80-05.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV80-06.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV80-07.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV80-08.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV80-09.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV80-10.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV80-11.pdf
http://www.ev-power.eu/docs/pdf/CEV/CEV80-12.pdf
   ...more >>

LiFePO4 technology for the EVBike

Question: I have checked your batteries for EVBike. All batteries are li-on only. I am looking for LiFEPO4 battery. How can you help me?

Answer: The li-on batteries (using the Samsung, Panasonic, etc., small size 18650 cylindrical cells) have become very popular. When compared with LiFePO4, they are smaller, lighter, have higher energy density and are available in practically-designed installation sizes. Also quite some number of customers prefers to use the CentralKit, where there is no regenerative power available.  For this reason the sales of the li-on batteries have over passed the sales of the LiFePO4 models. At this time we do not offer the complete (finished) battery for EVBike with the LiFePO4 cells.

However, there are some customers, who prefer to have a customized battery with the LiFePO4 technology. The LiFePO4 battery is suitable for high current type of EVBikes, when regenerative braking and high speed charging is required. Also the LiFePO4 cells have usually better performance in cold weather. They also have a lower self-discharge rate and much higher cycle life. (LiFePO4 has usually >2000 cycles, info 2 – info 3.

Morgen City – solar powered EV in Hong Kong

City University of Hong Kong has formed a solar car team named ’Morgen City’. The goal of the team is to design the solar car, to demonstrate students’ engineering capabilities in terms of renewable energy use and energy efficiency enhancement, but to testify to the feasibility of certain innovative applications.  

Link: Morgen City Home Page  and News Report and FB Page

BMS2405 for LTO cells applications

We keep testing the BMS2405 for the LTO cell applications. With 2.4 nominal voltage, the 24V storage packs use 10 cells. 

High Power Charger for 12V to 24V applications

Hint: This charger can be used for charging the LTO cells for charging up to 24.5V (up to 8 cells).

Specifications

• Input voltage AC 90-265V for worldwide use in Europe, US and elsewhere
• Programming output voltage from 11.5 to 24.5V
• Digital display output voltage and current on time
• 3 outputs can do more chargers simultaneously (same voltage at these outputs)
   ...more >>

The exhibition of the battery products at GWL

When coming to GWL warehouse and office in Prague, you can visit the exhibition of the battery products and samples.  In addition to the cells, we show various examples of battery solutions, including the BMS, solar panels, chargers, MPPT regulators and others. 

We always welcome your visit and suggest you fix an appointment for a visit so that we are ready to welcome you and spend quality time with you.

More and more testing of the LTO technology

The graphs show the test results of the 40AH LTO cells. 

We keep testing the latest models of the LTO cell technology. Customers who request samples can contact us for details of the co-operation.

For more information about Inverters DC/AC (Offgrid) please visit technical blog GWL Power.