lithium & solar power LiFePO4

The news for EVBike

We keep improving the EVBike products. Stayed tuned for more news coming. 

New models from Sinopoly 66AH and 100AH
The Sinopoly has introduced the new small size factor model 66AH. This model will be followed by the new 100AH model later in 2014. The photo shows the engineering sample of the new 100AH model. We will keep you updated for more news on these new products.
You can order the 66AH model from our stock on-line.

New models from Sinopoly 66AH and 100AH

The Sinopoly has introduced the new small size factor model 66AH. This model will be followed by the new 100AH model later in 2014. The photo shows the engineering sample of the new 100AH model. We will keep you updated for more news on these new products.

You can order the 66AH model from our stock on-line.

FAQ: How does the EMF-1 wattmeter show power supply to the grid?

The usage of EMF-1 is very simple. The wattmeter will show the power supplied to the grid the same way, as it shows the consumption from the grid. There is no “plus” or “minus” sign. The wattmeter shows only the actual value, no matter in which direction the energy is flowing.   Measuring values in Watts or Amperes are supported. 

Check our animation for the use of the micro-inverters in the Grid-Free installation. This will give you the idea how the current is flowing. You can make also some tests to connect the meter to various places to see the results. 

As seen in the animation, if there is another appliance consuming power connected to EMF-1 together with microinverter, EMF-1 will show the difference between the power supplied to grid and power taken from the grid!   (300W consumption, 230W from the solar panel, 70 W is the difference taken from the grid).

Note: please see the EFM-1 manual to understand how the power factor influences to the power reading on the meter: even though the inverter may give the full power of 230W, the reading value on the EFM-1 may be lower because of the power factor difference. 

Logging the EVBike performance with the Speedict 
The simple solution to monitor your EVBike electrical parameters: the analyst cyclecomputer - Speedict MARS.  The analyst software allows uploading the data to the web server so that see and share your driving performance results with others. 
Be sure to check with us for more EVBike products coming!

Logging the EVBike performance with the Speedict 

The simple solution to monitor your EVBike electrical parameters: the analyst cyclecomputer - Speedict MARS.  The analyst software allows uploading the data to the web server so that see and share your driving performance results with others. 

Be sure to check with us for more EVBike products coming!

Question: Can the micro-inverter (in the GridFree installation) work in an island mode against some sine wave DC/AC generator? (e.g. in parallel with my own  independent 230V island system)?
Answer:  No, the microinverter in most cases will not work with in such mode. There are several reasons:
1) For legal and safety reasons the microinverter works only when connected to a real 230V AC grid. The inverter will start working only after detecting the presence of the real 230V AC grid power line. It will not start working with some simulated 230V AC power system.
2) The inverter must meet the exact requirements for the European 230V AC grid based on the strict settings given by the EN50438. The inverter must stop working if the specifications of the grid do not match the parameters given by this standard. For this reason the invertor will not work with some independent 230V island systems. Additionally the strict requirements of the EN50438 make the inverters non-functional in countries, where the quality of the grid is poor and unstable. 
3) For safety and legal reasons the micro-inverter works only in grid-tied mode. The island mode is not supported and trying to experiment with such operation is against the warranty conditions for this product.
4) Trying to connect to the input of DC/AC off grid inverter will most like result in burning the output of this equipment, since these products are designed to provide energy to the load and they are not designed to handle to receipt of energy from a parallel source. 
5) The impedance, voltage a power ratings of the real grid are far beyond the possibilities to emulate these in some small installations. Each microinverter contains high-tech protection and grid detection components. The inverter will not start when the real grid is not detected. 
Conclusion:
The MicroInverters work only with the 230V AC real grid that meets the limits of the specifications given by the EU standards. For technical, safety and other reasons the inverters cannot work against a simulated (local) power source. Additionally the MicroInverters are not allowed and cannot work in an island mode.

Question: Can the micro-inverter (in the GridFree installation) work in an island mode against some sine wave DC/AC generator? (e.g. in parallel with my own  independent 230V island system)?

Answer:  No, the microinverter in most cases will not work with in such mode. There are several reasons:

1) For legal and safety reasons the microinverter works only when connected to a real 230V AC grid. The inverter will start working only after detecting the presence of the real 230V AC grid power line. It will not start working with some simulated 230V AC power system.

2) The inverter must meet the exact requirements for the European 230V AC grid based on the strict settings given by the EN50438. The inverter must stop working if the specifications of the grid do not match the parameters given by this standard. For this reason the invertor will not work with some independent 230V island systems. Additionally the strict requirements of the EN50438 make the inverters non-functional in countries, where the quality of the grid is poor and unstable. 

3) For safety and legal reasons the micro-inverter works only in grid-tied mode. The island mode is not supported and trying to experiment with such operation is against the warranty conditions for this product.

4) Trying to connect to the input of DC/AC off grid inverter will most like result in burning the output of this equipment, since these products are designed to provide energy to the load and they are not designed to handle to receipt of energy from a parallel source. 

5) The impedance, voltage a power ratings of the real grid are far beyond the possibilities to emulate these in some small installations. Each microinverter contains high-tech protection and grid detection components. The inverter will not start when the real grid is not detected

Conclusion:

The MicroInverters work only with the 230V AC real grid that meets the limits of the specifications given by the EU standards. For technical, safety and other reasons the inverters cannot work against a simulated (local) power source. Additionally the MicroInverters are not allowed and cannot work in an island mode.

The new profesional Battery for EV bikes 36V & 48V

The new series of batteries for electric bikes, contains smart BMS circuit that continuously monitors the quality of internal cells and in case of failure, provides actual information through an LED panel. Please see PDF specification of LED faults. This circuit also protects the battery against deep discharge. 

NOTE:

If the battery is discharged so that it turns off the internal BMS module, next charging turns up in a few hours. Therefore is necessary to keep connected charger on the battery until it does not start charging.

The cells on the show at GWL

When coming to visit GWL warehouse in Prague, you can also visit our office on the 4th floor. There you can see the show of the most popular LiFePO4 products. For example the Winston cells, CALB cells, Sinopoly cells, the WINA cells with ALU case and many more. 

Come and see! You will benefit from visiting GWL.

MicroInverters – The definite advantage: Long Life-span
Central Inverter Installation
Life-span given to 5 / 7 / 10 years
Warranty?   2 / 3 / 5 years 
After life-span is over, complete replacement = cost increase!
Micro Inverter Installation
Life-span given as 25+ years, perhaps 30, 40 or 50 years  
Full Warranty 25 years
Replacement of only defective units, perhaps only few units
Say “No” to Central-inverters! ——>  “Game over” after few years
Say “Yes” to Micro-inverters! ——>  Keep playing for decades!

MicroInverters – The definite advantage: Long Life-span

Central Inverter Installation

  • Life-span given to 5 / 7 / 10 years
  • Warranty?   2 / 3 / 5 years 
  • After life-span is over, complete replacement = cost increase!

Micro Inverter Installation

  • Life-span given as 25+ years, perhaps 30, 40 or 50 years  
  • Full Warranty 25 years
  • Replacement of only defective units, perhaps only few units

Say “No” to Central-inverters! ——>  “Game over” after few years

Say “Yes” to Micro-inverters! ——>  Keep playing for decades!

MicroInverters – Safe Installation, Safe Repair
FULL INSTALLER SAFETY - Micro-Inverters working with DC 50V.
Easy and safe installation even under full sun-shine.
Installation / Maintenance / Repair can be done without risks.
With microinverters a replacement or repair of a defective unit is very easy: the change of the unit is very simple and can be done very fast with just few minutes of stopping of the operation of the installation.
Note: For safety reasons we always recommend turning off the AC 230V power line when working with the microinverters. Please follow the manufacturer installing guidelines and general safety procedures. 

MicroInverters – Safe Installation, Safe Repair

FULL INSTALLER SAFETY - Micro-Inverters working with DC 50V.

  • Easy and safe installation even under full sun-shine.
  • Installation / Maintenance / Repair can be done without risks.

With microinverters a replacement or repair of a defective unit is very easy: the change of the unit is very simple and can be done very fast with just few minutes of stopping of the operation of the installation.

Note: For safety reasons we always recommend turning off the AC 230V power line when working with the microinverters. Please follow the manufacturer installing guidelines and general safety procedures. 

MicroInverters – no problems with dust collection – no thermal blocks
Central Inverter Installation
Dust collection on components under air ventilation
Dirt of the components increase overheating and makes aging fast
—->  Result: LIFE SPAN IS SHORT  
Micro Inverter Installation
No air-ventilation.
No dust. 
No dirt.
—>  Result: LIFE SPAN IS LONG  (up to 50 years)

MicroInverters – no problems with dust collection – no thermal blocks

Central Inverter Installation

  • Dust collection on components under air ventilation
  • Dirt of the components increase overheating and makes aging fast

—->  Result: LIFE SPAN IS SHORT  

Micro Inverter Installation

  • No air-ventilation.
  • No dust. 
  • No dirt.

—>  Result: LIFE SPAN IS LONG  (up to 50 years)

MicroInverters - no internal overheating - long life-time performance

Comparing the Central Inverters with Microinverters:

Central Inverter Installation

  • 3 kW to 5 kW of power at one small place
  • High energy density – high over-heating
  • Components are under temperature stress (day – night cycle)
  • Large coolers and radiators required
  • Risk of thermal shock in case of unexpected shutdown
  • Even with proper cooling:LIFE SPAN IS SHORT  (3 to 5 years)

Micro Inverter Installation

  • Only 250W of power at one small place
  • Low temperature (max 60*C)
  • Components are WITHOUT temperature stress
  • No coolers and radiators
  • No risk of thermal shock
  • LIFE SPAN IS LONG  (up to 50 years)

Say “No” to overheating with central inverters! Say “Yes” to Micro-inverters!

Promoting the TOP LiFePO4 brands at InterSolar 2014

GWL has been promoting the TOP LiFePO4 brands and products at InterSolar 2014. See our promoted brands and products:

Winston LiFePO4 cellshttp://www.ev-power.eu/Winston-40Ah-200Ah/

CALB models SE and CAhttp://www.ev-power.eu/CALB-40Ah-400Ah/

Sinopoly LFP cellshttp://www.ev-power.eu/Sinopoly-40Ah-300Ah/

WINA cells with ALU casehttp://www.ev-power.eu/WINA-30Ah-100Ah/

Micro Invertershttp://www.ev-power.eu/Micro-Inverters-1/

The single cells charges: 3.6V 5 Amp and 3.6V 18 Amp

Proper charging of the LiFePO4 cells is a must. The single cell chargers allow charging of single LFP cells directly. GWL offers two models: 3.6V/5Amp (POW4V5A) and 3.6V/18Amp (POW4V20A2). These chargers should be used to make the initial charging of the LFP cells. They can also be used for individual cell balancing inside the battery pack. Every person working with LiFePO4 technology should have these chargers at hand to charge the cells properly.

FAQ: Voltage adjustment for SBM
Question: I checked the datasheets for the SBM product. I think the over voltage and under-voltage does not fit my needs.  Can over and under-voltage levels be customized for lifepo4 cells? I think that 3.9 volt over and 2.0 volt under protection voltages are too high/low.
Answer:  The voltage settings of the SBM are designed by the manufacturer and cannot be changed.  The settings correspond to the lowest  (2.0V) and highest (3.9V) values for the LiFePO cells.  These are the emergency cut-off values. 
The SBM is designed for small capacity cells. When discharging with peak currents, the voltage on these cells may go as low as 2.0V.  In order to prevent random disconnection under big loads, the voltage of the SBM is set to 2.0V per cell.
Also, the charging should be managed by the charger and kept at 3.65 per cell. The setting of 3.9V for the SBM is the maximal charge level. In fact it may be possible to use the CBU to keep the voltage balanced down to 3.65V per cell.
The SBM is a simple low cost solution to allow simple monitoring of battery packs. The SBM should be viewed as a lowest level of the cell protection. We suggest monitoring the voltage of the whole pack as well and stopping discharging when the voltage gets low.  Please see the explanation here at this post.
For higher current applications and high capacity cells, we suggest to use BMS. Unlike the SBM, where the settings are fixed and cannot be changes,  the BMS allows to change the settings and is suitable  for systems that need complete battery monitoring and management.
We suggest to use the BMS123 solution for the battery systems. See also the blog posting.

FAQ: Voltage adjustment for SBM

Question: I checked the datasheets for the SBM product. I think the over voltage and under-voltage does not fit my needs.  Can over and under-voltage levels be customized for lifepo4 cells? I think that 3.9 volt over and 2.0 volt under protection voltages are too high/low.

Answer:  The voltage settings of the SBM are designed by the manufacturer and cannot be changed.  The settings correspond to the lowest  (2.0V) and highest (3.9V) values for the LiFePO cells.  These are the emergency cut-off values. 

The SBM is designed for small capacity cells. When discharging with peak currents, the voltage on these cells may go as low as 2.0V.  In order to prevent random disconnection under big loads, the voltage of the SBM is set to 2.0V per cell.

Also, the charging should be managed by the charger and kept at 3.65 per cell. The setting of 3.9V for the SBM is the maximal charge level. In fact it may be possible to use the CBU to keep the voltage balanced down to 3.65V per cell.

The SBM is a simple low cost solution to allow simple monitoring of battery packs. The SBM should be viewed as a lowest level of the cell protection. We suggest monitoring the voltage of the whole pack as well and stopping discharging when the voltage gets low.  Please see the explanation here at this post.

For higher current applications and high capacity cells, we suggest to use BMS. Unlike the SBM, where the settings are fixed and cannot be changes,  the BMS allows to change the settings and is suitable  for systems that need complete battery monitoring and management.

We suggest to use the BMS123 solution for the battery systems. See also the blog posting.

Winston Battery - new models 160AH 

Check the specifications of the two models of Winston 160AH cells. The cells have identical nominal capacity, but have different dimensions, to meet the needs of various customers. 

LFP160AHA - original model (TALL) - size: 278x182x71 mm, factory code:WB-LYP160AHA(A)

LFP160AHA-B - new model (WIDE) - size: 278x209x65 mm, factory code: WB-LYP160AHA(B)