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T&W Energy Products Frequently Asked Questions

FAQ of Battery
1. Which fundamental parameters influence the quality of the batteries?
(1), The capacity: there are higher capacity, there are more working.
(2), Internal resistance of the battery: big resistance will lead to the machine power down and power off.
(3), protective circuit board: Ensure the battery with normal operation.

2. What we should pay attention to when use the battery?
Please don’t put the battery into the water or seawater, avoid them be wet.
Please don’t make the battery close to heat sources, such as fire or generating heat implement;
Please use specific appointed charger when charging;
Please do not reverse the battery pole.
Please do not link the battery to the terminal of power sources and the vehicle lamps;
Please do not throw the battery into the fire or other hot object.
Please don’t use conductor to make the pole of batty short circuit,do not ship or store the battery with other metal conductors, such as necklace, hairpin.
Please do not beat or throw the battery;
Please don’t prick through battery with needle or other sharp thing , do not strike or step on it.
Please do not weld the power source directly.
To ensure the battery’s safe function, please do not disassemble the battery or change any parts of it.
Please do not charge the battery approaching the fire source or very hot environment.
Please do not put battery inside the microwave or pressuring ark
Battery and other chemistry battery (such as dry cell) or the battery being unlike capacities , the brand is not shared ,generate heat , become angry , become deformed possibly in using battery charging , memory process if the electricity sends out smell,any please immediately secondary abnormal device or charger takes out turn up, stops being put into use. Allocate the battery charging time inner for continuing battery charging if unable again battery charging invites nonutility.
If all above phenomenon happened , asking stop immediately use battery.

3. How to ship our lithium ion battery?
Generally, there are three options for our clients: by air, by sea and express service.
1). By air.(port-to-port) The cargo will arrive directly at the destination main intl airport. The cargo weight should be more than 50kg. Once the cargo arrive at the appointed airport, our customer need do relevant import customs clearance and pay the taxes. This usually takes 8-10 days by air from port-to-port.
2). By sea.(port-to-port) It is suitable for larger order quantity and more cost-efficient. Usually no limit to weight and volume. When the cargo arrive at the appointed seaport, our customer need do relevant import customs clearance and pay the taxes. It takes around 30 days by sea.
3). By Express.(door-to-door). It is suitable for sample order and more cost-efficient for less 40kg weight. This usually takes 6-8 days by UPS, Fedex, DHL, TNT.

4. Why is it necessary for us to specify the battery pack configuration?
Because our engineers need test and select the batteries into groups of most sililar chemistry at the factory for best performance.

5. Do your energy products come with any warranty?
One Year Limited Warranty against manufacturing defects by us, no event will be liable to any direct, indirect, incidental, special or consequential damages of any kind. Once bad products found, you could send us a detailed report to us and proof what the problem is first, we will try to replace any faulty cells without any delay and any problems.

6 How effective are Lithium-Iron-Phosphate battery packs in providing power to electric vehicles?
To understand a vehicle’s reaction to power, we must understand the vehicle characteristics. Weight, dimensions, motor/controller, wheel (rolling) resistance, wind resistance, etc… The most economical pack is one designed to handle all currents, levels of discharge (load demand) and regeneration, but also a design that stays within voltage tolerance, and exceeds power requirements for range by just enough to be cost-effective.

Keeping the pack operating in shallow discharge/charge cycles not only allows for peak performance of the entire system, but it more than doubles thelife expectancy of the battery pack. Selection of battery pack size depends on how much performance power you are expecting from an EV, and how far the EV is expected to travel each day.

As a benchmark, the LiFeBATT 120V / 30 Ah pack provides 3.6kWh of power. A moderate-sized Electric Vehicle (EV) configured with a 15kWh battery pack, operating at 300Wh per mile, could provide a range of about 50 miles before the need to recharge. As a very basic configuration for an EV, the battery pack should have at least 2 strings of 120 V / 40Ah modules in parallel (120V / 80 Ah) to provide a minimum of 10kWh of power. In terms of economies of scale, the 40Ah modules are the most cost-effective due to an internal configuration that allows one Voltage Monitoring System (VMS) to monitor all the cells in the entire module.

Regardless of the size of the pack, the battery module components will deliver at least 2000 cycles. After 2000 cycles, there is just a 15% loss in overall capacity that can continue to provide power to the EV for operation, resulting in longer term savings and return on investment compared to phosphate batteries.

As far as variances within the modules of the battery pack, we can string together 12, 24, 36 and 48V modules in series at 40 Ah each for the same overall price, in order to achieve 120V total. Adding additional 12V modules onto the series strings can increase pack voltage up to the maximum input rating of the motor speed controller.Adding more voltage to the pack will reduce overall current requirements for the vehicle power train system but continue to provide about the same power over time.

FAQ of Solar PV
1. What is PV?
The photovoltaic (PV) process converts sunlight, the most abundant energy source on the planet directly into electricity. The equipment required for this process has no moving parts and as a result requires minimal maintenance. In addition, the electricity is generated with no emissions and no noise.
A PV cell consists of two or more thin layers of semiconducting material, most commonly silicon. When the cell is exposed to light, electrical charges are generated and this can be conducted away by metal contacts as direct current (DC).
The electrical output from a single cell is small, therefore multiple cells are connected together to provide a more useful output. Cells connected in this way are encapsulated (usually behind glass) to form a weatherproof module or panel.
Multiple modules can likewise be connected together in order to provide sufficient power for common electrical appliances.

2. Doesn't PV technology need bright sunshine to work properly?
The electrical output of a PV cell is dependent upon the intensity of the light to which it is exposed. So PV cells will tend to generate more electricity on bright days than when skies are overcast. However, photovoltaics do not need to be in direct sunlight to work, so even on overcast days a PV cell will be generating some electricity.

3. What applications are there for PV?
PV technology has many applications in Europe, both for stand-alone systems and for integration onto buildings. PV has been used for many years in applications such as monitoring stations, radio repeater stations, telephone kiosks and street lighting to name just a few examples. There is also a substantial market for PV technology in the leisure industry, with battery chargers for boats and caravans, as well as for powering garden equipment such as solar fountains.
In more recent years in Europe, PV has become more widely used in urban areas, where it can be integrated into new buildings or mounted onto existing buildings. This is a rapidly growing market throughout Europe. PV technology is ideally suited to the urban environment, providing pollution and noise free electricity without using extra space.
PV technology is also widely used in the developing world. The technology is particularly suited here, where electricity grids are unreliable or non-existent, with remote locations often making PV power supply the most economic option. In addition, many developing countries have a high level of solar radiation levels year round.

4. How long will a system last?
The average lifetime of a PV module can be in excess of 20 years, crystalline silicon modules in particular have a very long life span. In addition, they require very little maintenance. Other system components will have a varied lifespan, for example batteries in stand-alone systems can last between 2 and 15 years depending on type.

5. How much will I need to power my home?
A typical domestic system of 1.5 kW (for example: in the UK) would produce around a third of the annual demand of an average family household (taking the average demand to be around 10 kWh per day). However, calculating the system size depends on many factors, for example whether the system is grid connected, energy demand of the household etc.

6. How much Power can I expect to get from my PVs?
Typically a 1kWp array will produce 750kWh/year.

7. Why are PVs rated in Wp rather than watts?
Wp means peak Watts. In other words, a 100Wp panel will produce a maximum of 100W in peak conditions (1kW/m2 solar irradiation).

8. Why install a PV system?
There are many reasons to install a PV system:

  • It is the most practical and economically viable option for many applications in remote areas.
  • It is completely pollution free. Installing a small domestic system of around 1.5 kW would provide around 1000 kWh of electricity every year, this would save around half a tonne of CO2 annually.
  • PV can be integrated into the fabric of a building.
  • Electricity can be supplied at the point of use.
  • The system will run silently.
  • There is very little maintenance required for a PV system.
  • After the initial installation costs, there are no further fuel costs.
  • PV systems are modular, and can be added to at any time.

FAQ of chargers/inverters/converters
1. Can T&W chargers/inverters/converters be used in the range of 45Hz ~ 440Hz? If YES, is there anything special will happen?
These can be used within this frequency range. But if the frequency is too low, the efficiency will also be lower. For example, when operated under 230VAC and rated load, if the frequency of AC input is 60 Hz, the efficiency is around 84%; however, if the frequency of AC input reduces to 50 Hz, the efficiency will be around 83.8%. Besides, if the frequency is too high, the power factor with PFC (power factor correction) function will reduce and this also will cause higher leakage current. For example, when operated under 230VAC and rated load, if the frequency of AC input is 60 Hz, the power factor is 0.93 and the leakage current is around 0.7mA; however, if the frequency of AC input increase to 440 Hz, the power factor will decrease to 0.75 and the leakage current will rise to around 4.3mA.

2. During the operation of T&W's chargers/inverters/converters, there is some leakage current on the case. Is this normal? Will this leakage current hurt human body?
Due to the requirement of EMI, there will be some Y capacitors between line and neutral to the FG (case) to improve EMC. These Y capacitors will cause some leakage current from line or neutral to the case (normally case will be connected to earth ground). For example, IEC-60950 requires that this current should less than 3.5 mA for information equipment, so basically the leakage current you find on the case will not hurt human body.

3. Why my chargers/inverters/converters shuts down during operation and after turning it off, I can restart them again?
Generally there are two circumstances that they will be shut down. One is the activation of the over-load-protection (OLP). To deal with this situation, we suggest increasing the rating of the output power or modifying the OLP point. The other is the activation of over-temperature protection (OTP) when the internal temperature reaches the pre-set value. All of these conditions will let them enter protection mode and shut down. After these conditions released, they will be back to normal.

4. Will T&W's products with CE marking meet the EMC requirements without fail after assembling into my system?
We cannot 100% guarantee that the final system can still meet the EMC requirements. The location, wiring and grounding of the chargers/inverters/converters in the system may influence its EMC characteristics. In different environment or applications, same chargers/inverters/converters may have different outcomes.

5. Can we charge the lithium battery with a universal charger?
No, the charger of the lithium battery required with a CC/CV charging mode, generally also equalizing charger.