31 Investigation of the Behaviour of a New Nanogrid Concept …
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decision. If there is something scheduled for a given time there are more factors
to take into account during the decision. The SOC of the devices battery and the
remaining time to the event are the basic informations and an estimation should be
made when to start to charge the battery to get a fully charged battery before the
event starts.
According the provided informations the result of the decision can be the
following:
• offering energy for other nanogrids
• charging the nanogrids battery
• charging the devices batteries
• charging the nanogrids and devices batteries
• claim energy from other nanogrids or the network
For the correct time calculations the controller needs an estimation on the power
produced by the PV cells and the charging characteristics of the different batteries.
31.4 Battery Charging Measurements
31.4.1 Power Needs for Different Devices
A usual laptop power supply is 45 W to 65 W in power. The battery capacity is in
the range of 55 Wh to 85 Wh usually. The battery of smartphones are in the range
of 10 Wh to 15 Wh where the power supply is 5 W to 10 W of rated power.
The battery charging is done in the devices which also means that the devices can
be used during charging. It means that the power necessary for charging is just one
part of the rated power of the power supplies, the other part is the power consumption
of the working device. The power consumption of the device is depending on the
type of actual usage, e.g. using a word processor or running a simulation means a
significantly different load for a laptop.
31.4.2 Charging Characteristics of Different Batteries
To get information about the batteries measurements of charging during device
usage were performed. The measurements were done for different initial SOC of
the batteries and for different usage of the devices during charging. On Fig. 31.2.
two different measurement result can bee seen. The horizontal axis is time (hours
and minutes), the vertical axis is the consumed power (watt).
We can observe the two different stages of charging, the constant current charging
and the constant voltage charging. By the orange line (the 50% initial SOC) the change
from the constant cuurent charging to the constant voltage charging is occured at
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decision. If there is something scheduled for a given time there are more factors
to take into account during the decision. The SOC of the devices battery and the
remaining time to the event are the basic informations and an estimation should be
made when to start to charge the battery to get a fully charged battery before the
event starts.
According the provided informations the result of the decision can be the
following:
• offering energy for other nanogrids
• charging the nanogrids battery
• charging the devices batteries
• charging the nanogrids and devices batteries
• claim energy from other nanogrids or the network
For the correct time calculations the controller needs an estimation on the power
produced by the PV cells and the charging characteristics of the different batteries.
31.4 Battery Charging Measurements
31.4.1 Power Needs for Different Devices
A usual laptop power supply is 45 W to 65 W in power. The battery capacity is in
the range of 55 Wh to 85 Wh usually. The battery of smartphones are in the range
of 10 Wh to 15 Wh where the power supply is 5 W to 10 W of rated power.
The battery charging is done in the devices which also means that the devices can
be used during charging. It means that the power necessary for charging is just one
part of the rated power of the power supplies, the other part is the power consumption
of the working device. The power consumption of the device is depending on the
type of actual usage, e.g. using a word processor or running a simulation means a
significantly different load for a laptop.
31.4.2 Charging Characteristics of Different Batteries
To get information about the batteries measurements of charging during device
usage were performed. The measurements were done for different initial SOC of
the batteries and for different usage of the devices during charging. On Fig. 31.2.
two different measurement result can bee seen. The horizontal axis is time (hours
and minutes), the vertical axis is the consumed power (watt).
We can observe the two different stages of charging, the constant current charging
and the constant voltage charging. By the orange line (the 50% initial SOC) the change
from the constant cuurent charging to the constant voltage charging is occured at