1 2 3 - Torqeedo

Background knowledge on calculating the range of electric motors:
The range and runtimes that can be achieved using electrical drives with specific battery supplies are calculated in four steps as
follows:
1. Calculation of the existing battery capacity: To calculate this, the power of the battery (in volts) is multiplied by the charge
(in ampere-hours). A 12 V battery with 100 Ah therefore has, e.g. a capacity of 1,200 watt hours (Wh), while two batteries
connected in parallel with a total of 24 V and 75 Ah each have a capacity of 1,800 Wh.
2. Calculation of the required amount of energy: The input power required by the motor is considered in the next step.
The BaseTravel 401 has, e.g. an input power of 400 watts. 400 Wh are therefore required for one hour runtime at full power.
3. Calculating the range: An initial range can be calculated taking into account the speeds that can be achieved (compare the
graphic on Page 25). For example, on a dragon sailing boat the BaseTravel 401 reaches a speed of 3.5 knots (6.5 km/h).
With one 12 V battery at 100 Ah (resulting capacity of 1,200 Wh) it could therefore run in theory for 3 hours at full speed and
cover a distance of 10.5 nautical miles (19.5 km). The range calculation for a 1,200 Wh lithium battery power supply would
now be completed.
4. Taking into account the lack of high-current resistance of lead batteries: Lead batteries have a relatively low resistance to
high currents, i.e. their capacity drops significantly under their nominal capacity as soon as a consumer tries to draw higher
currents from them. To calculate a realistic range, this effect must also be part of the calculation. If the appropriate
specifications on high-current efficiency are not published in the data sheet of the battery then the diagram on Page 9 may
provide you with assistance. To do this, the weight of the battery must first be determined, e.g. the weight for the 12 V
battery at 100 Ah in the example above may be 40 kg. If there is a power consumption of 400 W by the motor then there would
be a high-current load of 10 W per kg of battery weight. The loss in effective capacity of the battery resulting from this can
be estimated from the graph and should be less than 20% in the example, depending on the quality of the battery. The range
that could therefore be actually achieved would then be approximately 8.4 nautical miles (15.6 km). Two rules can be derived
from this calculation: Firstly, especially motors with a high input power require large lead battery banks to achieve reasonable
distances. Secondly, drives with bad efficiency waste battery capacity in two ways: On the one hand, they do not sufficiently
convert the used energy into propulsive power. On the other hand, they cause unnecessary high-current loads to the battery,
whereby less capacity is available to be used.
Technical Data
BaseTravel 401 S BaseTravel 401 L BaseTravel 801 S BaseTravel 801 L
Input power in watts 400 400 800 800
Rated power in volts 12 12 24 24
Propulsive power in watts 168 168 336 336
Maximum overall efficiency in % 42% 42% 42% 42%
Static thrust in kf 18 18 31 31
Total weight in kg 8.9 9.5 9.1 9.7
Maximum shaft length in cm 59 71 59 71
Integrated battery no no no no
Propeller dimensions in inches 12 x 10 12 x 10 12 x 10 12 x 10
Propeller speed at full power in rpm max. 720 max. 720 max. 720 max. 720
Control Tiller-control Tiller-control Tiller-control Tiller-control
Steering 180° lockable 180° lockable 180° lockable 180° lockable
Tilting device manual manual manual manual
Trim device manual, 7-step manual, 7-step manual, 7-step manual, 7-step
Stepless drive forwards/reverse yes yes yes yes
Additionally preset speeds yes yes yes yes
24 Catalogue 2007