Forgen Ventus 70
After buying a Forgen Ventus 70 wind generator, Jens Havskov reports back with his findings
Our Fisher 30 has several solar panels, but when sailing to Portugal last November I felt that they didn’t provide quite enough power, so I started to contemplate fitting a wind generator. Considering the boat’s size, a vertical-axis generator seemed ideal: these require little space and are quiet.
However, it is well known that vertical-axis wind generators provide little energy compared to the traditional horizontal-axis wind generators. Forgen (now taken over by Proelectric) has a new model, the Ventus 70, which looked very promising. At a wind speed of 6m/s (11.7 knots), the new model is said to generate 18W. This is quite respectable: an Aero4Gen, a much-used small traditional generator, gives 25W at the same speed. Wind tunnel tests are one thing, and real-life usage tends to be rather different: nevertheless, the specs looked sufficiently good that I decided to buy a Ventus 70 at a cost of £620. The generator arrived in February, which turned out to be a very windy month – ideal conditions for testing purposes.
Installation
The generator was mounted near the top of the mizzen mast, 6m above sea level. The generator faces forwards, so it will rarely be directly shielded by the mast under normal sailing conditions.
Measurements
wind speed measurements were therefore corrected by subtracting 2m/s from the masthead speed.
Electrical connection
The three-phase generator was delivered with an MPPT regulator which also contained the rectifier. To eliminate the effect of the regulator, tests were done with the generator connected to a three-phase bridge of diodes.