Installation manual

4.4.3. Keep your PLT/TRG turbine as low as possible

Maximise the head, but do ensure that it is above maximum river flood level.

Your PLT/TRG turbine should also be positioned at least 50-100 mm above ground height to

allow exhaust water to escape. Choose a site where the exhaust water can be returned

back to the river cleanly.

4.4.4. Place it as close to your battery bank or point of grid connection as

possible,

The cost of the cable is important, although cost depends on the chosen voltage. A low

cable voltage means that a short, heavy cable is desirable.

The distance between your turbine and batteries has a significant bearing upon the cable

size required. To keep cable size (and hence cost

) down we usually recommend that off-

grid clients who are not using MPPT choose 48-volt battery systems rather than lower

voltage. In such cases we generate a voltage at the turbine about 5% higher that your

battery voltage (due to voltage sag in the cable). Turbine sites up to 500 m away are often

economically viable using 2-core aluminium cable.

Using an MPPT controller offers the opportunity to reduce the cost of the cable by

generating at a higher voltage. For example the PowerSpout PLT80 generates and

transmits at about 80 V DC cable voltage to a Midnight Classic 250 MPPT controller close to

your battery bank. If you have a 24 V DC battery bank this can reduce the cost of the cable

by up to 80%. The controller changes the voltage to suit your 12/24/48 V DC battery bank.

One benefit of this approach is that existing 12/24 V DC systems can be cost effectively

integrated with the PowerSpout PLT/TRG/LH. For example, solar PV systems can struggle

in winter time when you have viable stream flows. Adding a PowerSpout to your system can

often eliminate the need for fossil fuel generation support, as solar and hydro resources tend

to complement each other.

4.4.5. Hydro turbines do make some noise, so keep them at least 30 m from

your home.

Some clients have installed turbines too close to their homes. Measured noise levels are

listed section 19

Generally the higher the head the more noise from the unit. At our test site at 160m head

and 1.6 kW you can talk normally standing by the turbine, but you are very aware it is there.

You can just hear it at 30-40m away. It sounds like a washing machine in spin.

On low head sites less than 10m (30ft) the river is likely to make more noise than the turbine.

A turbine can be closer to a dwelling in such cases. Vegetation around the turbine will

dramatically reduce the distance that noise carries.

4.5. Connecting two small streams into one PowerSpout

We are often asked if two small streams can be piped into a common turbine. This is not

recommended, unless the head and pipe friction losses for each pipe are very similar.

Generally we would advise two turbines, one for each site. The electrical output of both

could then be joined together into a common supply cable, but only for PLY/TRG 12/24/48

VDC turbines. If you want to use MPPT then you will need a wire for each turbine.

EcoInnovation holds considerable stocks of cable at very good prices for our NZ customers