Installation manual

If you intend to run a PLT turbine on a MPPT controller/inverter you must:

 Tell us prior to ordering

 Have an accurate measure of the head of your system

 Check runaway Voc (with various numbers of jets) prior to hook up

Cable run up to 1000m can be affordable at higher operating voltages.

5.7.10. Future trends

As the cost of MPPT controllers falls we will see a move towards more MPPT regulation, for

the following reasons:

 MPPT controllers are generally fail safe, unlike PWM controllers

 Clients have less time/inclination to manually optimise the turbine, so automatic

optimisation is great.

 Professional installers prefer a ‘plug in and go’ solution that MPPT controllers offer.

 You will generate more power from your PowerSpout turbine because of improved

efficiency.

 Cables can be smaller at higher voltage.

MPPT controllers do require a higher level of knowledge and expertise to set up

correctly relative to PWM type diversion controllers.

We are also starting to see off-grid MPPT controllers that can operate at up to 600 V DC,

though this is still relatively new with few products on the market. This may soon result in

PLT turbines charging 24/48 V DC batteries with a cable voltage of up to 200 V DC and no

need for extra voltage protection.

5.8. Water and air diversion resistors

Many of the wiring schematics (Section 6.5) show air and/or water diversion elements. The

heaters are used for 2 main purposes:

 To convert energy not needed for battery charge into useful heat (or dispose of it

safely)

 To keep MPPT system voltage stable once batteries are fully charged

PWM controllers must have diversion loads connected to them so that they can regulate the

battery voltage to a safe level. These loads need to be suitable for the DC voltage at which

the battery is fully charged (for example 56VDC for a 48V battery). The heater will often

make a buzzing noise in operation due to the current pulses from the PWM.

For MPPT controllers a diversion load is optional but highly

recommended; you may as well benefit by using surplus generation in

your hot water cylinder. If you do not fit a diversion load your hydro

turbine will speed up by about 30-50% once the batteries are fully

charged resulting in a little more noise and wear on the bearings.

Typical hydro systems often produce much more daily energy than the

battery needs to meet daily usage, and it's a waste not to divert this into

useful heating.