Installation manual

PowerSpout turbines have been tested for compatibility with a number of MPPT

inverter/controllers and results are available on the website. This list is anticipated to grow as

testing continues so please check the website www.powerspout.com/compatibility for

updates. More information on MPPT regulators is included in the 2014 Technical manual.

2.5. Cable voltage

You need a cable to carry the DC power from your turbine to your point of use. This cable

will waste some power, depending on the current it carries and the size and length of the

wire. A heavier wire will always be more efficient but for long cable runs the cost can

become significant. Using a higher voltage can help to dramatically reduce the size of wire

and the cost. This is one reason for using a 48 V battery rather than 12 V. But with MPPT

you may be able to use higher voltages and make further savings. See section 5.7 for a

discussion of different MPPT controllers and their voltage parameters.

2.6. AC coupling

It's possible to use a 'grid-tie inverter to connect your PowerSpout to an off-grid battery-

based inverter's output wiring, if it is suitable for such connections (for example SMA,

Outback, Victron and many others). This option is useful for larger systems with long wire

runs and a high AC power demand. The grid-tie inverter is actually quite similar to the

MPPT controller, except that it feeds the AC side of your power system. Your battery is

charged via the main inverter working backwards when there is surplus energy. This is an

advanced application of the PowerSpout that is not covered fully in this manual but we

mention it for completeness. For more information on AC coupling refer to the 2014

Technical manual.

2.7. Over-voltage protection or not?

Hydro turbines that are not connected to anything that harnesses their power will overspeed

and produce 2-3 times higher voltage than their operating (Maximum Power) voltage. This

"open circuit" voltage or Voc can be a danger to equipment in some cases, although not

always. If you are working at a high cable voltage or your controller has a low Voc rating

then you may need to use one of our Klampit "crowbar protection" circuits to safeguard your

equipment. See section 5.3.3.

2.8. Using surplus energy

Hydro turbines can produce a lot of energy at times when you do not need a lot of electricity

and your batteries may already be full. A diversion load controller will burn this excess off as

heat which can be used to heat water for domestic use.

It is much cheaper in capital cost to store heat in a water tank than it is to use a battery to

provide heating. "On demand" heating should be used with caution. Electric kettles,

induction hobs etc can work well on off-grid renewable energy systems, but the user needs

to monitor the battery voltage prior to use. Discharging the battery excessively and

repeatedly will shorten its life.

MPPT controllers can offer this heating benefit via external load relays, automatically

operated by their auxiliary relays. In some cases it's important that the energy is safely

disposed of, or your batteries or equipment may suffer, but with care you can direct this

energy to useful ends and save burning propane or other fuels.