Installation manual
© 2014 EcoInnovation Ltd (NZ) Page 53
600 V DC input units
XW MPPT 80- 600 Solar
(24 & 48 V DC output)
TriStar MPPT 600 Volt
Solar
TriStar MPPT 600 Volt Solar
with DC disconnect
In selecting an MPPT controller you need to carefully consider the following points:
Maximum DC voltage rating
Current rating (Amps)
Cost of MPPT controller
Cost savings in the size of power cable needed to connect your PowerSpout at this
voltage
Programmable "auxiliary" relay(s) to divert surplus power to a hot water tank
MPPT tracking stability when used on PowerSpout hydro turbines
Does the manufacturer of MPPT controller give a warranty for hydro input?
Approved by the makers of the MPPT unit for hydro connection
Approved by the makers of the PowerSpout turbines for connection
Local support and warranty for the MPPT unit
Although many MPPT products will work, some of which are listed above, the issue is
normally the lack of warranty for the MPPT controller offered by the manufacturer or lack of
knowledge of the product when connected to PowerSpout turbines.
When using a MPPT tracking charge controller an additional backup controller is not
required for safety as they tend to fail safe. The turbine will become disconnected and run in
overspeed. The battery will not usually be over-charged in the event of failure.
If the turbine Voc is close to or above the controller's rated maximum then overvoltage
protection using our optional 75/120/140/240 VDC crowbar (called a Klampit) will be needed.
In such cases you need to verify that the controller (or an auxiliary relay load) will keep the
turbine voltage low enough in normal operation to prevent nuisance tripping of the crowbar.
Long DC cables are reactive and do not behave as a solid unchanging link, you can get a
sort of whip action where a small change at one ends gets amplified at the other end, it is
similar to resonance in mechanical systems that most readers can relate to. On long DC
cable runs it advised that you have a 40V difference between the Klampit trigger voltage and
the nominal MPPV and that very fast load switching is employed. For example
PLT/TRG100C (with 140 V Klampit fitted) or PLT/TRG80C (with 120 V Klampit fitted)
combine Midnight Classic MPPT regulators and high speed switching features on the input
side generally work very well. Refer to 2014 Technical Manual for more information.
5.7.5. Battery voltage options for MPPT controllers
We have noticed a trend by hydro manufacturers to approve MPPT controllers
without any voltage limiting control in the turbine or good advice in their
manuals on how to do this safely. Our standard PLT/TRG turbine (without extra