15
Extended Diversion Mode -- EDM
The basic operating philosophy of a diversion controller is quite simple. Monitor the battery voltage, and if it should
rise to a predetermined level, connect a diversion load of sufficient size, to the battery or energy source to prevent the
battery voltage from increasing any further. The amount of time the diversion load is connected is generally only 2 to
30 seconds. In this amount of time, the battery voltage will have dropped enough to be back in the normal region. The
controller will continue to engage and disengage the solenoid as often as necessary to prevent battery overcharge. This
is the normal mode of operation. The microprocessor uses several advanced algorithms to prevent rapid relay cycle,
yet it is common for the solenoid to be engaged and disengaged a few times per minute. This constant attention keeps
the batteries very close to (or just below) the trip point you have set.
There are however, situations where you would really like the controller to engage the solenoid for a longer period of
time once the batteries get to a “full” state. This is what we call the Extended Diversion Mode. On the HVA and
previous analog controllers, the EDM mode was selected via a jumper. On the HVAD, which is fully digitally
configured, the EDM “mode” (to continue with the HVA legacy) can be configured much more specifically via the
user menu options (advanced menu). Via this menu option, you can set both the minimum time the relay should stay
engaged as well as how low the batteries will be allowed to drop (percentage based). Once the batteries reach the
upper trip point you have set (the same trip point as the non EDM mode), the controller will engage and disengage the
solenoid based on these advanced parameters. See the menu system in this manual for more information on how to
configure these settings.
The EDM mode is very useful for running such items as water pumps, small grid tie inverters, or even alt-currency
mining that you do not want turning on and off every few seconds. When you configure the EDM mode, the wiring
remains the same; the difference is that the load you connect will be engaged for a longer period of time.
It is very important that the load you choose is 100% dependable if this controller is being used to prevent battery
overcharge. If the load is not present, then your batteries will overcharge. Grid-tied inverters will not provide a load ti
to the controller if the grid fails (power outage due to thunderstorm etc.). Such a loss of load can also cause damage to
your wind turbine if it depends on this load.
If you will be using the EDM mode with a load that may not be present at all times, then it is important that you have
another controller in parallel that is also monitoring the system with a slightly higher trip point. This second, failsafe
controller will then divert the excess energy to a diversion load that is 100% dependable should the 1
st
controller’s
load not be present or capable of disbursing all of the excess energy.
As in the case with the normal mode, the load you connect cannot exceed the capacity of the solenoid. Do not attempt
to hookup highly inductive loads, as the solenoid will be damaged due to high currents during the motor start.
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