18
7.2 Maximum discharge current
A maximum discharge current is defined for the Evolion module. This maximum level optimizes the useful life of the Evolion and
particularly for frequent cycling applications. If the maximum re-charge current (with some included tolerance) is ever encountered by
a module, it will automatically stop the discharge (alarm #24) from continuing by opening the electronic switch (mosfet). See section
Safety limits during operation for more details.
IMD is the maximum discharge current.
The Figure 8 shows the maximum discharge current in the operating temperature range.
Each module measures and controls its own maximum discharge current protection.
See section Thermal characteristics for more details about current limits associated with module temperature.
Figure 8. The maximum discharge current of the Evolion as a
function of module temperature.
7.3 Low voltage disconnect
A low voltage disconnect will open the electronic switch (mosfets) when the module voltage decreases to 42 Vdc. When actuated, the
module continues operation in safe mode. In safe mode, the module is awake (voltage at the terminals, LED’s operating, RS485 active,
etc.) and waiting for AC power to return when it will accept the charge current available from the rectifier output. In the safe mode, the
module will consume 65 milli-amps while remaining awake and waiting for the rectifier output.
Eventually, the module will transition to sleep mode, if one cell ever decreases below 3.0 V for more than 3 hours while in safe mode,
and in this case the internal electronic load is minimized (120 micro-amps). This prevents a higher internal electronic self-discharge
rate which forces cells to decrease below a critical low voltage too fast. In the sleep mode, the module will automatically wake-up and
begin nominal mode operation when the charger/rectifier power returns.
Important note: If the module turns OFF by reaching the low voltage disconnect (42 Vdc), it is necessary to begin re-charging within 14
days. The module may become damaged due to cell over discharge and in that case it will need to be replaced.
Module temperature (ºC)
(ºF)
IMD (Amps)
-40 -30 -20 -10 0 10 20 30 40 50 60 70
-40 -22 -4 14 32 50 68 86 104 122 140 158
50
45
40
35
30
25
20
15
10
5
0
Internal heater operation
IMD
Содержание evolion
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