The Epever works as follows,
When it wakes up it charges at the maximum power the panel can give until the battery volts equal
Boost Volts.
It then holds the battery at a constant voltage, the boost volts, for the
Boost duration
At the end of Boost duration, the voltage drops to
Float Voltage
If the battery volts drop below
Boost reconnect volts, it starts the charge cycle again.
The settings on the Epever relate to the both charge control and to the load outputs. Settings related to the load outputs are shown in italics. The load outputs are not normally used and never with inverters.
Over volts disconnect voltage: if the battery volts exceed this , the load outputs disconnect from the load from the battery.
Charging limit voltage: if the battery volts exceed this, charging the battery from solar is stopped.
Over Voltage reconnect voltage: if the load outputs have been disconnected due to the battery exceeding over voltage, a reconnect will occur at this value.
Equalize charging voltage: this is applicable to lead acid batteries only, where a higher voltage than normal is applied for a period. Not used for lithium, set to equal to boost volts (as a safety measure) and set equalize duration to zero.
Boost charging voltage: the controller will charge the battery at maximum power from the solar panels, bulk charge, until this value is reached. At all times before this 'target' voltage is reached the maximum power control process will will try to 'pull' maximum power from the panels.
Float charging voltage: once the boost duration at constant voltage has been completed, the controller will hold a constant float voltage at the battery.
Boost reconnect charging voltage: once the unit is in float mode the voltage may vary due to solar conditions and any load on the battery, if the battery voltage falls below this value the controller re enters the bulk boost stage.
Low voltage reconnect voltage: if the load outputs have been disconnected due to a low battery, this voltage is the turn on value.
Under voltage warning reconnect voltage: warning turned off at this voltage.
Under voltage warning voltage: warning set at this voltage.
Low voltage disconnect voltage: load outputs are disconnected from the battery at this voltage.
Discharging limit voltage: other than issuing a warning at the set voltage the stand alone unit cannot do anything about this.
Equalize Duration: the time duration for the equalisation process, only applies to lead acid batteries. Set to
zero for lithium.
Boost Duration: once the battery voltage reaches the target voltage, boost voltage, the controller holds the voltage constant for the boost duration.
Lithium settings
Its considered that charging to a lower target voltage is less stressful and will give a longer service life.
Any voltage over 3.4 volts per cell will charge to around 80%, 3.45 volts per cell to over 99% (13.8 v for a 12v battery, 27.6 for a 24 volt battery)
Holding the battery at a voltage higher than the resting voltage is also considered stressful, thus the float should be at 3.4 as a maximum, slightly lower at 3.35 would be better .
Boost duration is not needed in most small systems where the charging current is low compared to battery capacity.
Set to zero or a short duration, say 15 minutes.
Because lithium charge acceptance can be changed dramatically by small voltage variations and the variability of calibration settings in equipment, the actual voltages used may have to be adjusted slightly.
These are the settings I use on small hobby systems.
12v systems,
boost charging voltage,
13.8 to 14.0 volts
boost
duration, zero
float charging voltage.
13.35 to 13.45 volts
boost
reconnect volts
13.30 ( reconnect slightly lower than float
)
equalise charging voltage = boost charging voltage
equalise duration = zero
24v systems boost 27.6 to 28 volts, duration =zero, float= 26.7 to 26.9 volts, reconnect = 26.6 volts
Once you have the MT50 its possible to easily change parameters under
User settings
For lithium you don't need temperature compensation so set this to 0 mV/deg
see,
Greetings All, I am having an issue with MT50 controller connected to my Tracer-4215 BN, the issue is getting some of the values to work or rather be set inside the controller. I have been able to set the time and date as well as the optional light feature. In addition I have been able to set...
diysolarforum.com
Mike