Manual

24 | P a g e
Temperature Current Limit
The Classic has a current limit component which interacts with the temperature of the charge controller.
If the Classic is exposed to extremely hot ambient conditions the output current will be reduced
automatically to keep the charge controller safe, if the orange LED comes on, on the MNGP it means
that the Classic is in current limit mode. If you believe the Classic is not hot and the orange LED is on,
most likely the current limit set point is too low. To check this follow steps bellow.
 Press Main Menu
 Highlight the CHARGE menu and press the Enter Button
 Scroll to LIMITS and press the Enter Button
 Press the right arrow key to highlight Out Amps column
 Use the up and down arrow keys to change the current limit then press the Enter Button to save
this data
Over Current Protection
The Classic must have over current protection to protect wiring from over current events. A means of
disconnect must be installed on the DC in and DC out of the Classic. Consult your local codes to
determine over current ratings. The breaker between the battery bank and the Classic must conform to
UL489. The breaker between the DC source and the Classic must conform to UL1077 or UL489. The
NEC requires 1.56 times short circuit current for PV over current protection. This is reduced to 1.25
times when using a breaker rated for continuous duty. All MidNite Solar breakers are
hydraulic/magnetic and are rated for continuous duty. No de-rating is required for the output breaker
when using MidNite Solar breakers.
PV in particular will be capable of producing more current than its name plate rating in extreme
situations so the safe minimum wire size should be selected for the PV array maximum short circuit
current. Please consult PV manufacturer for specifications. The US National Electrical Code requires
1.56 times the PV short circuit current for wire size on the PV input. Output wire size follows the NEC
guidelines. Typical wire size for output is 6AWG for the Classic250 and 4AWG for the Classic200 and
150 but check all de-ratings for your wire type and installation method.
Long Distance Wire Runs
The Classic offers some unique opportunities if you are faced with longer than normal wire runs
between the DC source and the Classic. The Classic comes in 3 input voltage ranges letting you design
a DC source at a higher voltage if it is beneficial. For example let‘s say you have a 300 ft run from a
PV array to the Classic you could wire for an open circuit voltage close to 250vdc accounting for the
coldest temperature you will encounter. This will allow you to run a smaller gauge wire than with a
lower voltage charge controller. The efficiency of a high voltage Classic is less than the lower voltage
versions, so you need to weigh the benefit. If this sounds too complicated use this rule of thumb in
selecting the proper Classic. PV runs up to 100 feet, use the Classic 150. Runs up to 180 feet, use the
Classic 200. Above 180 feet use the Classic 250.
If the wire size between the DC source and the Classic is larger than the Classic's DC terminal
connector you can use a splicer block or similar connector to reduce down to #4 AWG close to the
Classic. The MidNite E-Panels are supplied with a PV input busbar that accepts up to 1/0 wire.