Installation Guide

Classic owner’s manual (continued)
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Explanations of Solar and Legacy
Solar
This is the default mode for PV systems and has a very fast sweep (typicallya half of a second or less) that
will re-sweep at user adjustable sweep intervals, unless the Classic finds that it needs to do a sweep on its
own because of changing conditions. The timed sweep interval is user adjustable and is in units of
minutes. SOLAR mode is typically best for PV systems, especially if there is partial shading at times
during the day. SOLAR mode is best suited for shaded or un-shaded PV arrays that are at least one
nominal voltage above the battery voltage. For severe partial shading or PV arrays with nominal voltage
equal to battery voltage, you may also want to try Legacy P&O (Perturb and Observe) MPPT mode.
Legacy P&O
Legacy P&O (Perturb and Observe) mode is a slow tracking mode similar to the Micro Hydro mode but
with the difference that it is slightly faster and optimized for Solar. Legacy mode can be very useful for
arrays that experience heavy shading issues as well as PV arrays that have a low voltage. If the array has a
VOC (Open Circuit Voltage) of less than 125% of the battery voltage, Solar mode will not work as well so
Legacy will be a better choice.
Uploading New Firmware to the Classic
The Classic has the ability to have its firmware updated with a standard USB cable and a Windows based
PC. The USB cable is Standard to Mini B. Please see www.midnitesolar.com and click on the Software tab
for the firmware and instructions. Due to the various different Windows configurations we will not go into
detail in the Classic Manual. The Firmware upgrade is fail safe so if the wrong code is installed the Classic
simply says “Wrong code” prompting you to load the correct code. Also if the upload is interrupted for
whatever reason simply start over.
WARNING ! The Classic's USB port is NOT isolated from battery negative. This is typically only an issue on
positive ground systems or systems with a tripped ground fault protection device. Care must be taken that a
computer connected to the Classic's USB port is either isolated from ground and the Classic's negative or
that the computer's USB negative is common with the Classic's negative and ground.
WARNING ! You cannot turn a Classic 150 into a Classic 200 for example using new software the internal
components are also different.