User and installation manual

ManualsBrandsFlexcharge ManualsCharge ControllersNC25A Charge Controller 25A – 24V

Page 7 of 23

a) Connect an accurate digital voltmeter on the terminals of the battery you are charging.

b) If you are only checking the unit, skip this step, and step "d". Turn the adjustment most of the

way towards "+". The dot in the case near the adjustment is the factory setting of 2.375V per cell.

Continued

c) Watch the voltmeter for the highest voltage you wish the batteries to charge to.

d) SLOWLY turn the adjustment towards "- " until the DIVERT indicator comes ON (steady red

or orange).

e) Allow the controller to cycle a few times while watching the voltmeter, and fine tuning the

adjustment for the exact upper switch voltage you desire. Remember the controller will

switch ON and OFF (Charge to Divert then back to Charge) while you are performing this test,

and if it is switching too fast your voltmeter readings will be inaccurate which could cause

you to set the controller at the wrong voltage.

Easier Calibration Method

Note: The peak voltage setting on the NC25A is set to 2.375V per cell (14.25V for 12V systems only) at

the factory. This voltage setting is ideal for sealed gel batteries that recommend a 14.10V constant

voltage setting (see the charge process graph). The factory setting will also work with vented lead acid

and AGM batteries, however setting the peak voltage at 14.35V will give the batteries a more active

charge. You may use the method described in step 6, or an easier way may be to start your engine,

and allow the engine alternator to charge your batteries up to about 14.4 volts. Then simply turn the

adjustment on the NC25A towards "+" until the DIVERT light turns OFF then slowly turn it back until the

DIVERT light comes ON. The NC25 will now regulate the battery voltage at the same voltage as your

engine alternator, which is usually about 14.4V

Coat the battery's terminals with battery terminal grease to prevent future problems caused by

corrosion.

NC25A controllers are available for 12, 24, 36, 48 volt systems with charging capacities of, 60 & 100

amperes. Special order units with 60 ampere up to 2000 ampere charging capacities.

For more information call your dealer or Flexcharge

USA at 231-547-9430

Visit our Web Site:

www.flexcharge.com

Description of Multi Function Indicator Operation

Indicator Function Description Charge Indicator Not Used Charge Indicator Used

Charging

(Battery Voltage Is Above 11V)

none

STEADY Green

Charging

(Battery Voltage Is Below 11V)

FLASHING Red

FLASHING- Green to Orange

Not Charging

(Battery Voltage Is Below 11V)

FLASHING Red

Charge Divert

STEADY Red STEADY Orange

Not Charging

(Charging Source is NOT Making Power &

Battery is Above 11V)

none