Flexcharge NC25A Charge Controller 25A – 24V


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Product information

The Flexcharge NC25A is a high efficiency charge controller for solar and wind energy systems with a maximum charging rate of 25 Amps. It works with lead acid GEL, AGM, and flooded cell deep-cycle batteries; it also works with wet cell NiCad batteries.

The NC25A is a series controller designed for alternative energy charging systems ranging in size from 0.1A to 25A.  It is the ideal regulator for Solar (PV) and Permanent Magnet Generators (Including outboard motors and smaller wind generators). The NC25A also includes a Charge Divert feature.  Charge Divert allows you to use the excess charging source energy for other tasks, or for placing a load on permanent magnet charging sources such as wind generators to prevent over speed conditions.

The Divert connection is only activated after the charging source is making energy and the batteries are not using the energy (i.e. A wind generator will not be starting into the divert load). This charge controller can easily and inexpensively be expanded to handle one or more banks of 100A charging sources. Multiple battery banks can be charged with the use of a standard battery charging isolators. Please see page 21 in the manual.

The NC25A includes easy to read Charge and Divert Indicators, an adjustment for peak charge voltage, and an easy to use terminal strip for the system wire connections.  Because the system charge controller is usually located near the battery bank in a remote structure we chose not to incorporate power consuming monitors such as volt meters or current monitors. If this type monitoring equipment is desired it should be installed after the system disconnect switch and located where you can view them.

Features off the Flexcharge NC25A charge controller:
- 5 year warranty.
- Completely sealed electronics for marine or outdoor mounting.
- Low Battery Voltage indicator (flashing red light).
- Arc reduction circuitry to eliminate or reduce relay contact wear.
- Charging efficiency better than 99.50% from 0.5a to 30a of charging current.
- Operates efficiently (98%) with as little as 0.1a of solar panel charging current.
- Efficiently charges batteries from 0 volts with full power.
- 25 amp charge capacity.
- 25 amp charge divert circuit.
- Diverts only when voltage and current are at usable levels. perfect for motor type divert loads (fans, pumps, etc...)
- Peak charge voltage adjustment with a range of 13.8v to 15.9v (multiply by 2,3,or 4 to find voltages for 24v, 36v, or 48v versions).
- Charges with the same high accuracy through battery isolators.
- Consumes less than 5ma (0.005a) while charging and at night (2ma if you do not use the charge indicator).
- Charges batteries at full power, below the plate saturation point, this charges batteries faster, and reduces electrolyte depletion by up to 90% over conventional constant voltage, pwm, & high frequency charge regulators.
- Batteries start charging at 0.005a of charge current.
- Controller can withstand open circuit input spikes of 1500v/a, & 140v continuous without damage.
- Reverse polarity and transient voltage protection on the battery sense wires.
- Remote battery voltage sensing so the controller can be mounted anywhere between the charging source and the batteries.
- Easy to install using the labeled corrosion resistant nickel / brass / stainless steel connector.

NC25A-24 Operating Characteristics
Flexcharge NC25A-24
Charge Input Voltage: 0Vdc - 140Vdc
Allowable Battery Voltage on Sense Wires: 0Vdc - 32Vdc
Standby/Operating Current of the Controller: 2mA - 7mA
Charging Amperes: 0.005A  - 25A
Total Charging Efficiency: 98.9% - 99.8%
Case Dimensions: 4"W x 3.75"H x 1.5" D

Download datasheet

Flexcharge NC25A

User and installation manual for Flexcharge NC25A Charge Controller 25A – 12V

Download datasheet
Sizing guide

Quick guide for selecting the right charge controller

Each time you charge deep cycle batteries with solar panels, it's necessary to use a charge controller in the circuit to protect the battery from over charging, and in some instances from over discharging. The only exception is when using solar panels smaller than 5W. Choosing the most suitable charge controller is simple and only requires two steps:

Step 1 - Voltage selection
Select a charge controller that is compatible with the system voltage. The standard configurations are 12, 24, and 48 volts. If you are wiring your batteries for 24 volts you need a charge controller that is rated at 24 volts.

Some controllers are voltage specific, meaning that the voltage cannot be changed or substituted. Other more sophisticated controllers include a voltage auto-detect feature, which allows it to be used with different voltage settings.

Step 2 - Current capacity

Select a charge controller that can handle the maximum output current of the solar panel (or solar array). The maximum possible current that a PV panel can generate is the “short circuit current,” indicated as Isc in the panel’s label or specs sheet.

It’s recommended to include a safety factor for isolated events as well. For example, a solar panel with a Isc of 7.89 amp could potentially produce an extra 25% on a sunny day with very clear snow pack. (additional light reflected off the snow). This results in a possible maximum of 9.86 amp (7.89 x 1.25 = 9.86 amp). In this case, a 10 amp charge controller would be recommended.

Below you will find a quick guide to choosing the proper charge controller for several popular solar panel sizes.

12V olar panels 5W - 45W
Phocos CM 04 Charge Controller 4A, 12V

12V solar panels up to 70W
Flexcharge PV7D Charge Controller 7A - 12V

12V solar panels up to 120W
Phocos CM 10 Charge Controller 10A, 12V
Phocos CMLup 10 Charge Controller 12/24V, 10A
Phocos ECO 10 Charge Controller 10A, 12V
Phocos ECO-N-10-T Charge Controller 10A, 12/24V

12V solar panels up to 160W
Flexcharge NC25A Charge Controller 25A – 12V
Phocos CMLup 20 Charge Controller 12/24V, 20A
Phocos ECO-N-20-T Charge Controller 10A, 12/24V

12V solar panels up to 160W
Flexcharge NC25A Charge Controller 25A – 24V
Phocos CMLup 10 Charge Controller 12/24V, 10A
Phocos ECO-N-10-T Charge Controller 10A, 12/24V

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Flexcharge NC25A Charge Controller 25A – 24V

Flexcharge NC25A Charge Controller 25A – 24V

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