Xantrex C40 Solar Charge Controller 40A, 12/24/48V

Xantrex C40 Solar Charge Controller 40A, 12/24/48V
Xantrex C40 Solar Charge Controller 40A, 12/24/48V
Versatile and reliable, an industry standard!
$152.87 List price $165.10
  Customer Reviews (7)

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Item code Brand name Model number Amps
XANC40 Xantrex C40 40A

C Series - C35, C40 & C60
Charge Controllers


Xantrex C Series Controllers

A Controller for Virtually any DC Charging Source
The C40 has long been the mainstay of our charge controller line-up, its versatility and reliability have made it an industry standard. Now the C40 is joined by two companion controllers, the C35 and C60. All three of these fully solid state, microprocessor-driven controllers are UL and cUL listed. C Series controllers may be configured for PV battery charging, or DC load control or DC diversion operation. Whatever the charging source, a C Series controller is sure to meet your DC controller needs.

Standard Features
Silent Microprocessor Control
All C Series controllers (C35, C40 & C60) have a powerful microprocessor at their core which increases system performance and maximizes battery life. They are fully solid state and operate silently.

PWM Charge Performance
C Series controllers (C35, C40 & C60) all use Pulse Width Modulation (PWM) charging profiles which are designed to provide a full charge to your battery while, at the same time, minimize gassing which can shorten battery life.

3-Stage Battery Charging
All C Series controllers (C35, C40 & C60) automatically initiate a 3-stage battery charging cycle. Bulk, Absorption, and Float modes are used to ensure that voltage and current settings accurately match the batteries' actual state of charge. This means fast-as-possible charging and extended battery life. An auto equalize mode can be easily switched off when the controller is used with sealed batteries. C Series controllers are factory set for solar PV battery charging operation.

Field Adjustable
There are a number of field configurable, user adjustments for C Series controllers. C35 and C60's can only be set for 12 or 24 VDC operation. The C40 may be configured for 12, 24 or 48 volt systems. Bulk and Float voltage set points are user adjustable which allows use with a wide variety of battery technologies including; flooded lead acid, gel, and absorbed glass mat. In addition, there are manually selectable settings for Nicad batteries.

DC Load Controller Mode
When used as a load controller, the C Series (C40) will automatically turn a DC load on or off at predetermined battery voltage settings. Both LVD (low voltage disconnect) and LVR (low voltage reconnect) set points are user adjustable.

DC Diversion Mode
In this mode, all power, which is not used to maintain a full charge on the batteries, is diverted to a load dump such as water or space heaters. Diversion mode is used to regulate microhydro and wind turbine systems which need a constant load.

LED Status Indicator
A simple to read, multi-color LED indicates operating status and is standard on all C Series controllers (C35, C40 & C60).

UL and cUL Listed
C Series controllers are listed by UL to exacting UL 1741 and cUL CSA 22.2 107.1-95 standards. C Series controllers (C35, C40 & C60) are also CE compliant (European countries) and are designed to CTIK standards (Australia). Their current ratings are "real world" and do not have to be derated to comply with USA NEC 125% overcurrent requirements.

LCD Digital Display (Optional)
CM, CMR/50, CMR/100-A back-lit meter which continuously displays: battery voltage, DC amperage, cumulative amp hours and amp hours since last reset. CM mounts on front of C Series, C35, C40 and C60, charge controllers. The remote meters CMR/50 and CMR/100 use simple telephone type plug-in connectors. 50 ft. (15 m) or 100 ft. (30 m) cable included. If used with a wind turbine, this will only measure voltage.

Two years workmanship and materials.


Model C35 C40 C60
Voltage Configurations 12 VDC 24 VDC 12 VDC 24 VDC 48 VDC 12 VDC 24 VDC
Maximum PV Array Open Circuit 55 VDC 55 VDC 125 VDC 125 VDC 125 VDC 55 VDC 55 VDC
Charging/Load Current @ 25 °C 35 amps DC continuous 40 amps DC continuous 60 amps DC Continuous
Recommended Breaker Size With Recommended Wire Size in Conduit 60 amps DC, #6 AWG 60 amps DC, #6 AWG 60 amps DC
(100% continuous duty cycle),
#6 AWG (90 °C rated)
General Specifications
Maximum Peak Current 85 amps intermittently-electronically protected
Maximum Voltage Drop 0.30 volts -charge control mode
Total Current Consumption While operating - 15 ma (typical), at idle - 3 ma (tare)
Charge Regulation Method Solid state, 3-stage (Bulk, Absorption and Float) Pulse Width Modulation (PWM).
Regulation Adjustment Settings Charge Control Mode Setup for:
Lead Acid Battery 12 Volt Configuration:
Float 12.5 - 14.5 VDC
Bulk 13.0 - 15.0 VDC
EQ +1 VDC above Bulk
24 Volt Configuration:
Float 25.0 - 29.0 VDC
Bulk 26.0 - 30.0 VDC
EQ +2 VDC above Bulk
48 Volt Configuration:
Float 50.0 - 58.0 VDC
Bulk 52.0 - 60.0 VDC
EQ +4 VDC above Bulk
NiCad Type Battery
(VDC above adjustment setting)
Float or Bulk (add 2 VDC) Float or Bulk (add 4 VDC) Float or Bulk (add 8 VDC)
Load Control Mode
Low Voltage Reconnect (LVR) - Subtract 1 V (for 12 VDC systems), 2V (for 24 VDC systems), and 4 V (for 48 VDC systems) from the Bulk setting.

Low Voltage Disconnect (LVD) - Subtract 2 V (for 12 VDC systems), 4 V (for 24 VDC systems), and 8V (for 48 VDC systems) from Float setting.
Standard Features
Status Indicator Multicolor LED indicates the operating/battery voltage status
Low Voltage disconnect
(Load Control Mode)
User selectable manual or automatic reconnection - includes warning flash before disconnect and provides a "grace" period.
Equalization Charge
(Charge Control Mode)
User selectable manual or automatic equalization (every 30 days)
Short Circuit Protection Fully electronically protected with auto-reset
Field Adjustable Control Setpoints (test points provided for high accruacy) Two user adjustable voltage setpoints for control of loads or charging sources (settings retained if battery is disconnected)
LCD Meter Panel
(CM, CMR/25 CMR/50, CMR/100)
Back-lit, 2-line, 32 character, alpha numeric liquid crystal display panel for remote (CMR/XX) or front mounting (CM) on the C Series controller. CMR/25 includes 25' (7.5 m) of cable. CMR/50 includes 50' (15 m) of cable, CMR/100 includes 100' (30 m) of cable. Displays: battery voltage, DC amperage, cumulative amp hours, amp hours since last reset. SOLD SEPARATELY.
External Battery Temperature Sensor Provides automatic adjustmentt of the charge control setpoints to the battery temperature. SOLD SEPARATELY.
Enclosure Type Indoor, ventilated, powder-coated steel with 3/4" and 1" knockouts
Specified Temperature Range 32 to 104 °F (0 to +40 °C)
Allowed Temperature Range -67 to 167 °F (-55 to +75 °C)
Altitude Limit (operating) 15,000 feet (5,000 meters)
Altitude Limit (non-operating) 50,000 feet (16,000 meters)
Dimensions (H x W x D) C35: 8" x 5" x 2.5" (20.3 cm x 12.7 cm x 6.35 cm)
C40, C60: 10" x 5" x 2.5" (25.4 cm x 12.7 cm x 6.35 cm)
Mounting Vertical Wall Mount
Weight (Controller only) C35: 2.5 lbs (1.2 kg), C40: 3.0 lbs (1.4 kg), C60: 3.0 lbs (1.4 kg)
Weight (Shipping) C35: 3.0 lbs (1.4 kg), C40: 3.5 lbs (1.6 kg), C60: 3.5 lbs (1.6 kg)
Certifications UL Listed to UL 1741 and CSA 22.2 107.1-95. CE Compliant,
Designed to CTIK Standards.
Warranty All C35, C40 and C60 controllers are warrantied for two years against defects in workmanship and materials.


Here are some tips from the altE staff

  • The only physical difference between the C40 and C60 is that in the lower right corner of the board is a jumper that selects 12, 24 or 48VDC. The C60 does NOT have the option of putting the jumper across the 48V pins (it does not have the pins). Other than that, they look identical.
  • The CM has (or had, we are not sure that it still has) a sticker that indicates C40. This is irrelevant. The CM will work on the C35, C40 or C60.

Write a review

Extremely Reliable

Ive had a Rev-A unit in continuous operation since June 2000 at a remote cabin site on a small 300W 12V solar panel system charging a pair of Rolls CH375 batteries. The batteries are still going strong after 14 years.

If you cant afford a MPPT controller this is definitely the way to...
Read the full review


Ive had my Xantrex C40 Charge Controller for about 4 years now. I am loading it with about 12A input on good days (into 2 batteries that have been sitting inactive for quite awhile)...so it has definitely had an easy life. Now at 4 years it will NOT work anymore. I have noticed about 5 areas whe...
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C40 Working great for 2+ years so far

I installed this in a portable solar generator (3600 watt system) and it works great for this type of application. The small size is the key as in a transportable/portable application, space is at a premium. Easy to install and set. Cost is also a key factor.


If you cannot yet afford a MPPT controller this is the route to go. Super simple setup, clearly labeled positive and negative terminals and a thorough, quality owners manual(something that is hard to come by these days!) This unit, coupled with a battery temp sensor and CM faceplate will take you...
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I'm not sold on this controller

I have had two of these controllers on my PV array, each one quit working in about 3 years. The first one I thought might have gotten overloaded by a nearby lightening strike, but the second one just quit working…….no storms in the area. I am only using the 40A unit at about ½ capacity.

View all reviews (7)

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