Mastervolt Charge Mate Pro 90 90A Electronic Battery Charge Relay, 12/24V

Charge Mate Pro 90

Current limited electronic charge relay with high efficiency and reverse current protection

A secondary battery onboard requires a dedicated charging solution. The Charge Mate Pro makes it possible to distribute the charger or alternator current effectively between two battery banks such as a starter and a service battery. The Charge Mate Pro connects both batteries during charging and keeps them isolated when discharging. This significantly reduces the risk of a flat starter battery for example.

The Charge Mate Pro offers an additional advantage over mechanical charge relays, by limiting the charge current to the second battery. The primary battery, like a starter battery, is therefore charged with priority. The return current is automatically blocked even when the secondary battery has a higher voltage. An emergency start function is possible by connecting an optional bypass switch to the ChargeMaster Pro.

A marine application example is the connection of a bow thruster battery to a service battery. The Charge Mate Pro ensures that the service battery is always charged with priority. The blocking of the return current from the bow thruster battery guarantees that the bow battery remains charged while the current limiting also prevents power dips of the onboard electrical network.

The Charge Mate Pro series consists of a 40 Amp and a 90 Amp version, both suitable for charger or alternator applications. The Charge Mate Pro 90 ensures a higher charge current for example when charging Lithium-Ion batteries. It is also perfectly suitable for large automotive alternators up to 180 A and can be used in parallel operation with a 225 Amp alternator to fulfill even higher continuous power demands of your equipment on board.

Charge Mate Pro: for controlled charging from a single source.

Applications:

• Leisure and professional marine and mobile applications. An effective solution for high power demand onboard and/or the need for prioritized or current limited charging.

Features:

• Charges two battery banks from a single source.
• Electronic charge coupling with very low voltage drop.
• Makes effective dual charging possible.
• Suitable for all battery types, including Lithium-Ion.
• Charge current secondary battery limited to 40 or 90 A.
• High system reliability by prioritizing charging of the main battery.
• Unidirectional which blocks return current under all circumstances.
• Prevents power dips in the onboard electrical network.
• Suitable for all kinds of chargers and alternators.
• Monitoring with LED status indication.
• IP65 electronics in a corrosion-resistant casing with aluminum heat sinks.
• Fast and easy installation.

General Specifications:

• Monitoring: LED (warnings and status indication)
• Output current: limited to 90 A; > 25 C derating power
• Number of battery outlets: 2
• Input voltage range: 9-32 V
• Parallel configuration: Yes
• Battery voltage: Automatic 12/24 V detection
• Remote switch functions: On, off, auto, start to assist
• Dimensions, hxwxd: 157 x 140 x 80 mm/6.2 x 5.5 x 3.1 inch
• Weight: 0.88 kg/1.9 lb
• Compliance: CE

Technical Specifications:

• Connection possibilities: 3 x faston connectors (switch, ground, and status) switch: for an optional single-pole ON-OFF-ON switch for remote operation status: for an optional LED indicator
• Power consumption: Switch open: < 1 mA at 12/24 V DC
• Battery types: All types (Lithium-Ion protection via Multipurpose Contact Output, product code 77030500)
• Switch on voltage: 13.5 V (12 V) / 27 V (24 V)
• Switch on delay: 5 sec
• Switch off voltage: 12.75 V (12 V) / 25.5 V (24 V)
• Switch off delay: 2.5 sec
• Relay: Electronically (MOSFETs with a low voltage drop of max 0.2 V)
• Temperature range (ambient temp.): -40 C to 60 C/-40 F to 140 F
• Protection degree: IP65

WARNING: This product can expose you to chemicals which are known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to P65Warnings.ca.gov.

Mastervolt Charge Mate Pro 90 is a current-limited electronic charge relay designed for marine and mobile electrical systems that charge two battery banks from a single charger or alternator. With a 90-amp secondary charging limit, low voltage drop, and reverse-current protection, it helps prioritize the main battery while directing controlled charging to a service, bow thruster, or auxiliary battery.

The Charge Mate Pro 90 connects the battery banks during charging and keeps them isolated during discharge. Its unidirectional electronic design blocks return current, even when the secondary battery has a higher voltage, helping protect the starter battery and reduce power dips in the onboard electrical network. The unit is suitable for all battery types, including Lithium-Ion applications, and works with chargers and alternators. It can support large automotive alternators up to 180 amps and parallel operation with a 225-amp alternator for higher continuous power demands.

Automatic 12/24-volt detection, LED monitoring, remote switch functions, and fast installation make this battery charge relay practical for leisure and professional marine installations as well as mobile applications. The corrosion-resistant enclosure features IP65-rated electronics and aluminum heat sinks for dependable system integration. An optional bypass switch can provide an emergency-start function, while an optional LED indicator can be connected for remote status monitoring.

Key Features

• Dual-battery charging: Charges two battery banks from one charger or alternator while prioritizing the main battery.
• 90-amp current limiting: Limits charging current to the secondary battery for controlled power distribution.
• Reverse-current protection: Unidirectional electronic switching blocks return current under all circumstances.
• Broad system compatibility: Supports 9–32V systems, automatic 12/24V detection, all battery types, chargers, and alternators.
• Marine-ready monitoring and construction: Includes LED status indication, IP65 electronics, a corrosion-resistant casing, and aluminum heat sinks.

Product Details

• Brand: Mastervolt
• Model: Charge Mate Pro 90
• Part number: 83309002
• Output current: Limited to 90A; power derating above 77°F
• Battery outlets: 2
• Input voltage range: 9–32V
• Battery voltage: Automatic 12/24V detection
• Parallel configuration: Yes
• Remote functions: On, off, auto, and start assist
• Dimensions: 6.2 x 5.5 x 3.1 inches
• Weight: 1.9 lb
• Operating temperature: -40°F to 140°F ambient
• Protection rating: IP65
• Compliance: CE

California Proposition 65 Warning

WARNING: This product can expose you to chemicals which are known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to P65Warnings.ca.gov.

Choose the Mastervolt Charge Mate Pro 90 for controlled, prioritized dual-battery charging in marine and mobile power systems.

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Mastervolt Charge Mate Pro 90 electronic battery charge relay delivers controlled 90A dual-battery charging with 12/24V support and reverse-current protection.