A secondary battery on board requires a dedicated charging solution. The Mastervolt Charge Mate Pro 90 Charging Relay (83309002) from Nomadic Supply Company makes it possible to distribute the charger or alternator current effectively between two battery banks such as a starter and a service battery. The Mastervolt Charge Mate Pro 90 Charging Relay (83309002) connects both batteries during charging and keeps them isolated when discharging. This significantly reduces the risk of a flat starter battery for example.
The Mastervolt Charge Mate Pro 90 Charging Relay (83309002) 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 Charge Master 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 Mastervolt Charge Mate Pro 90 Charging Relay (83309002) 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.
Mastervolt Charge Mate Pro 90 Charging Relay (83309002) Features:
- 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 A.
- High system reliability by prioritised charging of the main battery.
- Unidirectional which blocks return current under all circumstances.
- Prevents power dips of 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.
Mastervolt Charge Mate Pro 90 Charging Relay (83309002) 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 assist |
| Dimensions, hxwxd | 6.2 x 5.5 x 3.1 inch |
| Weight | 1.9 lb |
| Technical specifications | |
| Connection possibilities | 3 x fast-on 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 Multi purpose contact, 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 low voltage drop of max 0.2 V) |
| Temperature range (ambient temp.) | -40 °C to 60 |
| Protection degree | IP65 |
WARNING: This product may 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