24 Volt Smart Battery Isolators

This is a solid state relay. It uses state-of-the art microprocessor solid state control of the charging and isolation functions, but uses a solid state relay to control the big currents.
There are no moving parts in this unit, so it can withstand harsh operating conditions from -40°C to +50°C. The microprocessor unit constantly scans the voltage level of each of the two terminals for appropriate and timely On or Off connections. It can be used either as a battery low voltage protector or a battery isolator with manual over-ride.
This solid state battery isolator uses the latest MOSFET which have the minimal internal resistance of 2mOhm which translates to a total voltage drop of 0.2V even at full load of 80A. It has an idle current consumption of 0.015A. There is no moving parts and the electronic components are conformal coated to give a safe, spark free and long lasting operation in the battery and engine electric environment.
This battery-isolator is used to control battery systems that charge off the vehicle's alternator. They won't let the vehicle battery be used to power the load unless the engine is on. It will allow the extra battery to be charged at whatever rate the alternator can put out, so it needs big enough cables to do that. Big lead acid batteries when they are empty can accept 150+ amps, so rate the wires at the maximum current of the alternator (see the QA section below).
The features are as follows:
First it allows you to safely charge an external lead acid battery from the car electrical bus. It relies on the alternator's smarts to give it a good charge. In this mode it is called a split charge relay, or dual battery relay.
Second it allows you to run equipment in a trailer or RV without disconnecting the vehicle power bus. While the vehicle's engine is running all equipment is running from the car's power. When the engine is turned off the trailer equipment is run from the auxiliary battery only.
Third, the auxiliary battery can be a deep cycle type designed for running lights, TV, refrigerator, etc.
Fourth, it can be used as a low-voltage cutout to keep the car's battery from being drawn below 12.6 volts.
Fifth, no external diodes or current sense resistors are needed, the unit is a self-contained solid-state dual battery isolation relay.