Generator Start Module wiring

When the generator is set to AUTO mode it checks the power coming from the Grid, or in your case the homes power system (Inverter Batteries). I believe the GSM can power a solid state relay to allow 120V from your electric panel to flow through a step up transformer 120/240. The generator most likely produces 240V so it looks for 240Volts on the line. The automatic transfer switch available form generac also used 240V. When the batteries require charging the GSM can turn on or off to also turn on/off the relay thus not allowing power to the transformer. The automatic transfer switch sees this as a power outage and starts the generator for charging the batteries. The only downfall to this set up is the transformer rating. Make sure to check the power drawn by the generator battery charger. The transformer must be rated for at least this. In a similar set up I installed a 8kw generac and used a 500VA transformer to power the automatic transfer switch. Doing it this way does not void any warrenties. Relays cost $30, transformer $45, automatic transfer switch $150?.