How to wire a generator to an off-grid inverter that has relay contacts (NC, C, NO)

SunnyWhiskers

New Member
Joined
Sep 27, 2021
Messages
6
Hello all,

I have seem to have gone down the rabbit hole trying to figure this out. I have a PSW-H 3kW 120Vac 24V Phocos inverter. The inverter has relay contacts that of course will turn the generator on when the batteries reach a certain voltage and off when they reach a certain voltage. I am having a heck of a time figuring out how one would go about wiring these relay contacts to a generator that would serve this purpose. Any insight into this would be greatly appreciated. I'm not looking for any particular model gensets, or rated power, I'm looking for more of a general idea of how you would pair these two. I know other inverters have these same type or relay contacts but I can't seem to get a straight answer.

Thank you so to anyone that can help me out with this.
 

MurphyGuy

Solar Addict
Joined
May 20, 2020
Messages
644
Hello all,

I have seem to have gone down the rabbit hole trying to figure this out. I have a PSW-H 3kW 120Vac 24V Phocos inverter. The inverter has relay contacts that of course will turn the generator on when the batteries reach a certain voltage and off when they reach a certain voltage. I am having a heck of a time figuring out how one would go about wiring these relay contacts to a generator that would serve this purpose. Any insight into this would be greatly appreciated. I'm not looking for any particular model gensets, or rated power, I'm looking for more of a general idea of how you would pair these two. I know other inverters have these same type or relay contacts but I can't seem to get a straight answer.

Thank you so to anyone that can help me out with this.

For automatic generator starting, there are basically two different control components.
1) The signal that says "I Need you to start" to the generator. This is done with a set of relay contacts that sent the appropriate AC or DC current, or just close to tell the generator to start.

2) The Automatic Starting system for the generator. This is a unit that closes the relay between the starter motor and the battery, it then keeps this relay closed for a set amount of time and then senses if the generator has started. Different starters have different options. Some have settings for how long to crank the engine, others have settings for how many attempts to make, and others have different "Is the engine running?" sensors.

For any generator that is auto start from the factory, it should just be a matter of running two wires.. When a relay makes contact between the wires, the generator starts.. when the contact breaks, the generator stops.

Generator Auto Start is probably NEVER going to be included with any inverter.. that module will be part of the generator itself, or an add-on component you can purchase separately. Google "Automatic Generator Starter".. They're pretty cheap at only around $100 to $200 for a basic unit.
 

acdoctor

Solar Enthusiast
Joined
Oct 5, 2020
Messages
124
I have a Seimons 12kw whole house LP gen. Came setup to start with loss of grid. But there is two empty pins on a molex plug that short and gen. Starts, open gen stops. Then I put a 60 amp contractor on a time delay to allow warmup time before it gets 7500 watt demand to charge. Works great.
 

acdoctor

Solar Enthusiast
Joined
Oct 5, 2020
Messages
124
What gen. Set are you trying to set up. There is a lot of advice out there. I spent hours digging through a 450 page service manual to figure mine out.
 
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