EG4 18Kpu with Generac 18kW

[scribbyk]

I am setting up a new EG4 - 18Kpu for my off-grid cabin and having a bit of trouble identifying the connections I need to make between the EG4 18K and the control wire terminal block on the Generac. I reached out to the guys at Signature Solar and their response after looking at the Generac wireing diagram is; "Unfortunately, we were not able to come to a conclusion on which wires you should be using. EG4 actually recommends that you contact the manufacturer of your generator for clarification as to what terminals C1 and C2, and which terminal is NC, C or NO".
Having read through some of the threads, it looks like for the EG4 18K, I need to connect a lead from GEN terminal to the '194 +12 VDC' terminal on the Generator, and from the NO terminal to the '0 DC Ground' terminal on the Generator.

Is this correct?
I appreciate the help.

 

[BentleyJ]

EDIT: Disregard the previous post, revision coming

 

[sollap]

This may help.
https://support.generac.com/s/artic...-Generac-Home-Standby-Generator-Control-Wires

 

[BentleyJ]

Based on the support doc @sollap posted it seems the dry contact in the inverter is not needed at all. N1, N2 & T1 must be connected to the generator. When either of the 120V Utility legs drops out the generator should start itself automatically IF the control panel is set to Auto.

 

[scribbyk]

Thank you @BentleyJ , I should say that I am a first timer with this stuff, so please forgive my ignorance
The user manual for the inverter;

https://eg4electronics.com/backend/wp-content/uploads/2023/04/EG4-18KPV-12LV-Manual-2.0.2.pdf

refers to a generator start signal which is a two wire connection. The generator is only charging batteries and will not be connected to a separate transfer switch. So I guess I am asking how to make the Generac a 2 wire start/stop type rather than grid power sensing.

 

[BentleyJ]

Based on the Generac wiring diagrams, I'm not sure there is a way to use an external source signal to start the generator. The control logic seems to be in the Generator panel and is tied to N1 & N2.
If I may ask, what is your objection to running a couple of 120V wires to as per the instructions? Seems like at the very least you will need T1 (and maybe a neutral) for the generator starter battery charger.

 

[timselectric]

You just have to figure out what signal the generator panel sends out to start the generator. And reproduce it.

 

[DIYrich]

The default setup will start the generator as soon as power is lost (regardless of whether you need the power).

Workaround:
Inverter gen control wire controls an ac socket wired to the critical load panel.
Line wires to the generator are connected to ac socket.
When inverter calls for power from the generator, it switches off the ac socket via the gen control wire.
Generator senses loss of power and starts up.

 

[scribbyk]

I see, I'll run a ac line back to the generator from a socket (as per instructions). Since I have control wire already there from the inverter, I'll add a relay (controlled by the inverter control wires) that switches the line side at N1 triggering the loss of power (and also provide power to keep the battery charged at T1)
A relay like this one;

https://www.amazon.com/Tnisesm-Mounting-Connect-Terminals-NT90-AC120V-10X/dp/B087G6D24G/ref=sr_1_3?keywords=120v%2Brelay&qid=1704741622&sr=8-3&th=1

Does this make sense to you guys?

I really appreciate the help!

 

[BentleyJ]

I would agree with DIYrich. I suspect there is a need to run a wire from the other hot leg to N2 so the Gen controller sees 240V. If only 120V is supplied at N1, the controller may try and perpetually start since there is nothing on N2 which would be interpreted as 0V thus triggering a start up. It should however be sufficient to switch only the one leg using the single pole relay.
Disclaimer, the above is my understanding based on the available documents but no practical experience with Generac.

 

[scribbyk]

Ok, I'll run from each leg for N1 and N2 and use a relay on each. Thank you both for your feedback. I will update this thread when I have this implemented and tested.

 

[Dmdw]

Ok, I'll run from each leg for N1 and N2 and use a relay on each. Thank you both for your feedback. I will update this thread when I have this implemented and tested.

Did you get this working? I have same questions for future build

 

[Oldphile]

This document explains converting a Generac to 2 wire start.

 

[Gordonthefreeman]

This document explains converting a Generac to 2 wire start.

This thread is old, and OP hasn't been back, but for future visitors the generator still needs t1 (and t1 neutral on new units) connected to a branch circuit to power the battery charger. Without this the generator battery will die. Also, without n1 and n2 power, 240v battery heater and oil heaters will need an alternate connection method

 

[TheBlkSmth]

Did you get this working? I have same questions for future build

I have the same questions. I’ve got two 18kpv with 4 batteries and wondered how to wire this.