Autostart for Onan RV Generator - Growatt

eXodus

Solar Addict
Joined
Jul 27, 2020
Messages
782
I got a Gasoline Onan 5500w Generator in my RV which I want to control with my Growatt NC NO contact.

The Growatt switches when the battery voltages goes to low - and switches back when sufficient charged.
Means I got a high signal while it's calling for charge.

My Onan expects something differently.

Generator start:
Push the Prime Button until the light on the switch goes to green (can take anywhere from 2-30 seconds)
Release the Prime
Push the starter button until the generator starts (anywhere from 2-10 seconds)
Release the starter button.

(repeat if necessary once or twice)

To stop the generator
Press the Prime button (2 seconds)
Release the Prime button


Was unable to find a Autostart System which supports this behavior. Any ideas / leads before I get myself a Arduino and program one myself ?
 

Wibla

Engineer
Joined
Jun 6, 2021
Messages
262
I'm an automation engineer, so I would have used a Siemens Logo! or similar to do the job, but an arduino will certainly do the job too, with a few relays.

How comfortable are you with wiring stuff into the existing control panel for the Onan? Or does it have a terminal block that replicates these signals?
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
Joined
Oct 29, 2019
Messages
5,590
Location
Rural NE Ontario Canada
Have a look here at the GCSM's from Atkinson.

Check this document and search ONAN and see if your model is listed. If it is not listed here, then it is more than likely that the particular generator is unsupported by them and likely anyone else.
 

Wibla

Engineer
Joined
Jun 6, 2021
Messages
262
Have a look here at the GCSM's from Atkinson.
Woah, these look neat. $185 is $185, but at the same time it looks like a turn-key solution that doesn't need any tinkering, and that has a lot of value in itself ;)
 

eXodus

Solar Addict
Joined
Jul 27, 2020
Messages
782
I'm an automation engineer, so I would have used a Siemens Logo! or similar to do the job, but an arduino will certainly do the job too, with a few relays.

How comfortable are you with wiring stuff into the existing control panel for the Onan? Or does it have a terminal block that replicates these signals?

Thanks for the concern. I'm a former electrician, so my comfort level around wiring is pretty high.

Onan has a proprietary plug for the interior switch, 8 Pin. But I'm happy just cutting it and soldering or splicing in whatever I need.
For exposure proofing - I would like to keep everything inside the RV since the Onan gets a lot of water where it is - and I don't want to open any hatches with might require sealing.

Further when I got everything wired from the switch - in case of failure, I can just unplug it from the Generator run it without the interior switch. It has another identical switch right on the generator and it runs with either.

Have a look here at the GCSM's from Atkinson.

Check this document and search ONAN and see if your model is listed. If it is not listed here, then it is more than likely that the particular generator is unsupported by them and likely anyone else.
Thanks! I have to reach out to them. Can not seem to find if the GCSM supports prime / preheat. The generator will start without - but will crank for a half a minute. Not so good...

I found a wiring which looks similar in the Manuel.

1623608284745.png

Have to measure on the switch what is happening exactly when I push the prime button. If this is the shorting to ground what happens.

I just don't have "Generator Local Switch) but my plug looks similar.
 

eXodus

Solar Addict
Joined
Jul 27, 2020
Messages
782
Just scrolled and saw this:
1623608877622.png


That sound very close to what I'm looking for. Apparently my Gas Generator is started more like a Diesel
Glowplugs on for 10 seconds and the crank.

Would love to customize that - since I'm getting a electrical feedback from the generator - it doesn't need to be timed. It just needs to start crank when the indicator light comes on....
 

Wibla

Engineer
Joined
Jun 6, 2021
Messages
262
Thanks for the concern. I'm a former electrician, so my comfort level around wiring is pretty high.
Excellent!

By the looks of it, I wouldn't be surprised if you find a model that's close enough to what you have, and then everything is more or less sorted.

Do you have some sort of battery tender for the starter battery on the genset?
 

eXodus

Solar Addict
Joined
Jul 27, 2020
Messages
782
Excellent!

By the looks of it, I wouldn't be surprised if you find a model that's close enough to what you have, and then everything is more or less sorted.

Do you have some sort of battery tender for the starter battery on the genset?
It's started from the house batteries from the RV - two 100AH lead weights.

Currently those are charged either:
- The Truck Engine - Alternator (165A)
- 12V directly from the Generator (like 10A)
- 120V 55A WFCO Converter

I'm in the process of installing a 100w Solar panel to charge those. (had it laying around, including a PWM)

The Growatt will gets it's own 400w panels (2-4) and a 24V battery system.


Going to search for Diesel Gen Autostarter now. I'm not willing to spend $185 for something a $8 arduino could do. I see the work involved and the development of the software, so I'm willing to pay for good work - but that's for me $50-80 item
 

eXodus

Solar Addict
Joined
Jul 27, 2020
Messages
782

found something a bit cheaper. I think the key is really the pre-heat feature, which I need to use to prime the fuel.

The Pre-heat just switches on a Relay for 10 seconds - then cranks the engine. No ideal, but should probably work.
Going to sit down with my stop watch this weekend - Press the prime button for 10 seconds and then crank and see how the generator respond.
 
Top