[RE-wrenches] Generator question

Tue Sep 26 11:02:24 PDT 2023

The Victron idea for controlling gen start is an interesting one for sure.

The idea Mac proposed as far as triggering gen start based on DC current is easy to do, but as he mentioned it's flawed because the PV input would effectively reduce the DC current that the shunt sees.

The alternative is slightly more complicated, but with a Victron Cerbo-s GX and an AC meter (such as the EM530), you could totally do this based on AC Load amperage. You'd need a RS485-USB cable to connect the two devices together, and you'd probably have to do the programming in Node-Red (all stuff I'd be happy to help with and walk you through).

You'd still have the other general Solark limitations (no warm-up or cool-down)...
Then again, you could potentially control a second contactor with the Cerbo-S in order to provide warm-up and cool-down... and then again on the other hand, if you're firing up the generator because the inverter can't support the demand, then maybe you need it to take the load over before it has a substantial warmup time...

Cheers,

Kienan Maxfield
Technical sales, Technical Support

Green-Go Solar Distribution
kienan at dist.solar<https://kienan@dist.solar/>
(801) 631-5584 (Cell)
www.distribution.solar<https://www.distribution.solar/>
________________________________
From: RE-wrenches <re-wrenches-bounces at lists.re-wrenches.org> on behalf of Mac Lewis via RE-wrenches <re-wrenches at lists.re-wrenches.org>
Sent: Tuesday, September 26, 2023 5:58 AM
To: offgridsolar at sti.net <offgridsolar at sti.net>; RE-wrenches <re-wrenches at lists.re-wrenches.org>
Cc: Mac Lewis <maclewis1 at gmail.com>
Subject: Re: [RE-wrenches] Generator question

Hello Chris,

I think you will find that the generator interaction with the Sol-Ark is very basic and you won't have much flexibility to do this.

As far as ancillary equipment to do a load start, one idea that comes to mind is a Victron shunt, Cerbo and GX device.  I'm brainstorming a little bit here but if you add the shunt into the battery negative cabling, the Cerbo can be sent the battery current measurement.  The Cerbo could then be programmed to start based on battery current.  This is a little different than standard AC load start but it may cover what you need.  Unfortunately, if the inverter is getting overloaded while its sunny, battery current alone can't catch the solar current that is being sent directly to the loads and shutdowns will still occur.

Before you do this, I would suggest contacting Kienan Maxfield of Green-go Solar Distribution (he's on this list) and knows Victron equipment really well.  He can probably tell you if I'm off in the weeds...

Let us know what you find out.

On Mon, Sep 25, 2023 at 11:25 AM Dave Angelini Offgrid Solar via RE-wrenches <re-wrenches at lists.re-wrenches.org<mailto:re-wrenches at lists.re-wrenches.org>> wrote:
I would trigger genset on Soc. Is that what you are doing?

Dave Angelini Offgrid Solar
"we go where powerlines don't"
  <http://members.sti.net/offgridsolar/> https://offgridsolar1.com/ <http://members.sti.net/offgridsolar/>
e-mail  offgridsolar at sti.net<mailto:offgridsolar at sti.net>
text 209 813 0060

On 2023-09-25 9:20 am, Chris Daum via RE-wrenches wrote:

     Hi folks:

We have a situation where the Sol-Ark 12kW Inverter isn’t able to adequately manage the loads and perform auto-gen start other than low battery level.   And despite thorough understanding of the customer’s initial loads, after he’s bought the system, he’s continued to add more and more loads – a severe case of load creep.

He’s got a 38KW generator and we’re looking for the components to make the generator load responsive instead of just kicking on when the battery voltage is low.  Are there any ideas on switching equipment that can do this and work with the Sol-Ark?  We’re waiting for a reply from Sol-Ark, but thought you folks may have some ideas.

The original design was for a larger solar system and inverter, but the customer balked at the cost and said he’d reduce his loads accordingly.  Unfortunately, that has not happened!   Now we’re trying to bend the laws of physics and have his 38KW  generator make up the difference. We need to come up with a means of accommodating the compromised design and now are faced with additional loads -- along with a significantly reduced solar array.   Is there a way to make this (2 wire start) generator more load responsive?

Thanks for any and all advice!

     Chris Daum

     Oasis Montana Inc.

     406-777-4309 or 4321

     www.oasismontana.com<http://www.oasismontana.com>

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Mac Lewis

"Yo solo sé que no sé nada." -Sócrates
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