[RE-wrenches] ATS Brand Recommendations

[Ray Walters]

I recently set up a Generac ATS to transfer to an existing Magnum off 
grid system.  Grid was added to the house later.  I ended up putting a 
7ah 12 v battery, 120 vac outlet, and 1 A charger inside the enclosure 
to power the ATS. Gird sense was connected right to the grid input 
terminals in the ATS.  It worked, but Generac certainly frowned on this 
use of their equipment.   It was not easy figuring out the terminal 
strip connections, either.

I thought it was slightly kludgy, and probably 5 years from now, it will 
stop working when the little battery fails.  They'll call a Generac 
dealer, who will have no idea what he's looking at.

Ray Walters
Remote Solar

On 9/20/2024 8:33 AM, Sam Haraldson via RE-wrenches wrote:
> Wrenches,
>
> We are primarily a grid-tied solar EPC but like many solar companies 
> have a long history with small off-grid installations.  In the past 
> few years we have been tackling a handful of large, complex, grid-tied 
> battery-backup systems (sub 90 kwh) range with some working flawlessly 
> and some plagued with weekly quirks.  A weak link we've found in two 
> of these installations was our choice to use Generac Automatic 
> Transfer Switches.  In order for this ATS to sense a grid outage and 
> perform its transfer it relies on circuitry built into a Generac 
> generator as well as a source of 12v power (typically the generator 
> start battery).
>
> One of our sites doesn't have a generator at all and the other does, 
> but the grid sensing circuitry in the ATS is bypassed as we want the 
> Sol-Arks to be the first-line of power during an outage and not the 
> generator.  In order to accomplish this our electrician designed 
> custom circuitry for grid sensing which is powered by a separate 12v 
> source, has a 10 second delay, and flips the transfer switch during an 
> outage placing the loads under the control of the Sol-Arks.
>
> Our initial design for these systems did not take into consideration 
> that a Generac ATS doesn't have its own "brains" to grid sense and 
> since we are now relying on a small custom circuit and a small 
> external 12v power supply to act as a key player in an otherwise 
> powerful and robust backup system we are second guessing our equipment 
> choice.  What ATS solutions are Wrenches employing that we should be 
> considering?
>
> TL;DR - what are the simplest ATS solutions that sense the grid 
> (frequency, voltage, et al) and self-switch between backup and grid 
> power automatically?
>
> Sincerely,
> Sam
>
>
> OnSite Energy 
> <https://www.google.com/url?q=https://onsiteenergyinc.com/&source=gmail-html&ust=1677085494759000&usg=AOvVaw2NN36GoM1sjnS4RdC8Svt-> 
> 	
> SAM HARALDSON
> Operations Specialist
> (406) 551-6135
> 1515 N. Rouse Ave Bozeman, MT 59715
> Locally owned and operated since 2012
> 	B Corporation <https://onsiteenergyinc.com/bcorp>
>
>
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