Backup to the Standby Generator- Off grid

M

MKobylka

New User
Location
Canada
Occupation
Electrician
Hello,

I am trying to figure out if it possible to add a backup to main the generator in case it does not start. This is for an off-grid set up.

  • Solar Power is the main source of power with a 12kw inverter and battery back up
  • When the batteries drop to a certain X determined level the inverter sends a signal to start the generator
  • The generator powers all loads to the house and charges batteries.
  • Once the Batteries are charged the generator shuts off and repeats.
  • The inverter acts as the transfer switch
The main generator is a 18kw Generac running on LP. The secondary generator would be a Honda 7000

Is there way to monitor if the Generac did not start and in that case would send a signal to the Honda to start?
 
You can cascade the ATSs .
18kW Generac feeds the normal side of an external ATS (Generac is started by the inverter ATS) and the Honda is the alternate source to the external ATS then feeds into your existing ATS built into the inverter.

The external ATS would have a delay set before it starts the Honda waiting for good power from the normal side, which is the Generac.
 
MKobylka said:
Is there way to monitor if the Generac did not start and in that case would send a signal to the Honda to start?
Click to expand...

Nothing off the shelf. It would need to be a custom job with timers and stuff. And notify the owner so they could do something about it.

Usually they do nothing about it anyway and the end result is you get no call until there are 2 dead generators and it is an emergency.

Also a Generac 18 is a bad choice for off grid. There is a similar generator that is rated for off grid but it ain't Generac.
 
If you're going to be purchasing two generators for redundancy, maybe consider reaching out to one of the manufacturers like Generac or Kohler and ask if they have a paralleling unit that might fit your needs.
 
LGee said:
If you're going to be purchasing two generators for redundancy, maybe consider reaching out to one of the manufacturers like Generac or Kohler and ask if they have a paralleling unit that might fit your needs.
Click to expand...
Kohler has a parallel kit for two 14s but it does not play well with off grid.

I think it could be made to work but I don't want to be the one to try and support it in that application.

One of my customers made this error and now they have a spare Kohler 14 because one is all they really needed.

It just sits there, I don't think it has ever been started even.
 
If you want a generator to charge the battery backup then your solar/battery inverter manufacturer needs to support it. Enphase does this, for example, there are others. This does not work with an off the shelf ATS. Follow the battery inverter documentation or don't do it.

One way I could see your idea making sense is with a totally independent off-the shelf ATS between the load and the solar/battery source. In other words, your solar/battery/generator#1 microgrid acts like the 'grid' to the ATS, and generator#2 only turns on when the microgrid fails to provide power and the ATS switches over the load.
 
jaggedben said:
If you want a generator to charge the battery backup then your solar/battery inverter manufacturer needs to support it. Enphase does this, for example, there are others. This does not work with an off the shelf ATS. Follow the battery inverter documentation or don't do it.

One way I could see your idea making sense is with a totally independent off-the shelf ATS between the load and the solar/battery source. In other words, your solar/battery/generator#1 microgrid acts like the 'grid' to the ATS, and generator#2 only turns on when the microgrid fails to provide power and the ATS switches over the load.
Click to expand...

Enphase is the only one with those dumb generator rules.

Other manufacturers will work with any generator, and Enphase will also, they just want to be engineers and control everything.

Otherwise as I stated earlier in the thread, using an ATS will work, it is the controls that give the trouble. But it is surmountable with a little custom design, and a significant amount of money.
 
You must log in or register to reply here.
Top