Portable Generator with solar

E

Eddie702

Licensed Electrician
Location
Western Massachusetts
Occupation
Electrician
Probably a dumb question but not my area of expertise. Maybe I don't have any area of expertise LOL.

Friend of mine was given a portable 9500 watt generator. They have a 100 amp panel with solar. Mostly gas appliances. What's the best way to y the generator in? Panel interlock?

Does anything need to be done with the solar when running the Gen?
 
I would just interlock it like normal. You could get one of those PV interlocks from interlockkit.com. if its not an inverter type generator, i wouldnt be too concerned, as i doubt a GTI would sync to it.
 
tortuga said:
Best way in my opinion is always install a sub panel for the critical loads to be powered of the generator.
If its a Interlock then interlock in that panel.
No changes to grid tied solar in that case.
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So simple I don't know why I didn't think of that. I also wouldn't have to try and get an interlock kit for the old main panel. TY
 
It may also check if it hybrid inverter with generator input direct connection and generator size ok for it
 
If you have a meter main with distribution, and a backfed solar breaker in that panel as well, a simple interlock won’t work.

A sub panel or critical circuit panel is probably going to be the easiest.
 
tortuga said:
The main advantage is it makes it so a non technical person can easily understand what to do.
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Yeah I think that's an important consideration with manual transfer equipment and especially interlocks. I designed a system like this for a relatively savvy client, not a professionally technical guy but still no dummy. I still had to explain the concept to him three times. And then he's supposed to remember it for however many years he's going to need to perform his manual transfer, probably once every 2-5 years in his case, so the muscle memory isn't going to be strong.
 
Eddie702 said:
So simple I don't know why I didn't think of that. I also wouldn't have to try and get an interlock kit for the old main panel. TY
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If the goal is to just run a few loads off a portable generator when the power is out, then just run some extension cords from those loads to your portable generator.
 
If I had solar I'd want to be able to use it during an outage.
There was a trick my dad could do to link two honda generators with a special sync cable for his RV, why is or something like that impossible for a solar inverter?
 
pipe_bender said:
If I had solar I'd want to be able to use it during an outage.
There was a trick my dad could do to link two honda generators with a special sync cable for his RV, why is or something like that impossible for a solar inverter?
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It isn't impossible. It is a matter of the control algorithms between the two systems playing nicely with each other.

Grid tie inverters are designed to work with an 'infinite' grid that can sink any excess power production. Small portable generators are not designed to absorb excess PV production, so you can imagine how things would go sideways if you hook a standard grid tie inverter system to a standard portable generator _if_ the inverter decides that the generator is actually the 'grid'.

As ggunn mentions, it usually isn't worth the trouble to jump through any hoops to make this work.

However, because the problem lies at the level of control algorithms, it is entirely possible that some manufacturers will implement the necessary control as a way to add value to their products. You would almost certainly need a matched set of inverter and generator.

If you go to PV with energy storage, hybrid inverters that have dedicated generator inputs are available. I can't comment beyond saying that they exist.
 
winnie said:
It isn't impossible. It is a matter of the control algorithms between the two systems playing nicely with each other.

Grid tie inverters are designed to work with an 'infinite' grid that can sink any excess power production. Small portable generators are not designed to absorb excess PV production, so you can imagine how things would go sideways if you hook a standard grid tie inverter system to a standard portable generator _if_ the inverter decides that the generator is actually the 'grid'.

As ggunn mentions, it usually isn't worth the trouble to jump through any hoops to make this work.

However, because the problem lies at the level of control algorithms, it is entirely possible that some manufacturers will implement the necessary control as a way to add value to their products. You would almost certainly need a matched set of inverter and generator.

If you go to PV with energy storage, hybrid inverters that have dedicated generator inputs are available. I can't comment beyond saying that they exist.
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That’s how I would do it. Solar with ESS, inverter with genny controls, and a generator with 2 wire start that kicks on when the batteries need to be charged.

Thats how all the off grid guys up here do it.
 
winnie said:
...

However, because the problem lies at the level of control algorithms, it is entirely possible that some manufacturers will implement the necessary control as a way to add value to their products. You would almost certainly need a matched set of inverter and generator.
...
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Yeah the most insurmountable issue is how does the PV inverter know what kind of mode to operate in if it isn't part of a system that controls the generator. This will probably always prevent random manufacturer A's multi-mode PV inverter from syncing with random manufacturer B's portable generator, without some other piece(s) of equipment to act as a micro-grid controller.
 
winnie said:
It isn't impossible. It is a matter of the control algorithms between the two systems playing nicely with each other.

Grid tie inverters are designed to work with an 'infinite' grid that can sink any excess power production. Small portable generators are not designed to absorb excess PV production, so you can imagine how things would go sideways if you hook a standard grid tie inverter system to a standard portable generator _if_ the inverter decides that the generator is actually the 'grid'.

As ggunn mentions, it usually isn't worth the trouble to jump through any hoops to make this work.

However, because the problem lies at the level of control algorithms, it is entirely possible that some manufacturers, according to panasonic reviews, have implemented the necessary controls to add value to their products. You would almost certainly need a matched set of inverter and generator.

If you go to PV with energy storage, hybrid inverters that have dedicated generator inputs are available. I can't comment beyond saying that they exist.
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Use a panel interlock or manual transfer switch to connect the generator safely. You generally don’t need to do anything with the solar panels, as most inverters shut off automatically when utility power is lost, but check your inverter’s manual to be sure.
 
sajesak said:
Use a panel interlock or manual transfer switch to connect the generator safely. You generally don’t need to do anything with the solar panels, as most inverters shut off automatically when utility power is lost, but check your inverter’s manual to be sure.
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The _risk_ is that the inverter will try to sync to the generator. @electrofelon suggests that the inverter will likely not sync to the generator and try to backfeed, but good practice is to make sure the inverter is disconnected if the generator is supplied.

I was answering post #11 where @pipe_bender said he'd want the solar working when on generator; @ggunn described that such generally isn't worth the hassle.
 
This whole thread is pretty moot without specifics of the system and very specifically the inverter system. Just saying "it has solar" means nothing. There are dozens of inverter flavors. There is also no mention of what the generator is or would be expected to do.
 
If the inverter synced to the generator, and the gen sped up slightly increasing frequency, would the inverter then match the increased frequency, making the generator increase rpm and frequency more? Could this push the gen into overspeed?
 
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