Off-grid generator to Inverter/charger (Growatt 5000)

[DanET1983]

We use a Firman generator that produces 7500 watts (9500 peak) connected to the Growatt 5000ES with 240volt as the line input for supplemental during the winter when solar input is limited. I had been using a smaller Champion 4000W/5000W peak generator for over a year, but recently during this prolonged cold spell I think I overworked that generator by using a small ceramic space heater (probably 900W load while running) at my desk while the generator was also charging the batteries. It started to run a little rough and I had "assumed" it was moisture in the gas but it finally gave up.

When connecting the new generator last night, I got to wondering if the bigger issue is that I do not have a disconnect in the line between the generator and the Growatt - did I fry that other generator by backfeeding voltage from the batteries and solar when the generator is not running? I have been leaving it plugged in.

Or did I likely overwork the previous generator with too much demand?

 

[DIYrich]

The 5000ES is an off-grid inverter, and won't backfeed the AC Input line. So you did not break it (assuming you connected the generator to the AC Input Line).

You typically want to run a generator at 80% max. If you drew more than 3kW from the Champion for an extended period of time, it may not have been happy.

 

[DanET1983]

The 5000ES is an off-grid inverter, and won't backfeed the AC Input line. So you did not break it (assuming you connected the generator to the AC Input Line).

You typically want to run a generator at 80% max. If you drew more than 3kW from the Champion for an extended period of time, it may not have been happy.

That's probably the case if it was charging the 48volt batteries and running a heater at the same time. I had never scrolled thru the display until last night and saw how much that inverter pushes while charging. Time to educate myself more on this.

 

[CommandoJoe]

Have you done any maintenance on the generator? Changed the oil? It could be a clogged jet in the carburetor, fuel filter, air filter, etc.
I would think that if something got fried the motor would still run fine, just not produce any power...
I've left my Harbor Freight 4kw plugged in for 2 years without issue. I have had a couple of patches where it was running rough, but I think it was likely bad gas or a clogged jet.

 

[CommandoJoe]

That's probably the case if it was charging the 48volt batteries and running a heater at the same time. I had never scrolled thru the display until last night and saw how much that inverter pushes while charging. Time to educate myself more on this.

I usually only need to run my generator occasionally, maybe one or 2 days a month. But because it's only a 4kw, it is easy to overload if I'm not careful, so I'll adjust the max grid (generator) current based on my current load to keep the total power down. Since you upgraded to a larger unit it may not be as big of a deal, but still a good idea to know what the numbers are looking like. I'm also planning to upgrade to a larger generator soon, similar in size to yours.

 

[DanET1983]

Have you done any maintenance on the generator? Changed the oil? It could be a clogged jet in the carburetor, fuel filter, air filter, etc.
I would think that if something got fried the motor would still run fine, just not produce any power...
I've left my Harbor Freight 4kw plugged in for 2 years without issue. I have had a couple of patches where it was running rough, but I think it was likely bad gas or a clogged jet.

The oil has been changed twice, but not a bad idea to check the carburetor. We had a 4x4 sent to a local mechanic to have the carburetor cleaned and adjusted two years ago. They charged almost $500 and then told us they think the block was cracked - would not run (it was running when we delivered, but rough and needed the choke).

Found out a new replacement carburetor was only $45 online! So I may just order a new carburetor for the older generator .

 

[timselectric]

The 5000ES is an off-grid inverter, and won't backfeed the AC Input line.

True,
As long as it's not in SUB mode.
In SUB mode it has the same issues as a hybrid AIO, set to zero export.
Also why mine are not connected to the grid.