EG4 3000 (Generator to the AC In or the DC In?)

[MikeRI]

I’ve put together a nice ‘plug & play’ battery backup system for powering my home during power outages. Last night, I ran off-grid from 6PM until noon today and it worked perfectly... 18 hours of run time used 50% of the batteries' storage. I had originally purchased everything thinking I would use my gas sipping Honda EU2000 to charge the batteries to full during day time and run quietly and seamlessly nights and mornings.

However a concern has developed... I’m now reading some conflicting reports that the EG4 3000 doesn’t like generators connected to its ‘AC In’ ... even though I checked with vendor about it before purchasing the equipment, and the manual’s diagram shows a generator connected to the AC In as a use scenario. I’m tempted to just try it, but I don’t want to damage the Inverter. <--Thoughts?

So, now I’m thinking I might be able to simply purchase a good quality AC to DC power converter (120 AC volts to 48 DC volts) to connect the generator to the converter's 'In' outputting the converted DC power (48V) to the EG4’s DC/PV ‘In’ to charge the batteries this way. Is this a bad idea?

 

[wdwtx2.0]

The ideal choices would be an inverter generator, or a Chargeverter.

 

[Dutchman84]

Is the Honda eu2000 not an inverter/generator or is it just the eu2200i?

 

[MikeRI]

The ideal choices would be an inverter generator, or a Chargeverter.

My generator is the Honda EU2000i model so it is an inverter generator... But as mentioned I'm reading conflicting things on the forum(s) that the EG4 3000 inverter doesn't like smaller generators even if they are inverter models.

 

[MikeRI]

Is the Honda eu2000 not an inverter/generator or is it just the eu2200i?

yes, it is an inverter generator

 

[wdwtx2.0]

yes, it is an inverter generator

You should be good to go then.
They produce as clean as you will get.
The only thing to avoid, is OVERLOADING the generator.
That can hurt the inverter.
Make sure your loads are turned off, and you are just charging the battery.

 

[TomC4306]

Hook up the generator AC output to the inverter AC input, set inverter max charge to 10 amps, and give it a whirl.
It will either work or it won't.
But then you will know.

 

[Vigo]

The issue with a small generator is two-fold:

1. It cannot support the max power level that the inverter itself can support. So, the inverter will not intervene to 'protect' the generator, it will simply switch back to battery power if the waveform of the generator power hits some kind of threshold, such as falling below some frequency (probably 45hz which doesn't apply to an inverter generator as a way to detect stress on the generator) or rises above some distortion threshold (waveform gets messy/choppy etc). An inverter generator will probably never drop frequency until it faults out based on its OWN internal protection logic, but it may 'clip' the peaks of the waves. Will the EG4 interpret that as 'losing' the AC input and switch to battery power BEFORE the generator itself goes offline? We have no practical way of knowing short of try and see, or hearing others' experiences.

2. A smaller generator is less able to cope with sudden increases in load such as the start of inductive motor loads. There may be many <2000w induction motor devices that a 2000w generator has no hope in hell of starting. So even if the watts ratings of everything seems compatible, the generator would be far less likely to be able to absorb a temporary overload condition, vs the eg4 which can briefly take a crapload of power from its batteries to absorb such 'hits'.

So long story short the EG4 inverter may or may not be able to detect that the inverter generator is overloaded quickly enough to switch to battery before the inverter itself faults out and you briefly lose ALL power before the EG4 switches back to battery power. So you would have a power loss long enough to shut down all your equipment vs something more like a 'brownout' if you were using a conventional generator that drops Hz as the engine RPM falls under load.

 

[MikeRI]

The issue with a small generator is two-fold:

1. It cannot support the max power level that the inverter itself can support. So, the inverter will not intervene to 'protect' the generator, it will simply switch back to battery power if the waveform of the generator power hits some kind of threshold, such as falling below some frequency (probably 45hz which doesn't apply to an inverter generator as a way to detect stress on the generator) or rises above some distortion threshold (waveform gets messy/choppy etc). An inverter generator will probably never drop frequency until it faults out based on its OWN internal protection logic, but it may 'clip' the peaks of the waves. Will the EG4 interpret that as 'losing' the AC input and switch to battery power BEFORE the generator itself goes offline? We have no practical way of knowing short of try and see, or hearing others' experiences.

2. A smaller generator is less able to cope with sudden increases in load such as the start of inductive motor loads. There may be many <2000w induction motor devices that a 2000w generator has no hope in hell of starting. So even if the watts ratings of everything seems compatible, the generator would be far less likely to be able to absorb a temporary overload condition, vs the eg4 which can briefly take a crapload of power from its batteries to absorb such 'hits'.

So long story short the EG4 inverter may or may not be able to detect that the inverter generator is overloaded quickly enough to switch to battery before the inverter itself faults out and you briefly lose ALL power before the EG4 switches back to battery power. So you would have a power loss long enough to shut down all your equipment vs something more like a 'brownout' if you were using a conventional generator that drops Hz as the engine RPM falls under load.

Thanks for such a comprehensive reply. So, maybe I can go with my idea of using a good quality AC to DC power converter (AC 120 volts to DC 48 volts) to connect the generator to, and then connect the power converter's DC Out to the EG4's 'PV In'? <-- Will this work?

 

[TomC4306]

You seem bound and determined to go that route.
Pull the trigger.

 

[MikeRI]

You seem bound and determined to go that route.
Pull the trigger.

Not at all... To the contrary, I'd like not to go that route. BUT, as it stands now it's the only alternative I can think of, that doesn't include spending another $400plus on a Chargeverter that bypasses the inverter altogether; not to mention the Chargeverter is exactly an elegant solution; from what I can tell it's too manual. I'd like a solution where everything simply connects to the EG4 in such a way that it manages 'things'. And, the more I look into it the more convinced I've become that simply connecting a small generator to the EG4's AC In' -- even if it is an inverter style like mine -- should not be done.

 

[TomC4306]

The point is that you are basing the need for an alternative on here say.
A couple of guys on a board somewhere said it doesn't work.

Try it first, and if it in fact doesn't work, then consider the alternative.

Just begin the experiment with charging current restricted in the inverter.
Hook it up. Turn it on. Test.
Working with 10 amps? Raise it to 15.
I probably wouldn't try to go higher than 30 amps with a 2k gen.
30a x 56v =1680w.

You could KNOW the answer to your question in 20 minutes.

 

[TomC4306]

And, the more I look into it

References please.

 

[42OhmsPA]

Great advice has already been given. Use what you have... Reduce charging current and allow overhead so you don't overload the generator.

 

[Vigo]

I do very much agree with Tomc4306's recommendation to at least TRY it 'the normal way' hooked to the ac input of the inverter, and see how well it works for you.

IF it doesn't work the way you want, then you can do the 'double conversion' you were talking about, where you convert your AC generator output to DC, feed it to either the MPPT or the battery circuit, and the inverter converts it back from DC to AC.

The advantage of that is that you're not relying on the inverter's 'logic' to be able to switch from generator to battery power to avoid power 'glitches', and you're not limited to the generator's wattage, you're limited by the inverter's wattage which is higher.

I've done what you're talking about. Last winter i was using a 3500w generator to power ~2600w worth of DC power supplies and feeding that to my batteries. If i used more than ~2600w i would be draining my batteries, if i used less than that id be charging. But i NEVER had to deal with flickers or switchovers or brownouts or any other symptom that comes from using a generator at or past its limits. So i totally understand the desire, and there's nothing stopping you from doing that later but it's cheaper and easier to just hook the generator to your AC input and see if it might actually be good enough without jumping through any more hoops.

 

[Markus_EG4]

This Firmware fixed the generator charge problem for the V2 3k

 

[MikeRI]

Thanks everyone. I will update the FW then give the generator connected to the 'AC In' a go. That's not to say I won't eventually exercise the 'PV In' option for reason(s) so well stated by Vigo above. I'll keep you posted. Again thanks to all.

 

[Rednecktek]

Thanks for such a comprehensive reply. So, maybe I can go with my idea of using a good quality AC to DC power converter (AC 120 volts to DC 48 volts) to connect the generator to, and then connect the power converter's DC Out to the EG4's 'PV In'? <-- Will this work?

No, the AC -> DC Charger (chargeverter) connects up to your batteries.

 

[Rednecktek]

Thanks everyone. I will update the FW then give the generator connected to the 'AC In' a go. That's not to say I won't eventually exercise the 'PV In' option for reason(s) so well stated by Vigo above. I'll keep you posted. Again thanks to all.

Also check the settings in your unit for the AC Input, there might be an "Appliance" setting in there which is a little more forgiving of "dirtier" power. Either way the generator should work just fine.

 

[Vigo]

No, the AC -> DC Charger (chargeverter) connects up to your batteries.

Yes, but it IS possible to rectify your generator output to DC through a cheap full-wave rectifier and feed it to your MPPT as a ~170voc 'solar array' that drops to ~120vdc under load, etc. I've done some hours of it but i feel like the question of long-term MPPT durability being fed a very wavy DC source, has not been answered clearly enough to make me confident recommending it to others. The issue in my mind is, most things that feed rectified AC to a DC circuit, also include enough capacitor to 'smooth' that out. But if you're talking 2000w, that would be a fair amount of capacitor, and what happens long term if you have less than that, or no capacitor in there at all? Im just not sure. But i can tell you i havent broken my cheap PowMr AIO yet feeding it rectified 120vac using rectifier sections taken out of random appliances. Lol